Written by Greg Arnold, DC, CSCS. Rats supplemented with branched chain amino acids were 22% lower in liver damage than a control group.
According to the Centers for Disease Control and Prevention, there are over 100,000 cases of chronic liver disease in the United States every year, resulting in 30,558 deaths (1). A central event in chronic liver disease is dysfunction of a protein called Bcl-xl that fails to control the release of another protein called cytochrome c when a liver cell dies (2). The release of cytochrome c sets off a chain of events in the liver (3) that leads to liver scarring (called “hepatic fibrosis”) and initiates chronic liver disease (4).
So finding ways to help maintain Bcl-xl activity to monitor cytochrome c and prevent liver scarring is crucial to helping maintain liver health. Now a new study in rats (5) suggests that branched-chain amino acids may help.
In the study, injections were given daily for one week to 26 male rats fed a casein protein-based diet (200 grams per kilogram of bodyweight per day (g/kg/bw/d) = control group) to initiate liver disease. Then, twice per week for the next 11 weeks the rats were either fed the control group diet or 175 g/kg/bw/d of casein supplemented with the 3 branched-chain amino acids valine (7 g/kg/bw/d) , leucine (12 g/kg/bw/d), and isoleucine (6 g/kg/bw/d). Blood samples were taken from the rats once per week for those 11 weeks while liver samples were obtained at the end of the study to assess liver health. The amount of the branched chain amino acids is slightly over one pound per day for valine and proportionately more for the other amino acids.
By the end of the study, blood levels of a liver enzyme called AST, an indicator of liver damage, was 22% lower in the branched-chain amino acid group compared to the control group (624 vs. 801 IU/L). Levels of a protein called CTGF in the liver tissue, a marker of liver scarring (6), were also 75% higher in the control group compared to the branched-chain amino acid group (350 vs. 200 arbitrary units). Finally, levels of cell death, as evidenced by an enzyme called caspase 3 (3) and a protein called albumin (7) were 100% (0.9 vs. 0.45 arbitrary units) and 80% (0.45 vs. 0.25 arbitrary units) higher in the control group compared to the branched-chain amino acid group, respectively.
For the researchers, “These results suggest that supplementation with branched-chain amino acids delays the progression of chronic liver disease caused…in rats by [slowing down liver cell death].”
Source: “Supplementation with brancheded-chain amino acids attenuates hepatic apoptosis in rats with chronic liver disease” in the July 2010 issue of Nutrition Research. Posted August 27, 2012.
- “Chronic Liver Disease or Cirrhosis” accessed from the CDC website August 23, 2012.
- Jurgensmeier JM, Xie Z, Deveraux Q, Ellerby L, Bredesen D, Reed JC. Bax directly induces release of cytochrome c from isolated mitochondria. Proc Natl Acad Sci USA 1998;95: 4997–5002.
- Liu X, Kim CN, Yang J, Jemmerson R, Wang X. Induction of apoptotic program in cell-free extracts: requirement for dATP and cytochrome c. Cell 1996;86:147–57.
- Takehara T, Tatsumi T, Suzuki T, Rucker III EB, Hennighausen L, Jinushi M, et al. Hepatocyte-specific disruption of Bcl-xL leads to continuous hepatocyte apoptosis and liver fibrotic responses. Gastroenterology 2004;127:1189–97.
- Kuwahata M, et al, Supplementation with brancheded-chain amino acids attenuates hepatic apoptosis in rats with chronic liver disease, Nutr Res 2012; 32(7):522-9.
- Lasky JA. Connective tissue growth factor mRNA expression is upregulated in bleomycin-induced lung fibrosis. AJP – Lung Physiol 1998; 275(2):L365-371.
- “Liver Function Tests” webpage accessed on the Mayo Clinic website August 24, 2012.