Eating lots of cheese and butter may raise your risk of prostate cancer, research suggests.
Scientists analyzed data from 47 studies which looked at the diet of more than one million men.
They found that those who regularly consumed dairy products such as milk and cheese were between 7 and 76 percent more likely to develop prostate cancer. Those who ate a vegan diet, meanwhile, saw their chances fall by around 20 percent.
Experts believe the link may be driven by calcium and growth hormones triggered by dairy consumption, both of which have been linked to prostate tumors. It may also explain why rates of the disease are higher in the West compared to Asian countries, where dairy intake is much lower.
Lead researcher Dr. John Shin, from Mayo Clinic in the US, said: "Our review highlighted a cause for concern with high consumption of dairy products.
"The findings also support a growing body of evidence on the potential benefits of plant-based diets."
The study, published in the Journal of the American Osteopathic Association, found no clear link of increased prostate cancer risk with other animal-based foods, including red, white and processed meat, fish and eggs.
But experts said it is too soon to advise men to abandon dairy completely. Tom Sanders, of King’s College London, said: "This review suffers from a number of weaknesses... that do not justify the strong conclusions drawn regarding dairy product consumption and risk of prostate cancer."
He said being overweight is a much stronger risk factor – and that vegans’ lower risk could be explained by the fact they are usually slimmer.
Professor Sanders added: "The prevalence of prostate cancer has increased markedly in south-east and east Asia... which would indicate that lifestyle factors, other than dairy food consumption, are responsible for the global epidemic prostate cancer."
Dr. David Montgomery, of charity Prostate Cancer UK, said: "This paper has reviewed some of the previous studies which looked at whether certain foods have an impact on prostate cancer risk.
"The previous studies are of variable quality and have not consistently taken account of other factors... that could impact the results.
"We would not encourage anyone to avoid or increase intake of certain foods as a result of this study. What we do know is that being overweight may increase your risk of being diagnosed with aggressive or advanced prostate cancer. Eating a healthy, balanced diet and keeping physically active can help you stay a healthy weight.
"The main risk factors that men should be mindful of include being over 50, of black ethnicity, or having a family history of the disease, and anyone who has concerns about their risk should discuss this with their GP."