|Considering Foods Functional|
Kate J. Claycombe
Over the past few years, there has been a surge in public interest in foods that contain natural ingredients with special health benefits. These have come to be called "functional foods".
Fruits are functional foods. Cherries, apples, berries, red grapes, oranges and grapefruits contain vitamin-like factors called flavonoids. Flavonoids have been found to increase fat metabolism, reduce inflammation and decrease muscle soreness after exercise.
Flavonoids are also found in some vegetables: yellow onions, scallions, kale and broccoli, as well as in tea and wine. These foods, and the flavonoids they provide, are thought to contribute to cardiovascular health. Soybeans, soy milk and tofu contain certain types of flavonoids called isoflavones, which have weak, estrogen-like effects. High intakes of soy foods have been shown to reduce low-density lipoprotein (LDL or "bad" cholesterol), a risk factor for cardiovascular disease.
Egg yolks, soybeans, whole grains, fish and legumes also contain choline. Choline is important in the metabolism of lipids, the function of nerves and the development of the brain. Clinical studies have shown that choline intake is related to cognitive performance. Low choline intakes during pregnancy have been associated with an increased risk of birth defects in the fetus.
Fermented foods such as yogurt are also functional. They contain microbes commonly found in the gastrointestinal tract that have favorable effects. Hence, these foods are referred to as "probiotics". The human intestine is home to more than 500 species of microbes that process fiber and other non-digestible components of the foods we eat. These microbes serve to maintain the cells that line gut, stimulating immunity and reducing inflammation. Probiotics support these healthful functions.
Salmon, cod and fish, flax and canola oils are functional because they provide omega-3 fatty acids. These fatty acids are thought to be responsible for the low prevalence of cardiovascular disease among Eskimos despite the fact that their diets are typically high in fat and contain few, if any, vegetables or fruits. Research has shown that consumption of omega-3 fatty acids is associated with reduced risks of cancer and depression. Certain omega-3 fatty acids, called EPA and DHA, have been found important for normal fetal development of the brain, retinal and immune system development. The USDA Dietary Guidelines for Americans in 2010 recommended the consumption of two 3 ounce servings of salmon, tuna, mackerel, herring or trout weekly. Research at the Grand Forks Human Nutrition Research Center showed that individuals following this recommendation effectively increased their omega-3 fatty acid status.
Flaxseed is a good source of dietary fiber and has been shown to have cholesterol-lowering effects.
Including functional foods in your diet is a smart way of supporting your own health. You can find more information about functional foods and their roles in affordable, balanced diets at www.choosemyplate.gov/.