WeeklySA_AdminPLAQUE: Amino acids, which are really the building blocks of the protein, can trigger heart disease, according to new study…
By WSAM Correspondent
Scientists have discovered a molecular mechanism by which excessive dietary protein could increase risk plaque formation in the arteries.
The study, conducted by researchers at Pittsburgh University School of Medicine, showed that consuming over 22 percent of dietary calories from protein could lead to increased activation of immune cells that play a role in the thickening or hardening of the arteries caused by a build-up of plaque in the inner lining in the arteries (also called atherosclerosis), driving risk to disease. The research combined small human trials with experiments in mice and cells in a Petri dish.
Furthermore, the scientists showed that one amino acid – leucine – seems to have a disproportionate role in driving the pathological pathways linked to atherosclerosis, or stiff, hardened arteries. The findings were published in Nature Metabolism on February 19.
Expanding on the findings, senior researcher and Pittsburgh University Professor Babak Razani said: “Our study shows that dialling up your protein intake in pursuit of better metabolic health is not a panacea. You could be doing real damage to your arteries. Our hope is that this research starts a conversation about ways of modifying diets in a precise manner that can influence body function at a molecular level and dampen disease risks’’.
According to a survey of an average American diet over the last decade, Americans generally consume a lot of protein, mostly from animal sources.
That trend is likely driven by the popular idea that dietary protein is essential to healthy living, said Razani. But his and other groups have shown that overreliance on protein may not be such a good thing for long-term health.
Following their 2020 research, in which Razani’s laboratory first showed that excess dietary protein increases atherosclerosis risk in mice, his next study delved deeper into the potential mechanism and its relevance to the human body.
To arrive at the answer, Razani’s laboratory teamed up with Mittendorfer’s group to combine their expertise in cellular biology and metabolism and perform a series of experiments across various models – from cells to mice to humans.
“We have shown in our mechanistic studies that amino acids, which are really the building blocks of the protein, can trigger disease through specific signalling mechanisms and then also alter the metabolism of these cells”.
Razani is careful to note that many questions remain to be answered, mainly: What happens when a person consumes between 15% of daily calories from protein as recommended by the USDA and 22% of daily calories from protein, and if there is a ‘sweet spot’ for maximising the benefits of protein – such as muscle gain – while avoiding kick-starting a molecular cascade of damaging events leading to cardiovascular disease.
The findings are particularly relevant in hospital settings, where nutritionists often recommend protein-rich foods for the sickest patients to preserve muscle mass and strength.
“Perhaps blindly increasing protein load is wrong,” Razani said. “Instead, it’s important to look at the diet as a whole and suggest balanced meals that won’t inadvertently exacerbate cardiovascular conditions, especially in people at risk of heart disease and vessel disorders.”
Razani also notes that these findings suggest differences in leucine levels between diets enriched in plant and animal protein might explain the differences in their effect on cardiovascular and metabolic health. “The potential for this type of mechanistic research to inform future dietary guidelines is quite exciting,” he said.
Meanwhile, Mayo Clinic recommends anywhere from 10 to 35 percent of your calories should come from protein. So if your needs are 2,000 calories, that’s 200–700 calories from protein, or 50–175 grams. The recommended dietary allowance to prevent deficiency for an average sedentary adult is 0.8 grams per kilogram of body weight. For example, a person who weighs 165 pounds, or 75 kilograms, should consume 60 grams of protein per day. Once you reach ages 40–50, sarcopenia, or losing muscle mass as you age, begins to set in. To prevent this and to maintain independence and quality of life, your protein needs increase to about 1–1.2 grams per kilogram or 75–90 grams per day for a 75-kilogram person.
People who exercise regularly also have higher needs, about 1.1–1.5 grams per kilogram. People who regularly lift weights, or are training for a running or cycling event need 1.2–1.7 grams per kilogram. Excessive protein intake would be more than 2 grams per kilogram of body weight each day.
If you are overweight, your weight is adjusted before calculating your protein needs to avoid overestimating. You can see a dietitian to help develop a personalized plan.
When is the best time to consume protein?
Spread out protein consumption evenly throughout the day. On average, people tend to get most of their protein during evening meals and the least at breakfast. Some newer studies show moving some protein from supper to breakfast can help with weight management by decreasing hunger and cravings throughout the day. Of course, more research is needed before these claims can be verified.
