Too much dietary calcium can increase the risk of developing prostate cancer, according to an 11-year study recently completed by researchers from Harvard University Medical School.

Dietary and lifestyle data from 20,855 male physicians was used in the study, and 1,012 men developed prostate cancer. Researchers focused on dairy intake as a possible explanation for the figures and created a daily dairy score for each participant, marked in relation to calcium intake through five common dairy foods; whole milk, skim milk, ice cream, cold breakfast cereal and cheese.

The study found a correlation between the incidence of prostate cancer and dairy intake, with participants facing a 34% greater risk of developing the disease if they were among the top 20% dairy consumers.

The researchers concluded: “These findings may serve to interject a note of caution into the current enthusiastic promotion of a higher intake of calcium in the US.”

Dr. June Chanl, lead author of the report, told HealthWorld however: “This is a ‘head’s up’ rather than the sounding of an alarm.”