Have you been living on protein shakes to build muscle mass? A new study has found that they may not be that safe—especially with long-term use.
The research on shakes promising to build muscle mass
A team from the University of Sydney looked at mice who were fed a diet high in branched-chain amino acids (BCAAs), which are made of the amino acids valine, isoleucine and leucine. The researchers found that consuming these shakes to build muscle mass had negative effects on mood, weight gain, food cravings and lifespan.
In part of the research, the scientists discovered that the BCAAs competed with tryptophan for transport in the blood to the brain. That started a chain reaction.
“Tryptophan is the sole precursor for the hormone serotonin, which is often called the ‘happiness chemical’ for its mood-enhancing effects and its role in promoting sleep,” explains co-lead author Professor Stephen Simpson. “But, serotonin does more than this. [This] lowered serotonin levels in the brain, which in turn was a potent signal to increase appetite. The serotonin decrease caused by excess BCAA intake led to massive overeating in our mice, which became hugely obese and lived shorter lives.”
These findings mean that men should aim to balance out their protein sources to avoid problems from consuming too many shakes to build muscle mass.
The results of the study were published in the journal Nature Metabolism.
The market for shakes that promise to build muscle mass
Many of the fitness protein powders that men buy at health supplement stores are made with whey proteins, which are high in BCAAs. It’s a big market, with reports showing that in 2017 the market was worth about $9.4 billion.
With estimates putting the future market of protein powders at close to $14.5 billion in 2023, the industry won’t be happy to see this study go public.
