Friday, March 27, 2015

Moderate Alcohol Consumption Will NOT Impair Your Gains, Despite Non-Sign. Reductions in Protein Synthesis!?

Athletes and alcohol don't mix, right? If we go by the results of a recent rodent study, this long-standing recommendation appears to be unwarranted for athletes whose main concern are increases in muscle size.
You will remember that I have written about studies investigating the effects of alcohol consumption on skeletal muscle gains in response to resistance training before. While previous studies tried to pinpoint the effects by measuring the effects of alcohol consumption on post-exercise muscle protein synthesis and did thus produce questionable results, boozers, ... ah I mean, researchers from the Penn State College of Medicine have now performed the true litmus test - albeit in mice.

In contrast to the previously discussed studies, Jennifer L. Steiner, Bradley S. Gordon & Charles H. Lang from the Department of Cellular and Molecular Physiology at the Penn State College of Medicine in Pennsylvania investigated the semi-chronic effects of "moderate" alcohol consumption in a rodent model.
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To induce hypertrophy of the plantaris muscle, the scientist removed a section of the gastrocnemius and soleus muscles from one leg of C57BL/6 adult male mice while the contralateral leg remained intact as the sham control.

The mice were then put on standardized, nutritionally complete alcohol-containing liquid diets (EtOH) or isocaloric, alcohol-free liquid diet (Con) for 14 days post-surgery.
To avoid "shock" effects, the EtOH intake was increased progressively (day 1–5) before being maintained at ~20 g/day/kg BW (for humans that's 1.6g/kg and thus ~130g per day or ~10 drinks, which is not exactly moderate, imho).
Alcohol is a killer: According to the WHO, morbidity attributable to alcohol in countries with an established market economy (10.3% of disability adjusted life years) comes second only to that of tobacco (11.7%; Murray. 1997). Avery recent study published in the scientific journal Addiction by the Pan American Health Organization, a branch of the World Health Organization, also shows that alcohol is a 'necessary' cause of death (i.e., death would not have occurred in the absence of alcohol consumption) in an average of 79,456 cases per year in 16 North and Latin American countries (Gawryszewski. 2014).
When the scientists removed the plantaris muscle from the sham and OL leg after 14 days, they found no difference in body weight between Con and EtOH-fed mice. More specifically, the muscle weight of the plantaris muscle of both groups increased by 90%, the protein synthesis by 125% (the non-significant inter-group differences can be ignored, because studies show that post-exercise protein synthesis and actual muscle gains don't correlate in humans beings and the same can be safely assumed for mice (Mitchell. 2014).
Figure 1: It's easy to see that the alcohol intake did not inhibit the increase in skeletal muscle weight (left) and the decrease in protein synthesis was not statistically significant (right | Steiner. 2015). It should be mentioned, though, that the model the scientists used may not translate 1:1 to human beings and / or long(er)-term alcohol exposure.
Similarly, the overload-induced increase in signaling proteins like mTOR (Ser2448), 4E-BP1 (Thr37/46), S6K1 (Thr389), rpS6 (Ser240/244), and eEF2 (Thr56) were comparable in muscle from Con and EtOH mice.

The only thing that differed and may indicate that you could see different results in the long-term is the fact that ULK1, p62, and LC3, three markers of autophagy, i.e. self-programmed cell death were elevated in the muscle of the "binging" mice.
The previously discussed human studies appear to suggest that regular alcohol consumption will have a negative impact on your gains | more
Overall, Steiner et al. are still right when they conclude that their "data show that moderate alcohol consumption does not impair muscle growth, and therefore imply that resistance exercise may be an effective therapeutic modality for alcoholic-related muscle disease" (Steiner. 2015).

In view of the previously discussed human data, I would still try my best to abstain from alcohol. Specifically if it is consumed in allegedly "moderate", but imho exorbitant amounts, as it was in the study at hand, the chances that it may have negative overall effects on your health are significant.

And remember: One of the main findings of the study at hand is actually that (modelled) "resistance training" can counter the proven ill effects of alcohol on skeletal muscle. If that's enough for you to keep drinking a substance that is unquestionably not good for your health (don't tell me about the sponsored epidemiological data that discards all other lifestyle habits of "moderate" drinkers which are - in this case - defined as people consuming one beer or one glass of wine per day | Comment on Facebook!
  • Mitchell, Cameron J., et al. "Acute post-exercise myofibrillar protein synthesis is not correlated with resistance training-induced muscle hypertrophy in young men." PLoS One 9.2 (2014): e89431.
  • Steiner, Jennifer L., Bradley S. Gordon, and Charles H. Lang. "Moderate alcohol consumption does not impair overload‐induced muscle hypertrophy and protein synthesis." Physiological reports 3.3 (2015): e12333.