In the developed world, obesity is one of the biggest health concerns, so weight loss is one of the hottest topics today. But while dietary supplements and gastric by-pass surgeries are becoming more and more popular, we are also starting to discover issues associated with these procedures. Recently, a study published in Cell showed that the new generation of weight loss drugs may actually favor cancer development.

Weight loss products typically work by encouraging and stimulating gut hormones and acids. All gut hormones and bile acids aid in digestion, but some actually encourage growth – for example, the peptide-2 (GLP-2) stimulated cell division in the intestines. Now, scientists at Mount Sinai Hospital in Toronto found a new gut-growth role for another gut hormone, glucagon-like peptide-1 (GLP-1). They report that the increase in GLP-1 activity, can increase the incidence of intestinal tumors, while removing the peptide actually reduces tumor incidence.

“For many years, people focused on GLP-1 as a b cell growth factor, and some investigators raised questions about the possibility of pancreatic cancer,” says senior author Daniel Drucker, MD, an endocrinologist at Mount Sinai Hospital’s Lunenfeld-Tanenbaum Research Institute and a Professor of Medicine at the University of Toronto. “We don’t have any evidence that that’s the case; however, our paper now raises the possibility that GLP-1 is an intestinal growth factor. No previous studies to date have linked long-term use of GLP-1-based drugs with increased rates of cancer; however, we think patients with a previous history, or increased risk, of colon cancer may not be ideally suited for these therapies,” he adds.

Based on data gathered on mice, Drucker is not only questioning the long term impact of weight loss products, but also raising concerns about new investigational drugs in clinical development for diabetes and other metabolic diseases, which elevate GLP-1, GLP-2, and bile acids.

“We’re pretty conservative about not overstating the potential clinical relevance of our studies done in mice, but mouse data always generate a hypothesis, and my hypothesis would be that if you have increased levels of gut-growth molecules, I would consider following up with regular colonoscopies for the appropriate patients,” Dr. Drucker says.

This study highlights once again that weight loss supplements and surgical procedures are not a replacement for a healthy lifestyle and a proper diet. The negative side effects are often far-reaching and unforseeable.

Journal Reference: Cell Metabolism.