In a recent study published in Nutrients, researchers analyzed how short-chain fatty acids (SCFAs) modulate cardiometabolic disease risk by interacting with an individual's adiposity parameters and diet.
Study: The Potential Role of SCFAs in Modulating Cardiometabolic Risk by Interacting with Adiposity Parameters and Diet. Image Credit: Net Vector/Shutterstock.com
Introduction
To this end, they performed a cross-sectional study among 77 healthy, non-obese men and women aged 30–45 years, where they analyzed the concentration of SCFAs in their stool.
They measured their body composition, including more advanced indicators of abdominal adiposity directly linked to cardiometabolic risks, such as the visceral-to-subcutaneous-fat ratio (VAT/SAT ratio), waist circumference (WC), body shape index (ABSI), select biochemical parameters and analyzed their diet, physical activity levels, and sleep duration to understand the influence of these lifestyle factors on SCFAs.
Background
SCFAs prevent fat accumulation in adipose tissue; thus, their levels in stool show a negative correlation with adiposity parameters, including VAT and WC.
Thus, dietary supplementation with SCFAs can help regulate weight gain due to a high-fat diet. SCFAs also regulate blood glucose, blood lipids, and energy homeostasis.
Overall, SCFAs can modulate cardiometabolic disease risk by interacting with diet and adiposity parameters. However, studies have not yet made robust conclusions about causality.
So, while evidence from previous studies suggests multiple benefits of SCFAs, their vital role in metabolic regulation was under scrutiny in this study.
About the study
The present study site was the Medical University of Warsaw in Poland, where 77 healthy, normal-weight adults aged 30-45 years with no chronic diseases and a body mass index (BMI) between 18.5 and 29.9 kg/m2 consented to participate.
The team analyzed their body composition using bioelectrical impedance analysis, following the European Society for Clinical Nutrition and Metabolism guidelines.
The participants fasted before the test, avoided physical activity, and abstained from certain beverages.
Next, they conducted biochemical tests on participants, measuring fasting glucose, insulin, total, low, and high-density cholesterol (LDL and HDL), triglycerides, and C-reactive protein (CRP) serum levels.
They also evaluated each participant's physical activity levels and sleep duration.
Furthermore, the team assessed each participant's diet, including energy, macronutrients, and dietary fiber intake. A trained dietitian cross-checked their three-day dietary records and performed nutritional calculations.
Importantly, the team performed SCFA quantification in stool using Liquid Chromatography with tandem mass spectrometry (LC-MS-MS) analysis, where the limit of quantification (LOQ) was ten μM for acetic acid, propionic acid, and butyric acid and 0.1 μM for isovaleric acid, valeric acid, and caproic acid, six SCFAs analyzed in participant's samples.
Finally, the team performed non-parametric statistics using the Shapiro-Wilk test and presented the median, Spearman correlation, and p-value from the Mann-Whitney test, considering a p-value under 0.05 as significant.
Results
The molar ratios of acetic, propionic, butyric acid, and other SCFAs in the stool samples of both study cohorts were comparable, with no gender-specific statistically significant differences.
The authors noted a notable negative correlation between six SCFA, namely, acetic, butyric, isobutyric, propionic, isovaleric, and valeric acid, and VAT/SAT ratio, BMI, and fat percentage in a group of females.
In contrast, only propionic and butyric acids had a significant negative association with WC in males.
Besides, there was a notable negative association between valeric acid with WC and fat in females and a positive association with the percentage of total body water (TBW) and fat-free mass.
Together, these findings support that acetic, butyric, and valeric acids may help prevent obesity in healthy individuals.
Another intriguing finding of the current study was the association between diet and some SCFAs.
A notable negative association existed between energy and fat intake and isobutyric, isovaleric, valeric, and isocaproic acids, favoring the theory that adhering to a low-energy diet may increase SCFAs quantities in the gut.
Moreover, the study analysis showed that a rise in dietary fiber intake led to elevated levels of acetic, propionic, butyric acid and total SCFAs among men and women alike. Additionally, caproic and valeric acid levels were elevated in men.
The percentage distribution analysis of SCFAs further confirmed this correlation, i.e., significantly elevated valeric and butyric acid levels in individuals with ≥25 g fiber intake.
Together, these findings confirm that gut microbiota synthesizes SCFAs using dietary fiber, and a fiber-rich diet comprising soluble fiber could increase SCFA biosynthesis.
The authors could not demonstrate a clear link between sleep and SCFAs and physical activity and SCFAs, necessitating further research for insights into these correlations.
Nonetheless, there was a negative correlation between total sleep time (TST) and carbohydrate consumption in some women.
Conclusions
Of lifestyle factors analyzed, diet had a direct link with SCFAs, which at least partly contributed to sleep improvement in some women enrolled in this study. However, physical activity and SCFAs showed no association.
Regarding biochemical outcomes, the authors noted a significant positive correlation between some fecal SCFAs and fasting blood glucose, CRP, and TG in men; however, these results require further validation.
Nonetheless, the study data support the theory that SCFAs might confer some protection against overweightness and obesity in healthy individuals, which, in turn, might reduce cardiometabolic disease risk.
Importantly, SCFAs exerted these effects by interacting with diet, mainly the soluble fraction of dietary fiber and adiposity parameters.
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