IRVINE, Calif., Jan 11, 2005 (BUSINESS WIRE) -- Research findings published in this month's issue of the Journal of Nutritional Biochemistry indicate that nutrients in avocados can work together to inhibit the growth of prostate cancer cells. The analysis was conducted at UCLA where researchers discovered that avocados are the richest source of lutein among commonly eaten fruits. Lutein is a carotenoid that acts as an antioxidant and has been linked to a reduced risk of prostate cancer in previous studies(1)(2).
According to Dr. David Heber, director of the UCLA Center for Human Nutrition and author of "What Color Is Your Diet?" (Harper-Collins, 2002), the study focused on inhibition of human prostate cancer cell growth when exposed to an extract of whole avocado fruit versus treatment with pure lutein. UCLA lab tests showed that when avocado extract was added to two lines of prostate cancer cells, cell growth was inhibited by up to 60 percent, whereas purified lutein alone was ineffective. Thus, the tests indicated that the family of compounds in avocados produced the observed effect.
"What's really exciting about this study is that the results indicate that the carotenoids, vitamins, and diverse compounds in California avocados might have additive or synergistic effects against prostate cancer compared with pure lutein alone," said Heber. "Our results suggest that further studies should be done to investigate the effects of the naturally occurring combinations of thousands of different bioactive substances (called phytonutrients) found in avocados and other plant foods."
Traditionally, lutein has been found in green vegetables such as parsley, celery and spinach but was recently discovered in the avocado fruit. In fact, research shows that avocados are the highest fruit source of lutein among the 20 most frequently consumed fruits. In addition to the new prostate cancer findings, lutein is also known to protect against eye disease such as cataracts and macular degeneration, the leading cause of blindness in the elderly.
Studies from around the world have shown that individuals eating 400 to 600 grams per day (over one pound) of fruits and vegetables reduce their risk of certain cancers by 50 percent. Heber supports this theory in his book "What Color Is Your Diet?," advising at least one serving per day of colorful fruits and vegetables from each of seven different color groups organized according to their contents of major groups of phytonutrients. These phytonutrients may help explain the association between eating a diet rich in colorful fruits and vegetables and a reduced risk of common chronic diseases of aging including common forms of cancer, diabetes, blindness, and age-related declines in mental function.
California avocados fall in the green-yellow group and contain such vital nutrients as vitamin E, which helps "mop up" free radicals that can damage cells and lead to disease; glutathione, which functions as an antioxidant like vitamin E; beta-sitosterol, which helps lower blood cholesterol; and lutein, recently linked to prostate cancer and eye disease prevention.
California avocados are naturally cholesterol-free and contain heart-healthy mono-unsaturated fats. Ounce for ounce, California avocados contain more fiber, thiamin, riboflavin, niacin and folate than any other commonly eaten fruit. For more information, visit www.avocado.org.
(1)Jain L, Du CF, Lee AH, Binns CW. "Do Dietary Lycopene and Other
Carotenoids Protect Against Prostate Cancer?" Int J Cancer
(2)Lu QY, et al. "Inverse Associations Between Plasma Lycopene and
Other Carotenoids and Prostate Cancer." Cancer Epidemiol Biomarkers