Plant Based Diet Prevents Prostate Cancer

"Studies have associated the Western diet not only with prostate cancer incidence but also with a greater risk of disease progression after treatment," said Gordon A. Saxe, MD, PhD, lead author of the study and assistant professor of Family and Preventive Medicine at the Moores Cancer Center at the University of California, San Diego. "Conversely, many elements of plant-based diets have been associated with reduced risk of progression."

Prostate-specific antigen (PSA) is a marker for prostate cancer recurrence and often the earliest sign of spread of the disease beyond the prostate gland, even in people with no symptoms. Saxe and colleagues conducted a six-month preliminary study to investigate whether a plant-based diet, reinforced with stress-management training, could prevent or lessen a rise in PSA among ten men with recurrent prostate cancer.

The men and their spouses or other support person participated in intensive group and individual diet and stress-reduction trainings. They were taught to shift their diet to more whole grains, vegetables, fruit, and legumes and to eat less meat, dairy, and refined carbohydrates (such as white rice, white flour, and sugar). The people took cooking classes, participated in group discussions, and were counseled regarding calorie intake (1,600 calories per day) and portion sizes.

Compared with the rate of PSA rise in the pre-study period, there was a significant reduction on the rate of rise throughout the intervention period. Nine of the ten men had a slower progression of PSA levels. Four of the ten men had a lower PSA level than when they started the diet. The time it took the men's PSA levels to double increased nearly tenfold over six months, suggesting a strong protective effect.

Prostate cancer is the second most common cancer affecting men in the Western world after skin cancer. About 35% of men who are treated for the disease will experience a recurrence within ten years. These men are at higher risk for life-threatening metastases. Prevention of such recurrences is, therefore, an essential element of therapy. Unfortunately, the conventional treatments to prevent recurrence, such as hormone therapy, cause many undesirable side effects, such as hot flashes, loss of libido, and loss of bone mass.

"These findings have significant therapeutic potential for recurrent prostate cancer," concluded Dr. Saxe. "A natural dietary- and lifestyle-based approach may serve as an adjunct or alternative to hormonal therapy."

More and more medical studies indicate that the antioxidants in vegetables, particularly tomatoes and broccoli, can lower prostate cancer risk, while foods with animal fats increase risk. While ongoing studies are still assessing the value of antioxidant supplements, food scientists say they are already comfortable advocating that men eat a more vegetable-based diet to lower their risk of prostate cancer, not to mention heart disease and colon cancer.

There is also growing observational evidence that both tomato and broccoli consumption helps reduce risk of prostate cancer. In the tomato products, attention has focused on nutrients called carotenoids, particularly lycopene. Lycopene is the major red carotenoid pigment found in tomatoes. In broccoli, a number of sulfur compounds are thought to detoxify carcinogens. Both of these are thought to benefit prostate health. Nutritionist familiar with prostate health recommend seven to ten servings of tomatoes and tomato based products a week, which is still only one serving a day. When counting tomato juices and raw tomatoes and ever popular pasta products, it is not difficult to reach this level. In fact, most men get more than one serving when they consume pasta or even pizza. It's that easy.

Preparation matters! Carotenoids are very poorly absorbed from raw foods, so some heating really helps bring out the benefits. Consumption with a little healthy fat helps, too. For example, take beta-carotene from carrots. Eating a carrot raw leads to 1 or 2 percent beta-carotene absorption. Steaming those carrots a little bit and add a little bit of oil in there, you'll get much more absorption of the beneficial carotenoids. The same is true for tomatoes. By overcooking tomatoes, for example, by simmering a tomato sauce for hours, you'll begin to break down the lycopene. However, everything should be in moderation.

Nutrients in foods can lower risk of prostate cancer. In observational studies and clinical trials there are suggestions that higher consumption of vitamin E and selenium lower prostate cancer risk. Vitamin E is found in basic plant foods, including nuts, vegetables, vegetable oils, as well as egg yolks. Vitamin E is also in most breakfast cereals because it is added when manufacturers fortify it. The metallic trace element selenium comes into plants from the soil, so it's in grains such as wheat, barley, hops, and rice. There is also some selenium from animal foods products, that is because animals also consume these grains.