Branched chain amino acids: A factor for zone 3 steatosis in non-alcoholic fatty liver disease

The association between dietary amino acids and the risk of nonalcoholic fatty liver disease among Tehranian adults: a case-control study

BACKGROUND

Amino acids (AAs) are important bioactive components in the diet that can be involved in various underlying biological processes that contribute to the development of nonalcoholic fatty liver disease (NAFLD). The present study investigates the association between dietary intake of amino acids and NAFLD in Iranian adults.

METHODS

This study was conducted among 225 newly diagnosed cases of NAFLD and 450 controls. A valid and reliable 168-item semiquantitative food frequency questionnaire (FFQ) was used to collect participants' dietary intakes. Multivariable logistic regression models were used to assess the association between tertiles of branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), and sulfuric amino acids (SAAs) intake with the odds of NAFLD among the study participants.

RESULTS

The mean ± standard deviation of age and BMI of participants (53% male) were 38.1 ± 8.8 years and 26.8 ± 4.3 kg/m2, respectively. In the final models, the OR and 95% CI of NAFLD among participants in the highest tertiles of BCAAs, AAAs, and SAAs intake compared with those in the lowest tertiles were (OR = 2.82; 95% CI: 1.50-5.30), (OR = 2.82; 95% CI: 1.50-5.30), (OR = 2.86; 95% CI: 1.49-5.48), respectively.

CONCLUSION

Our study indicated a direct association between the intake of AAs groups, including BCAAs, AAAs, SAAs, and the odds of NAFLD. We suggest that other researchers examine the association between AAs groups and NAFLD in large cohort studies.

Preparation and Antioxidant Activities of High Fischer's Ratio Oligopeptides from Goat Whey

This study aimed to obtain high Fischer's ratio oligopeptides from goat whey (HFO) and investigate antioxidant property of it. Hydrolysis of goat whey was done with the approach of sequential digestion of pepsin and flavourzyme. With the adsorption of aromatic amino acids by activated carbon, HFO with a Fischer's ratio of 27.070 and a molecular weight of 200-1,000 Da were obtained, and the branched-chain amino acids accounted for 22.87%. Then the antioxidant activity of HFO was evaluated. At the concentrations of 2.0 mg/mL and 0.50 mg/mL, HFO scavenged 77.27% and 99.63% of 1,1-diphenyl-2-picrylhydrazyl and 3-ethylbenzthiazoline-6-sulphonate free radicals respectively. The scavenging rate of HFO against hydroxyl radicals reached 92.31% at the concentration of 0.25 mg/mL. Animal experiments demonstrated that HFO could moderate the changes of malondialdehyde, superoxide dismutase and glutathione peroxidase caused by CCl4-induced oxidative stress in vivo. This study indicated that HFO from goat whey was capable of oxidation resistance both in vivo and in vitro, which provided a scientific basis for the high-value processing and application of goat milk whey.

Circulating branch chain amino acids and improvement in liver fat content in response to exercise interventions in NAFLD

Nonalcoholic fatty liver disease is likely to be associated with increased circulating branched-chain amino acids. We investigated the relationship between changes in branched-chain amino acids levels in the serum and improvement in liver fat content caused by exercise intervention in individuals with nonalcoholic fatty liver disease. The exploratory study included 208 central obesity and nonalcoholic fatty liver disease individuals from an exercise intervention randomized clinical trial for nonalcoholic fatty liver disease. The participants were randomly assigned to control, moderate, and vigorous-moderate exercise groups for 12 months. Changes in total branched-chain amino acids, leucine, isoleucine, and valine levels from baseline to 6 months were calculated. Liver fat content was determined by proton magnetic resonance spectroscopy. Reductions in circulating levels of total branched-chain amino acids, leucine, and valine levels from baseline to 6 months were significantly associated with the improvement of liver fat content at 6 months and 12 months (p < 0.01 for all) after adjustments for age, sex, total energy intake, protein intake, intervention groups, HOMA-IR, BMI, liver fat content, total branched-chain amino acids, leucine, and valine at baseline, respectively. These associations were still significant after further adjustments for changes in HOMA-IR and BMI from baseline to 6 months (p < 0.05 for all). Our findings indicated that reductions in circulating branched-chain amino acids levels were associated with an improvement in liver fat content by exercise intervention among patients with nonalcoholic fatty liver disease, which was independent of changes in BMI or HOMA-IR.