(P01-033-20) Effects of Amino Acid Supplementation on Liver Lipid Content: A Randomised, Double-Blinded, Placebo-Controlled Trial

Objectives: To test whether chronic ingestion of essential amino acids (EAAs) plus arginine lowers liver lipid content when compared with a placebo (non-essential amino acids; NEAAs).

Methods: Older adults (50-75 y) with elevated fasting plasma triacylglycerol (TAG) concentrations were recruited into the study.  After screening (week -2), all participants ingested placebo (NEAAs; alanine, aspartic acid, and serine) capsules twice daily (between meals) for two weeks and 3 T nuclear magnetic resonance spectroscopy scans were used to determine baseline (week 0) liver lipid percentage.  Participants were then randomised to receive capsules containing 11 g of EAAs plus arginine (n = 10) or NEAAs (n = 9) twice daily for eight weeks, using a double-blinded design.  Follow-up NMR spectroscopy scans were conducted at eight weeks after the onset of randomised supplementation (week 8) to determine the impact on liver lipids.

Results: Liver lipid percentage (mean ± standard deviation) was not significantly altered by randomised supplementation in either the EAAs plus arginine group (Pre: 9.08 ± 7.90 %; Post: 8.94 ± 6.91 %; P = 0.65) or the NEAAs group (Pre: 10.23 ± 7.20 %; Post: 9.65 ± 7.70 %; P = 0.18).  Change in fasting plasma TAG during placebo run-in (Week 0 minus screening) was significantly negatively correlated with change in liver lipid content (week 8 minus week 0) for the EAAs plus arginine group (r = -0.722; P = 0.02), but not for the NEAAs group A (r = -0.479; P = 0.19).

Conclusions: Eight weeks of essential amino acids plus arginine ingestion did not significantly lower liver lipid content in older adults. However, ingestion of non-essential amino acids during the run-in period may have influenced the effect on liver fat of subsequent randomised amino acid supplementation, suggesting further investigation is warranted.

Funding Sources: The study was sponsored by NIH/NIA (award to EB), and the Roy and Christine Sturgis Charitable Trust (award to NMH).  Screenings and study visits were undertaken within the ITS-Clinical Research Center at UTMB, funded by NIH/NCRR, and within the UAMS Donald W. Reynolds Institute on Aging at UAMS, funded by NIH/NIA.  NMH and EB were also funded by the Arkansas Biosciences Institute, the major research component of the Arkansas Tobacco Settlement Proceeds Act of 2000.