Smoking Causes Muscle Breakdown By Increasing Myostatin

[Bouncer]

Smokers' muscle tissue breaks down more quickly than the muscle tissue of non-smokers. Researchers at the Copenhagen Muscle Research Centre discovered this when they compared muscle cells from the quadriceps muscle of 8 smokers and 8 non-smokers. Smokers produce more myostatin, a hormone that inhibits muscle growth.

As the western population ages, sarcopenia or age-related loss of muscle mass is becoming more common, so researchers are looking for ways to help elderly people maintain muscle strength. According to some epidemiological studies, elderly smokers are more likely to develop sarcopenia than non-smokers. So the Danish researchers set up a lab experiment to find out exactly what effect smoking has on muscle cells.

The researchers compared the muscle cells of 8 smokers, who all smoked over 20 cigarettes a day, with muscle cells of 8 non-smokers of the same age. The subjects did no sport. Before taking a cell sample from the subjects' thigh muscle, the researchers gave the subjects a dose of labelled leucine. This enabled them to see whether the cells absorbed amino acids and built them into muscle protein.

The cells of the smokers absorbed amino acids just as well as the non-smokers' cells did. But their mixed-muscle protein fractional synthesis rate - their muscle protein manufacture, in simple language - was lower, analysis of the muscle cells showed.

Smoking causes inflammatory reactions. The concentration of inflammatory factors TNF-alfa, CRP and Interleukine-6 did not increase in the smokers' blood. Nor did smoking increase the activity of the TNF-alfa gene in the muscle cells. So inflammatory processes would seem to have nothing to do with the catabolic effect that smoking has.

"Smoking is a potent inhibitor of the muscle protein synthetic machinery", the researchers sum up in their conclusion.

Source:
Am J Physiol Endocrinol Metab. 2007 Sep; 293(3): E843-8.

[Bouncer]

Why bodybuilders who still smoke should use BCAAs

Smoking is bad for pretty much everything, and that includes your muscles. Researchers at Nara Medical University in Japan made an interesting discovery for bodybuilders and other strength athletes who still smoke: supplementation with BCAAs can help counteract the negative effects that smoking has on muscles.

Smoking, Muscles & BCAAs

Smoking boosts myostatin activity in muscle cells, causing muscle degeneration. Smoking also encourages the formation of advanced glycation end products [AGEs] in the muscles, thus reducing muscle strength.

< The Japanese were curious as to whether the muscle-shrinking effects of smoking were in any way related to BCAAs [structural formulas shown below]. Did smokers' muscles absorb fewer BCAAs perhaps? And if so, could smokers maintain muscle strength by taking a supplement containing BCAAs?

Study

To answer these questions the researchers devised an animal experiment in which one group of young rats was exposed to cigarette smoke for four weeks, and one group was not.

Of both groups, half was given standard food and the other half was given food to which BCAAs had been added. The BCAA-enriched food contained approximately the same amount of amino acids as the standard food.

Results

The rats that inhaled cigarette smoke grew less fast. That was partly because they ate less.

The BCAA supplementation did not normalise the growth rate of the smoking rats, but it did counteract the negative effects of smoking on muscle mass. The figure below shows the weight of the gastrocnemius [calf muscle] in the four groups.

The Japanese discovered that smoking reduces the concentration of BCAAs in the blood. BCAA supplementation can negate the effect of smoking and restore the quantity of BCAAs in the bloodstream.

The muscles of the animals that inhaled smoke also contained lower amounts of BCAAs. That's why their muscles were smaller than those of the other lab rats. BCAA supplementation also normalised the amount of BCAAs in the rats' muscles.

Mechanism

In 2011 the researchers published the results of another animal experiment in which they had studied the effects of cigarette smoke. [J Toxicol Sci. 2011 Jun;36(3):261-6.] In that experiment they observed that exposure to tobacco smoke caused the immune cells in the intestines to use more glutamine. That might explain why the amount of BCAAs goes down as a result of exposure to cigarette smoke: smokers' bodies use larger amounts of BCAAs to synthesise glutamine.

Source:
J Toxicol Sci. 2014;39(2):331-7.

[Mr I]

Not only muscle

It inflames the cardiovascular system, burns off the lung fur and also dehydrates the discs in the back and ages them.

Bad shit I'm glad I quit

[Bouncer]

One thing I'll say I notice on the west coast that surprises me. You'd think Cali would be more "healthy" and it is when it comes to fitness and working out. But at the same time I see more people on average smoking here compared to Chicago or Jersey. Strange.

[somidiscount]

thanks for shearing about smoker.