Researcher Lesley M. Butler, Ph.D., assistant professor of epidemiology at Colorado State University, Fort Collins, Colo claims to be the first to reveal calcium consumption and prostrate cancer association among Chinese men in its former stage and mainly including non- dairy products. They were found to be more prone to prostrate cancer even with relatively low levels of calcium and from non-diary food sources such as soy, grains and green vegetables
It is anticipated that calcium in milk is the driving factor for prostrate cancer; however this finding is not really clear. Some studies conducted in North America and European populations alerted that there is a huge consumption of dairy products which enhance the chances of prostrate cancer.
It was identified that tofu, grains, vegetables such as broccoli, kale and bok choy which is famous among the Asians were the prime contributors of calcium. It was feared that greater exposure to these calcium rich foods would increase the risk of prostrate cancer as speculated by Butler and colleagues.
The study was conducted on 27,293 Chinese men aged 45 to 74 years, belonging to two major dialects. It included Chinese people living in Singapore namely the Hokkiens and the Cantonese. Information about the individuals was collected from the Singapore Chinese Health Study. This helped the researchers analyze if the dietary calcium with low dairy consumption had greater risk of prostrate cancer.
The participants were asked to complete a food questionnaire regarding their diet over the past year. It was identified on the basis of the questionnaire that 298 participants were affected with incident prostrate cancer.
The participant’s diet was taken as a baseline for the research conducted by Butler and colleagues at Colorado State University, the National University of Singapore and the University of Minnesota. The researchers reveal that calcium is absorbed more in smaller individuals. Therefore they accounted for body mass index (BMI) in this Chinese population
The outcome was that 25 percent of the population increased the possibilities of getting affected by prostrate cancer as compared to those who consumed a tolerable amount that is 659 mg vs. 211 mg of total calcium a day as per the study.
The main sources of food that increased calcium levels in this population were vegetables at 19.3 percent, dairy products at 17.3 percent and grain products at 14.7 percent. Soy foods had 11.8 percent chances of increasing calcium levels while fruits and fish figured in at 7.3 percent and 6.2 percent respectively. The researchers nevertheless emphasize that there was no direct relation of prostrate cancer with any particular food source. They noticed that men with less than average BMI had twofold increased risk of prostrate cancer.
“It was somewhat surprising that our finding was consistent with previous studies because nearly all of them were conducted among Western populations with diets relatively high in calcium and primarily from dairy food sources,” Butler said.
The findings of the study appeared to persuade more on calcium being the main factor that caused prostrate cancer as commented by Edward Giovannucci, M.D., Sc.D., professor of epidemiology and nutrition at Harvard School of Public Health, who is not associated with this study.
The experts suggest further analysis to better understand this association. This is mainly because the causes of prostrate cancer were first linked with low intake of calcium while most previous studies highlighted high intake of calcium might be the main reason. Moreover, associations were mostly found in lean men. These findings have to be confirmed says Butler. He mentions that more study needs to be conducted on possible roles of calcium as opposed to other dairy product components that increase the chances of prostrate cancer.
The results are published in Cancer Research, a journal of the American Association for Cancer Research