Status of carnitine and circulating amino acids and its association with pre-frailty, sarcopenia and diet in an Uruguayan older population

BACKGROUND: Frailty is a clinical-biological syndrome in older adults that carries an increased risk for poor health outcomes. Biomarkers of disability are being studied and some acylcarnitines and amino acids are part of the predictive models. OBJECTIVE: To characterize the status of L-carnitine, some acylcarnitines and amino acids and relate them to frailty, sarcopenia and diet in a community-dwelling Uruguayan older population. METHODS: Participants were enrolled and assessed through a multi-step process, that included frailty and sarcopenia criteria. L-carnitine, its acyl derivatives and amino acids were determined in blood by LC-MS/MS and dietary intake by a 24-h recall and a food frequency questionnaire. RESULTS: Sixty-three older adults were enrolled, and 54 completed the initial assessment. Pre-frailty criteria were fulfilled by 41 participants and frailty only by one. No nutritional indicators of undernutrition were found. Probable sarcopenia was found in 20 cases. Males consumed more total meat and red meat than women. Hexanoylcarnitine levels were higher in pre-frail/frail individuals and in weak ones. Analysis by sex showed a distinct pattern between gender, being significant only for weak females. Methionine also showed some differences between sexes. Weak males presented significantly higher levels of methionine, whereas weak females showed significantly lower ones. CONCLUSIONS: No associations were found for diet components and L-carnitine, acylcarnitines and amino acids values, except for the percentage of animal protein that was higher in weak males. The clinical impact of these results needs further investigation.