Prostate cancer is cancer that occurs in the prostate – a small walnut-shaped gland in men. The main function of the prostate is to produce a thick white fluid that creates semen when mixed with the sperm produced by the testicles, explained the NHS. While it is not known exactly what causes it, certain factors can increase a person’s risk of developing the cancer. Evidence has linked high calcium intake to an increased risk of developing the disease.
A study of 29,133 men in Finland found that those who consumed 2,000 mg of calcium or more daily had a marked increase in prostate cancer risk.
High consumption of dairy foods was also associated with an increased risk of the disease, which the researchers attributed to the calcium (or a closely related component) in those foods.
Worryingly, a study published in Cancer Research, a journal of the American Association for Cancer Research, found that among Chinese men, calcium consumption – even at relatively low levels and from non-dairy food sources such as soy, grains and green vegetables – may increase prostate cancer risk.
“Our results support the notion that calcium plays a risk in enhancing the role of prostate cancer development,” said lead researcher Lesley M. Butler, Ph.D., assistant professor of epidemiology at Colorado State University, Fort Collins, Colo.
She added: “This study is the first to report an association at such low levels and among primarily non-dairy foods.”
Some studies conducted in North American and European populations have linked high consumption of dairy products to an increased risk of prostate cancer.
A few studies have suggested that calcium in milk is the causative factor, however the evidence is not clear.
In an Asian diet, non-dairy foods like tofu, grains and vegetables such as broccoli, kale and bok choy are the major contributors of calcium intake. Therefore, Butler and colleagues speculated that people who are exposed to those calcium-rich food sources in an Asian diet may also be at increased risk for prostate cancer.
Using data from the Singapore Chinese Health Study, the researchers evaluated whether dietary calcium increased prostate cancer risk in a population of 27,293 Chinese men aged 45 to 74 years, with low dairy consumption.
The study was restricted to men who belonged to two major dialect groups of Chinese people living in Singapore: the Hokkiens and the Cantonese.
Participants completed a food frequency questionnaire to assess their diet over the past year. Of these men, 298 were diagnosed with incident prostate cancer.
Butler and colleagues at Colorado State University, the National University of Singapore and the University of Minnesota assessed the participant’s diet at baseline.
Since it is suggested that calcium is absorbed more so in smaller individuals, the researchers accounted for body mass index (BMI) in this Chinese population.
Results showed a 25 percent increased risk of prostate cancer when comparing those who consumed, on average, 659 mg versus 211 mg of total calcium a day, according to the study.
Major food sources of calcium in this population consisted of: vegetables (19.3 percent), dairy (17.3 percent), grain products (14.7 percent), soyfoods (11.8 percent), fruit (7.3 percent) and fish (6.2 percent). However, the researchers stress that there was no positive association with prostate cancer risk and any one particular food source.
Among men with less than average BMI (median BMI was 22.9 kg/m2), the researchers found a twofold increased risk of prostate 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.
According to the NHS, other risk factors include:
- Age – the risk rises as you a person gets older, and most cases are diagnosed in men over 50 years of age
- Ethnic group – prostate cancer is more common among men of African-Caribbean and African descent than in Asian men
- Family history – having a brother or father who developed prostate cancer before age 60 seems to increase a person’s risk of developing it; research also shows that having a close female relative who developed breast cancer may also increase a person’s risk of developing prostate cancer
- Obesity – recent research suggests there may be a link between obesity and prostate cancer, and a balanced diet and regular exercise may lower a person’s risk of developing prostate cancer
Published at Mon, 12 Aug 2019 11:57:00 +0000