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As people age, they often joke about how they can no longer drink like they did in the college days. Although people might observe that they lose tolerance to alcohol, the exact mechanisms at work are unknown. Previous studies have found that chronic drinking leads to wasting. Researchers had theorized that when people start to age, there is a decrease in muscle protein synthesis, which contributes to body deterioration. In a new study, researchers provide a biological explanation as to why drinking starts to wear and tear at the body faster as a person ages. They found that chronic drinking in later years had an effect on muscle mass and appeared to lead to a greater loss of it.

The researchers headed by Charles H. Lang from Penn State College of Medicine and Donna H. Korzick from the Pennsylvania State University used young and old mouse models to test the effects of alcohol. The researchers used rats that were three months old, which represented young adults and rats that were 18 months old, which represented the senior citizens. All of the rates were fed a liquid diet for 20 weeks that was created with all the daily nutrients. Half of the rats in both age groups were fed alcohol at an increasing rate. By the third week and onward, alcohol made up of 36 percent of the rats' diet.

The researchers studied the samples from each rats' calf muscle, also known as the gastrocnemius. They found that all alcohol-fed rats weighed less than the rats in the healthy diet group. The researchers also noted that the alcohol-fed group had lower lean body mass and lower muscle mass. Even though alcohol appeared to have an effect on each rat, researchers found that age seemed to exacerbate that effect. The older alcohol-fed rats were 17 percent lighter than the older, healthy group of rats. Overall, the older rats that were fed alcohol exhibited the worse amount of wasting. The researchers reported that this group had over half the rate of protein synthesis in their muscles.

"Collectively, our results suggest that sustained excessive alcohol consumption by the elderly should be discouraged to minimize the sarcopenia typically seen in this patient population," the authors explained. "As muscle mass and strength are predictive of disability and all-cause mortality."

The study, "Aging Accentuates Alcohol-Induced Decrease in Protein Synthesis in Gastrocnemius," can be found in the American Journal of Physiology - Regulatory, Integrative, and Comparative Physiology, which his published by the American Physiological Society.