The team from the University of Kent in the UK found participants following three healthy diets resulted in reduced blood pressure readings, however the team revealed that a select few people responded less well to the regimen.
An inspection of bacterial metabolites in the urine found individual differences in gut bacteria.
“Variation in metabolic phenotypes in response to specific healthy diets…..points to the potential importance of the gut microbiome in accounting for differences in dietary response and the subsequent impact on BP,” said the team, led by Dr Ruey Leng Loo, senior lecturer at the Medway School of Pharmacy based at the University of Kent.
“The workflow presented here provides a framework to develop tailored dietary interventions designed to reduce blood pressure and other cardiovascular disease (CVD) risk factors.”
While Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets are linked to a reduced CVD risk genetic influence on variable dietary responses remains conflicting.
Modifiable factors such as changes in body weight or variation in the composition of the gut microbiome have been implicated in variation in dietary responses.
Led by Dr Loo, a team was created that included researchers from Imperial College London and Johns Hopkins University in the US.
Here, urine samples from 158 study participants with pre-hypertension and stage 1 hypertension were collected at the start of the trial.
These samples were then collected again following the consumption of a carbohydrate-rich, a protein-rich, and a monounsaturated fat–rich healthy diet (6 wk/diet)
All three diets encouraged a similar pattern of change in the urinary metabolic profiles for the majority of participants (60.1%).
Blood pressure (BP) was significantly associated with six urinary metabolites reflecting dietary intake [proline-betaine (inverse), carnitine (direct)], gut microbial co-metabolites (inverse), phenylacetylglutamine (inverse)], and tryptophan metabolism (inverse).
“Notably, we identified 2 gut microbial-host co-metabolites associated with BP: phenylacetylglutamine and 4-cresyl sulfate, deriving from phenylalanine and tyrosine, respectively, resulting from bacterial putrefaction of protein in the distal colon,” the study detailed.
“Although 4-cresyl sulfate has never been formally linked to BP, its dietary excretion has been shown to be highly correlated with that of phenylacetylglutamine.”
More gut proof
The study provided more evidence for the gut microbiota’s influence on blood pressure, in particular the species Firmicutes and Bacteroidetes, which the team said could adapt to dietary changes and induce changes in host metabolism.
Other researchers have manipulated gut microbiota balance via probiotic administration with consequent beneficial effects on BP levels.
“More recently, blood concentrations of phenylacetylglutamine were found to be strongly anti-correlated with BP, consistent with our results, and with carotid-femoral pulse-wave velocity, a measure of aortic stiffness.”
Source: The American Journal of Clinical Nutrition
Published online ahead of print: 10.1093/ajcn/nqx072
“Characterization of metabolic responses to healthy diets and association with blood pressure: application to the Optimal Macronutrient Intake Trial for Heart Health (OmniHeart), a randomized controlled study.”
Authors: Ruey Leng Loo, Xin Zou, Lawrence Appel, Jeremy Nicholson, Elaine Holmes.