Supplements and Obesity

Dietary supplements are regulated in the United States as foods, not as drugs. Dietary supplements can be consumed by the obese to supplement a restricted diet, or, more likely, in an attempt to aid in weight loss. Although billions of dollars are spent each year in the United States by consumers buying supplements to aid weight loss, there is little to no scientific evidence at this time that dietary supplements aid in significant weight loss.

Definition of a Supplement and Regulation

In the United States, a dietary supplement is defined under the Dietary Supplement Health and Education Act (DSHEA) of 1994 as a product that is intended to supplement the diet and contains one or more of the following dietary ingredients:

Individual vitamin and mineral supplements taken in large amounts (that is, well above the recommended daily allowance) can be toxic.

• a vitamin,
• a mineral,
• an herb or other botanical (excluding tobacco),
• an amino acid,
• a dietary substance for use to supplement the diet by increasing the total dietary intake, or,
• a concentrate, metabolite, constituent, extract, or combination of any of the above.

Furthermore, it must be:

• intended for ingestion in pill, capsule, tablet, powder, or liquid form; and,
• not represented for use as a conventional food or as the sole item of a meal or diet,
• labeled as a “dietary supplement.”

The U.S. Food and Drug Administration (FDA) regulates dietary supplements as foods, and not as drugs. A supplement manufacturer does not need to prove efficacy or safety to sell their supplements. The FDA may step in to regulate supplements only after evidence shows the supplement harmful.

The claims that a dietary supplement makes are subject to regulation by the FDA. If a dietary supplement claims to cure, mitigate, or treat a disease, it would be considered to be an unauthorized new drug and in violation of applicable regulations and statutes.

Adoption of good manufacturing practices, mandatory in manufacturing of processed food items, is not mandatory in manufacturing supplements. Therefore, product quality (contamination, accuracy of labeling, etc.) of supplements is variable and uncertain and is not subject to regulation. Some supplement manufacturers have voluntarily adopted good manufacturing practices and indicate this with seals on their supplements. An example of contamination occurred recently when an herbal weight-loss supplement was found to be contaminated with amphetamines.

Use of Weight-Loss Supplements

It is estimated that approximately 7 to 15 percent of U.S. adults use a weight-loss supplement, and almost 75 percent of users consume a supplement containing stimulants such as caffeine and/or bitter orange. The highest use of weight-loss supplements was among obese young women. Recent estimates of sales of weight-loss supplements were approximately $2 billion per year. Interestingly, sales of weight-loss supplements appear to have slipped after the FDA (in 2004) banned supplements containing ephedrine (ephedra).

People with obesity consider supplements for several reasons. Supplements can provide nutrients for diets that are restricted, such as a calorie restriction. Special dietary restrictions can limit essential nutrients, requiring supplementation. For instance, consumers on diets of less than 1,200 calories typically have a hard time obtaining all the recommend dietary allowances (RDA) or adequate intake (AI) levels of certain vitamins and minerals. Sometimes, a multivitamin-mineral supplement may be suggested for consumers on these restricted diets. Single-nutrient supplements may also be indicated. For instance, if the consumer was restricting diary products and did not have an adequate intake of calcium, then a calcium supplement could be used to make up the deficiency. It should be noted that individual vitamin and mineral supplements taken in large amounts (i.e., well above the RDA) can be toxic.

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