Mediterranean Diet May Activate Tiny Proteins That Protect the Heart and Brain

A Mediterranean-style diet may influence aging through an unexpected biological pathway involving tiny proteins produced inside mitochondria, according to a new study led by researchers at the USC Leonard Davis School of Gerontology.

Mitochondria are best known as the structures that generate energy inside cells, but scientists increasingly recognize that they also release chemical signals that affect metabolism, inflammation, stress responses, and aging. The researchers found that older adults who followed a Mediterranean diet most closely had higher blood levels of two mitochondrial microproteins called humanin and SHMOOSE. Both have previously been associated with protection against cardiovascular disease and neurodegeneration.

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These microproteins are remarkably small — just 16 to 24 amino acids long — which may explain why they were overlooked for so long. Standard protein-detection methods are biased toward larger molecules, and microproteins were largely dismissed as biological noise until recent advances in proteomics revealed they are widespread and functionally important.

The diet-microprotein connection held even after adjusting for age, sex, body mass index, and other health factors. This suggests the effect is not simply due to the diet's known benefits for weight and metabolic health, but represents an independent molecular pathway linking food choices to cellular aging.

The study opens the door to testing whether specific components of the Mediterranean diet — such as polyphenols from olive oil or omega-3 fatty acids from fish — directly stimulate microprotein production. If confirmed, it could lead to targeted nutritional strategies for healthy aging that work through the mitochondrial signaling system.