How do our joints and muscles respond to dietary protein as we age? That’s the question UC Davis researcher Keith Baar and an international team of scientists set out to answer in a first-of-its-kind clinical study. Using an innovative stable isotope tracing technique, the researchers measured protein synthesis across multiple musculoskeletal tissues—including muscle, bone, cartilage, tendons, ligaments, and meniscus—in older adults over a two-week period. Their findings provide one of the most comprehensive maps to date of how these tissues remodel under real-world conditions, revealing that muscles have the highest rates of protein turnover, while connective tissues and bone remodel more slowly.
For the UC Davis Innovation Institute for Food and Health (IIFH), this work reflects the kind of translational research that advances nutrition science beyond traditional measures of muscle health. While the study found that adding a daily 40-gram whey protein supplement for two weeks did not significantly increase protein synthesis across these tissues in older adults already consuming adequate protein, the findings establish an important scientific foundation for developing more targeted nutrition strategies. By identifying how different musculoskeletal tissues respond—or don’t respond—to dietary protein, researchers can better design future interventions, including specialized proteins, collagen-based ingredients, or nutrition paired with exercise, to support healthy aging, recovery from surgery, and long-term mobility. It’s a reminder that breakthrough research doesn’t always come from confirming assumptions—it often comes from generating the evidence needed to ask smarter questions and accelerate innovation in food and health.
