Mike Keenan at Louisiana State University just published his 15th animal study with RS2 resistant starch from high amylose corn. Surprisingly, it was sponsored by Merck and examined the potential synergism between Merck’s drug Januvia® (sitagliptin) and resistant starch. Both impact GLP-1 in the gut, but by different mechanisms. Sitagliptin inhibits the breakdown of GLP-1 by interfering with the DPP-4 enzyme, while resistant starch increases the production of GLP-1 in the gut.

While resistant starch alone did not decrease body fat, the combination of resistant starch and sitagliptin did in mice. As the percentage of resistant starch in the diet increased, the percentage of body fat and abdominal fat mass decreased. The data suggest that sitagliptin is able to reduce adiposity and the effect is enhanced by resistant starch. This was surprising, as sitagliptin has been shown to improve glucose metabolism and insulin sensitivity but has not been shown reduce body weight in previous studies.

The animals were fed high fat diets, which inhibits the intestinal fermentation of resistant starch, so the RS effects were likely blunted.

Once again, the body shows that multiple mechanisms are active and that different approaches to boosting metabolically important hormones, i.e., GLP-1, are in play. The drug effect was improved by simultaneous consumption of resistant starch. This is really important work as people are trying multiple approaches to manage their weight and metabolism.

Sometimes 1+1 might really equal 3.