Fitness enthusiasts will most likely be familiar with drinking protein shakes, with these beverages helping to replenish muscles after a big workout.
Indeed, protein is renowned for supporting muscle growth and recovery, supplementing nutrition, and helping people feel fuller for longer so they can reduce their portion sizes.
However, scientists at The University of Sydney have warned those in the fitness and bodybuilding communities not to consume excessive amounts of protein-rich products as they could have a negative impact on health.
The study, published in Nature Metabolism, revealed branched-chain amino acids (BCAAs), found in protein powders, could lead to a reduce lifespan, low mood and weight gain.
Dr Samantha Solon-Biet, one of the academics behind the research, said: “While diets high in protein and low in carbohydrates were shown to be beneficial for reproductive function, they have detrimental effects for health in mid-late life, and also led to a shortened lifespan.”
She added that a balance is important, with the best option being to vary protein sources to avoid becoming reliant on BCAA-rich protein powders.
To conduct the research, mice were given a diet of BCAA and other essential amino acids, including tryptophan.
It found that too much tryptophan resulted in lowered levels of serotonin in the brain, which is famous for its mood-lifting effects. Report author Professor Stephen Simpson, academic director of the Charles Perkins Centre and researcher from the School of Life and Environmental Sciences, said:
“The serotonin decrease caused by excess BCAA intake led to massive overreacting in our mice, which became hugely obese and lived shorter lives.”
If you want to improve your fitness goals, with or without protein shakes you could consider vitamin D supplements to help boost serotonin levels but remember, as with most things, moderation and balance is key to maintaining a healthy lifestyle.