If your morning routine consists of downing a protein shake before you head out the door, or you regularly drink one after your work out, you may want to consider changing things up a bit. While consumers have been told for years that protein shakes are healthy, a new study is showing the negative effects of drinking protein shakes in the long run.
The study, conducted by the University of Sydney and published in Nature Metabolism, found that branched-chain amino acids, the same amino acids found in protein powders and protein shakes, can actually cause depression and mood changes, and lead to weight gain and a shorter life expectancy when used excessively.
The protein supplement industry was a $14 billion industry worldwide last year, The Daily Mail reports, meaning lots of people are turning to protein shakes to supplement their diets and enhance their fitness regime. Experts are now suggesting that consumers switch up how they get their protein in their diets and not to rely solely on protein shakes as they may not be as healthy as they once were thought to be.
“While diets high in protein and low in carbohydrates were shown to be beneficial for reproductive function, they had detrimental effects for health in mid-late life, and also led to a shortened lifespan,” Dr. Samantha Solon-Biet, one of the authors of the study, stated. “What this new research has shown is that amino acid balance is important – it’s best to vary sources of protein to ensure you’re getting the best amino acid balance."
The study found that high levels of the branched-chain amino acids in the blood competed with other amino acids, like tryptophan. Tryptophan helps create serotonin and when there isn't enough serotonin it can lead to mood changes and changes in appetite.
“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. But serotonin does more than this, and therein lay the problem," Professor Stephen Simpson, co-author of the study said. “This then 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.”
The study suggests eating a healthy and balanced diet to ensure you are getting the appropriate amount of protein from natural sources.