The Importance of Getting a High Dietary Intake of Carotenoids
Lets connect some cancer-prevention dots...
- Lymphocytes are key immune-system cells they produce antibodies that attack cancerous cells.
- Lymphocytes malfunction when oxidation damages cell DNA.
- When this mechanism that regulates cell growth is ineffective, the stage is set for the development of cancer and other chronic diseases.
- Population-based studies have indicated that antioxidant-rich carotenoids in fruits and vegetables might reduce cancer risk.
- A new study demonstrates how carotenoid supplements may protect lymphocyte cells from DNA damage.
Damage control
In several e-Alerts Ive stressed the importance of getting a high dietary intake of carotenoids: the organic plant pigments that have been shown to help control inflammation.
Researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging recently teamed up with scientists at the Tufts University School of Medicine in Boston to measure the effect of carotenoid supplements on lymphocytes.
Nearly 40 healthy postmenopausal women over the age of 50 (all non-smokers) were divided into five groups to receive either a placebo or one of these daily supplement regimens:
- Beta-carotene, lutein and lycopene (4 mg of each
carotenoid) - Beta-carotene only (12 mg)
- Lutein only (12 mg)
- Lycopene only (12 mg)
Blood samples were assessed for carotenoid concentrations throughout the eight-week test period. The condition of lymphocyte DNA for each subject was determined with a common technique for detecting DNA damage known as comet assay.
Results were striking. All four of the supplement groups showed significantly lower DNA damage compared to damage levels recorded at the outset of the study, but the placebo group showed no significant change in DNA damage. In the mixed supplement group and the beta-carotene group, DNA damage was reduced after just
15 days.
Writing in the American Journal of Clinical Nutrition, the researchers note that the supplement levels used to produce DNA protection can be achieved through diet alone.
Todays specials
Beta-carotene (a precursor of vitamin A) is abundant in dark green leafy vegetables, colourful orange vegetables and fruits such as carrots, pumpkins, squash, sweet potatoes, peaches, apricots, cantaloupe melons and mangoes.
Lutein has been shown to support vision health and helps prevent age-related macular degeneration. Good sources of lutein include spinach, eggs, broccoli, carrots, tomatoes, oranges, lettuce and celery.
Lycopene (found mostly in tomatoes and watermelon) is a powerful antioxidant that promotes heart health and has been shown to reduce the risk of prostate cancer.
If you eat a good mix of all these foods youll be getting a variety of carotenoids, including zeaxanthin, alpha carotene and others. And the key word here is variety. As Amanda Ross noted in a 2005 issue of her Health e-Tips e-letter: Based on the results of numerous studies, its becoming more and more clear that carotenoids function similarly to the B-complex of vitamins in that theyre more powerful together than they are alone. Which is why a rich diet with a full array of carotenoids may provide more health benefits than isolating and supplementing with any one individually.
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