A review of over 350 studies suggests that reducing protein intake may support healthy aging, though researchers emphasize that individual needs vary significantly.

A new review published July 31 in Cell Press Blue suggests that reducing protein intake may support healthy aging and longevity. By analyzing more than 350 laboratory and animal studies, researchers found that protein restriction may improve metabolism, reduce inflammation, and decrease cellular damage. However, the study notes that these potential benefits depend on individual factors such as age, activity level, and overall health.

Findings from Animal Studies

The review found that restricting protein, particularly specific amino acids like methionine, isoleucine, and valine, extended life span in rodent studies. In one instance, valine restriction increased the life span of middle-aged male mice by 23%. Researchers also observed that protein restriction in mice could raise FGF21 levels, which were associated with longer life spans, with some female mice living 40% longer and males 30% longer.

Metabolic and Cellular Impacts

Protein restriction may influence biological pathways by altering nutrient sensors such as mTORC2 and GCN2. This process promotes autophagy, the body's method of removing damaged cellular components. Additionally, the review suggests that restriction may improve mitochondrial function, reduce oxidative stress, and help preserve youthful gene expression patterns.

Human Health Considerations

While short-term clinical trials in humans linked protein restriction to improved blood sugar and reduced fat mass, researchers found no direct evidence that it extends human life span. Experts caution that protein remains essential for muscle growth and exercise response, particularly for active individuals. Older adults, or those with chronic conditions like sarcopenia, may require higher protein intake, ranging from 1.0 to 2.0 grams per kilogram of body weight.