High-Protein, Low-Carb Diet May Increase Colon Cancer Risk

ABERDEEN, ScotlandIndividuals who adhere to a high-protein diet that is low in carbohydrates and fiber to lose weight may increase their risk of colon cancer over time, according to a new study published in the American Journal of Clinical Nutrition.

Researchers at the University of Aberdeen observed 17 obese men with a defined weight-maintenance diet (85 g protein, 116 g fat and 360 g carbohydrate/d) for seven days followed by four weeks each of a high-protein and moderate-carbohydrate (HPMC; 139 g protein, 82 g fat and 181 g carbohydrate/d) diet and a high-protein and low-carbohydrate (HPLC; 137 g protein, 143 g fat and 22 g carbohydrate/d) diet in a crossover design.

The men on the high-protein diets had higher levels of N-nitroso compounds, substances often linked to cancer. Those on the high-protein, low-carbohydrate diet had lowered concentrations of fiber-derived compounds thought to help fight cancer.

According to the findings, the weight-loss diets that were high in protein but reduced in total carbohydrates and fiber resulted in a significant decrease in fecal cancer-protective metabolites and increased concentrations of hazardous metabolites.