A 67-metabolite blood marker of Mediterranean-style eating tracks with lower mortality

A blood signature of diet quality was linked to 23% lower death risk across 14,584 people, but the evidence is observational and needs wider validation.

Researchers from the University of Navarra, Harvard T.H. Chan School of Public Health and other institutions tested whether a blood signature of Mediterranean-style eating relates to how long people live. The signature is made up of 67 metabolites, mostly lipids. It was developed in 2020 and had already been linked to diet adherence and cardiovascular disease risk. The new work, covering 14,584 people in Spain and the United States, appears in The American Journal of Clinical Nutrition.

The Spanish group was 1,880 PREDIMED participants: older adults with no cardiovascular disease at enrollment but at high risk of developing it. Over about 13 years, the top third of signature scores had 23% lower mortality risk than the bottom third, after adjusting for age, smoking, BMI and existing conditions. In the US, 12,704 participants from three long-running studies were followed for an average of 25 years. The top fifth of scores had the same 23% lower risk versus the bottom fifth. In the Spanish group, the link held up largely intact after adjusting for self-reported diet adherence.

The appeal is an objective measure of diet quality. Food questionnaires are noisy, and a blood test could make risk screening cheaper and more consistent. It could also help target nutrition advice at people most likely to benefit, which would make good dietary guidance more precise and more widely usable.

The caveats are large. The mortality analysis is observational, so it cannot show that raising a score would extend life. The US participants were health professionals, mostly white and relatively healthy, so testing in more diverse populations is needed. It also remains to be shown that the signature improves prediction beyond established risk factors. Changes in the signature over the first year of intervention were not associated with mortality, and it is uncertain whether one year is too short to capture dietary effects. Estefanía Toledo, a University of Navarra epidemiologist, stressed that the result shows risk differences between groups, not an individual's lifespan. The authors only suggest a test might eventually help identify who benefits most.

Source: ScienceAlert