Bmj Usa: Editor's Choice

Food, functional food

BMJ 2004; 328 doi: (Published 11 March 2004) Cite this as: BMJ 2004;328:E277
  1. Douglas Kamerow, editor

    Where do foods leave off and medicines begin?

    As functional foods become more popular, it's hard to know. The Japanese coined the term functional foods almost 20 years ago to define foods having ingredients (in addition to their basic nutritional content) that prevent or treat disease. They can be plant-based foods (think of oats and cholesterol or cranberry juice and urinary tract infections) or products from animals (oily fish and heart disease).

    Two clinical reviews in this issue address functional foods. Jehangir Din and others (p 121) discuss the reasonably good evidence for use of omega-3 fatty acids in patients with documented coronary heart disease and after myocardial infarction. The evidence is much less clear for use to prevent cardiovascular disease in healthy patients. Mark Lucock (p 127) reviews folic acid, the “ultimate functional food component,” and the large number of potential positive effects it has. This is an example of a functional food that really does prevent at least one disease—neural tube defects—and perhaps many. Folate is now in our bread, but since no one eats bread any more because of one low-carb diet or another, perhaps it should be in our water as well.

    The food industry, seeing a marketing bonanza in functional foods, has jumped on the chuck wagon to publicize existing functions or add additional ones to foods. So we have orange juice “fortified” with calcium, cholesterol-lowering margarine, and many more. Adding biologically active ingredients to foods raises all kinds of concerns, including effectiveness, safety, and drug interactions. Unlike drugs, and to a lesser extent, supplements, there is no suggested “dose” for functional foods. If your cookies are laced with folic acid and you go on a carbohydrate binge (we call it a “packathon” in our house), will you get a folate overdose?

    And as Martijn Katan points out (p 76), regulation of claims relating to functional foods varies broadly. In the United States, the FDA regulates drug claims carefully, but there is much less oversight of claims relating to food supplements or conventional foods themselves. As long as a standard disclaimer is included, all kinds of non-specific wonders may be touted with very little evidence.

    Our supermarket shopping lists are turning into prescription pads: garlic to prevent heart disease, broccoli and green tea to prevent cancer, milk for strong bones, and Cheerios to keep our cholesterol down. It does not seem unreasonable to request impartial and evidence-based guidance for shoppers as they choose which medicines—er, foods—to put in their carts.

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