More than half of American adults take some kind of dietary supplements, according to a new report released by the Centers for Disease Control and Prevention (CDC), but are they any healthier for the reported $27 billion spent each year purchasing them?

The report, which appeared in a CDC National Center for Health Statistics’ Data Brief, looked at dietary supplement use from 2003 to 2006 and compared it to the use of supplements from 1988 to 1994 as reported by the National Health and Nutrition Examination Survey (NHANES) III. NHANES is an ongoing series of surveys designed to assess the health and nutritional status of adults and children in the United States.

For most people, the money spent on dietary supplements is better spent purchasing healthy foods.

The report found that the number of people who reported taking dietary supplements increased from 42% between 1988 and 1994 to 53% between 2003 and 2006, an 11% increase. Multivitamin/mineral supplements were the most commonly-used supplements with about 40% of both men and women reporting their use.

It is not clear why there has there been an increase in the use of dietary supplements, but according to Dr. Regan Bailey, RD, one of the authors of the report, "We [do] know that when compared to people who do not use dietary supplements, consumers of dietary supplements tend to have higher education, higher incomes, and lower body mass index. Also, females take more than males."

Among women aged 60 and over, the use of supplemental calcium increased overall by 44% with non-Hispanic white women taking the most. More than two-thirds of older women take a calcium supplement. Calcium, found chiefly in dairy foods, is essential for bone health and may reduce the risk of osteoporosis among older adults, and older white women are particularly at risk. However, recently supplemental calcium has been linked to an increased risk of heart problems.

Not surprising, due to the amount of media attention it has received in recent years, vitamin D supplement use increased between the years of 2003 and 2006, especially among men and women aged 40 years and above. Vitamin D has been the subject of much controversy in recent years. Experts disagree as to the optimal intake of vitamin D as well as its health benefits or harmful effects.

The human body manufactures vitamin D when exposed to sunlight, and it is found in fortified milk and milk products. The few natural food sources of vitamin D include fatty fish and egg yolks. Some studies have linked a deficiency of vitamin D to a variety of health problems, including cancer and heart disease, though there is disagreement as to what constitutes a deficiency.

Are dietary supplements really necessary for optimal health? According to Dr. Bailey, "Ideally, eating a healthy variety of foods should provide the vitamins and minerals that most people need. However, some groups of people need higher nutrient intakes than others — for example, women of reproductive-ages are recommended to have an additional 400 micrograms of folic acid; older adults have higher needs for calcium and vitamin D to prevent osteoporosis; and menstruating females may require higher iron intakes."

Health professionals need to be aware of the dietary supplements consumed by their patients, and patients need to be forthcoming in telling their health care providers about any supplements they consume. Some supplements may interfere with the effectiveness of prescription drugs. Some people may unknowingly be taking supplements in excessive amounts, supplements that interact with each other, or taking products that are considered unsafe.

So, are Americans healthier due to their increased reliance on dietary supplements? Jaime Gahche, MPH, the main author of the CDC report, said that it is unclear whether the increased use of supplements has made Americans any healthier. For most people, the money spent on dietary supplements is better spent purchasing healthy foods. There are valid reasons for taking dietary supplements, however, to think that putting components of a food in pill form takes the place of getting the full array of nutrients and other compounds found naturally in food is misguided thinking.

The full report from the CDC can be accessed here. Information on dietary supplements from the National Institutes of Health’s Office of Dietary Supplements can be downloaded here.