Test Your Knowledge

Many organizations associated with nutrition recommend that people receive all their daily nutritional requirements through food instead of using supplements. These organizations include the American Dietetic Association, American Heart Association (AHA), National Academy of Sciences and the National Research Council.

The AHA makes an exception for omega-3 fatty acids because this substance is difficult to get in sufficient quantities through diet alone. According to the AHA, people at risk for cardiovascular disease may benefit from increased amounts of omega-3, which can be obtained from supplements. The AHA recommends that people who fit this profile consult with their physician about the potential benefits of taking omega-3 supplements.

In addition, certain populations may benefit from supplement use. For example, physicians recommend that a woman who is pregnant take folate. The physician may also recommend calcium and/or iron supplements if the woman is not able to get adequate levels of these vitamins and minerals through diet alone. People who consume certain types of vegetarian diet, those with allergies or food intolerances, and older adults may benefit from the use of supplements. Anyone in doubt about whether supplements are appropriate for them should consult their physician or a registered dietitian.

Relying on supplements may give people a false sense of security about their level of protection against certain diseases. People using supplements may be less likely to seek needed medical care for ongoing health problems. In general, supplement use has a tendency to encourage self-diagnosis and care instead of seeking proper medical attention.  

Benefits of obtaining daily nutrients from food (instead of also using supplements) include:

• Safety. An overdose of nutrients rarely occurs from food sources, but can easily occur with supplements. In addition, tolerance levels may differ among people, and it can be easy to receive toxic levels of certain nutrients by consuming a single pill or liquid.  Also, some dietary ingredients are more safely received in conventional foods or beverages. For example, drinking green tea is generally considered safe but green tea supplements may actually be harmful. Many supplements can result in adverse side effects in people with certain medical conditions and may interact with current medications (prescription or over-the-counter).
  
  
• Added nutrients. Most whole foods contain more than just one type of nutrient. For example, an orange contains vitamin C, calcium, fiber and other essential nutrients. Supplements (except for multivitamins) may provide only one specific type of nutrient. It is easier to meet a wide variety of nutritional needs through food sources than through supplements.
  
  
• Specific health benefits. Many foods (plant- and animal-based) contain non-nutrient chemicals or compounds that are associated with specific health benefits, in addition to their basic nutrients. For example, there are hundreds of phytochemicals in plant foods that are associated with reduced risks of cancer and heart disease. Many act as antioxidants, which help prevent cellular damage in the body. Certain fatty acids (e.g., omega-3 fatty acids, conjugated linoleic acid) from animal sources can help reduce blood cholesterol levels and the risk of some cancers. Although some of these are available in supplements, it is much more difficult to get all the health benefits available from foods in the form of supplements. Also, in some cases, when certain substances are taken in supplement form, they do not provide the same level of health benefit as when they are consumed in food (e.g., the phytochemicals lycopene and flavonoids).
  
  
• Reliability and cost. For many over-the-counter supplements, especially herbs and botanical products, the strength of the scientific evidence is not conclusive. There have not been enough scientifically valid research studies performed to determine the potential benefit and risks of these products. Some experts have also argued that using supplements is expensive and may offer no real return for the money spent on them.