Fasting alters microbiome to reduce weight, control BP

Fasting induces alterations in the gut microbiome, which in turn helps reduce body weight and control blood pressure (BP) in hypertensive patients with metabolic syndrome, a recent study has found.

The researchers sought to determine the effect of a Dietary Approach to Stop Hypertension (DASH) diet with (n=35; mean age 58±8 years, 23 women) or without (n=36; mean age 62±8 years, 21 women) a preceding 5-day fast in eligible patients. Outcomes included 24-hour ambulatory systolic BP (SBP) and homeostasis model assessment-index, both measured at 12 weeks.

DASH alone was able to significantly reduce office SBP after 3 months, though there was no significant impact on 24-hour ambulatory SBP (p=0.27). Patients who also underwent fasting, however, saw significant and sustained reductions in 24-hour ambulatory SBP and mean arterial pressure (MAP; p<0.05).

Similarly, those who combined the DASH diet with fasting experienced a significant drop in body mass index (BMI) and body weight at 12 weeks (p<0.05), an effect absent in the DASH diet-only comparators.

However, the changes in BMI and body weight were not enough to explain the corresponding reductions in SBP.

In order to identify other potential factors, the researchers looked at participants’ gut microbiome and immunome. They found that the fasting group showed affected microbiome signatures, with altered bacterial taxa and genes associated with the production of short-chain fatty acids.

Cross-system analysis also revealed that circulating mucosa-assisted T cells, as well as nonclassical monocytes and CD4⁺ effector T cells, were associated with SBP, while regulatory T cells correlated with BMI and body weight.