News summary produced by Claude AI
Researchers at the USC Leonard Davis School of Gerontology have identified a biological mechanism that may explain how a Mediterranean-style diet protects against age-related diseases. The study examined blood samples from older adults and found that those with the strongest adherence to a Mediterranean diet had significantly higher concentrations of two mitochondrial microproteins called humanin and SHMOOSE. Both proteins have been associated in previous research with protection against cardiovascular disease and neurodegeneration, the gradual decline in nerve cell function seen in conditions such as Alzheimer’s disease.
The Mediterranean diet emphasizes olive oil, fish, legumes, fruits, vegetables, whole grains, and minimally processed foods while limiting refined carbohydrates and heavily processed products. Decades of research have linked this eating pattern to lower risks of cardiovascular disease, type 2 diabetes, cognitive decline, and premature death. The new findings suggest that individual components of the diet may influence mitochondrial health differently. Higher consumption of olive oil, fish, and legumes was associated with increased humanin levels, while olive oil consumption and lower intake of refined carbohydrates were linked to higher SHMOOSE levels. Participants with stronger diet adherence also showed lower indicators of oxidative stress, a form of cellular damage caused by unstable molecules that can injure proteins, fats, and DNA.
Humanin and SHMOOSE are produced from sections of the mitochondrial genome known as small open reading frames. Humanin was first identified in 2003 and has been connected to improved insulin sensitivity, cardiovascular protection, and preservation of cognitive function. SHMOOSE was discovered later and has been linked to brain health, with certain genetic variants associated with increased Alzheimer’s disease risk. The researchers also identified a potential connection between humanin and Nox2, an enzyme that produces reactive oxygen species, suggesting that humanin may help limit oxidative damage to the heart and blood vessels.
The study was observational in nature, meaning it identified associations between diet and microprotein levels but could not prove direct causality. Other factors including physical activity, health status, medication use, genetics, and lifestyle could have influenced the results. Despite these limitations, the findings point toward the emerging field of precision nutrition, which aims to use biological measurements and personal characteristics to create individualized dietary recommendations. Future research will test whether dietary changes can directly raise microprotein levels and whether such increases reduce disease risk.