Blood Metabolite Signature Linked to Long-Term Survival in Mediterranean Diet Study

Evaluating dietary adherence has traditionally relied on self-reported food frequency questionnaires, which can occasionally misclassify actual intake due to recall limitations. To gain a more objective biological perspective, researchers recently investigated whether a specific blood plasma profile could track dietary habits and associate with long-term survival rates. The findings were published in The American Journal of Clinical Nutrition.

Understanding the Plasma Metabolomic Signature

The study evaluated a pre-developed plasma metabolomic signature consisting of 67 metabolites designed to reflect adherence to the Mediterranean diet. This eating pattern typically includes olive oil, vegetables, fruit, nuts, legumes, and fish. While previous investigations connected this biological signature to a reduced future risk of cardiovascular issues, researchers sought to determine if the same profile could predict long-term mortality across diverse populations.

To test this, investigators analyzed data from the Spanish multicenter PREDIMED randomized nutritional intervention trial, which followed adults at high cardiovascular risk over an average period of approximately 13.2 years. Plasma samples were examined using liquid chromatography-tandem mass spectrometry to measure the selected compounds. External replication of the findings was subsequently conducted using data from 12,704 participants across independent United States cohorts, including the Nurses’ Health Studies and the Health Professionals Follow-Up Study, with an average follow-up of 25 years.

Key Findings and Survival Associations

In the PREDIMED analysis, participants with higher baseline metabolomic signature scores generally showed better adherence to the Mediterranean diet and were less likely to smoke or live with type 2 diabetes. Specifically, individuals in the highest third of signature scores demonstrated a 23% lower relative hazard of death compared to those in the lowest third. Furthermore, each standard deviation increase in the signature corresponded to a 19% lower relative hazard of all-cause mortality.

• Participants in the highest third of baseline signature scores had a 23% lower relative hazard of death.
• Each standard deviation increase in the signature was associated with a 19% lower relative hazard of all-cause mortality.
• The 1-year follow-up signature in PREDIMED showed that each standard deviation increase was associated with a 26% lower relative hazard of cardiovascular death.
• In the independent US cohorts, participants in the highest fifth of signature scores experienced a 23% lower relative hazard of all-cause mortality.

Study Limitations and Considerations

While the results show consistent inverse associations between the metabolomic signature and long-term mortality, authors emphasized several important limitations. Because the evaluations were observational, the data do not establish direct causation or prove that artificially raising the signature score or altering diet directly reduces mortality. Additionally, the profiling platform could not measure certain antioxidants and phenolic compounds, and the specific selection criteria for the US cohorts may limit how broadly the results can be applied. Further clinical research is required to determine the exact utility of these blood markers in routine healthcare settings.