Nutrition and Supplements for Fitness and Health

Get a well-balanced diet by eating food rather than pills and supplements.
Many diet supplements are not going to help; however there are definite benefits to carbo loading, caffeine, and hydration.

Protein shakes, energy drinks, glucosamine, and creatine have not been scientifically proven to enhance athletic performance.
Athletes need to be aware of their activity level and adjust their calorie intake according to their goals.

Nutrition and Supplements for Fitness and Health

Finding the right balance in your diet has gotten mighty confusing. Dietary guidelines for the best nutrition continue to be revised and rethought. Figuring out what to eat-and what to avoid-has gotten harder and harder to figure out.
The U.S government stepped in 1946 with its first National Nutrition Guidelines. The Basic 7 listed the main food groups for recommended daily intake, including a group for citrus, tomato, cabbage, salad greens, and one for butter and margarine. The plan was revised in 1956 with a simpler approach that featured four food groups. In 1992, the food pyramid was introduced: breads and cereals at the base and sweets at the top. Responding to feedback from physicians that there was too much emphasis on carbohydrates, the pyramid was revised in 2005 as MyPyramid, which added exercise and focused on proportions, variety, and moderation.
“The key is to be aware of what you’re eating and learn about what’s not good for you,” said Bryant Lin, MD, a clinical assistant professor of medicine, who discussed nutrition and diet supplements at a presentation sponsored by the Stanford Health Library. “There’s still some controversy over the current food pyramid, but it’s a reasonable place to start. The key is balance.”

Dr. Lin discussed the components of the pyramid with advice on how to obtain optimal nutrition from your diet. He suggested fresh or frozen fruit since canned fruit usually has too much sugar in the syrup and juice lacks fiber. Reduce quantities of meat, sticking to a 3-ounce serving, and learn where your meat comes from. Eat whole grain foods for roughage.
Athletes, in particular, need to be aware of their activity level and adjust their calorie intake according to their goals. Learn the daily recommended values and read packages carefully to keep track of your nutritional intake. “Exercise by itself is not the way to lose weight permanently,” he said. “For optimal performance you may need to increase calories for your energy needs. Keep track and modify your diet based on your health needs. That’s the nutritional foundation for everyone.”
Dr. Lin also discussed the benefits-and hype-of some of the more common diet supplements and packaged foods. Unlike drugs, which must be approved for safety before entering the market, dietary supplements are not regulated by the FDA.

• Protein shakes, cans, and powders, which are promoted as building muscle mass, do not necessarily make you stronger, said Dr. Lin. “There is little evidence of increased muscle mass over the protein you get in your diet. Since the primary source of protein in your diet is lean meat, that’s probably a better way to go,” he advised. “As long as you’re eating a healthy diet, adding extra protein-either through protein shakes or other sources-isn’t necessary.”
• Creatine is also believed to increase muscle mass, and Dr. Lin said that there is some evidence that it enhances lifting strength. However studies have shown some people have an allergic reaction and the supplement may cause some nominal liver and kidney damage. “It’s not worth the risk,” he said.
• Caffeine supplements, such as Red Bull, NoDoz, coffee, or energy drinks, do appear to improve athletic performance, especially long-term endurance sports like runs of 5K or more.
• Electrolytes, such as potassium and magnesium, conduct electricity in the body, playing a key role in digestion and muscular function, and are often used to treat muscle cramps. Most people get all of the potassium they need from a healthy diet rich in vegetables and fruits, and stretching and hydration are better ways to treat cramps, said Dr. Lin.
• Sports drinks like Gatorade do help improve performance. By mimicking the electrolyte content in sweat, they help with hydration-possibly because many athletes tend to under-hydrate. New electrolyte waters are probably no better than Gatorade, he said, but in general seem to be a reasonable addition to the diet.
• Carbohydrate loading is primarily beneficial if you’re an endurance athlete, such as a marathon runner, swimmer, or cyclist preparing for a high-intensity competition of 90 minutes or more. Carbo loading does appear to enhance endurance performance by increasing glycogen in the muscles.

Glucosamine and chondroitin have been used to treat arthritis or joint pain. However the gastrointestinal track serves as a barrier for products like Joint Juice, Dr. Lin said. Although initial trials showed some joint improvement, two more recent studies did not demonstrate any real benefit from using these proteins. “They won’t do you any good, but they won’t hurt anything but your wallet,” he said.

There are some supplements that have been proven to be beneficial, including:

• Calcium and Vitamin D, since most people do not get enough
• Folic acid, which is especially beneficial for pregnant women and older people
• Omega 3, for high cholesterol. However Dr. Lin expressed concern about levels of mercury in many fish oil supplements and suggested eating walnuts instead.
• Niacin, which also appears to lower cholesterol levels
• Iron, for vegetarians
• “In general, most people can get a well-balanced diet by eating food rather than pills and supplements,” Dr. Lin said. “And count calories and portions in light of your activity level.”
• About the Speaker
• Bryant Lin, MD, is a clinical assistant professor of medicine who specializes in primary care medicine, cardiac electrophysiology research, and biodesign He did his residency and internship at Tufts-New England Medical Center in Massachusetts and competed his fellowships at Stanford. He is Board Certification by the American Board of Internal Medicine. He joined Stanford in 2008.

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