In obese children, hyperinsulinaemia induces adverse metabolic consequences related to the risk of cardiovascular and other disorders.
Branched-chain amino acids (BCAA) and acylcarnitines (Carn), involved in
amino acid (AA) degradation, were linked to
obesity-associated
insulin resistance, but these associations yet have not been studied longitudinally in obese children. We studied 80 obese children before and after a one-year lifestyle intervention programme inducing substantial
weight loss >0.5 BMI standard deviation scores in 40 children and no
weight loss in another 40 children. At baseline and after the 1-year intervention, we assessed
insulin resistance (HOMA index), fasting
glucose, HbA1c, 2 h
glucose in an oral
glucose tolerance test, AA, and Carn. BMI adjusted metabolite levels were associated with
clinical markers at baseline and after intervention, and changes with the intervention period were evaluated. Only
tyrosine was significantly associated with HOMA (p < 0.05) at baseline and end and with change during the intervention (p < 0.05). In contrast, ratios depicting BCAA metabolism were negatively associated with HOMA at baseline (p < 0.05), but not in the longitudinal profiling. Stratified analysis revealed that the children with substantial
weight loss drove this association. We conclude that
tyrosine alterations in association with
insulin resistance precede alteration in BCAA metabolism. This trial is registered with ClinicalTrials.gov Identifier NCT00435734.