The Science Of Supplements

An A-Z of vitamins, nutrients and 'go-faster' supplements: what do they do, and does a runner need them?


Posted: 5 June 2002
by Liz Applegate

This section is apapted from the book, Eat Smart, Play Hard, by Liz Applegate. Buy this book

It’ll make you fast, lean, and strong. Do you want some? Who wouldn’t? That kind of marketing is hard to resist – an estimated 40 percent or more of people living in the United States take some form of dietary supplement. The problem is that with more than 29,000 supplements to choose from, separating what you need from what the manufacturers want you to think you need can be tricky.

Sorting through the Hype

Unlike the restrictions put on food products, the FDA allows supplement manufacturers to make virtually any claim other than that their product can prevent a disease. These structure-and-function claims, as they’re called, generally suggest that a supplement improves the body’s functioning. For example, a supplement might say that it boosts immune health rather than state that it prevents bacterial infection.

The FDA doesn’t regulate supplements because they fall into an odd category. They are definitely not a food, but because they are available over the counter, they are not classified as drugs. The FDA does evaluate structure-and-function claims and will pursue a supplement company over consumer complaints or if adverse side effects occur. From time to time, the FDA will issue statements regarding specific supplements, especially if it considers them dangerous. Still, as a smart consumer, you should keep in mind that when a supplement claim sounds too good to be true, it usually is. Be on the lookout for words and phrases such as "breakthrough," "magical," "miracle cure," and "new discovery."

In addition, testing has shown that many supplements don’t contain the active ingredients that are listed on the labels. (To see how various US brands stack up, go to www.consumerlab.com.) Many supplements claim to do amazing things for your body with virtually no science to back them up, so you’ll need to do your own research to make sure you get what you pay for.

Who Needs Them?

Most people who supplement don’t need to, and most who don’t supplement should, says hematologist Randy Eichner, M.D., at the University of Oklahoma Medical Center in Oklahoma City. Besides getting a blood test, how can you find out if you are deficient in a particular nutrient? Some things make it more likely.
  1. Dieting. If you restrict your daily caloric intake to fewer than 1,200, you’re likely missing out on several important nutrients.
  2. Lactose intolerance. If you can’t eat dairy products, you may fall short on calcium and riboflavin.
  3. Food allergies. If you can’t eat particular foods such as wheat and fruit, you’ll have a tougher time getting some of the nutrients you need.
  4. Vegetarian diet. Going without meat makes it harder to get enough iron and zinc, especially if you’re female. You also may come up short on vitamins B12 (not found in plant foods) and D as well as riboflavin.
  5. Pregnancy. Supplement with iron and folic acid or eat fortified cereals just in case, and follow your physician’s advice on prenatal supplements.

In addition, some supplements may offer therapeutic benefits that you can’t get from food alone. For example, you won’t find glucosamine in any food. But the supplement may do wonders for your joint health without the side effects of common prescription medications.


23 Popular Supplements

The claims made for some supplements are seriously far-fetched, but a handful of others have grabbed the attention of scientists as well as athletes because studies have shown promising results. To set the record straight, here’s a close look at 23 of the most popular supplements on the shelves. If you have any doubts about whether a particular supplement is right for you, ask your physician.

Previous article
Fuel On The Move
Next article
Food Groups: The Basics

supplements, vitamins, nutrients
TwitterStumbleUponFacebookDiggRedditGoogle

Discuss this article

We'd love you to add a comment! Please login or take half a minute to register as a free member

Smart Coach
Free, fully-personalized training plans, designed to suit your racing goals and your lifestyle.