Calcium-fortified orange juice, special fortified margarine, nutrient enhanced salad dressings, and other "functional foods" are advertised everywhere these days. Is there a scientific basis for the claims made on these products -- and should they be used by everyone? There is no across-the-board answer to this question; whether these foods are beneficial depends on several factors.
People should not automatically assume that consuming "functional foods" -- also called "phoods" to suggest pharmaceuticals -- will allow them to live longer, healthier lives. In a society that already has a ready stock of healthy fruits and vegetables, flocking to "functional foods" may bring no additional benefits. Some enhanced foods are useful for segments of the population with unique nutritional needs, such as vegans, who won't drink milk and need to find their calcium elsewhere. In other cases, such as prune juice laced with Lutein, the evidence supporting the benefits of the added nutrient is weak. For the general population, factors such as the overall nutritional value and calorie intake of your diet -- as well, of course, as whether sound scientific evidence backs the claims on the package labels -- should be considered before incorporating these foods into your routine. In addition, consumers should be aware that certain nutrients can interact with prescription or over-the-counter drugs. For example, calcium-fortified orange juice can decrease the effectiveness of some antibiotics.
There is strong evidence for some of the claims but only weak evidence for others. Some foods provide medical benefits when used at the dose recommended, such as Benecol (a fortified margarine), which has been shown in clinical trials to lower blood cholesterol levels. But if you do not have high cholesterol, you don't need this product. (If you do have high cholesterol, you should be under guidance of a physician.) But at least Benecol's claims are supported. Contrast this with Green tea, which is said to reduce the risks of some types of cancer; you will find only minimal evidence for such claims. Studies have shown that while a component in the tea, catechins, is successful in reducing the risk of cancer in experimental animals, the results of studies on humans conflict. In some instances, tea drinkers have not shown any reduction in cancer risk as compared to nondrinkers. Finally, there are "phoods" whose claims have much weaker supportive evidence, such as foods with Lutein, said to reduce the risk of age-related macular degeneration. Such preliminary claims are not yet strongly supported.
The FDA started allowing companies to use "qualified health claims," warns Dr. Clare Hasler, an ACSH Advisor. As noted in a recent Washington Post article, the intent of the health claim is to inform consumers about the ingredients in certain foods that scientists suggest may have medical benefits, and many companies are petitioning the FDA to allow sometimes debatable claims. Dr. Hasler expresses concern that the flood of claims bombarding the public may cause them to "tune out" claims about health benefits in general, rendering all the claims useless.
As more and more "phoods" become available, consumers should consider the evidence behind the claims, the relevance of those claims to their personal situation, and the potential downsides. Adding a food that contains a particular nutrient to one's diet does not necessarily mean that the nutrient will have the desired effect; issues like effective dosage also must be considered. These "functional foods" are not a substitute for a well-balanced diet, which is the cornerstone of good nutrition. While some products have merit for certain consumers, we should all remain skeptical about whether these "functional" foods are useful for everyone.
Rachel Kleinerman is a research intern at the American Council on Science and Health.