NUTRITION AND CANCER, 58(2), 146–152 Copyright C  2007, Lawrence Erlbaum Associates, Inc. Protein and Legume Intake and Prostate Cancer Mortality in Puerto Rican Men Ellen Smit, Mario R. Garcia-Palmieri, Nayda R. Figueroa, Daniel L. McGee, Mark Messina, Jo L. Freudenheim, and Carlos J. Crespo Abstract: Prostate cancer is the number 1 cancer killer among Puerto Rican (PR) men. Plant foods have been in- versely associated with prostate cancer. Legumes play a significant role in the PR diet; consumption of legumes in PR (14 lb/capita) was double that of the United States (7 lb/capita). We examined dietary protein consumption (from baseline 24-h dietary recalls) and prostate cancer mortality in the PR Heart Health Program, a cohort study of 9,824 men aged 35–79 years at baseline (1964) with follow-up un- til 2005. Total protein intake in the cohort was 85 g/day, and sources of protein were 30% vegetable, 30% dairy, 31% animal, and 8% seafood protein. Legume intake was 2.3 serv- ings/day (1/4 cup each). Legume intake was not associated with prostate cancer mortality [comparing highest quartile to lowest quartile—odds ratio (OR) 1.40 [95% confidence interval (CI) 0.91–2.18], P trend 0.17]—nor were total pro- tein, animal, seafood, dairy, or vegetable protein intakes. Consuming 1–2 servings of fruit was inversely associated (OR 0.50, 95% CI 0.32–0.77), whereas consuming more than 2 servings of fruit was not associated with prostate cancer mortality. Thus, we find no association between legumes or protein intake and prostate cancer mortality in this longitu- dinal cohort study of PR men. Introduction Puerto Ricans are the second largest group of Hispanics in the United States and have higher cancer mortality rates than all other Hispanic groups combined. Although prostate cancer mortality rates in Puerto Rico are similar to those observed in the United States, prostate cancer kills more men in Puerto Rico than any other cancer, including cancer of the lungs (1). Plant foods have been associated with a protection against prostate cancer in several epidemiological E. Smit and C. J. Crespo are affiliated with the School of Community Health, Portland State University, Portland, OR 97201. M. R. Garcia-Palmieri is affiliated with the School of Medicine, University of Puerto Rico, San Juan, PR 00936. N. R. Figueroa is affiliated with the Puerto Rico Central Cancer Registry, San Juan, PR 00936. D. L. McGee is affiliated with the Department of Statistics, Florida State University, Tallahassee, FL 32306. M. Messina is affiliated with the Department of Nutrition, School of Public Health, Loma Linda University, Loma Linda, CA 92350. J. L. Freudenheim is affiliated with the Department of Social and Preventive Medicine, University at Buffalo, Buffalo, NY. studies (2,3). More specifically, reduced prostate cancer risks have been associated with higher intakes of carotenoid-rich vegetables and soy products in Japan (4); higher intakes of beans, lentils, peas, and dried fruits among Seventh Day Adventist men (5) and higher tofu intake among Japanese men in Hawaii (6). Reduced mortality from prostate cancer has been also reported for men with higher intakes of cereals (7,8). Legumes include peas, beans, lentils, and peanuts and are a rich source of protein and dietary fiber. Beans and peas are staple foods of the Puerto Rican diet, particularly pinto, kidney, small white, black-eye and black beans, and green pigeon peas and chick-peas. Consumption of legumes in Puerto Rico (14 lb/capita) (9) is double that of the United States (7 lb/capita) (10). There is interest in the role that legumes may play in reduc- ing cancer risk, but the relationship between prostate cancer and legumes is not well established (3,11–13). In a small case control study (n = 60), Strom et al. (14) found that higher phytoestrogen intake was associated with a lowered risk of prostate cancer, but overall phytoestrogen intake was quite modest among the subjects in this study. In a meta-analysis of case-control studies in Canada, Jain et al. (3) reported re- duced risks of prostate cancer associated with intake of beans, lentils, and nuts. In a multicenter case control study that in- cluded African Americans, Whites, Japanese, and Chinese populations from the United States and Canada, the relation- ship between prostate cancer risk and intake from soy and non-soy legumes were studied separately. An inverse associ- ation between prostate cancer risk and non-soy legumes was found for African Americans but not for Whites, Japanese, or Chinese. However, soy foods were not significantly related to prostate cancer risk for any of the groups studied. Combin- ing all legumes into 1 category yielded significant protection against prostate cancer for African Americans and Chinese men but not for White or Japanese men (13).