0649 GMT February 25, 2020
Further, the new research showed that high-protein diets spur unstable plaque — the kind most prone to rupturing and causing blocked arteries. More plaque buildup in the arteries, particularly if it's unstable, increases the risk of heart attack, according to medicalxpress.com.
The new study, by researchers at Washington University School of Medicine in St. Louis, appears in the journal Nature Metabolism.
"There are clear weight-loss benefits to high-protein diets, which has boosted their popularity in recent years," said senior author Babak Razani, MD, Ph.D., an associate professor of medicine. "But animal studies and some large epidemiological studies in people have linked high dietary protein to cardiovascular problems. We decided to take a look at whether there is truly a causal link between high dietary protein and poorer cardiovascular health."
The researchers studied mice fed a high-fat diet to deliberately induce atherosclerosis, or plaque buildup in the arteries. According to Razani, mice must eat a high-fat diet to develop arterial plaque. Therefore, some of the mice received a high-fat diet that was also high in protein. And others were fed a high-fat, low-protein diet for comparison.
"A couple of scoops of protein powder in a milkshake or a smoothie adds something like 40 grams of protein — almost equivalent to the daily recommended intake," Razani said. "To see if protein has an effect on cardiovascular health, we tripled the amount of protein that the mice receive in the high-fat, high-protein diet — keeping the fat constant. Protein went from 15 percent to 46 percent of calories for these mice."
The mice on the high-fat, high-protein diet developed worse atherosclerosis — about 30 percent more plaque in the arteries — than mice on the high-fat, normal-protein diet, despite the fact that the mice eating more protein did not gain weight, unlike the mice on the high-fat, normal-protein diet.
"This study is not the first to show a telltale increase in plaque with high-protein diets, but it offers a deeper understanding of the impact of high protein with the detailed analysis of the plaques," Razani said. "In other words, our study shows how and why dietary protein leads to the development of unstable plaques."