High Protein Intake May Curb Age-Related Inflammation

Building on previous work, researchers at the Jean Mayer USDA Human Nutrition Research Center On Aging at Tufts found adults aged 60 who had diets that on average included adequate protein, especially plant based protein, showed fewer signs of inflammaging, which is low grade age related chronic inflammation associated with frailty and illness. 

As published in the journal Current Developments in Nutrition inflammaging was categorized by combining 9 common biomarkers of inflammaging and oxidative stress to create a composite score, and involved 2,106 participants of the Framingham Heart Study’s Offspring Cohort of adults in a long term study of cardiovascular disease. Composite inflammation scores from the participants were compared against their protein intake using results from their food questionnaires. 

The risk of chronic low grade inflammation increases with age. While examining higher intake protein in general those that averaged 95 grams a day tended to have more favorable markers of inflammation; plant based protein appeared to be the most beneficial, 10 grams a day in plant protein intake between the high and low intake groups was enough to show a beneficial association with inflammation. 

 “Inflammation plays an important role in diseases related to aging. Our previous research had seen a striking maintenance of physical function and lower risk of disability with age among older individuals who consumed higher amounts of protein since mid-life. The science would suggest that people with inadequate levels of protein might benefit from more,” says epidemiologist Paul F. Jacques.

“To our knowledge, no study thus far has examined the impact of regular protein intake over a long period of time and the effect it may have on measurable markers of age-related inflammation and oxidative stress. Our goal was to assess how habitual protein intake in a sample of generally healthy, aging adults might affect the changes we see in chronic inflammation,” explains epidemiologists Adela Hruby

“Biomarkers are evidence in the body of existing disease or health. We were fortunate to have a large group of people who were followed over a long period of time as part of an existing study. The participants underwent regular medical exams, which included blood work and urine samples to measure various biomarkers. We created our composite score by combining nine commonly used biomarkers of inflammation and oxidative stress. The higher the score, the greater the level of inflammation. These biomarkers were measured twice, with measurements coming seven years apart, and we looked at changes in the scores over this time period,” says Hruby.

“While our results do not reflect all possible biomarkers of chronic inflammation, these biomarkers are broadly associated with chronic diseases and their risk factors.  In previous research, food sources have been shown to have differing effects on these biomarkers, and that was the case in our study. While total protein intake was associated with lower inflammation scores, the most favorable results were for participants who consumed higher levels of plant protein. Although we did not see improved scores associated with higher consumption of animal protein alone, it's important to note that participants consumed both animal and plant protein. The difference is likely a consequence of other components of the foods that may be pro-inflammatory or anti-inflammatory. A question for further study is whether it is protein per se that helps counteract age-related inflammation, or is it other components of the foods?” says Jacques.

“The recommended daily amount of protein for adults is calculated based on several factors, including age, weight, and gender. As a broad example, an average 165-pound adult would need 60 grams of protein per day—about the equivalent found in three cans of tuna or four containers of Greek yogurt. For plant protein sources, a cup of cooked quinoa contains about 8 grams of protein, and a quarter cup of almonds has 6 grams. While most study participants were consuming adequate amounts of protein, those who took in a bit more were doing better in terms of their inflammation status. Our research suggests that including enough protein in the diets of older adults, especially from plant sources, may help reduce the burden of frailty, sickness, and disease that is associated with the chronic inflammation of aging,” said Hruby.

“Meeting protein needs in aging populations is important not just for maintenance of lean muscle mass, strength, and physical function, but our work also indicates protein may have a role in counteracting age-related changes in the inflammatory response,” said Jacques.

“Our research suggests that including enough protein in the diets of older adults, especially from plant sources, may help reduce the burden of frailty, sickness, and disease that is associated with the chronic inflammation of aging,” says Hruby, Ph.D.

“The American food landscape and patterns of protein supplement use have changed pretty substantially since the time of data collection for this study,” Hruby said. “In addition, our study is just one contribution to a large body of research that hasn’t yet reached definitive conclusions about the role of protein in age-related inflammation.”