You are probably thinking: “What the heck are phytochemicals?” Even if you are not connecting the dots right now, I’m sure you’ve heard of them before. Many articles have been written recently emphasizing the potential benefits of phytochemicals. Phytochemicals are a relatively new class of nutrients. Technically, phytochemicals are not considered nutrients per se, because they don’t provide energy or building blocks to the body. They aren’t considered essential either. However, these substances are believed to have health-protective properties. Recent research suggests that these compounds can perform fundamental protective roles, reducing the risk of developing many diseases such as heart disease and cancer.
Phytochemicals are compounds naturally found in plants that give them their bright colors and distinct aromas. These substances protect plants from insects, excessive sunlight exposure, and other environmental factors. A phytochemical is not a single compound but a family of diverse substances. They are found in many edible plants such as fruits, vegetables, legumes, whole grains, nuts and seeds. A single plant typically contains an array of different phytochemicals, but usually one or two are more prominent than the others.
Even though scientists have been able to identify and isolate many of these phytochemicals, it is still hard to attribute health benefits to single substances. It is believed that the protective effects come from a combination of various substances rather than a specific compound. Thus, the best way to ensure the health benefits associated with these substances is by consuming a diet rich in a variety of fruits, vegetables, legumes, whole grains, nuts and seeds. Moreover, eating foods closer to their natural state (not processed and gently cooked) guarantees better absorption and bioavailability[1]. Supplements containing single phytochemicals are commercially available, but their effectiveness is questionable.
Following is a list of phytochemicals and their potential health benefits.
Allyl sulfides/organosulfurs found in garlic, onions and leeks. They have been linked to cancer prevention.
Beta glucan found in oats. It is believed to reduce the risk of coronary heart disease.
Capsaicin found in chili peppers. It may reduce the risk of clotting in heart disease.
Carotenoids found in orange, red, and yellow fruits and vegetables such as carrots, mango, and tomatoes, among others. Also found in dark-green vegetables such as broccoli, kale and spinach. These substances act as antioxidants. They may reduce the risk of certain cancers, have a protective effect on the eyes and strengthen the immune system.
Curcumin found in a spice called turmeric. It has been linked to reduced risk of cancer.
Flavonoids found in many fruits, whole grains, nuts, teas, chocolate and red wine. These compounds are considered powerful antioxidants, helping the body fight infections, inflammation, and degenerative diseases. They may protect against cardiovascular disease and cancer.
Monoterpenes found in citrus fruits. They may act as antioxidants. These compounds have been associated with lower risk of cancer.
Phytic acid found in whole grains. It has been linked to cancer prevention.
Isoflavones found in soy products. They have been associated with reduced risk of heart disease and certain types of cancer.
Tannins found in grapes, wines and teas. These substances act as antioxidants and may have a protective effect against cancer.
References
Boyle, M. and Long, S. Personal Nutrition. Belmont, CA: Wadsworth Cengage Learning. 2010.
Wardlaw, G. and Smith, A. Contemporary Nutrition. New York: McGraw-Hill. 2009.
“Phytochemicals.” Available at http://www.cancer.org/ Accessed in March 2012.
[1] Bioavailability is the extent to which a substance is absorbed by a specific tissue or organ after ingestion.