Recent data feature short-chain fatty acids (SCFAs), products of gut microbial fermentation, as modulators of the blood pressure of the host. Such modulation may evoke (or arise from) changes in the autonomic reflexive mechanisms, but the link remains unexplored. Therefore, the study aims to explore potential relationship between the dietary intervention-induced changes in the SCFA plasma/fecal content and alterations in the sensitivity of the cardio-respiratory autonomic reflexes.

In this cross-over, placebo-controlled study, a group of healthy volunteers will undergo three distinct stages of a four-week dietary intervention, separated by at least two weeks of washout periods. During each stage, participants will receive one of the following interventions:

• raw potato starch (a source of resistant type 2 starch, which is a substrate for the endogenous production of SCFAs)
• sodium butyrate (a direct, exogenous source of this SCFA)
• an amylase-accessible waxy maze starch (a placebo). Plasma and fecal SCFA concentrations will be measured, along with the comprehensive evaluation of the cardio-respiratory parameters and the sensitivity of the autonomic reflexive mechanisms.

Inclusion Criteria:

• age 18-40 years

Exclusion Criteria:

• chronic disease of the nervous, cardiovascular or respiratory system
• disease of the digestive system, including history of the intestinal surgery, inflammatory bowel disease, celiac disease, lactose intolerance and other malabsorption disorders
• blood pressure-lowering treatment within the past year
• tobacco smoking within the past year
• antibiotic/probiotic treatment and laxative/prokinetic usage in three months preceding the anticipated enrollment

This is a small trial which includes solely healthy volunteers. Therefore, data will not be shared at this instance.