A new study confirms the suspicion that increasing vegetable intake lowers the risk of developing aggressive prostate cancers – the kind that spread beyond the prostate into surrounding tissues. (Kirsh VA, et al., Prospective study of fruit and vegetable intake and risk of prostate cancer. J Natl Cancer Inst. 2007 Aug 1;99(15):1200-9.)
In this study of 29,361 men over four years, those who consumed more than one serving per week of cruciferous vegetables (broccoli, cauliflower, Brussels sprouts, and cabbage) reduced their risk by 59 percent, compared to those men who ate these vegetables less than once per month. They did not find an overall lower incidence of prostate cancer, only fewer aggressive ones.
Cruciferous vegetables, also known as the Brassica family, include other vegetables as well, such as kale, collards, broccoli rabe (rapini), turnip greens, mustard greens, bok choy, Chinese cabbage, mizuna, tat soi, and others. Non-brassica cruciferous veggies include arugula, radish, watercress, daikon, and horseradish.
While this study did not show an overall reduction in prostate cancer incidence, I suspect that the reason is their inclusion of anyone over one serving per week in the “high-intake” category. I am curious whether a truly high intake would be more like 3 to 6 servings per week, and whether that level, would indeed lower overall prostate cancer incidence. They are known to reduce lung and colorectal cancer, as well as breast cancer.
Cruciferous vegetables contain sulfur compounds, such as indole-3 carbinol and phenethylisothiocyanates, (glucosinolates) that are known to reduce cancer risk, and other beneficial phytochemicals. These help by reducing DNA damage and by favorably modifying hormone metabolism. They are also rich in vitamin C, fiber, folic acid, vitamin K, and fiber, and contain some omega-3 fatty acids. In addition, broccoli, for example, contains 6 gms of protein for every 50 calories (for comparison, 50 calories from ground beef contains only 4 gms of protein).
Vitamin C and other antioxidants provide important protection against free-radical damage to DNA and cell membranes, and this may be part of the reason that they appear to reduce the risk of cancer. However, this is not their only benefit. Researchers have shown that in mice implanted with human cancer cells, the antioxidants vitamin C and N-acetylcysteine also inhibit the growth of the tumors. (Gao P, et al., HIF-Dependent antitumori-genic effect of antioxidants in vivo. Cancer Cell. 2007 Sep;12(3):230-8.)
The antioxidants apparently reduce the level of a substance that protects tumor cells from attack, and this effect results in growth inhibition.
This information is an important addition to our understanding of how nutrients can work in many different ways. Unlike side effects of drugs, the unexpected effects of nutrients are almost always beneficial. The researchers suggested that this effect might also block colon cancer and cervical cancer growth.
For some inexplicable reason, the researchers cautioned(!) against taking large doses of vitamin C. Increasing evidence supports the value of very high doses of vitamin C in cancer prevention and treatment, as was reported by Linus Pauling decades ago. His position is now being vindicated by the latest research.
Lutein and zeaxanthin are two antioxidant carotenoids that appear to protect the retina from age-related decline. These nutrients are plant pigments that protect the plants and impart to them a yellow to yellow-orange color. A study of 4519 subjects from 60-80 years old showed that over six years, those with the highest level of consumption of these two nutrients had a 35 percent lower risk of macular degeneration than those with the lowest level of intake. (SanGiovanni JP, et al., The relationship of dietary carotenoid and vitamin A, E, and C intake with age-related macular degeneration in a case-control study: AREDS Report No. 22. Arch Ophthalmol. 2007 Sep;125(9):1225-32.) Some of the atrophic retinal changes were reduced by 65 percent.
Lutein and zeaxanthin are found in dark green vegetables such as spinach and broccoli, corn, peas, zucchini (good for gardeners to know in this harvest season), eggs, and romaine lettuce. Supplements of lutein are often derived from the yellow pigment in marigolds, and they usually contain small amounts of zeaxanthin.
The Mediterranean diet appears to provide relief for arthritis sufferers. Patients with rheumatoid arthritis, an autoimmune inflammatory condition of the joints, improved when they were instructed in the benefits of the diet that is rich in fruits, vegetables, beans, fish, and olive oil, and low in red meat and saturated fat. (McKellar G, et al., A pilot study of a Mediterranean-type diet intervention in female patients with rheumatoid arthritis living in areas of social deprivation in Glasgow. Ann Rheum Dis. 2007 Sep;66(9):1239-43.)
Researchers instructed 75 women from 30 to 75 years old with hands-on classes in food preparation for two hours a week for six weeks, backed up by written instructions. Another 55 women were given written instructions only, and all the women were evaluated at the start of the study and again at three and six months for food intake, arthritic symptoms, and overall health assessment.
The women who were given the hands-on classes increased their fruit, vegetable, and legume consumption, and improved the ratio of their intake of monounsaturated oils to saturated fat. The subjects who received only the written instruction did not improve their diets, suggesting the importance of specific instruction rather than just a handout without support.
Symptoms were markedly reduced in the intervention group; their pain score and stiffness were both significantly better and the overall assessment was improved. In addition, the systolic blood pressures were better in this group. The control group had no change in symptoms or blood pressure or their overall health assessment.
Vitamin E has anti-inflammatory, antioxidant, and anti-platelet effects, all of which serve to reduce risks of heart disease, cancer, and inflammatory disorders. A new clinical study shows that supplements of vitamin E help to prevent blood clots in the veins, also called venous thromboembolism, or VTE. (Glynn RJ, et al., Effects of random allocation to vitamin E supplementation on the occurrence of venous thrombo-embolism: report from the Women's Health Study. Circulation. 2007 Sep 25;116(13): 1497-503.)
VTE can lead to strokes and lung blood clots with potentially lethal consequences. Researchers evaluated 39,686 women in the Women’s Health Study, half of whom were given 600 IU of vitamin E on alternate days, and half a placebo. Over 10 years, the vitamin E group had a 21 percent lower risk of VTE than the control group (perhaps they should have taken their vitamin E every day to further lower the risk).
Among the subgroup of women who had a prior history of VTE, the benefits were even greater. Those vitamin E takers had a 44 percent reduced risk of recurrence of the VTE during the same time period. A specific subgroup of women with a genetic propensity to excessive blood clotting had a 49 percent reduction in risk.
Nonetheless, Reuters Health reported that the American Heart Association does not recommend vitamin E supplements to reduce cardiovascular risks. Perhaps the scientific data is not adequately confirmed, but considering the high safety profile of vitamin E, who wants to wait for perfect proof?
Even mild exercise is beneficial when it comes to preventing diabetes. Japanese researchers studied 8600 men who worked for the same company, and evaluated the amount of walking they did to get to work, and then followed them for four years.
The study found that those who walked 21 minutes or more per day to get to work had a 25 percent lower risk of developing diabetes than those who reported walking less than 10 minutes per day. (Sato KK, et al., Walking to work is an independent predictor of incidence of type 2 diabetes in Japanese men: the Kansai Healthcare Study. Diabetes Care. 2007 Sep;30(9):2296-8.)
Exercise improves insulin sensitivity and helps with weight control, both of which are potential contributors to the prevention of diabetes. Of course, exercise has numerous other benefits in prevention of heart disease, improving sleeping patterns, increasing energy and bone density, and elevating mood, and as this study shows, any extra activity helps.
The value of lifestyle changes (diet and exercise) in the prevention and management of diabetes is even more important in light of a recent report on two commonly prescribed diabetes medications, Avandia (rosiglitazone) and Actos (pioglitazone). This meta-analysis of other studies on 14,291 patients taking these drugs showed that they had double the risk of developing heart failure and a 42 percent greater risk of heart attacks compared to those not taking the drugs. (Singh S, et al., Long-term risk of cardiovascular events with rosiglitazone: a meta-analysis. JAMA. 2007 Sep 12;298(10):1189-95.)
Surprisingly, the cardiac risks were present even in younger patients, within a very short time (26 months on the drugs), and even at low doses. Lifestyle changes are free of side effects, and unlike the medications, they are without cost.
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