Supplements vs. exercise

A look at nine major health issues and the benefits of exercise versus supplements.
Supplements vs. exercise
By Harvard Medical International
Thu 06 Mar 2008 04:00 AM

A look at nine major health issues and the benefits of exercise versus supplements.

Can you find good health in a bottle of supplements? Many people seem to think so, or at least have enough hope to spend billions of dollars a year on supplements.

All in all, there is little to recommend supplements for muscles.

In view of the constant drumbeat for vitamins, minerals, and herbs - and the scant FDA oversight - you can hardly blame people for embracing supplements. Indeed, objective scientific studies are needed to learn which claims are valid and which are not.

But while research goes forward, we should all look for other natural ways to improve our health. Good nutrition is one essential, exercise another.

When comparing the effects of supplements and exercise on heart disease and cancer, exercise comes out on top. Now, let's see how the two compare on nine other health issues.

1. Muscles and bones.

Strong muscles are important for health - and they are also important for athletic performance and for the muscular physique that is particularly valued by young men.

Vitamins have no role in making muscles stronger or bigger, but vitamin D may help reduce falls by improving neuromuscular function. And other supplements may work, at least to some extent.

Chemicals that are related to the male hormone testosterone are the best example, which is why androstenedione (Andro) and dehydroepiandrosterone (DHEA) have become best sellers.

Trouble is, they can also have side effects; most experts strongly discourage their use, explaining that the potential harm far outweighs the possible gain. Creatine and various protein supplements have a less toxic potential, but they are also much less likely to enhance muscular function.

All in all, there is little to recommend supplements for muscles.

Bones are different. Strong bones lack the sex appeal of bulging biceps, but the fractures and deformities caused by osteoporosis bespeak the importance of maintaining bone calcium in the face of age.

About 34 million Americans have osteopenia, or low bone calcium, and another 10 million have the thin, brittle bones of osteoporosis.

Virtually all authoritative medical groups recommend vitamin D (at least 200 international units, or IU, a day for adults younger than 50, 400 IU a day between 51 and 70, and 600 IU a day above age 70) and calcium (1,000 mg a day below age 50, 1,200 mg a day thereafter) to help prevent osteoporosis.

An important 2007 meta-analysis of 29 trials involving over 63,000 subjects recommends 1,200 mg calcium and 800 IU of vitamin D a day. Most Americans will require supplements to reach these goals. Although osteoporosis is more prevalent in women, men are far from exempt.

At present, both genders should still follow the general guidelines, but men may be wise to limit their daily calcium to about 1,200 mg; some (but not all) studies suggest that a high intake may be linked to an increased risk of prostate cancer.

And new evidence suggests that boosting vitamin D to 800 to 1,000 IU a day may help. But since high doses of vitamin A increase the risk of osteoporosis, men should keep any vitamin A supplements below 3,000 IU a day.

When it comes to musculoskeletal health, exercise has a crucial role. But not all forms of exercise are equally effective. Weight-bearing and resistance exercise are needed to enhance muscle mass and strength.

It's why strength training is important, particularly for older men and women. Fortunately, you don't have to hit the gym to benefit. In fact, simple routines at home two to three times a week will do the trick.

2. Neurological and psychological disorders.

Cognitive impairment, dementia, and Alzheimer's disease are among the most feared diseases that can strike older people. Sad to say, the supplement industry preys on these fears, touting various products to keep the brain young.

There is no credible evidence that any can help. One well-performed study did show that very high doses of vitamin E can slow the progression of Alzheimer's disease slightly, but the benefits were very small, and there are no data to support any supplement's ability to prevent, delay, or reverse cognitive decline.

Exercise is good for the body, but can it also help the mind? Animal studies show that exercise training can increase blood flow to the brain and enhance communication between nerve cells by promoting new connections (synapses) between brain cells.

A study of mice even found that exercise increased the production and survival of new nerve cells in the aging rodents' brains.
What's good for mice also seems to be good for men. Ten recent studies of more than 53,000 older Americans, Canadians, and Europeans have all linked cognitive decline in seniors to a lack of exercise.

Compared with the least active people, those who got the most exercise enjoyed a 15% to 52% lower risk of mental decline. In one study, for every mile a woman walked each day, her risk of cognitive dysfunction dropped by 13%.

Among the supplements, vitamin D makes the most sense, and fish oil can help people at risk for heart disease.

In another, regular exercise between the ages of 20 and 60 was linked to a nearly fourfold decrease in the risk of developing Alzheimer's disease. In addition, researchers in Baltimore reported that people who carry a gene that increases the risk for Alzheimer's obtain the greatest protection from exercise.

Psychological well-being is harder to quantify than physical health, but one supplement, St. John's wort, does seem to help lift mild to moderate depression, at least in the short term. Exercise can also help fight depression, promote sleep, and dissipate stress.

3. Obesity and diabetes.

Obesity is a big problem in America, and it's a big market for the supplement industry. It would be nice if a supplement could help, but none has a meaningful or sustained effect on body fat, and some, such as ephedra, have proved very dangerous.

Many of America's 21 million cases of diabetes are spawned by obesity. Chromium is a mineral that is sold in various forms to promote weight loss. It can't do that, but it may have a small role in improving glucose (sugar) metabolism. More study is needed.

Exercise burns calories. It is a necessary partner to dietary caloric restriction for sustained weight loss. Weight loss helps prevent and treat diabetes - but even without weight loss, exercise sensitizes the muscle cells to insulin, lowering blood sugar levels in both diabetics and others.

4. Arthritis.

Supplements are praised and exercise is blamed for joint pains that plague millions of Americans. There is some truth to the former, little to the latter. Although not all studies agree, there is a body of evidence that one supplement may help, at least to some degree.

Glucosamine may partially reduce the pain of osteoarthritis for some patients. A companion supplement, chondroitin sulfate, does not seem to help. Although these supplements are expensive, they appear generally safe.

There is much less evidence to support the claims of other supplements. If exercise produces a major joint injury, it will increase the risk of osteoarthritis in later years.

But aside from a slip on the ski slope or a hit on the gridiron, exercise is actually easy on joints. In fact, exercise helps cartilage cells get the nutrients they need from joint fluid.

Even the steady pounding of long-distance running doesn't cause symptomatic arthritis of the knees or hips, though it can produce minor abnormalities that will appear on x-rays.

5. Infections.

In the "contest" between supplements and exercise, this one ends in a dead heat - not because both can help, but because neither lives up to hope and hype.

Vitamin C, echinacea, and zinc have all been touted to prevent or treat upper respiratory infections, but none of their claims has stood up to the scrutiny of careful, objective scientific study.

Vitamin E has fared even worse, actually increasing susceptibility to colds in one investigation. And, various claims notwithstanding, exercise does not have an important effect on infections for good or ill.

6. Vision.

There's no benefit for exercise here. But in one situation, a supplement can help. Age-related macular degeneration (AMD) is a distressingly common cause of visual loss in older people.

The landmark Age-Related Eye Disease Study showed that a daily supplement containing 500 mg of vitamin C, 400 IU of vitamin E, 15 mg of beta carotene, 80 mg of zinc, and 2 mg of copper can reduce the risk of progression to severe AMD by about 25%.

It's one of the very few optimistic studies of antioxidants and health.

7. Anaemia.

There's no role for exercise here, either. In fact, very high levels of exercise can actually reduce red blood cell counts ("marathoner's anemia"). But with two exceptions, supplements don't help, either.
Older people can have trouble absorbing vitamin B12 from food; the crystalline form of B12 in supplements is much easier to absorb and can prevent anaemia.

Strict vegetarians and some people who have had gastrointestinal surgery need B12 supplements, and patients with pernicious anemia need high doses. Iron won't help healthy men, but it can prevent iron-deficiency anaemia in menstruating women. (And speaking of women, folic acid is vital to prevent birth defects during pregnancy.)

8. Energy and sexuality.

This oft-repeated claim for supplements is another likely cause for disappointment. Vigor is hard to measure, but many people report that exercise boosts their energy, both mental and physical.

It's mostly anecdotal evidence, and like the testimonials for supplements, it may be subject to a strong placebo effect. But there is hard scientific evidence that regular exercise is linked to a reduced risk of erectile dysfunction (ED).

A Harvard study linked walking for about 30 minutes a day to a 41% reduction in the risk of ED. And in 2004 a randomized clinical trial reported that moderate exercise can help restore sexual performance to obese middle-aged men with ED.

9. Aging and longevity.

"Anti-aging" supplements have understandable appeal but no scientific merit. In this case, though, disappointment may take longer to set in.

Exercise can't turn back the clock, either, but there are sound reasons to believe it can slow the tick of time. Bodily disuse contributes to many of the physiologic changes that accompany aging, and exercise can slow the rate of change. Regular exercise prolongs life.

According to the calculations of the University of Chicago's Dr. Willard Manning and his colleagues, each mile you walk as part of a regular exercise program will extend your life by 21 minutes.

The Harvard Alumni Health Study is even more optimistic; calculations based on its data say that you'll gain about two hours of life expectancy for each hour of regular exercise, even if you don't start until middle age.

Calculations are one thing, observations another. Scientists have gathered facts by evaluating elderly men in Hawaii, Seventh-Day Adventists in California, male and female residents of Framingham, Massachusetts, Harvard alumni, elderly American women, British joggers, middle-aged Englishmen, retired Dutchmen, and residents of Copenhagen - among others.

Although the details vary, the conclusion is remarkably uniform: Regular exercise prolongs life and reduces the burden of disease and disability in old age.

In reviewing the data, Dr. J. Michael McGinnis of the U.S. Office of Disease Prevention and Health Promotion concludes that regular physical activity appears to reduce the overall death rate by more than a quarter and seems to increase life expectancy by more than two years compared with the sedentary population's average. Exercise and longevity - it's Darwin redux, the survival of the fittest.

Perspectives

Regular exercise is important, even essential, for optimal health. But it doesn't have to be intense or prolonged; you don't need mega-exercise any more than megavitamins.

In fact, about 30 minutes of moderate exercise a day will yield an enormous benefit. Walking, taking the stairs, gardening, and biking are a few of the many ways to improve your health through physical activity.

Add modest "doses" of strength training, stretching, and exercises for balance and you'll have a complete prescription for health.

Except in a few special circumstances, exercise far outshines supplements for health. Among the supplements, vitamin D makes the most sense, and fish oil can help people at risk for heart disease.

Extra amounts of B12 are harmless and may help certain individuals, but extra amounts of other vitamins may do more harm than good.

Don't waste your money on high potency, "all-natural," or designer vitamins. Vitamin-mineral combinations are also unnecessary.

Above all, remember that any supplement is just an insurance policy - a supplement, not a substitute, for a healthful lifestyle that incorporates moderate physical activity into the fabric of daily life.

When it comes to a supplement for exercise, though, the best choice is not a pill but a balanced, healthful diet. In fact, good nutrition is more than a supplement, it's the natural partner of exercise.

Together, they are the hand-and-glove of prevention and good health. Think of them, perhaps, as the unofficial ‘vitamins' E (exercise) and D (diet).

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