Nutrition Notes: Obesity, Diabetes and Prostate Cancer: What’s the Link?

The new findings are particularly interesting because men who have diabetes – a disease usually marked by excess weight and high insulin levels – seem to be at reduced risk of developing prostate cancer. Data from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, which followed more than 33,000 men for almost nine years, were released earlier this year and noted that men who had diabetes showed a 20 percent lower risk for non-aggressive, early stage prostate cancers.

These findings might seem to contradict theories that high levels of insulin – often associated with diabetes – can promote growth of prostate cancer. Why then, might diabetes show an opposite protective effect? For starters, high insulin levels due to insulin resistance usually develop years before the most common form of diabetes is diagnosed. In the years after diagnosis, insulin levels may start to fall.

The new study, published in the Lancet Oncology, followed 2,500 men for 24 years. According to the researchers, the link between excess weight and death from prostate cancer held up again: Compared to healthy weight men, men who started the study overweight were 47 percent more likely to die from prostate cancer. Men who were obese at the start of the study were two-and-a-half times more likely to die from the disease.