Put down the protein shake? Overconsumption could slash lifespan, study says

01 May 2019 --- Fueled by a surge in consumer interest in exercise and health, protein has been riding a wave of fruitful product development. Yet recent research has identified that excessively consuming branched-chain amino acids (BCAAs) could result in a reduced life span, low mood and weight gain. Published in Nature Metabolism, the study notes that while BCAAs may be great for adding muscle mass, your health could pay for it later. The researchers instead advocate for a diet that includes a variety of protein sources and balanced amino acid consumption.

Dr. Solon-Biet of the University of Sydney investigates the complex role nutrition plays in mediating various aspects of metabolic health, reproduction, appetite and aging. She notes that while diets high in protein and low in carbohydrates have been shown to be beneficial for reproductive function, they had detrimental effects for health in mid-late life and also led to a shortened lifespan.

“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,” she adds.

Protein products have proven very popular among consumers and NPD has surged – particularly in the sports nutrition space. Innova Market Insights reports that more than 5 percent of new global food and beverage launches featured protein claims, with a CAGR of 29 percent from 2013-2017. Protein has a strong hold in the beverage space, with a NutritionInsight webinar poll finding that industry developers are targeting on-the-go beverage solutions that incorporate at least 10 and 20 grams of protein. 

Further research at the university examined the impacts that dietary BCAAs and other essential amino acids such as tryptophan had on the health and body composition of mice.

Mice were fed double the normal amount of BCAAs (200 percent), the standard amount (100 percent), half (50 percent) or one fifth (20 percent) for life. Mice who were fed 200 percent BCAAs increased their food intake, resulting in obesity and a shortened lifespan.

“Supplementation of BCAAs resulted in high levels of BCAAs in the blood which competed with tryptophan for transport into the brain,” explains Professor Stephen Simpson, Academic Director of the Charles Perkins Centre and Researcher from the School of Life and Environmental Sciences.

“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,” he says.

Serotonin levels in the brain were then lowered, which in turn was a potent signal to increase appetite. The serotonin decrease caused by excess BCAA intake led to overeating in the mice, which became obese and lived shorter lives.

As a result of the findings, the researchers say that a wider range of protein varieties is necessary for a healthy diet, which should also be rich in fiber, vitamins and minerals. 

BCAAs are a group of three essential amino acids: leucine, isoleucine and valine, and are most commonly found in red meat and dairy. Whey protein - the most popular form of fitness protein - is made from dairy by-products and contains high levels of BCAA.

The significant uptake in protein supplementation, such as shakes and bars, may mean that people are consuming too much protein, which could be harmful. According to the UK Reference Nutrient Intake (RNI), it is recommended we consume 0.75g of protein for each kg of weight, which, based on average weights roughly equals 55g for men and 45g for women. However, according to Nutritionist Charlotte Stirling-Redd, UK consumers are often consuming more than this.

One consumer group that is often deficient in protein is the senior group. A study published in the Journal of Nutrition, Health and Aging found that one in three adults aged over 50 are not consuming enough of the macronutrient. The analysis also revealed that protein consumption is a reliable indicator of adults’ overall diet, nutrition and physical well-being, as low protein consumption is often associated with a poorer quality diet and lower physical activity levels.