Reduction of prostate cancer risk by a few tablespoons of beans a day
Men who eat an average of three large tablespoons of peas, kidney beans or other legumes every day roughly halve their risk of prostate cancer. This is suggested by an epidemiological study published in the British Journal of Nutrition.
Study
Abou Diallo, a researcher at the French SERM, followed a group of 3,313 men between 1994 and 2007. The men were cancer-free when the study began. Diallo knew the diet of the men and divided the men into three equally sized groups [tertiles] on the basis of their intakes of vegetables, fruit and beans, among other things. He then kept track of which of them got prostate cancer. And who didn't.
Results
Diallo found no protective effect of fruits and vegetables. While there was a tendency for men to develop prostate cancer less often the more fruits and vegetables they consumed, there were no significant associations.
However, a high intake of peas and other legumes appeared to reduce the risk of prostate cancer. The number of men who developed prostate cancer in this study was small, but the association between legume intake and prostate cancer was nevertheless statistically significant.
Men who ate an average of more than 26.5 grams of legumes per day had a 47 percent lower risk of prostate cancer than men with a lower intake.
Research technical details about the data can be found here.
Mechanism
Diallo suggests several mechanisms that may explain how legumes might reduce the risk of prostate cancer. Perhaps the small amounts of phytoestrogens in beans are sabotaging the hormones that make prostate cancer cells grow, he writes.
The strongest phytoestrogens in our diet are those in soy. When Diallo brushed off the effect of soy consumption, legumes still protected against prostate cancer. So this is not the complete explanation.
Another possibility is that the fiber in beans, which slows the absorption of carbohydrates, is causing the effect. Some tumor types grow faster with high glucose levels. This is not the case for eighty percent of prostate cancer tumors.
Conclusion
"Our results suggest an inverse association between legume intake and prostate cancer risk, supported by mechanistic plausibility", writes Diallo.
"As very few prospective studies have been published on the topic, these results should be confirmed by large-scale observational and intervention studies."
Source:
Br J Nutr. 2016 May;115(9):1579-85.
Men who eat an average of three large tablespoons of peas, kidney beans or other legumes every day roughly halve their risk of prostate cancer. This is suggested by an epidemiological study published in the British Journal of Nutrition.
Study
Abou Diallo, a researcher at the French SERM, followed a group of 3,313 men between 1994 and 2007. The men were cancer-free when the study began. Diallo knew the diet of the men and divided the men into three equally sized groups [tertiles] on the basis of their intakes of vegetables, fruit and beans, among other things. He then kept track of which of them got prostate cancer. And who didn't.
Results
Diallo found no protective effect of fruits and vegetables. While there was a tendency for men to develop prostate cancer less often the more fruits and vegetables they consumed, there were no significant associations.
However, a high intake of peas and other legumes appeared to reduce the risk of prostate cancer. The number of men who developed prostate cancer in this study was small, but the association between legume intake and prostate cancer was nevertheless statistically significant.
Men who ate an average of more than 26.5 grams of legumes per day had a 47 percent lower risk of prostate cancer than men with a lower intake.
Research technical details about the data can be found here.
Mechanism
Diallo suggests several mechanisms that may explain how legumes might reduce the risk of prostate cancer. Perhaps the small amounts of phytoestrogens in beans are sabotaging the hormones that make prostate cancer cells grow, he writes.
The strongest phytoestrogens in our diet are those in soy. When Diallo brushed off the effect of soy consumption, legumes still protected against prostate cancer. So this is not the complete explanation.
Another possibility is that the fiber in beans, which slows the absorption of carbohydrates, is causing the effect. Some tumor types grow faster with high glucose levels. This is not the case for eighty percent of prostate cancer tumors.
Conclusion
"Our results suggest an inverse association between legume intake and prostate cancer risk, supported by mechanistic plausibility", writes Diallo.
"As very few prospective studies have been published on the topic, these results should be confirmed by large-scale observational and intervention studies."
Source:
Br J Nutr. 2016 May;115(9):1579-85.
