As I discuss in my video The role of soy foods in the prevention and treatment of prostate cancer, a compilation of 13 observational studies of soy food consumption and prostate cancer risk found that soy foods appear to be “protective”. What are observational studies? In contrast to interventional studies, researchers in observational studies watch what people eat, but do not intervene and try to change their diet. In these studies, they observed that men who ate more soy foods had less prostate cancer, but the problem with observational studies is that there might be confusing factors. For example: “People who choose soy also make other lifestyle choices that lower their risk of cancer (e.g. lower fat intake, higher intake of vegetables and fruits, more exercise). Maybe that’s why they have less cancer. Most studies have tried to control these other lifestyle factors, but you cannot control everything. In addition, most of the studies were carried out in Asia. Perhaps consuming tofu is just a sign of a more traditional diet. Is it possible that non-tofu consumers have more cancer because they gave up their traditional diet? If only we could look at a Western population who ate a lot of soy. We can: the Seventh-day Adventists.
In the 1970s there were more than 12,000 Adventists asked on their use of soy milk and then followed up for up to 16 years to see who got cancer and who did not. So what did you find? Frequent consumption of soy milk has been linked to a whopping 70 percent reduction in prostate cancer risk, as you can see in my article at 1:33 Video. Similarly, soy was ingested in a multi-ethnic study that included multiple groups appeared Protection in Latinos too.
Prostate cells wear Beta-type estrogen receptors that appear to act as a tumor suppressor, a kind of “gatekeeper … which inhibits invasion, proliferation and … prevents the prostate cells from becoming cancerous. And those are the receptors targeted through the phytoestrogens in soy, such as genistein, which inhibits prostate cancer cell invasion and spreads in a petri dish in the amount that soy foods might consume. Preventing metastasis is vital because death from prostate cancer is not caused by the original tumor but spreads throughout the body explained why it is “recommended that men with prostate cancer consume soy foods like soybeans, tofu, miso, and tempeh.”
Wait a moment. Dean Ornish and his colleagues have amazing results, apparently reverse the progression of prostate cancer with a herbal diet and lifestyle program. Was it because of the soy? Their study included not only a vegan diet, but also a vegan diet supplemented with a daily serving of tofu and a soy protein isolate powder. There are studies showing that men were given soy protein powder develop less prostate cancer than control group, but what did control group get? Milk protein powder. Those randomized to the milk group had six times more prostate cancer than the soy group. But was that due to the beneficial effects of soy or the harmful effects of milk? Dairy products are not just associated with to get Prostate cancer, but also with To die of prostate cancer. Men diagnosed with prostate cancer who then ate more milk tended to die earlier, and “both low-fat and high-fat milk consumption were positively associated with an increased risk of fatal outcomes.”
The best study we have on soy protein powder supplementation for prostate cancer patients found no substantial benefit and neither did a range of soy phytoestrogen supplements. But maybe that’s because they used isolated soy components instead of a whole soy food. “The whole foods approach may be more effective,” but it can be difficult to conduct controlled trials of whole foods: they can make counterfeit pills, but how do you give people placebo tofu?
A group of Australian researchers creative came with a specially made bread that contains soy grains to compare it to a regular placebo bread gave Discs for men diagnosed with prostate cancer waiting for surgery. As you can see in mine at 4:31 am Video, She saw A remarkable difference in just three weeks. It was the first study to show that a whole soy-based diet can positively affect prostate cancer markers, but you can’t just buy soy bread. Another study was a little more practical. Twenty men with prostate cancer who had been treated with radiation or surgery but appeared to be relapsing were asked drink three cups of regular soy milk a day. The PSA levels in each of the 20 patients were all increasing before starting the soy milk, they suggested that they were growing recurrent or metastatic cancer. During one year of drinking soy milk, 6 of the 20 subjects got better, 2 got worse, and the remaining 12 stayed the same as you can see from 5:02 in mine Video. So that you completed that soy foods can help a subset of patients.
Based on all of these studies, the results of Ornish and his colleagues have were likely due to more than just the soy. Similarly, the low rates of prostate cancer in Asia are likely not solely due to soy, as the lowest rates are also found in parts of Africa, where I don’t think they eat a lot of tofu. In the multiethnic study, other types of beans were used in addition to soy appeared Protection for Latinos and all groups combined when considering the most aggressive forms of prostate cancer. Therefore, the protection associated with plant-based diets may come from eating a variety of healthy foods.
This soy milk status from the Adventist study is astonishing. What about fermented soy foods? That was the subject of Fermented or Unfermented Soy Foods for Prostate Cancer Prevention?.
Reverse Cancer Progression? See How not to die of cancer.
Given the power of diet, I am amazed at how difficult it is Diet change in a man after being diagnosed with prostate cancer may be. However, it is not all or nothing. Check out Prostate Cancer Survival: The A / V Ratio.
For information on soy and breast cancer survival, see Is Soy Healthy For Breast Cancer Survivors?.
Michael Greger, MD
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