By Jeremy Appleton, ND, CNS
Healthnotes Newswire (November 2, 2006)—Over the past decade, a flood of research has demonstrated health benefits from tomatoes and tomato products, such as tomato juice, tomato sauce, and even ketchup. The best evidence suggests that the antioxidant lycopene (a relative of beta-carotene) may be the key ingredient in tomatoes responsible for decreased risk of cardiovascular diseases and several types of cancer. However, as with other foods, the temptation to identify a single health-promoting ingredient can lead to misguided supplementation of that nutrient alone, when the true benefit comes from eating the whole food.
“Tomatoes are a valuable source not only of lycopene but of several other nutrients including carotenoids, polyphenols, potassium, folate, vitamin C, and vitamin E,” said Dr. Victorine Imrhan of the Department of Nutrition and Food Sciences at Texas Women’s University. Dr. Imrhan and a colleague recently published a review of research on lycopene in the European Journal of Clinical Nutrition. “Lycopene, the main antioxidant in tomato products, contributes to the health-protective effects of tomato products, but its role as a single nutrient has not been determined.”
Many of the nutrients in tomato products provide health benefits of their own, and their interaction with each other and with lycopene is sometimes difficult to assess. Cooking and other ingredients in a tomato dish influences tomatoes’ health effects in the body. For example, cooking tomato products is known to enhance lycopene absorption, particularly when they are eaten along with dietary fats. Also, constituents in the tomato peel may make lycopene more available to the body
Lycopene, one of the most powerful antioxidants in food, protects the body’s various molecules (DNA, proteins, fats, and cholesterol) from becoming damaged by unstable free radicals. By preventing LDL (“bad”) cholesterol from being oxidized, lycopene can prevent one of the key steps that leads to hardening of the arteries (atherosclerosis). It has also been shown in laboratory studies to prevent the body’s cells from undergoing excessive growth and abnormal transformation, thus potentially helping to prevent cancer (breast, stomach, prostate, lung) and diseases like benign prostatic hyperplasia.
Although laboratory research shows promise for lycopene as an individual supplement, most animal and human studies have only demonstrated its benefits in the form of whole tomato products. Population studies have shown an association between lycopene and disease protection, but that association is almost always due to consumption of lycopene-containing foods, not supplements.
Tomatoes account for 85% of the lycopene in the standard American diet. Watermelon is another source. Eating two to four servings per day of tomato-containing foods (such as, tomato soup, tomato juice, tomato puree, and tomato paste) will significantly raise the level of lycopene in the body and will supply the recommended daily intake of 35 mg. The increase in lycopene levels is most pronounced when the tomato products are eaten along with dietary fats, like olive oil or avocado.
“In light of recent clinical trials, a combination of naturally occurring antioxidants, including lycopene, in foods is a better approach to disease prevention and therapy than a single nutrient,” said Dr. Imrhan. “Lycopene has shown distinct antioxidant and anticancer effects at the cellular level, but until more is known, health benefits are best obtained from eating lycopene-rich foods.”
(Eur J Clin Nutr 2006 Aug 16 [e-pub ahead of print])
Jeremy Appleton, ND, CNS, is a licensed naturopathic physician, certified nutrition specialist, and published author. Dr. Appleton was the Nutrition Department Chair at the National College of Naturopathic Medicine, has served on the faculty at Bastyr University of Natural Health Sciences, and is a former Healthnotes Senior Science Editor and a founding contributor to Healthnotes Newswire. He has worked extensively in scientific and regulatory affairs in the supplement industry and is now a consultant through his company Praxis Natural Products Consulting and Wellness Services.
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