The Many Benefits of Alpha-ketoisocaprotic Acid
By Dwayne Jackson
Mar 4, 2011
There is no doubt that the branched chain amino acid (BCAA) leucine is a valuable asset to bodybuilders.
In fact, among the BCAAs leucine promotes anabolism (Anthony et al., 2000;Yoshizawa et al., 2002;Yoshizawa, 2004) and suppresses catabolism (Li & Jefferson, 1978;Fulks et al., 1975;Buse & Reid, 1975) better than any of them. Until recently, the mechanisms by which leucine is anti-catabolic remained a mystery. So now you may be saying to yourself "great, but what does that have to do with KIC?"
Alpha-ketoisocaprotic acid is the metabolic product of transaminated leucine and some have implied that Î±-KIC is responsible for the suppression of proteolysis observed with leucine supplementation. In an early study, Tischler et al. reported that Î±-KIC inhibits proteolysis in skeletal muscle (Tischler et al., 1982). However, their conclusions were not definitive enough to directly implicate Î±-KIC as the only factor responsible for their anti-catabolic observations. Nakashima et al., tested whether leucine itself or Î±-KIC was responsible for its anti-catabolic effects (Nakashima et al., 2006). In this animal based and comprehensive molecular level investigation, they compared the effects of L- and D- leucine and Î±-KIC on myofibullar proteolysis in skeletal muscle of chicks (baby chickens, not girls). Their results indicated that L-leucine had an inhibitory effect on proteolysis, but D-leucine and, even more so, Î±-ketoisocaprotic acid had greater anti-catabolic effects. Their results clearly indicate that Î±-KIC is responsible for the anti-catabolic effects of leucine supplementation and that D-leucine is more effective in converting to Î±-KIC. This does not discount leucine as a supplement to increase anabolism, as leucine is widely recognized for this property. However, if you want to throw catabolism out the window, then skip the middleman and add Î±-KIC to your supplement regime.
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