Lancet Oncology in 2008 published a report associating worse prostate cancer outcomes—death, that is—with overweight, obesity, and hyperinsulinemia.
Researchers looked at data from the respected Physicians’ Health Study, finding 2,546 men who developed prostate cancer during many years of observation. Of these men, 38.8% were overweight (body mass index 25–30) and 3.4% were obese (BMI over 30).
(For definitions of overweight and obesity, and to calculate your body mass index, click here.)
Compared with normal-weight men (BMI under 25) who developed prostate cancer, overweight men with prostate cancer were one-and-a-half times more likely to die from the cancer. Obese men with prostate cancer were two-and-a-half times more likely to die.
A blood test called C-peptide is a marker of insulin resistance and hyperinsulinemia. Obesity is often accompanied by high insulin levels and insulin resistance. Overweight, not so much. Eight hundred twenty-seven of the men with prostate cancer had C-peptide levels drawn at baseline, before diagnosed with cancer. Men with the highest C-peptide levels were almost two-and-a-half times more likely to die of prostate cancer than men with the lowest C-peptide levels.
Study participants having both excess body weight and high C-peptide levels had the worst outcome.
Prostate cancer is the most common invasive cancer in U.S. men, with about 185,000 cases diagnosed every year. It is one of the cancers that can be prevented by following the traditional Mediterranean diet for years. The other prevented cancers are breast, uterus, and colorectal. Obesity predisposes men to cancer of the prostate, colon, rectum, kidney, and esophagus.
The study at hand suggests that if you are overweight or obese and then develop prostate cancer, you have a greater risk of dying from the cancer compared with healthy-weight men. Given that prostate cancer is so common, why not cut your risk of getting it and dying from it by controlling your weight with a Mediterranean-style diet?
Reference: Ma, Jing, et al. Prediagnostic body mass index, plasma C-peptide concentration, and prostate cancer-specific mortality in men with prostate cancer: a long-term survival analysis. Lancet Oncology, online publication October 6, 2008. DOI: 10.1016/S1470-2045(08)70235-3