Increasingly, foods sold in the supermarkets come with health claims on the label. To name just a few, oatmeal and soy are said to help prevent heart disease, milk and calcium-fortified orange juice to fight osteoporosis, and folate-enriched flour to prevent birth defects. These are all “functional foods”—foods marketed as offering specific health benefits.

There are two main categories of functional foods. The first (and largest) category consists of ordinary foods that contain health-promoting substances. This category essentially includes all fruits, vegetables, and whole grains, soy and other legumes, and numerous other foods such as herbal teas, yogurt, and cold-water fish. When these foods are presented as functional foods, their specific health benefits and healthy constituents are highlighted, such as fiber, vitamins, minerals, and non-nutrient chemicals with potential health benefits.1

The second category of functional foods consists of foods that have been enriched with a potentially health-promoting ingredient. Examples include margarines containing stanol esters, orange juice enriched with calcium and other nutrients, and beverages to which echinacea and other herbs have been added.

Some of these functional food products are based on good, solid science. For others, however, the supporting evidence is weak or speculative. Furthermore, the requirement for good taste sometimes forces manufacturers to limit the amount of herbs and other additives to a level so low that they are unlikely to have any effect.

In the following table, we list some of the more promising functional foods, as well as natural products that are added to food products to create functional foods.

Cancer prevention Diindolylemethane (found in broccoli-family vegetables),
Fish oil (found in salmon and other cold-water fish)
Flaxseed (contains lignans)
Folate
Garlic
Green tea
I3C (found in broccoli-family vegetables)
IP6 (found in nuts, seeds, beans, whole grains, cantaloupe, and citrus fruits)
Lycopene (found in tomatoes)
Resveratrol (found in grape skin)
Selenium
Soy foods
Turmeric (added to many foods as a preservative)
Vitamin C
Vitamin E
Cataracts Lutein (found in dark-green vegetables)
Cavities Xylitol (added to chewing gum and candy)
Colds and flus Echinacea (herbal tea)
Garlic
Diabetes Chromium (whole grains, brewer’s yeast, fortified nutritional yeast, liver)
Evening primrose oil
Diarrhea Probiotics (Friendly bacteria) (found in yogurt)
Digestive problems Probiotics (Friendly bacteria) (found in yogurt)
Ear infections Xylitol (added to chewing gum and candy)
Easy bruising Bioflavonoids (found in citrus fruits, buckwheat, and most fruits and vegetables)
Eczema Probiotics (Friendly bacteria) (found in yogurt)
General nutrition Fortified grains and beverages
Heart disease prevention Alpha-linolenic acid (found in flaxseed oil)
Calcium (added to beverages; found in milk and other dairy products)
Garlic
Fish oil (found in salmon and other cold-water fish)
Potassium (found in orange juice, bananas, and other foods)
Soy products
Stanols/Sterols (added to margarine and other spreads)
Fiber (oats, etc.)
Wine and other alcoholic beverages (in moderation)
High cholesterol Fiber (found in whole grains and fruits, legumes, and vegetables)
Garlic
Krill Oil
Soy products
Stanols (added to margarine and other spreads)
Menopausal symptoms Soy products
Nausea Ginger (beverages)
Osteoporosis Calcium (added to beverages; found in milk and other dairy products)
Vitamin D (added to butter, milk, and other beverages)
Soy foods
PMS Calcium (added to beverages; found in milk and other dairy products)
Krill Oil
Ulcerative colitis Probiotics (Friendly bacteria) (found in yogurt)
Urinary tract infections Cranberry juice
Vaginal infection Probiotics (Friendly bacteria) (found in yogurt)