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Wednesday, September 21, 2011

Tips On Improving Your Cholesterol Profile

The beneficial effects on the heart and circulatory system of a having a low blood level (below 130) of LDL cholesterol and a high blood level (above 55) of HDL cholesterol are well established. It is also good to have a ratio of total cholesterol to HDL cholesterol of no more than 4.0. If your levels don’t meet these criteria, you might benefit from the recommendations listed in an online Men’s Health Magazine article by Bill Phillips dated September 13, 2011. It presents the following ways, purportedly based on scientific studies, of improving your cholesterol profile without drugs:

Raise Your HDL Level

  • Eat at least 2 oz (57 gm) of nuts per day.
  • Do endurance exercise at least 20 min/day
  • Do 3 sets of 6-8 reps of the half squat, leg extension, and leg press, with 2 min max rest between sets, 2x/wk
  • Take a 1000 mg calcium supplement daily with 400 IU of Vitamin D-3
  • Eat fresh, not processed, white fish (e.g. cod, sole, flounder)
  • Take a daily 10-20 mg polycosanol supplement
  • Drink cranberry juice
  • Eat 2.5 oz of dark chocolate daily
Lower Your LDL Level
  • Eat a grapefruit daily
  • Eat several small meals a day
  • Eat food fortified with oat bran
  • Switch from a margarine containing trans fats to a spread that doesn’t
  • Drink Concord grape juice
  • Take phytosterol or phytostanol supplements in pills or margarine form
  • Add whole grains, nuts, and beans to your diet
Bottom Line

These seem like good recommendations. Just observe the following precautions:
  • Don’t overdo the calories by adding these items to your diet. Remove other items when you add these.
  • Endurance exercise is important for everyone. Weight training alone is not optimal for health.
  • Do not exceed 1000 mg of calcium/day from all sources (1200 mg/day if you're over 70) because of a possible increased risk of prostate cancer.
  • Don’t eat only white fish, because darker, fattier fish like salmon and mackerel are high in beneficial omega-3 fish oil.
  • Don’t overdo the juice because even natural juices contain a lot of sugar, especially fructose, which can increase fatty deposits in the liver and around the midsection.
  • Look for brands of dark chocolate without added milk fat.
  • Several small meals means SMALL.
  • The margarine brands that contain phytosterols and phytostanols contain some trans fats that are not listed because they're less than 0.5 mg per serving. So you may prefer getting these supplements in tablet form.


Monday, September 12, 2011

Important Information About Vitamins

An article in the September 2011 issue of the Nutrition Action Health Letter, published by the Center for Science in the Public Interest, examined research data on the value of taking multivitamins. Key points of the articles are:

Three major studies with a total of 426,000 study subjects over the age of 40 showed no difference between those who took and those who didn’t take multi-vitamins as to lifespan or the incidence of cardiovascular disease, cancer, or stroke.

Other studies showed no effect of multi-vitamin use on the incidence of colds, other infections, length of illness, or absence from school, work or other planned activities.

Cognitive performance was not improved in various study groups that took multi-vitamins for 6-12 months

However, the U.S. Dietary Guidelines Advisory Committee found that the following nutrients that are deficient among a large number of Americans:

  • Vitamin D
  • Folic acid
  • Vitamin B-12
  • Iron (among women due to menstruation)
  • Calcium
Most brands of multivitamins do not provide large enough doses to cause harm. However, there is concern that some people may be ingesting enough of the following to increase their risk of health problems:
  • Folic acid: Too little folic acid can increase the risk of colorectal cancer, and pregnant women who are deficient in folic acid are at risk for having babies with neural tube defects. That is why the U.S. government now mandates that folic acid be added to grain products. However, there is some evidence that too much folic acid taken over several years can increase the risk of having colorectal pre-cancerous growths (adenomous polyps) as well as prostate cancer. Thus, it is prudent not to ingest more than 1,000 micrograms a day of folic acid. Some breakfast cereals contain 400 micrograms per serving, and many people eat more than the standard serving size. Eating such cereals every day as well as taking a multivitamin and eating fortified bread, pasta, or rice can easily lead to exceeding 1,000 micrograms. This can be prevented by avoiding multivitamins with more than 400 micrograms of folic acid and limiting consumption of cereals that are fortified with 400 micrograms of folic acid per serving (e.g. Kashi Heart to Heart, Total, Multigrain Cheerios, Kellog’s Mueslix, Product 19, Smart Start, and Special K Original).
  • Selenium: Although there is marginal evidence that selenium may lower the risk of certain types of cancer, a study showed that people who took 200 micrograms of selenium daily for 8 years were almost 3 times as likely to be diagnosed with diabetes than those who didn’t take the supplement. So it is best to avoid multivitamins that contain more than 100 micrograms of selenium.
  • Vitamin A: While a Vitamin A deficiency can cause various health problems, very few Americans are deficient in the vitamin. However, a study showed that excess Vitamin A (more than 1667 IU/day) doubled the risk of hip fracture among women. The safest alternative is to take a multivitamin that contains beta-carotene rather than Vitamin A. Beta carotene is converted to Vitamin A as needed by the body and doesn’t cause any harm itself.

Bottom Line
  • Unless you feel you can get all your needed nutrients from your food, take a multivitamin that has 100% of the recommended daily value of each vitamin, rather than taking megadoses.
  • It is advisable not to exceed 1000 micrograms per day of folic acid by avoiding multivitamins with over 400 micrograms per serving and limiting intake of breakfast cereals containing more than 200 micrograms per serving.
  • Limit selenium in supplements to 100 micrograms per day.
  • Limit Vitamin A in supplements to 100% of daily value (5000 IU). Or, even better, take a supplement that contains beta-carotene rather than Vitamin A.

Wednesday, August 24, 2011

Are dairy products healthy?

Many books and articles contain health recommendations based on little or no scientific evidence. So when making personal decisions about how to maintain and improve one’s health, it is important to look for books and articles based on solid studies, especially large, well-controlled ones. A good example of science-based health information can be found in the July/August 2011 issue of the Nutrition Action Health Letter, published by the Center for Science in the Public Interest. It evaluates the pros and cons of consuming dairy products, Some of its key points:

We all know that milk is a major source of dietary calcium, which is needed to maintain bone density. Recently however, some health writers have contended that eating animal protein lowers bone density. Because protein contains amino acids, the alleged mechanism is increased acidity of the blood, prompting the body to respond by leaching calcium from the bones to neutralize the acid. Since milk is a protein source, it is implicated in bone loss. However, scientific study has refuted this contention. In actuality, bone mineral density is higher among people who eat more protein and lower among people who eat less protein. Radio isotope studies that tracked actual deposition and depletion of calcium have verified that consumption of dairy foods does not increase bone loss as we age.

Colon Cancer
A major analysis by the Harvard School of Public Health of 10 studies conducted in 5 countries, involving over 500,000 people concluded that people who drank at least one cup of milk per day had a 15% lower risk of colon cancer than those who drank less than 2 cups per week. Similarly, people treated for colon cancer who took 1200 mg of calcium per day and who had an above-average Vitamin D level had 15% less chance of recurrent colon cancer than those who didn’t take the calcium. Twenty-five percent of experimental animals fed a high-fat diet low in fiber, calcium, Vitamin D, and folic acid, developed colon tumors, but those supplemented with calcium and Vitamin D got none.

Prostate Cancer
There is some inconsistent evidence that high calcium consumption (in excess of 1500 mg/day) may increase the risk of prostate cancer. Milk increases the body’s level of insulin-like growth factor-1 (IGF-1), a hormone that stimulates the growth of both muscle and bone, but may also stimulate prostate-cancer growth. Even though a study of men receiving a 1200 mg calcium supplement daily showed no prostate cancer increase, the article recommended that men limit their calcium intake from food and supplements combined to 1000 mg/day if under 70 years of age and 1200 mg/day if over 70.

Blood Pressure
Adding 2 servings per day of low-fat dairy foods to a diet rich in fruits and vegetables, lowered blood pressure even further. In addition, a study of 28,000 women over 10 years showed that those consuming at least 2 cups/day of low-fat dairy foods reduced their risk of high blood pressure by 10%.

Weight Loss
When restricted to the same number of calories per day, women consuming more dairy products showed no difference in weight loss than those who consumed less dairy. However, when allowed to eat all they wanted at the end of the study, the dairy group consumed fewer calories. The implication is that dairy may help control appetite. While the weight-loss results were equivocal, the women in the low-dairy group lost bone density in their hips, while the high-dairy group did not. This is an important finding, considering that dangerous loss in bone density is common among both women and men as they age.

Lactose Intolerance
Lactose is the sugar found in milk. The following is the lactose content of some dairy products:
  • 8 oz cup of milk: 12 grams
  • 6 oz cup of yogurt - 10 grams
  • 1 oz hard cheese or cream cheese - 1 gram or less
  • ½ cup cottage cheese - 4-5 grams
  • ½ cup ice cream - 4-5 grams
Many people think they are lactose-intolerant, However, the article cites evidence that between one-third and three-quarters of people who think they are lactose-intolerant are actually not so. Many of them show none of the typical symptoms of gas or diarrhea when lactose is put in their non-dairy drinks without their knowledge. Many people’s digestive systems can adjust to lactose by building up intestinal bacteria over a period of time. So the authors recommend that people who think they are lactose intolerant try to adjust to lactose by:
  • Limiting lactose to 12 grams at a time (the amount in one 8 oz glass of milk).
  • Consuming lactose along with other foods to give it more time to be digested
  • Eating dairy foods regularly to maintain lactose-digesting bacteria
  • Other Health Issues Related to Dairy Products
A study of 200,000 people over 20 years showed that those consuming 3-5 servings per day of dairy products had a 14% lower risk of Type II diabetes than those consuming less than 1.5 servings per day. However, it is not known whether that is an effect of the dairy products or another factor common to people who consume more dairy products.

Breast and Ovarian Cancer
Eight studies of 350,000 women in several countries did not find any link between milk consumption and breast cancer. However, research on 500,000 women in the U.S. and Europe did show a weak and marginally significant increased risk of ovarian cancer for women who consumed more than 30 grams of lactose per day. However, two major cancer research organizations did not feel the evidence was conclusive.

Bottom Line
Dairy products made from skim or one-percent milk can be considered health-promoting foods. They contain large quantities of calcium necessary for maintaining bone-density as we age. Also, most are excellent sources of protein (except products made primarily from milk fat, such as cream cheese and butter). Milk appears to help control blood pressure and avoid colon cancer, and may also help control appetite. However, high milk consumption may increase the risk of prostate cancer among men and ovarian cancer among women. Therefore, men should limit calcium consumption from food and supplements combined to 1000 mg/day below age 70 and 1200 mg/day above age 70. Adequate Vitamin D intake is essential for healthy bone mineralization, even if calcium intake is adequate. Many people are deficient in Vitamin D because of low sun exposure. Current recommendations for daily Vitamin D supplementation are in the neighborhood of 1,000-2,000 IU.

Additional Note
The main type of saturated fat found in milk (myristic acid) is particularly potent in raising blood cholesterol, specifically the harmful low-density variety (LDL). Because of that, consumption of milk fat should be very limited. High proportions of milk fat are found in cream, butter, ice cream, cheese (especially cream cheese and soft cheeses like Brie), whole milk, and 2% milk. That is why non-fat and 1% fat milk products are preferable. Unfortunately, many dishes popular in the U.S., such as cheese burgers cheese ravioli, macaroni and cheese, and pizza, contain large amounts of cheese. The evidence indicates that the cardiovascular health of Americans would benefit from a reduction in cheese consumption.

Wednesday, July 20, 2011

How to Avoid Inflammation of Your Arteries

Inflammation of the blood vessels and other bodily tissue has become increasingly recognized as being complicit in heart disease, arthritis, and decline of mental capacity. Fortunately, the choices we make concerning what and how much we eat and drink, and how much exercise we do, can dramatically influence the degree of inflammation we experience. The information presented herein concerning lifestyle factors that affect inflammation, comes from a review article by O’Keefe, Gheewala, and O’Keefe in the Journal of the American College of Cardiology (vol. 51, no. 3, 2008).

Meals that are high in calories, and/or contain easily digestible, quickly absorbable, calorie-dense processed food and drink result in spikes in blood glucose and triglycerides (blood-borne fats), overwhelming the body’s ability to process them. Oxidative free radicals are then produced which attack the lining of the arteries (endothelium), inflaming them, causing them to constrict, and building up fatty deposits (atherosclerosis). In contrast, smaller meals containing ingredients that digest more slowly (e.g. fiber) produce smaller surges in blood sugar and triglycerides, and are thus not inflammatory.

Even a single meal high in saturated fat results in an increase of triglycerides, oxidative free radicals and inflammation, which negatively affects the function of the endothelium, causing constriction of the arteries, and raising systolic blood pressure.

A high glycemic meal is one that causes a spike in blood glucose. The Glycemic Index rates foods in comparison to glucose. Foods scoring closer to 100 cause relatively large spikes in blood sugar, while foods scoring closer to zero produce relatively small spikes. See a table listing the glycemic index of various foods from Harvard medical school. The body often responds to high glycemic index foods with insulin surges that remove sugar from the blood and can actually result in low blood sugar (hypoglycemia), an ebb in energy, and hunger. Regularly eating this way predisposes one to excess fat on and around the organs below the abdominal muscles (visceral fat) which, in turn, leads to inflammation and insulin resistance and raises the risks of diabetes, high blood pressure, and cardiovascular disease.

Dietary changes that reduce the magnitude of the triglyceride spike following meals by 20% and 40% respectively have been shown to reduce the risk of coronary artery disease by 30% and 40%. In addition to avoiding foods with a high glycemic index, adding certain foods to the diet can slow down digestion and reduce the spikes in glucose, insulin, and triglycerides. For example, nuts eaten along with a high-carbohydrate meal slow digestion and reduces blood sugar spikes by 30-50%. This both reduces oxidative stress, and provides antioxidants that combat such stress. In fact, a Mediterranean diet supplemented with either 30 grams of nuts or olive oil was found to reduce systolic blood pressure, blood sugar, and biomarkers of inflammation significantly better than a low-fat diet. Eating nuts 5 times per week was found to reduce risk of diabetes and cardiovascular disease by 20-50%. Quality protein sources low in saturated fat have a similar beneficial effect. These include egg-whites, lean meats, fish, casein, and whey protein, among others. Fish oil lowers triglyceride levels by 16-40%.

As expected, physical exercise has a positive effect, reducing post-meal spikes in blood sugar and triglycerides. Exercise is most beneficial in this regard if it is done within 2 hours before or after a large meal. Loss of body fat by diet control and/or exercise can also reduce post-meal spiking of blood sugar and triglycerides.

Alcohol consumption shows a J-shaped relationship with inflammation and blood sugar spiking, in addition to various other health problems such as coronary artery disease, diabetes, stroke, dementia, and all-cause death, with the lowest levels of these problems at 1-2 drinks per day for men and 0.5-1 drink a day for women. The J-shape means that drinking no alcohol increases the risk of these problems somewhat, while drinking in excess greatly increases the risks of these problems.

Characteristics of Inflammatory Meals

  • High in calories
  • High in calorically-dense foods
  • High in saturated fat
  • High in refined carbohydrates
  • Contain foods with high glycemic index

Characteristics of Diets That are Not Inflammatory
  • Smaller meals spread over the day
  • Low in saturated fat
  • Low in, or free of trans fats
  • Low in processed carbohydrates
  • Low in foods with high glycemic index
  • High in unprocessed fruits and vegetables rich in antioxidants
  • High in nuts, seeds, and whole grains
  • Contain vinegar (1-2 tbsp eaten with a meal high in refined carbohydrates reduces the blood sugar spike by 25-35% and reduces hunger)
  • Moderate amounts of lean animal protein
  • Moderate amounts of beneficial fats such as fish oil and monounsaturated oils (e.g. olive,canola)
The following Foods High in Antioxidants Help Prevent Oxidative Damage to the Endothelium
  • Berries
  • Red wine
  • Chocolate
  • Tea
  • Pomegranates
  • Cinnamon (also reduces glucose spike caused by high-glycemic-index meal)
If you are concerned about the possibility of inflammation in your arteries, you can ask your doctor about testing the C-reactive protein level in your blood when you get a checkup. However, if your total cholesterol level is below 200 and your HDL level is above 55, it is very unlikely that you have a problem with arterial inflammation. If your C-reactive protein level is above 1.0 or the ratio of your total cholesterol level to your HDL level is above 4.0, you would likely benefit from following an anti-inflammatory diet and exercising regularly.

Friday, June 24, 2011

Cold Weather and Air Conditioning Can Raise Your Blood Pressure

High blood pressure, also called hypertension, is defined as a systolic pressure above 140 mm of mercury (mmHg) and/or a diastolic pressure above 90 mmHg. Hypertension increases the risk of several major health problems, including heart disease, stroke, and kidney disease. While it is widely recognized that excess sodium intake increases the risk of hypertension, few people know that the ambient temperature at which people live affects the risk of hypertension. And ambient temperature varies with the seasons of the year. The following studies provide evidence for the seasonal variation in blood pressure and risk of hypertension.

In a study by Woodhouse, Khaw, and Plummer, 96 men and women, aged 65-74 years had their blood pressure taken for a full year. It was found that both systolic (SBP) and diastolic blood pressure (DBP) were greatest during the winter for people with both normal and high blood pressure. There was four times the incidence of blood pressures above 160/90 mmHg in winter than in summer. In a strong seasonal trend, a 1 deg C (1.8 deg F) decrease in living-room temperature was associated with increases of 1.3 mmHg in SBP and 0.6 mmHg in DBP. The authors linked this to the greater incidence of cardiac-related deaths of the elderly in winter.

In a study by Brennan, Greenberg and Miall, blood pressure measurements taken for the Medical Research Council's treatment trial for mild hypertension were analyzed according to the month in which the readings were made. For all age, sex, and treatment groups, both systolic and diastolic pressures were higher in winter than in summer. Blood pressure was also highly and significantly related to maximum and minimum daily air temperature. The seasonal variations in blood pressure were greater in older than in younger people.

In a study by Fujiwara et al., blood pressure was measured on 25 hypertensive outpatients (mean age 57), who spent virtually the entire day indoors in both summer and winter. Both systolic and diastolic blood pressure in the morning and night-time periods were significantly higher in winter than in summer (respective differences of 7.5 and 4.1 mmHg in the morning and 8.2 and 4.5 mmHg at night). Despite the fact that the patients lived essentially indoors at a relatively stable environmental temperature, the seasonal variation in blood pressure was statistically significant.

In a study by Kimura et al. of the Department of Integrated Medicine, Kagawa University, Japan, 15 healthy elderly Japanese (mean age 79) measured their blood pressure at home each morning more than 25 times per month for 3 years. The highest levels of both systolic and diastolic blood pressures (129 and 81 mmHg) occurred in February, the coldest month (avg temp. 5.0 deg C, 41 deg F), while the lowest levels (117 and 73 mmHg) were observed in August, the hottest month (mean temp 29.2 deg C, 84.6 deg F). Thus, both systolic and diastolic blood pressure demonstrated a close inverse relationship to outdoor temperature. A one degree C (1.8 deg F) decrease in the mean outdoor temperature was associated with rises of 0.43 mmHg in systolic blood pressure (SBP) and 0.29 mmHg in diastolic blood pressure (DBP).

In a study by Hozawa et al. at the Tohoku School of Medicine in Japan, 79 male and female volunteers (mean age 72.7 years) measured their blood pressure at least once a month for 3 years beginning in September 2000. The mean number of measurements was 19.0 times per month. Blood pressure levels were lowest in the warmest months. A clear inverse association between temperature and blood pressure values was evident when the outside temperatures was above 10°C, producing a respective decrease in systolic and diastolic blood pressure of 0.40 and 0.28 mmHg for each 1 deg C (1.8 deg F) increment of outside temperature.

A study by Sinha et al. at Maulana Azad Medical College, in India, 275 females 18-40 years of age showed that the prevalence of hypertension based on SBP was 12.7% in summer and 22.2% in winter. The prevalence of hypertension based on DBP was 11.3% in summer vs. 26.6% in winter, a highly statistically significant difference. Overall prevalence of hypertension (SBP = 140 or DBP = 90 mm of Hg) was 1.9 times greater in winter than in summer.

Bottom Line

The temperature at which we live can affect our blood pressure. This is likely related to the fact that, when we are cold, the small arteries in our skin constrict to avoid loss of body heat. That creates resistance to blood flow, thus increasing pressure. When we are hot, the small arteries in the skin widen to allow more heat dissipation, thereby reducing resistance to blood flow. Also, we tend to perspire more when we are hot, thereby losing water and salt, both of which tend to increase blood pressure. The most common medications for reduction of blood pressure are diuretics, which promote loss of water and salt through urination. Sweating can accomplish similar results.

People with hypertension or prehypertension (systolic pressure 120-140) can help control their blood pressure by avoiding being cold. In summer, air conditioning use should be minimized. Most people can adjust to a room temperature of 77 degrees without feeling uncomfortable, and even higher temperatures in locales with low humidity. In winter, the home can be kept warm and, if that is not economically feasible, dressing warmly indoors is a viable alternative. Exercise can be used to warm the body as well.


Brennan, P.J., G. Greenberg, W.E. Miall, S.G. Thompson. Seasonal variation in arterial blood pressure. Br Med J (Clin Res Ed) 285 : 919, 2 October 1982.

Fujiwara, T., M. Kawamura, J. Nakajima, Jun, T. Adachi, K. Hiramori. Seasonal differences in diurnal blood pressure of hypertensive patients living in a stable environmental temperature. Journal of Hypertension, vol. 13, no. 12, 1995.

Hozawa A., S. Kuriyama, T. Shimazu, K. Ohmori-Matsuda, I. Tsuji. Seasonal variation in home blood pressure measurements and relation to outside temperature in Japan. Clin Exp Hypertens, vol. 33, no. 3, pp. 153-8, 2011.

Kimura, T., S. Senda, H. Masugata, A. Yamagami, H. Okuyama, T. Kohno, T. Hirao, M. Fukunaga, H. Okada, F. Goda. Seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese studied by home measurements.Clin Exp Hypertens. 2010 Jan;32(1):8-12.

Sinha P, D.K. Taneja, N.P. Singh, R. Saha. Seasonal variation in prevalence of hypertension: Implications for interpretation.Indian J Public Health, vol. 54, no. 1, pp. 7-10, 2010.

Woodhouse, P.R., K.T. Khaw, M. Plummer. Seasonal variation of blood pressure and its relationship to ambient temperature in an elderly population. Journal of Hypertension, vol. 11, no. 11, 1993.

Tuesday, June 14, 2011

Updated List of the Most-Contaminated Fruits and Vegetables

We have all been well-informed that eating plenty of fruits and vegetables is good for our health. Yet there is a continuing problem with pesticide contamination. It is recommended that we avoid pesticide exposures that are more than a thousandth of the levels known to be toxic. Yet, a 2009 study by the Environmental Protection Agency found that about 40% of U.S. children have levels of at least one pesticide well above this limit.

The nonprofit organization, Environmental Working Group, while reaffirming that eating a lot of fruits and vegetables is good for our health, suggested that by avoiding the most pesticide-contaminated fruits and vegetables, and choosing the least-contaminated ones, we can lower pesticide residues in our bodies. To assist us in making such choices, the organization just published a list of the dozen most pesticide-contaminated fruits and vegetables, based on testing done in 2009 by the U.S. Department of Agriculture and the Food and Drug Administration. It also published a list of the 15 least-contaminated fruits and vegetables to provide us with healthy alternatives. The group estimates that by avoiding the “Dirty Dozen” (or buying organic versions of these items) and selecting from the “Clean 15” we can cut our pesticide exposure by 92%.

The Dirty Dozen - Most Contaminated Fruits and Vegetables (number 1 is the worst)
  1. Apples
  2. Celery
  3. Strawberries
  4. Peaches
  5. Spinach
  6. Nectarines (imported)
  7. Grapes (imported)
  8. Sweet bell peppers
  9. Potatoes
  10. Blueberries (domestic)
  11. Lettuce
  12. Kale/collard greens
The Clean 15 - Least Contaminated Fruits and Vegetables (Number 1 is the best)
  1. Onions
  2. Sweet corn
  3. Pineapples
  4. Avocados
  5. Asparagus
  6. Sweet peas
  7. Mangoes
  8. Eggplant
  9. Cantaloupe (domestic)
  10. Kiwi
  11. Cabbage
  12. Watermelon
  13. Sweet potatoes
  14. Grapefruit
  15. Mushrooms
Bottom Line
Obviously, buying all organic produce is the best alternative for health. However, most of us cannot or choose not to incur the major budget hit it would entail. So the next best alternative is to avoid the “dirty dozen” while selecting more items from the “clean 15 “ list. Going organic for selected items can still keep our food budgets from skyrocketing.

Tuesday, May 31, 2011

Drinking Too Much Water Can Be Harmful And Even Fatal

Drinking large quantities of water has been widely promoted over the past few years as a means of maintaining health, improving appearance, controlling weight, and preventing dehydration. It is now not unusual to see people regularly carrying and sipping from water bottles. Eight 8-ounce glasses of water a day has been commonly recommended as the minimum requirement. However, the evidence shows that this recommendation has little scientific basis. In addition, excess water consumption can be harmful and even fatal.

A June 4, 2009 article by Karen Bellenir, in the online Scientific American, a highly-respected journal, analyzed the origins of the 8 glass a day recommendation and presented the opinions of scientists in the area of hydration. The conclusion was that there was no scientific basis for the recommendation. Some key points from the article:
  • Most people do not have to drink 64 ounces of water per day.
  • Water needs differ widely among individuals and depends on many factors including body size, physical activity, ambient temperature and humidity.
  • Much of our fluid needs are met from the water content in food.
  • The only people who benefit from drinking large amounts of water are those who sweat a lot due to their participation in heavy physical activity, especially in hot environments, and people with specific medical conditions such as kidney stones or urinary tract infections.
  • For hydration purposes, all drinks composed largely of water, including milk, juice, coffee, and tea are roughly equivalent to drinking plain water. While caffeine does somewhat stimulate urination, the net effect of these drinks is to provide the body with water. Only alcoholic beverages cause a net water loss.
  • Drinking when thirsty is the best means of meeting our physiological need for fluid.
  • Drinking water before meals does not reduce appetite or food consumption. However, eating foods that contain a lot of water but few calories (e.g. salad vegetables, fruit) can help control appetite.
One might think that excessive water-drinking is relatively harmless, with the only downsides being a bloated stomach, frequent urination, the expense of buying water and the inconvenience of carrying it. However, excessive water-drinking can actually be harmful and even fatal, as revealed in a June 21, 2007 article by Coco Ballentyne in the Scientific American online. Fatalities cited in the article include those of a woman who died after drinking 6 liters of water in a radio-station sponsored contest to see who could hold their urine the longest and an aspirant to a college fraternity who was prompted to drink excessive amounts of water. In addition, several athletes and military personnel have died after drinking excessive quantities of water in an effort to avoid dehydration.

The cause of these deaths is hyponatremia, which is a dangerously low concentration of sodium in the blood. Warning symptoms of this disorder include frequent urination, fatigue, headache, nausea, vomiting, and disorientation. Much of the damage is caused by entry of the excessive water into brain cells, with resultant brain swelling and damage.

It particularly dangerous for people engaged in endurance sports to drink excessive water because such physical activity stimulates the secretion of a hormone that tends to conserve water in the body by reducing excretion, even when drinking is excessive. This can reduce the kidneys’ ability to remove water from the bloodstream by 90%. Sport drinks, which contain sodium and other electrolytes as well as carbohydrates can help in preventing dangerous dilution of the blood, yet even excessive drinking of these fluids can cause hyponatremia. Drinking to thirst is still seen as the best recommendation.

Another possible negative effect of drinking too much water is the effect on blood pressure. A study by Callegaro et al. published in the Journal of Human Hypertension (vol. 21, pp. 564-570, July 2007) concluded that, after ingesting 500 ml (a little over 2 cups) of water, the systolic blood pressure of both subjects with and without high blood pressure rose 17-19 points and the diastolic blood pressure rose 14 points. These are major increases. While other studies did not observe this effect, it appears that excess water consumption may increase the possibility of high blood pressure. Thus, drinking to thirst is the best means of taking an amount of water that will avoid both dehydration and hyponatremia.

Monday, May 2, 2011

Omega-3 Fats from Fish Oil Raise Risk of High-Grade Prostate Cancer

It has been increasingly evident that there are trade-offs in the quest to get and stay healthy. In other words, there are actions we can take that will reduce the risk of one health problem, but increase the risk of another. One example is playing high-impact sports such as basketball, which is great for improving and maintaining physical fitness while having fun, but also increases the risk of sprains, strains and other musculoskeletal problems. Now, an article by Brasky et al. in the American Journal of epidemiology (published online April 24, 2011)  points up a trade-off involved in taking fish-oil supplements, which have been widely recommended for reducing the risk of cardiovascular diseases and other health problems.

The researchers analyzed blood samples of 3,461 men to measure levels of omega-3 fats (DHA and EPA from fish consumption), omega-6 fats (from common vegetable oils), and trans-fats (from hydrogenated oils in margarine, shortening, and processed foods). The men were then followed over a 7-year period in order to see the association of the different fat types to the incidence of prostate cancer. The hypotheses were that:
  • Because of the anti-inflammatory effect of the omega-3 fats, men with the highest blood levels of them would have a lower incidence of prostate cancer
  • Because of the inflammatory effect of the trans- fats, men with the highest blood levels of them would have a higher incidence of prostate cancer
The statistical analysis produced the following surprising results:

   > There were no effects of any of the fat types on overall incidence of prostate cancer.
   > When looking at the high-grade form of prostate cancer that progresses rapidly and is the most lethal:
  • Those men with the highest blood levels of DHA from fish oil had more than twice the risk of contracting high-grade prostate cancer as men with the lowest blood levels of DHA.
  • EPA from fish oil had no effect on the incidence of high-grade prostate cancer.
  • Those men with the highest blood levels of trans-fats had about half the risk of contracting high-grade prostate cancer as men with the lowest blood levels of trans-fats
  • Blood levels of the type of omega-3 fat from vegetable sources (e.g. flax seeds, walnuts) had no effect on the incidence of high-grade prostate cancer.
Bottom Line
The results of highly surprising, given the widespread view of fish oil as all-good and trans-fats as all-bad. Here is a clear case of trade-off. There is considerable evidence that fish-oil is good for the heart and cardiovascular system and reduces the incidence of heart attacks. Yet, here we see that it increases the risk of high-grade prostate cancer. Eating omega-3 fats from flax-seeds or other vegetable sources is not a solution because that type of omega-3 fat has not been proven to reduce the risk of cardiovascular disease. The good news is that most prostate cancer is of the low-grade variety. Given that heart disease remains the number one killer of both men and women, it doesn’t appear that fish and fish-oil be abandoned as a health-promoting dietary elements. Yet men must be aware of the trade-off in risk of eating fatty fish or taking fish-oil supplements in order to make an informed decision about how best to promote their health.

Update (May 8, 2011):, a company that tests the quality of supplements from various companies, contacted Dr. Theodore Brasky, the lead author of the study described herein. He stated that the blood levels of DHA and EPA measured in the study were largely based on fish consumption rather than fish-oil supplements. However, a recent study of his, soon to be published, shows no link between fish oil supplementation and risk of prostate cancer. He also noted another study (Szymanski, Am J Clin Nutr 2010) that found fish consumption associated with a large reduction in late state or fatal prostate cancer.

Friday, April 29, 2011

Soy Products Have a Negative Effect on Masculinity

Because it is a relatively inexpensive source of protein, soy is widely used to fortify many high-protein foods such as bars, cereals and shakes. However, as detailed on our website, the estrogen-like qualities of soy proteins (isoflavones) have a negative effect on masculinity.

A recent study by Wada et al. in the American Journal of Epidemiology (vol. 173, no. 9, pp. 998-1003, 2011) indicates that such demasculinizing effects can begin very early. The researchers collected dietary histories and urinary testosterone levels from 230 Japanese boys aged 3-6 years. When the boys were divided into 4 groups based on the quantity of soy they ate, the group that consumed the least soy had a notably mean higher testosterone level than the other 3 groups. The same was true when the grouping was made based on isoflavone consumption.

The American Academy of Pediatrics, but not the U.S. government, has recommended that infants who cannot be breastfed be nourished with formula based on cow milk rather than soy. Also, several countries including Israel, France, New Zealand, and Australia have officially recommended against soy-based baby formula. While the U.S. has made no such official recommendation, parents here would do best to avoid soy-based infant formula as well as soy-containing foods for their older children.

Bottom Line
Men should carefully read nutrition labels and avoid foods containing soy or isolated soy protein. Preferable sources of protein include fish and lean meats, low-fat dairy products, and eggs in moderation. Acceptable protein supplements include whey protein and casein, both derived from milk. Some men avoid milk because they believe they are intolerant of lactose (milk sugar). Yet many of these men are not actually lactose intolerant. For those who really are, there are many alternatives. Whey protein and casein do not contain lactose, and have shown in studies to be very effective for muscle building. Most cheeses are made up mainly of protein and fat, with very little lactose, but should be eaten in moderation because of the high saturated fat and cholesterol content. Milk products should be of the low-fat or non-fat varieties to limit saturated fat and cholesterol. Lactose-free milk is also available in most supermarkets.

Tuesday, April 12, 2011

Our Changing Eating Patterns

The U.S. Department of Agriculture recently published information on the sources of our daily caloric intake between 1970 and 2008, a time period in which our daily caloric consumption increased by 23.2% from 2,169 cals to 2,672 cals, and rates of overweight and obesity have risen sharply. An interactive graphic was created from the data that allows users to scroll along a time-line to see how the amount of daily calories in each food category has changed over time. The following are the percentage changes in calories coming from each food category:

meat, eggs, and nuts: +4.1%
fruit:                         +22.9%
added fat:                 +56.3%
dairy:                          -3.7%
grains:                      +44.7%
vegetables                   -2.4%
added sugar              +14.2%

Some Observations on the Data

In Terms of Absolute Calories
  • The biggest contributors by far to our increased daily caloric intake are added fat (231 cals) and grains (193 cals).
  • Much more modest contributors to our increased daily caloric intake are added sugar (57 cals), meat/eggs/nuts (19 cals), and fruit (16 calories).
  • Our daily consumption of dairy actually decreased by 10 calories and of vegetables by 3 calories.
In Terms of Percentage of Daily Calories
  • The only foods that increased as percentages of our diet from 1970 to 2008 are added fats (from 18.9% to 24.0% of daily calories) and grains (from 19.9 % to 23.4% of daily calories).
  • Caloric consumption from fruit was steady at 3.2 % of calories.
  • All other foods declined as percentages of our daily calories including meat/nuts/eggs (from 21.3% to 18.0% of daily calories), dairy (from 12.3% to 9.6% of daily calories), added sugar (from 18.5% to 17.2% of daily calories), and vegetables (from 5.8% to 4.6% of daily calories).
Bottom Line
The greatest contributors to our increase in caloric consumption are grains and added fat. While we have increased our intake of all other foods except vegetables, grains and fat together account for 84% of our increase in caloric consumption and should therefore be the prime focus of cutting back calories. This makes it clear that the low-fat and low-carb diets are both missing something because the intake of both must be reduced. Any diet that emphasizes what you eat rather than how much you eat is bound to fail. Overweight and obese people who seek to attain a healthy body weight must face the reality that total intake must be lessened. Focusing on eating both fewer grain-based foods and fewer added fats is a good start.

Friday, April 8, 2011

Can Video Games Improve Physical Fitness?

With the development of video game devices that detect body motions of players and use those motions to control games, the opportunity for turning the formerly sedentary activity of video gaming into physically active fun has greatly expanded. However, it is only recently that the exercise stimulus of such games has been scientifically evaluated. One such study, by Worley, Rogers, and Kraemer was recently reported in the Journal of Strength and Conditioning Research (vol. 25, no. 3, pp. 689-693, 2011).

Experimental Procedure
8 young women averaging 22 years of age were first tested for the maximal rate at which their bodies could process oxygen (VO2max). Then they played 2 different Nintendo Wii Fit video games (Hula and Step) at the beginner and intermediate levels for 10 minutes each. During each game session, each subject was connected to a metabolic cart that measured the rate of oxygen consumption.

The percentage of VO2max elicited during the video games ranged from 30.6% for the beginner level Step game to 39.4% for the intermediate level Hula game. These levels respectively corresponded to walking speeds of 2.5 mph and 3.6 mph, categorized as mild to moderate exercise.

Bottom Line
Video games that require physical activity have excellent potential for getting people who would not ordinarily exercise to do so. Nintendo’s Wii system involves a controller that is held in the hand and picks up movements using accelerometers. The XBOX game with the Kinect accessory is revolutionary in that it senses whole body movements without anything held in the hand or attached to the body. While the games in this study only elicited mild to moderate levels of exercise, the advanced game levels were not tested, probably because they require a lot of practice. Thus, the potential for higher exercise levels is certainly there. These games are a great way of getting people who are not attracted to sports or typical exercise routines but who like video games to become more physically active.

Monday, April 4, 2011

Effectiveness of Different Kinds of Strength Training Periodization

Periodization of strength training entails changing over time the weight handled in each exercise along with the number of repetitions per set. When the weight used is higher, the number of repetitions is lower and when the weight used is lower, the number of repetitions is higher. It is widely agreed among strength and conditioning professionals that periodized strength training is more effective than non-periodized training.

There are various versions of strength training periodization, including:
  • Traditional periodization - The trainee starts with relative light weights and high repetitions, and over a period of several weeks, increases the amount of weight lifted while decreasing the number of repetitions. For example, the trainee might begin by doing 10 repetitions per set with 60% of the maximum weight that can be lifted for a single repetition and progress to 4 repetitions with 80% of the max weight.
  • Daily Undulating Periodization - On different days, the trainee uses a different combination of weights and repetitions. A sample schedule might be medium weight and medium reps on Monday, light weight and high reps on Wednesday, and heavy weight and low reps on Friday.
  • Weekly Undulating Periodization - Weight and reps fluctuate from week to week. A sample schedule might be low weight and high reps on week 1, medium weight and medium reps on week 2, and high weight and low reps on week 3, with this 3-week pattern repeating several times.
A recent study by Apel, Lacey, and Kell in the Journal of Strength and Conditioning Research (vol. 25, no. 3, pp. 694-703, 2011) sought to determine the relative effectiveness of traditional vs. weekly undulating periodization.

Experimental Procedure
Forty-two young, physically active men were divided into three groups of 14 that trained for 12 weeks as follows:
  • Control group - Performed no strength training
  • Traditional periodization (TP) - Increased the resistance in a fairly linear manner from 57% of max the first week to 80% of max the final week.
  • Weekly Undulating Periodization (WUP) - Started at 57% of max, but increased resistance over 3 weeks before reducing weight close to where it started and increasing it back again over 3 weeks. This was done over 3 cycles in which both the starting and ending weight for each 3-week cycle became greater than for the previous 3-week cycle, ending at 78% of max.
There were 15 different exercises selected to work the entire body. The exercises used, rest time, total exercise volume and average percent of maximum weight used were the same in both groups. There were 3 training sessions per week for the first 2 weeks and 4 per week for the remaining weeks, in which half the exercises were performed 2 days per week (e.g. Mon. and Thu.) and the other half on 2 other days per week (e.g. Tue. and Fri).

  • Both periodized training groups increased significantly in strength, while the control group did not.
  • Increases in back squat strength were significantly greater for the TP group (54%) than for the WUP group (34%).
  • Increases in bench press strength were significantly greater for the TP group (24%) than for the WUP group (19%).
  • Increases in pull-down strength were significantly greater for the TP group (29%) than for the WUP group (19%).
  • Increases in dumbbell shoulder press strength were significantly greater for the TP group (48%) than for the WUP group (36%).
  • Increases in leg extension strength were greater for the TP group (39%) than for the WUP group (27%), although the between-group difference did not reach statistical significance.
  • There was more muscle soreness and fatigue reported among the WUD group, which may have hindered training progress.
Bottom Line
For this group of recreationally active males, traditional periodization produced superior results to weekly undulating periodization. The between-group differences were great enough to be meaningful.

Thursday, March 31, 2011

Is Cycling Actually Detrimental to Bone Health?

An article by Nichols and Rauh in the Journal of Strength and Conditioning Research (vol. 25, no. 3, March, pp. 727-734, 2011) showed that hours of weekly bicycling exercise, in the absence of weight-resisted or impact exercise may actually be worse for bone density than no exercise at all. While such exercise seems fine for keeping the heart, lungs, and circulatory system healthy, and bodyweight under control, the evidence shows that it is a poor exercise for bone health.

Experimental Procedure
The study tracked, over a 7-year period, bone density in the lumbar spine, total hip, and femoral neck (segment of the thigh bone adjacent to the pelvis) as well as body fat and lean tissue measurements of 19 Master’s competitive cyclists and 18 non-athletes, who averaged 51 years of age at the start of the study.

  • At both the initial and final testing, the cyclists had consistently lower bone mineral density at all sites measured than the non-athletes.
  • After statistical adjustment for changes in body mass index, lean mass, calcium intake and exercise habits, the cyclists lost more bone mineral density over the 7 years than the non-athletes.
  • The subjects who reported doing weight-bearing or impact exercise lost significantly less bone density in the spine and femoral neck than those who did not do such exercise.
  • At initial testing, 84% of the cyclists and 50% of the non-athletes met the criterion for osteopenia (subnormal bone density).
  • At the final testing, 90% of the cyclists and 61% of the non-athletes met the criterion for osteopenia.
  • Six of the cyclists but only one of the non-athletes had full-blown osteoporosis (critically low bone-density) by the end of the study.
  • Even when they were made aware of bone-density problems, very few of the subjects changed their diets to include more calcium.
Bottom Line
The evidence provides a strong indication that cycling is not beneficial to bone health. If done in the absence of weight-resisted exercise (e.g. squat, deadlift) or impact exercise (e.g. running, gymnastics, dance) bone loss is likely to result. One hypothesis is that the lack of impact or weight on the bone fails to stimulate mineralization, while calcium-containing sweat is lost during heavy cycling exercise. Another possibility is that endurance exercise tends to suppress testosterone, which helps maintain bone mass. Older competitive cyclists are at great risk for bone fracture because of their low bone density and high risk of bicycle crashes. Weight-resisted or impact exercise should be started when people are young because that is when bone is most readily mineralized.

Tuesday, March 29, 2011

Maintaining Strength and Muscle Mass As We Age

An article entitled, “Staying Strong: How exercise and diet can help preserve your muscles” appeared in the April 2011 issue of the Nutrition Action Health Letter, a publication of the Center for Science in the Public Interest. The article stated some interesting facts, including:
  • Starting in their late 30s and early 40s, most people lose a quarter pound of muscle per year.
  • Several studies have shown that resistance exercise can restore and preserve strength and power, even at an advanced age.
  • Resistance exercise also helps prevent loss in bone density and may even reverse age-related loss.
  • People with Type II diabetes can lower their blood sugar by doing resistance exercise.
  • After a large protein feeding (~ 30 grams, the quantity in 4 ounces of cooked meat) both younger and older people show equivalent protein synthesis (muscle-building) responses.
  • After a small protein feeding (~ 14 grams, the quantity in an egg plus a glass of  milk) younger people synthesize about half the protein they synthesized in the large feeding BUT PEOPLE OVER 60 SHOW ALMOST NO PROTEIN SYSTHESIS. In other words, the larger protein portions are necessary for the older people to synthesize any protein at all. However, anything above 30 grams of protein in a meal is either burned off as energy or stored as fat. So extremely large protein meals do not aid in muscle-building.
  • Of the 9 essential amino acids that our bodies can’t manufacture and must ingest, leucine is by far the most important for muscle development, especially for older individuals. Researchers recommend a minimum of 3 grams of leucine per meal, in addition to other amino acids. Animal products generally have relatively high percentages of leucine. Protein from whey (a byproduct of cheese-making) is relatively high in leucine and makes a good protein supplement.
  • Plant protein contains a smaller percentage of leucine, but soy is the best of the common plant proteins in regard to leucine content.
  • According to researchers, ingesting protein shortly after exercise provides the greatest boost for muscle building. Two hours is the longest one should wait before ingesting protein after resistance exercise.
  • While the U.S. Institute of Medicine set a Recommended Daily Allowance (RDA) of 0.36 grams of protein per pound bodyweight per day, researchers feel that about 0.50 grams of protein per pound bodyweight per day can best promote muscle building and minimize muscle loss as we age.
Bottom Line
Regular resistance exercise and adequate protein intake are essential for increasing and maintaining strength and muscle mass, especially as we age. A daily protein intake of half a gram per pound bodyweight is recommended (e.g. a 200 lb person should take in 100 grams of protein daily). The protein should not be concentrated in one meal but should be distributed over the day in meals containing about 30 grams of protein.

Thursday, March 3, 2011

New Army Physical Fitness Test to Simulate Battlefield Activities

On February 28, 2011 the Official U.S. Army website reported that, after 30 years of using the same physical fitness test, the Army is developing a new physical fitness test battery to better simulate battlefield activities. The previous test was comprised of the following 3 tests done with a short rest in between:
  • As many pushups as possible in 2 minutes
  • As many situps as possible in 2 minutes
  • Running 2 miles a quickly as possible
Scoring was based on age and gender. See our web site for testing details and scoring charts.
The revised test has not been finalized, but trials are being held this month on 7 Army bases and at the U.S. Military Academy at West Point. A review and approval process will take place before full implementation. The article states that there will be a general physical readiness test for all soldiers and a physical readiness test for those going into combat:

Army Physical Readiness Test
  • 60-yard shuttle run
  • one-minute rower (see diagram)
  • standing long-jump
  • one-minute push-up
  • 1.5 mile run
Army Physical Readiness Test
The examinee will be timed while performing the following obstacle-course sequence while wearing a combat uniform and helmet and carrying a rifle:
  • 400-meter run
  • Low hurdles
  • high crawl
  • Over and under
  • casualty drag
  • Balance beam while holding ammo cans
  • Point and move
  • 100 yard shuttle sprint while holding ammo cans
  • Agility sprint around cones
See the Army article for a diagram of the course. As with the current Army Physical Fitness Test, scoring charts will be developed that take age and gender into consideration.

The change in the fitness tests appears to be a good one because the new test more closely simulates battlefield physical demands. It might even be better if the Physical Readiness Test were performed while the examinees carried a combat load similar to those normally worn by soldiers. is very supportive of functional training that seeks to improve performance in sports, combat, or daily living. Function-based training programs emphasize improved physical performance rather than appearance. Workouts designed to “get big” generally train isolated muscle groups and do not prepare the body for strenuous whole-body physical demands.

Tuesday, February 8, 2011

Active vs. Passive Recovery Between Exercise Bouts

Active recovery between bouts of exercise involves the performance of low-level exercise rather than rest, while passive recovery involves rest only. Opinions vary as to whether active or passive recovery produces better performance on subsequent exercise bouts. Two articles in the January 2011 issue of the Journal of Strength and Conditioning Research ( vol. 25, no. 1) address this issue.

The first article, by Toubekis et al. (pp. 109-116), examined the effects of passive and active rest on repeated swim sprint speed:

Experimental Procedure
10 male competitive swimmers averaging 18 years of age performed eight 25-meter swim sprints separated by 2 minute recovery periods. After the last 25-m sprint, a 6 minute recovery period was provided before a single 50-meter sprint. On different occasions each subject’s recovery periods were as follows:
  • A - passive rest
  • B - swimming continuously at 40% of the maximum velocity they could sustain for 100-m.
  • C - swimming continuously at 60% of the maximum velocity they could sustain for 100-m.
The 25-m sprints took in the range of 11.5-13.0 seconds to complete.

  • Statistically, the passive recovery and 40% of max speed recovery produced significantly faster 25-m times than did the 60% of max speed recovery.
  • The average 25-m time with the passive recovery was faster than the time with the 40%-max recovery. However, the difference did not reach statistical significance.
  • There was no statistically significant difference between recovery methods for the 50-m sprint.

The second article, by Miladi et al. (pp. 205-210) examined the effects of recovery by passive rest, active rest, and dynamic stretching on 4-minute work bouts and subsequent stationary bicycling time to exhaustion.

Experimental Procedure:
10 soccer athletes averaging 26 years of age exercised on a stationary bicycle at high intensity (20% higher than the power output they exhibited at their maximal rate of oxygen uptake) 4 times for 30 seconds, with 30 seconds of passive rest in between for a total of 3.5 minutes. They then had a 4 minute recovery period before doing another 3.5-minute exercise bout of the same kind. Following another 4-minute recovery period, they then cycled as long as they could at the same high intensity used in the exercise bouts. On three different occasions the 4-minute recovery periods consisted of:
  • passive recovery: no exercise
  • active recovery: they kept cycling, but at low intensity (30% of the power output at their maximal rate of oxygen uptake)
  • dynamic stretching using 4 different lower body stretches, each done for 30 seconds. Between the stretches, "dynamic awakening" muscular exercises were done.
  • Dynamic stretching and active recovery both resulted in significantly longer time until exhaustion (~20%) than passive recovery.
  • Dynamic stretching resulted in about 8% longer time until exhaustion than active recovery, but the difference didn't reach statistical significance.
Bottom Line
The first study indicates that passive recovery or low-intensity active recovery were most effective for 2-minute recovery periods separating 11.5-13.0 second bouts of swim sprinting. However, the second study found that stretching or active recovery was more effective than passive recovery following 3.5 minute work bouts separated by 4-minute recovery periods. The main difference between the studies lies in the duration of the work bouts and rest periods. The activities also differed - swimming and cycling.

Looking at the results of these two studies and the results of similar studies, it appears that for short sprints (under 20 seconds) and short rest periods (under 3 minutes) passive recovery is most effective, allowing short-term energy stores in the muscles to replenish. However, for longer sprints and longer recovery periods, active recovery or dynamic stretching may be more effective.

Since the effectiveness of a recovery method depends on sprint duration, recovery interval, and type of activity, it seems best for coaches to try the different recovery methods to see which one is most effective for their specific sport program.

Friday, February 4, 2011

13 Iowa Football Players with Rhabdomyolysis: A Case of Coaching Incompetence

Thirteen University of Iowa football players were recently hospitalized for rhabdomyolysis caused by extreme physical exertion. Symptoms of the ailment include dark-colored urine, fatigue, muscle weakness, and muscle tenderness. Although the athletes have since been released from the hospital, information has not been released as to whether any permanent injury has resulted.

Rhabdomyolysis is a serious medical problem. It occurs when myoglobin leaks out of muscle cells due alcoholism, crush injuries, heatstroke, extreme physical exertion and other causes. Just as hemoglobin in red blood cells carries oxygen to the muscles and other body tissue to provide energy through oxidation of carbohydrates and fats, myoglobin carries oxygen within the muscle cells to the mitochondria, which are the oxidative energy-production units within the cells. Myoglobin is a large molecule and, when it leaks into the blood stream, it travels to the kidneys for removal. However, the myoglobin molecules are too large for the kidneys to readily clear, and can easily block the kidney’s filtration system. In addition, myoglobin breaks down into potentially harmful compounds. Permanent kidney damage or even kidney failure may result, which may require lifelong dialysis or a kidney transplant. See the National Institutes of Health for further information on rhabdomyolysis.

Extreme muscle soreness brings with it with a significant risk for rhabdomyolysis. Virtually all muscle soreness is attributable to the eccentric phase of exercise, which occurs when the muscle is lengthened while resisting. This occurs in the lowering phase of every weightlifting or calisthenic repetition, and also in the initial ground-contact phase of running, particularly downhill running. It also occurs during the deceleration phase of sports activities, as in braking for directional change and bringing a moving limb to a halt.

There is no excuse for any strength and conditioning coach to induce rhabdomyolysis. The press has reported that the workouts of the Iowa football players were extremely severe and may have been used as a punishment. One athlete said, “I had to squat 240 pounds 100 times and it was timed. I can’t walk and I fell down the stairs.” Another one said, “Hands Down the hardest workout I’ve ever had in my life!”. In addition, the severe workout occurred just after the athletes returned from winter break, during which most of them had not engaged in heavy resistance exercise. That made them particularly vulnerable to extreme muscle soreness and rhabdomyolysis.

Such an approach is totally unnecessary. Firstly, exercise should never be used as a punishment. Secondly, any knowledgeable and competent coach has to be aware that any exercise regimen that induces extreme muscle soreness presents a significant risk for rhabdomyolysis. Muscle soreness is not a prerequisite for muscle strengthening! The most effective way to increase strength is to start with light resistance and gradually increase the weight lifted over a period of time as the muscles strengthen. High repetitions are totally unnecessary for strength and power athletes like football players. Muscle fatigue following a workout is expected and desirable within limits, but muscle soreness is unnecessary and can actually slow down progress in strength development.

An extensive article and interview of coaches, doctors, and a parent of one of the players is available on the Internet.

Wednesday, January 26, 2011

Fatty Liver Disease: Another Reason to Avoid Obesity

An article in the January 2011 issue of the Harvard Health Letter reveals that the epidemic of obesity has increased the occurrence of fatty liver disease. Previously, most cases of fatty liver disease were related to excess alcohol consumption, but now, many cases are related to excess body fat, which can lead to Type II diabetes. Fatty liver disease affects 70-90% of those who are obese and/or have diabetes.

Abdominal obesity can lead to metabolic syndrome (elevated blood pressure and levels of triglycerides and blood sugar, and low HDL (good cholesterol). Overfilled fat cells become resistant to insulin (which lowers blood sugar by storing it in the cells) resulting in excess fatty acids in the blood. Fat then accumulates in liver cells, which can lead to inflammation and liver tissue damage.  This can in turn bring about liver fibrosis (buildup of fibrous tissue) or cirrhosis (buildup of scar tissue). Cirrhosis increases the risk of liver cancer.

Fatty liver disease increases the risk of heart attack and stroke because a fatty liver produces inflammatory factors that can promote the deposition of plaque in the arteries, leading to arterial narrowing.

The only effective treatment for fatty liver disease is to lose weight.

Bottom Line
If you want to avoid or reverse fatty liver disease, avoid gaining unnecessary body fat or lose existing excess body fat through a program of good nutrition and exercise. Both caloric restriction and exercise are essential parts of any weight-loss program.

Wednesday, January 19, 2011

As We Age, Cholesterol Level Loses Its Value as a Risk Factor

Because both a high total cholesterol level and a high LDL-cholesterol level are risk factors for heart disease, statin drugs, which lower both levels, are widely prescribed. In the U.S., more prescriptions are written for Lipitor, the most popular statin, than for any other drug. Estimates for the number of people who take statins range between 11 million and 30 million. But should so many people be taking statins? A recent analysis, in which scientists reviewed 14 studies that included data from over 34,000 patients, showed little evidence that statins prevent heart trouble in patients with no history of cardiovascular disease. And because there is some evidence linking low cholesterol levels with increased risk of death from other causes, the study authors feel that doctors should be more cautious about prescribing statins.

An important factor to consider when deciding whether or not to prescribe statins is the patient’s age. A study by Kronmal et al., entitled, “Total Serum Cholesterol levels and mortality risk as a function of age” in the Archives of Internal Medicine (vol. 153, pp. 1065-1073, 1993) examined how age affected the ability of cholesterol level to predict the risk of dying, and it showed that the predictive value declined with age.
The most important consideration when judging mortality risk is the overall likelihood of dying from any cause. In that regard, at age 40, those people with higher total serum cholesterol levels had a significantly higher all-cause mortality risk. However, the relationship declined with age, and by age 60, the relationship between total cholesterol level and all-cause mortality had vanished. By age 80, the relationship actually reversed, so that those with higher cholesterol levels were at significantly lower risk of dying.

Looking specifically at the risk of death from coronary heart disease, the death risk at ages 40, 50, and 60 years was greater for those with higher cholesterol levels, although the effect got smaller with age. By age 70, the relationship was still positive but weak, but by age 80 the relationship reversed, and those with higher cholesterol levels actually had less chance of dying.

Looking at death due to causes other than heart disease, (e.g. cancer), from age 50 on, there was a lower risk of dying as cholesterol levels rose. This apparent protective effect of cholesterol against non-heart-disease death increased with age. Seventy-three percent of 80 year-old men with cholesterol levels above 240 survived for 5 years, while only 49% of those with levels below 240 did. The effect was in the same direction but weaker for women, with a 74% and 70% 5-year survival rates for women with cholesterol levels respectively above and below 240 mg/dl. In regard to cancer alone, higher cholesterol level was associated with lower death risk.

Bottom Line
The current practice of the medical establishment of prescribing statins to anyone with a total cholesterol level above 200 appears to be unjustified. For patients with elevated cholesterol levels and a history of heart disease, statins provide a proven reduction in risk. However, for patients with mildly elevated levels and no history or heart disease, the evidence in favor of prescribing statins is weak or nonexistent. And for men above age 70, even those with cholesterol levels above 240, statins could very well increase the risk of death.

Friday, January 14, 2011

New Insights into Obesity

The December 2010 issue of the Nutrition Action Health Letter, published by the Center for Science in the Public Interest, featured an interview with Eric Ravussin, head of the Nutrition Obesity Research Center of the highly regarded Pennington Biomedical Research Center in Baton Rouge, LA. The discussion centered on new clues as to why we gain weight, and revealed the following:
  • Leptin, a hormone discovered in 1994, is produced by fat cells and  tells the brain when the cells are full.
  • When people diet and lose weight, leptin levels drop sharply, causing food cravings and weight regain.
  • Loss of 10-20% of body weight slows the metabolism and rate of caloric burn.
  • Injecting leptin can bring the metabolism back up.
  • However, most overweight people are resistant to leptin, just as Type II diabetics are resistant to insulin.
  • Using drugs to shut down hunger mechanisms doesn’t work well because the human body has developed several redundant systems to stimulate eating as protection against starvation.
  • People have natural ranges of body fat depending on their genes that control energy intake and expenditure.
  • Nutrition in the womb and infancy can affect propensity for overweight and obesity by switching different genes on and off.
  • Brown adipose tissue, which burns calories to produce body heat, previously thought to exist only in infants, was recently discovered in adults.
  • By maintaining homes at a steady comfortable temperature throughout the year, we don’t burn calories via brown fat to keep warm in winter, and we miss the appetite-suppressing effect of heat in the summer.
  • A common cold virus (adenovirus-36) makes experimental animals gain a lot of weight. Antibodies to this virus, an indication of exposure, are much more common in obese than in normal-weight people.
  • Gut bacteria can be a factor. Transplanting feces from a fat animal to a lean one results in weight gain for the latter, while transplanting from the lean to the fat animal makes the fatter one leaner. Similar transplants in humans have reduced insulin-resistance of people with metabolic syndrome, a set of symptoms indicative of heart-disease risk characterized by excess fat around the waist, low HDL, and elevated blood pressure, blood triglycerides, and fasting blood glucose.
Ravussin feels that we should tax soft drinks and other unhealthy foods while subsidizing healthy foods, create areas where kids can safely play, and make physical education mandatory so that everyone, not only the athletically-gifted, engages in physical activity,

Tuesday, January 4, 2011

Does Heavily Advertised Exercise Equipment Really Provide Advantages?

Advertisements on TV and elsewhere make it appear that, if you buy the latest innovative exercise device you will make faster and greater gains than you could using more conventional exercise equipment. Unfortunately, such claims, however seductive, do not usually stand up to scrutiny. The following articles in the December 2010 issue (vol. 24, no. 12) of the Journal of Strength and Conditioning Research highlight instances in which such equipment fails to provide any training advantage over standard exercises.

An article by Youdas et al. (pp. 3552-3562) compared the electrical activity of 4 chest, arm, and shoulder muscles of 20 subjects doing pushups using the Perfect-Pushup device and the same subjects doing standard pushups. The Perfect-Pushup device allows free horizontal rotation of the hands during the pushup movement while, during the standard pushup, the hands maintain their position throughout the movement. Pushups both with and without the device were done 3 different ways - using wide, shoulder-width, and narrow hand placements. While the results showed some small advantages of either the Perfect-Pushup or standard pushup as to the intensity of involvement of specific muscles when using particular hand positions, neither the Perfect-Pushup nor standard pushup showed any overall superiority to the other form of exercise. Hand position had a much more striking effect on muscle involvement, indicating that pushups should be done at various hand placements in order to stimulate a wide range of chest, shoulder, and arm musculature.

Another article by Youdas et al. (pp. 3404-3414) compared exercise using the Perfect-Pullup device to standard pull-ups (overhand grip) and chin-ups (underhand grip) using an overhead straight bar. The Perfect-Pullup device allows free horizontal rotation of the hands during the pull-up movement while, during the standard pull-up and chin-up, the hands maintain their position throughout the movement. Muscle electrical activity sensors were used to monitor the effort of 7 different muscle groups for 21 men and 4 women during the exercises. The results showed that, while there were some significant differences in muscle activation between the chin-up and pull-up, there were no significant differences between the Perfect-Pullup device and either the chin-up or pull-up. The authors concluded that the Perfect-Pullup device did not provide any advantage over standard pull-ups or chin-ups.

An article by Willardson et al. (pp. 3415-3421) compared the electrical activity of 3 abdominal muscles and 1 set of back muscles during 3 traditional trunk exercises and abdominal exercise using a device called the Ab Circle. Results showed no statistically significant differences in muscle activity between the Ab Circle and standard exercises. Yet the mean activity of the rectus abdominis muscles (6-pack) and lower abdominal stabilizer muscles was highest during the standard crunch, and the erector spinae (low back) muscles and external obliques (lateral waist) were most active during the side bridge. Thus the Ab Circle provided no advantage over standard calisthenic exercises for working the abdominal and low back musculature.

An article by Schoffstall, Titcomb, and Kilbourne (pp. 3422-3426) compared the electrical activity of 5 muscles involved in abdominal and hip flexion (upper rectus abdominis, lower rectus abdominis, internal obliques, external obliques, and rectus femoris) during the following isometric exercises:
- Crunch
- Supine V-up (while facing upward, back and legs rise off the ground to make a V-shape)
- Prone V-up (while facing down, butt rises up while hands and feet approach each other, making inverted V-shape) done as follows:
  • Feet on ground (no equipment)
  • Feet on FB large exercise ball
  • Feet on Power Slide
  • Feet supported by TRX suspension straps
  • Feet on Power Wheel
The results showed that:
  • All exercises stimulated the external obliques, upper rectus abdominis, and lower rectus abdominis similarly
  • The supine V-up without equipment showed greater internal oblique activity than the V-up done on the slide board.
  • The rectus femoris was less active during the crunch than during any of the other exercises. This is not surprising since the knees are specifically bent during a crunch to take the hip-flexors out of play and focus only on the abdominal muscles.
  • Overall, the prone and supine V-up exercises done without equipment provided as much training stimulus to the muscles tested as did the prone V-up using any of the commercial equipment.
Bottom Line
These studies indicate that much of the exercise equipment heavily marketed to the public provides no advantage in training stimulus over standard exercises. The only advantage of such equipment is that it provides variety, which may be important to maintain the motivation to exercise. Some exercise enthusiasts, even when informed that such equipment usually provides no shortcuts to the results they desire, may still wish to purchase them in order to keep their workout fresh, and that is fine. However, for those who would rather use their money for different purposes, there are other ways to add variety to a workout. Using standard gym equipment, a wide variety of exercises can be performed, especially using free-weight barbells and dumbbells and an overhead bar for hanging exercises.