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Bacterial fermentation end‐products are related to hepatic steatosis among overweight and obese adults
Author(s) -
Thompson Sharon V.,
Berndt Jake W.,
Edwards Caitlyn G.,
Erdman John W.,
Khan Naiman A.,
O'Brien William D.,
Holscher Hannah D.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.138.6
Subject(s) - steatosis , nonalcoholic fatty liver disease , overweight , medicine , population , fatty liver , propionate , endocrinology , physiology , obesity , biology , biochemistry , disease , environmental health
Background Nonalcoholic fatty liver disease (NAFLD) is an increasingly prevalent manifestation of metabolic dysfunction characterized by elevated hepatic fat accumulation and elevated liver enzymes. Currently it is estimated that NAFLD may affect up to half of the US population. Although previous work has linked excess adiposity with NAFLD, there is a paucity of data examining whether hepatic steatosis is also related to gut microbiota fermentation end‐products, particularly among humans. Discovering this knowledge stands to benefit future dietary approaches to preventing the development of NAFLD in the increasingly overweight and obese US population. Methods Accordingly, this study aimed to characterize the relationships between hepatic steatosis and markers of liver function, fat mass, and gut microbiota fermentation end‐products. We conducted correlational analyses concerning adiposity (%Fat), volatile fatty acid (VFA) concentrations, and measures of hepatic health within a sample of overweight/obese (BMI ≥ 27.5 kg/m 2 ) adults (N=57, 64.9% females). Whole body and total, visceral, and subcutaneous abdominal adiposity (% Fat Mass) were measured using DXA. Gas chromatography mass spectroscopy was used to assess VFA concentrations, including short‐chain fatty acids (SCFAs; acetate, propionate, butyrate) and branched‐chain fatty acids (BCFAs; isovalerate, valerate, and isobutryate). Hepatic enzyme concentrations (whole blood) were assessed using an automated chemical analyzer. Hepatic steatosis (fat fraction [FF]) was measured using quantitative ultrasound in a subset of participants (n=21). Initial bivariate correlations were conducted to examine relationships between hepatic health measures, adiposity, and bacterial fermentation end products. Subsequently, a partial correlation was conducted to determine whether the relationships between bacterial fermentation end‐products and hepatic measures persisted following the adjustment of adiposity. Results Elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), and hepatic FF were present in 16.7%, 13.0%, and 5.1% of participants, respectively. Whole body %Fat was negatively correlated with butyrate concentrations (r=−0.29, p=0.03, n=57). Hepatic FF was positively related to isovalerate (r=0.48, p=0.03, n=21) and tended to correlate with isobutyrate (r=0.40, p=0.07, n=21). Partial correlational analyses revealed that the relationships between hepatic FF and BCFA concentrations may be mediated by BMI and whole body, visceral, and subcutaneous adiposity. Conclusions Results of the present study indicate that VFA concentrations differ by hepatic health and adiposity status. Further research is needed to determine if these observed relationships are mediated by dietary factors or gastrointestinal microbial abundances.