In addition to myostatin's ability to stop muscle growth, more recent scientific evidence highlights myostatin's capacity to increase body fat, primarily by decreasing sensitivity to the hormone leptin.3 Given that leptin is a signal to the brain that decreases appetite while simultaneously stimulating the rate of fatty acid oxidation, a decreased sensitivity to leptin brought on by myostatin increases food consumption while decreasing fat burning— causing the unwanted accumulation of body fat.
The recently discovered "fat increasing" characteristic of myostatin represents one more bona fide reason to want to decrease myostatin function, especially for anyone trying to build a more lean and muscular physique. Interestingly, a number of innovative ways have been discovered recently that inhibit myostatin activity, conceivably enhancing muscle growth and fat loss in remarkable ways.
LOW-INTENSITY AEROBIC EXERCISE DECREASES MYOSTATIN, SUPPORTING MUSCLE GROWTHAs expected, lifting weights has been shown to decrease myostatin levels, representing one of the many ways that intense weightlifting triggers muscle growth. However, a recent study by Hittel et al.4 unexpectedly showed that low-intensity aerobic exercise can also considerably decrease the amount of myostatin— establishing a unique way to manipulate myostatin, supporting muscle growth.
In the above study, researchers found that myostatin levels decreased by approximately 37 percent after all 10 male subjects performed cardiovascular training at a pretty low intensity level that only burned approximately 1,200 calories per week. Interestingly, this study also showed that when myostatin levels decreased there was a substantial increase in insulin sensitivity. Because insulin is an extremely anabolic hormone that has the ability to drastically increase muscle protein synthesis, enhancing muscle growth, this finding represents an additional mechanism by which myostatin reduction, due to low-intensity aerobic training, could enhance muscle growth.
CREATINE DECREASES MYOSTATIN, BOOSTING MUSCLE STRENGTHCreatine is a well-characterized compound that has been clearly shown to enhance muscle size and strength. Although creatine's exact mechanism of action is unknown, research scientists have heavily examined it and some of its functional details have been elucidated.
In addition to creatine's obvious function as a primary energy storage molecule used to regenerate muscle ATP, thus prolonging muscle contraction, creatine has also been shown to stimulate muscle cell formation5 and muscle growth by stimulating the production of muscle proteins such as myosin.6 More recently, however, a study by Saremi et al.7 demonstrated that creatine consumption causes a decrease in myostatin levels in muscle cells, leading to significant muscle growth.
In a double-blind study, 27 healthy males performed resistance training or resistance training supplemented with creatine (0.3 grams of creatine for every kilogram of the subject's bodyweight per day for the first week loading phase, followed by 0.05 grams of creatine for every kilogram of the subject's body-weight for the rest of the study) for a total of eight weeks. Both groups showed decreased levels of myostatin, but the group that performed resistance training and consumed creatine had a considerably larger decrease in myostatin levels along with greater gains in muscle mass and strength.
Although the precise molecular interactions between creatine and myostatin are still unknown, this study clearly demonstrates creatine as an ergogenic aid that regulates myostatin levels— improving muscle growth and strength.
VITAMIN D DECREASES MYOSTATIN, INCREASING MUSCLE GROWTHVitamin D is a fat-soluble steroid-like vitamin that functions as a prohormone, aiding many different processes such as the absorption and metabolism of calcium and phosphorous— promoting bone health. Vitamin D also has several muscle-promoting properties associated with the ability to boost testosterone levels.
A recent study by Garcia et al.8 uncovered another interesting influence that vitamin D has on muscle growth. Researchers showed that vitamin D exposure decreases the amount of myostatin found in isolated muscle cells, generating greater muscle growth. In addition to the decrease in myostatin, this study showed that vitamin D triggers an increase in follistatin, which is a powerful inhibitor of myostatin— which increases muscle mass by inhibiting myostatin.9
Ultimately, this study indicates that the decrease in myostatin level and activity caused by vitamin D significantly increased muscle fiber size— demonstrating vitamin D's substantial ability to increase muscle mass.
ESSENTIAL AMINO ACIDS (EAAs) GENETICALLY ALTER MYOSTATIN LEVELSMany different studies have previously reported that EAAs potently activate mTOR-stimulated muscle protein synthesis, leading to greater muscle size.10,11 However, a recent study by Drummond et al.12 demonstrated that EAAs possess the uniquely powerful ability to also decrease genetic expression of myostatin in muscle cells.
EAAs decrease myostatin levels by stimulating the production of a class of molecules known as micro-RNA that have the ability to strongly decrease the expression level of specific genes. The unique finding in this study was that several micro-RNA molecules were produced in human skeletal muscle following the ingestion of 10 grams of EAAs, which subsequently decreased myostatin expression by approximately 50 percent.
Interestingly, another study by Callis et al.13 also showed that myostatin was the target of micro-RNA regulation—where the micro-RNA molecule called miR-208a boosted muscle hypertrophy by suppressing myostatin expression.
Although further work is needed to elucidate the precise role that micro-RNA has in the regulation of myostatin and muscle mass following EAA consumption, taken together, these two investigations represent a completely novel and forceful way to decrease myostatin— conceivably initiating new approaches to trigger tremendous muscle size.
In summary, myostatin is an unbelievably responsive target where even the slightest reduction in its activity produces remarkable muscle growth while radically decreasing body fat. Moreover, recent scientific insight has shed light on a number of diverse ways to decrease myostatin activity— potentially transforming the capacity to pack on muscle while simultaneously reducing body fat. More precisely, a diet supplemented with creatine, vitamin D and EAAs in combination with low-intensity cardiovascular exercise at the end of your workout should potently inhibit myostatin's physique-destroying capacity, while maximizing muscle growth and fat loss.
By Michael J. Rudolph, PH.D.
From Muscular Development
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