Monday, April 21, 2008

Very-Low-Fat Vegan Diet May Offer Cancer Protection

This article can be found at the Cancer Monthly website.

There’s yet another reason to pass on the meat and potatoes and instead fill your plate with fruit, vegetables, and whole grains. New research from the Preventive Medicine Research Institute in Sausalito, California, finds that a very-low-fat vegan diet is packed with protective nutrients that may help ward off prostate cancer, as well as other diseases.

Ninety-three men with early-stage prostate cancer took part in the one-year study. The men were randomly assigned to eat either a vegan diet in which only 10 percent of their calories came from fat, or to continue eating their regular diet.

The vegan diet focused on whole-grains, fruits, and vegetables, while avoiding oils, margarines, high-fat foods such as nuts and chocolate, and processed foods. Although meats and refined foods have become staples of the modern Western diet, the vegan plan followed in this study is actually more of “a traditional diet in terms of how our ancestors ate,” says study author Gerdi Weidner, PhD, Vice President and Director of Research at the Institute. Study co-author Dean Ornish, MD, founder and president of the Institute, is a big proponent of the very-low-fat diet for disease prevention, and has written several books on the subject.

Prostate cancer patients who followed the diet also ate fortified soy protein powder and tomato-based vegetable juice, which contain phytochemicals believed to slow prostate cancer growth. As part of the lifestyle intervention, the men also exercised and participated in stress management and social group support programs. Meanwhile, the control group continued their regular diet and lifestyle program under their doctor’s care.

The group that followed the very-low-fat vegan diet decreased their consumption of substances thought to increase the risk of disease, including saturated fat, which has been linked to a higher risk of prostate, breast, and colon cancers. At the same time, they ate more of several nutrients thought to protect against disease, including:
  • Fiber (lowers risk of heart disease, type 2 diabetes, colorectal cancer, and death in general)
  • Vegetable protein (may protect against cancers of the breast, colon, and prostate)
  • Vitamin E (may reduce the risk of prostate and other cancers)
  • Folate (protects the heart, and may help prevent prostate and other cancers)
  • Selenium (lowers the risk and slows progression of prostate cancer)

The study didn’t investigate whether these nutrients actually slowed prostate cancer progression or increased participants’ survival, but “the entire program was found to be beneficial for the patients,” Dr. Weidner says. An earlier study by the same researchers did find an improvement in prostate-specific antigen (PSA) levels (a marker of prostate cancer progression) in men who followed a vegan diet and incorporated other lifestyle techniques.

Based on the results of this and other research, it appears that eating a very-low-fat vegan diet can provide some protection against not only prostate cancer, but other types of diseases as well, according to Dr. Weidner.

For those interested in following a program like this, please discuss with your doctor.

Sources:

Dewell A, Weidner G, Sumner MD, Chi CS, Ornish D. A very-low-fat vegan diet increases intake of protective dietary factors and decreases intake of pathogenic dietary factors. J Am Diet Assoc. 2008;108:347-356.

Ornish D, Weidner G, Fair WR, Marlin R, Pettengill EB, Raisin CJ, et al. Intensive lifestyle changes may affect the progression of prostate cancer. J Urol. 2005;174:1065-1070.

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