High Carb Diets Newly Linked With Higher Colorectal Cancer Recurrence

By Curt Pesman

Low-carb (and lower sugar) diets may soon look a lot better to colorectal cancer survivors. In a recent data-rich study of more than 1000 stage III colon cancer survivors, researchers from Dana-Farber Cancer Institute found that those who consistently ate a high-carbohydrate, sugar-laden diet appeared to have markedly higher recurrence rates of their disease than patients whose diets were more varied and contained less-sugar. The results were published in the Nov. 7 Journal of the National Cancer Institute.

The main finding after surveying and following 1,011 patients during and 6 months after chemotherapy? That those who reported having the highest dietary levels of carbohydrate intake (and related glycemic load) also had an 80 percent increased risk of colon cancer recurrence or death compared with those who had the lowest carb diets.

 But because cancer patients (and health-minded others) are advised not to make a nutritional or lifestyle change based on just one research study or peer-reviewed journal article, it’s worth noting that in the Feb. 7^th issue of Nature, doctors from the University of California-San Francisco (UCSF) argued that sugar effects are so detrimental that the substance should be regulated like alcohol and tobacco to protect consumers’ health. 

Robert H. Lustig, M.D., professor of pediatrics in the division of endocrinology at UCSF, and colleagues stated that beyond fueling a global obesity problem, sugar in all forms contributes to 35 million deaths annually worldwide due to diseases like heart disease, diabetes, and cancer.

So how might excess sugar and high-carbohydrate diets lead to the formation of rogue cancer cells? “In light of our and other’s research, we theorize that factors including a high glycemic load [resulting in excess glucose or sugar byproduct throughout the bloodstream] may stimulate the body’s production of insulin,” Jeffrey Meyerhardt, M.D., M.P.H., of Dana-Farber, said. In turn, this “may increase the proliferation of cells and prevent the natural cell-death process in cancer cells that have metastasized from their original site.”

Dr. Meyerhardt noted that the Dana-Farber study doesn’t prove that high-carb, high glycemic diets cause recurrence of colon cancer. But the strong association between high glycemic load and higher recurrence rates—especially in obese patients– strongly suggests that these dietary factors do play a role. “Our findings may offer useful guidance for patients and physicians in ways of improving patient survival after treatment.”

Sources: Journal of the National Cancer Institute, published online Nov. 7, 2012 ,  and Nature 482, 27–29 (02 February 2012)