Information Sheet 12: Legumes (Pulses)
Key Points
‐ There is limited evidence that eating legumes, particularly soy foods, reduces the risk of prostate cancer ‐ Examples of legumes: o Soy foods, beans, chickpeas, lentils, peas, peanuts
Introduction Eating legumes, particularly soy foods, may protect against prostate cancer and stomach cancer [1]. The association between eating legumes and lower prostate cancer risk is stronger in Asian populations than Western populations [2]. This may reflect the higher consumption of legumes in Asian populations.
The benefits of eating legumes are attributed to their high content of isoflavones, which have been shown to inhibit prostate cancer growth in animal models and inhibit prostate cancer cell growth in the laboratory [3].
Legumes Legumes are most commonly consumed in Latin American, Middle Eastern and Asian countries. They are a rich source of many nutrients which may have protective effects against cancer [1]. The most widely researched are isoflavones, particularly genistein and daidzein [3]. Soy beans have the highest content of isoflavones and are more strongly associated with a lower prostate cancer risk than other legumes [1].
Common Types of Legumes Legume [1] Examples [1] ‐ Soy bean ‐ Tofu ‐ Soy milk ‐ Soy sauce ‐ Miso ‐ Soy bean oil ‐ Other beans ‐ Baked beans ‐ Kidney beans ‐ Cannellini beans ‐ Bean sprouts ‐ Refried beans ‐ Chickpeas ‐ Hummus ‐ Falafel
‐ Lentils ‐ Soup ‐ Salads ‐ Dahl
‐ Peas ‐ Soup ‐ Mixed vegetables
Summary of Research There is limited evidence that legumes, including soy foods, protect against prostate cancer. The evidence is stronger in populations with higher soy intake [3, 4].
While a few studies have found a significantly decreased risk of prostate cancer, many studies have found no association. This may be because most studies are conducted in Western countries and have limited power because populations in Western countries tend to have low consumption of legumes, particularly soy foods [1].
In a meta‐analysis of 14 studies, high consumption of soy foods was associated with a 26% reduction in prostate cancer risk. Analysis of separate soy foods found that high consumption of tofu and soy milk was associated with a 30% reduction in prostate cancer risk [3]. However, another meta‐ analysis only found a significant association with consumption of tofu and not soymilk [5]. This suggests that consumption of soya foods, particular tofu, may decrease the risk of prostate cancer.
The potential benefits of eating soy foods may be due to its high content of isoflavones. A major isoflavone, genistein, inhibits prostate cancer growth in animal models and inhibits prostate cancer cell growth in the laboratory. In a 2009 meta‐analysis, isoflavone was associated with a significant reduction in prostate cancer risk in Asian populations but not in Western populations. This may reflect the differences in isoflavone intake between these two populations [3].
References 1. World Cancer Research Fund / American Institute for Cancer Research, Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective http://discovery.ucl.ac.uk/4841/1/4841.pdf. 2007, Washington DC: AICR. 2. Giovannucci, E., et al., A prospective study of cruciferous vegetables and prostate cancer. Cancer Epidemiology, Biomarkers & Prevention, 2003. 12(12): p. 1403‐9. 3. Yan, L. and E.L. Spitznagel, Soy consumption and prostate cancer risk in men: a revisit of a meta‐analysis. The American journal of clinical nutrition, 2009. 89(4): p. 1155‐1163. 4. Kurahashi, N., et al., Soy product and isoflavone consumption in relation to prostate cancer in Japanese men. Cancer Epidemiology, Biomarkers & Prevention, 2007. 16(3): p. 538‐45. 5. Hwang, Y.W., et al., Soy food consumption and risk of prostate cancer: a meta‐analysis of observational studies. Nutrition and cancer, 2009. 61(5): p. 598‐606.