Background: Hypertension is a global health crisis linked to increased heart disease and stroke. Black individuals have the greatest burden of hypertension and related diseases. Recent research suggests that the gut microbial production of short‐chain fatty acids, such as butyrate, is associated with blood pressure (BP) regulation. We hypothesize that acutely increasing gut butyrate would lead to a significant reduction in BP within a 24‐hour period. Methods: Ten Black adults with normal BP and 10 with stage 1 hypertension (age and sex‐matched) participated in this study. In a crossover experiment, participants with hypertension randomly self‐administered a low dose (5 mmol/L) and a high dose (80 mmol/L) butyrate enema 7 days apart. Blood butyrate levels were measured before and 30 minutes post enema, with BP monitored via 24‐hour ambulatory devices. Preintervention fecal samples were sequenced via the V4 region of the 16S rRNA gene and microbiome characteristics assessed. Results: We observed that daytime systolic BP was significantly lower after the 80 mmol/L butyrate enema. There was no significant difference in blood butyrate between controls and the group with hypertension before or after either enema. Microbial diversity did not significantly differ between groups; however, pathways for carbohydrate fermentation were significantly lower with differentially abundance butyrate‐producing microbes in participants with hypertension compared with those with normal BP. Conclusions: This study suggests that increasing gut butyrate availability can improve BP. The findings bolster the evidence that gut butyrate regulates BP and supports studies needed to test strategies to boost gut butyrate availability for BP control. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier NCT04415333.

Background: African Americans (AA) are disproportionally affected by hypertension (HTN). Gut microbiome metabolites (e.g., butyrate) may mediate the relationship between the microbiome and blood pressure (BP). Previous research reports a consistent indirect relationship between gut butyrate, a product of gut microbial nutrient fermentation, and BP. Thus, this study assessed the relationship between individual diet intake on BP changes after a butyrate treatment. Methods: AA aged 30–50 with HTN underwent treatment with a blinded placebo (5 mmol) and butyrate enema (80 mmol) with a one-week washout period. Ambulatory BP monitors collected measures up to 24 h post-enema. The Nutrition Data System for Research was used to assess diet and Healthy Eating Index (HEI-2015) scores from diet records. Paired t-tests and Kendall’s correlation tests determined group differences and relationships between variables (p < 0.05). Results: Positive correlations were found between other vegetables and 24 h diastolic BP (r = 0.64), daytime diastolic BP (r = 0.68), and MAP (r = 0.72). Positive correlations were also found between 24 h systolic BP and HEI-2015 greens and beans sub-scores (r = 0.64) and 24 h DBP and total vegetables (r = 0.64). Negative correlations were found between nighttime arterial stiffness and total grain intake (r = −0.71). Conclusion: These data suggest diet impacts BP measures in response to acutely increasing gut butyrate. These results provide preliminary evidence linking food groups, not individual nutrients, with BP outcomes and gut butyrate availability.

Purpose: This study aimed to characterize the association between microbial dynamics and excessive exercise. Methods: Swabbed fecal samples, body composition (percent body fat), and swimming logs were collected (n = 94) from a single individual over 107 days as he swam across the Pacific Ocean. The V4 region of the 16S rRNA gene was sequenced, generating 6.2 million amplicon sequence variants. Multivariate analysis was used to analyze the microbial community structure, and machine learning (random forest) was used to model the microbial dynamics over time using R statistical programming. Results: Our findings show a significant reduction in percent fat mass (Pearson; p < 0.01, R = −0.89) and daily swim distance (Spearman; p < 0.01, R = −0.30). Furthermore, the microbial community structure became increasingly similar over time (PERMANOVA; p < 0.01, R = −0.27). Decision-based modeling (random forest) revealed the genera Alistipes, Anaerostipes, Bifidobacterium, Butyricimonas, Lachnospira, Lachnobacterium, and Ruminococcus as important microbial biomarkers of excessive exercise for explaining variations observed throughout the swim (OOB; R = 0.893). Conclusions: We show that microbial community structure and composition accurately classify outcomes of excessive exercise in relation to body composition, blood pressure, and daily swim distance. More importantly, microbial dynamics reveal the microbial taxa significantly associated with increased exercise volume, highlighting specific microbes responsive to excessive swimming.