Beneficial Effects of Macaroni Made with Resistant Starch Type 4 from Unripe Banana and Turmeric Extract on Blood Clinical Chemistry and Gut Microbiota of Healthy Rats

Unripe banana is rich with resistant starch (RS) and this non-processed food confers many health benefits. However, unripe banana is not consumed directly and when cooked its native RS is rendered digestible. We have developed macaroni from chemically modified unripe banana flour (RS4), which maintains their content of resistant starch after being cooked, with and without the supplementation of turmeric extract. We hypothesized that consuming our banana RS4 macaroni would confer beneficial effects on metabolic profiles. Healthy Wistar rats were fed for 6 weeks with cooked banana RS4 macaroni, with and without the turmeric extract supplementation, and compared to rats fed with standard wheat macaroni. No significant physiological differences between groups were observed except rats that consumed banana RS4 macaroni had significantly smaller stomachs (p<0.05). Rats receiving banana RS4 macaroni had significantly lower triglyceride levels (p<0.05) and a trend for lower fasting blood glucose and increased expression of insulin-like growth factor-2 in theirs livers. Although it was not statistically significant, turmeric supplementation showed a trend of reducing serum total cholesterol and LDL-cholesterol as well as liver expression levels of genes involved in cholesterol metabolism, HMG CoA reductase (HMGR) and LDL-receptor related protein-1 (LRP-1). Banana RS4 macaroni did not significantly change fecal microbiota, nevertheless, addition of turmeric extract significantly increased alpha diversity and the relative abundance of Lachnospiraceae Erysipelotrichaceae and Clostridiaceae. In conclusion, the consumption of banana RS4 macaroni by healthy rats receiving a regular diet improved their blood chemistry profile associated with metabolic syndrome, and the addition of turmeric extract can significantly alter fecal microbiota.