Effects of Resistant Starch Intake in Humans

Due to the rise in obesity and obesity-related conditions, there is growing commercial and public interest in foods and food components that promote health and lower risk of chronic metabolic diseases. Resistant starch (RS) is a non-viscous fermentable fiber that has beneficial metabolic effects on glucose tolerance, insulin sensitivity, and colon health in humans. While the mechanism behind the effects of RS are unclear, the benefits are thought to result from fermentation of RS in the large bowel by colonic bacteria resulting in a more favorable gut microbial composition and increased concentration of short-chain fatty acids (SCFAs). Evidence indicates that RS may result in increased colonic bacterial species Ruminococcus bromii (R. bromii), and in phylum level changes in Bacteriodetes and Fermicutes. The increase in SCFAs has been shown to potentially play a role in lowering gut pH to improve health, contribute to appetite control and reduced adipose tissue lipolysis; and reduce postprandial serum oxidative stress. Additionally, evidence indicates RS aids in treatment of diarrheal disease by interacting with both the human to increase SCFA concentration, water retention, and fecal weight and to interact with the disease-causing agent such that the insult to the human lumen cells is reduced. Therefore, RS may be a potent dietary therapy for individuals at risk for conditions including metabolic syndrome, type-2 diabetes, colorectal cancer, and diarrheal diseases. The effects of type, dose, and duration of RS intake and subsequent impact on health are important areas of further research.