Eating too much protein can lead to a dangerous build-up of plaque in the arteries, research claims

It’s been hyped for its muscle-building and appetite-suppressing properties, but scientists fear protein could be bad for your blood vessels.

Researchers from the University of Pittsburgh found that mice fed a diet high in macronutrients had a buildup of plaque in their arteries.

They suggested this was caused by high protein levels causing problems in the immune system, leading to white blood cells collecting in ‘cemeteries’ in the artery walls and causing fatty deposits.

It comes as demand for a high-protein diet is increasing, with bars, cereals and yoghurts hitting the shelves claiming their high protein content helps them build muscle.

Dr. Babak Razani, a cardiologist who led the study, warned that their research suggested that “boosting” protein intake was “not a silver bullet” for a good diet.

He suggested that people should instead ensure they eat a ‘balanced’ diet that contains sufficient carbohydrates, fats and essential nutrients.

Americans are advised to eat about 0.36 grams (g) of protein per pound of body weight per day.

For the average 199-pound man, this is about 71 grams per day – equivalent to two chicken breasts or one and a half salmon fillets.

And for the average woman who weighs 170 pounds, this is 61.2 ounces per day – equivalent to one and a half tuna steaks or two cups of chickpeas.

But gym culture promotes consuming much more, and some plans suggest doubling this amount – or about 0.8 grams per pound of body weight per day.

Once consumed, the protein is broken down into amino acids that are used to repair torn muscle fibers and grow new ones.

But if a person does not exercise, the unused proteins are filtered from the body by the kidneys and excreted through the urine. The body cannot store proteins.

In their theory, revealed in the magazine Nature metabolismscientists warned that high levels of protein in the diet could activate macrophages – a type of white blood cell responsible for clearing away cell debris.

They suggested that these activated cells, however, would not function properly and would instead collect in ‘cemeteries’ within the artery walls.

This would cause fatty deposits to form in the fat deposits and build up plaque, which is linked to atherosclerosis.

In particular, they suggested that the amino acid leucine – one of three types – could cause the troublesome activation.

Dr. Bettina Mittendorfer, a metabolism expert at the University of Missouri who was also involved in the research, said: ‘We have shown in our mechanistic studies that amino acids, which are actually the building blocks of the protein, can cause disease through specific signaling. mechanisms and subsequently also change the metabolism of these cells.’

‘For example, small immune cells in the vascular system called macrophages can cause the development of atherosclerosis.’

Dr. Razani added: ‘Maybe blindly increasing protein loads is wrong (especially in hospitalized patients).

‘Instead, it is important to look at the diet as a whole and propose balanced meals that will not inadvertently worsen cardiovascular disease, especially in people at risk of cardiovascular disease.’

Limitations of the study include that it was only conducted in mice and over a short period of time, with human results now needed to confirm the findings.

It is also not clear whether other factors, such as stress or other substances in the diet, could have played a role in the build-up of plaques in the blood vessels of mice.