Evaluation of the relative concentration of serum fatty acids C14:0, C15:0 and C17:0 as markers of children's dairy fat intake

Background/Aims: Biomarkers can provide objective measures of dietary exposure, but their relationship with dietary intake in different populations needs to be characterized. This study aimed to determine the association between C14: 0, C15: 0 and C17: 0 and children's dairy fat intake, and to ascertain whether these fatty acids can be used as biomarkers for detecting change in dairy fat intake.

Methods: Data from a randomized controlled trial (114 healthy children of 4-13 years of age) was used. The intervention was a replacement of regular-fat dairy foods with reduced-fat or low-fat items. Serum fatty acid composition was measured and dairy intake was assessed via 3 × 24-hour diet recalls at baseline and at 12 weeks (the end of the intervention). Correlation analysis was used to evaluate the relationship between dietary intake and fatty acids at baseline and at week 12, and for the change in biomarkers and diet between these time points.

Results: Total dairy fat intake correlated with C14: 0, C15: 0 and C17: 0 at baseline (n = 114; r = 0.24; r = 0.42; r = 0.25 re- spectively, all p < 0.05), but not at week 12. The change in the total amount of dairy fat (g/day) after 12 weeks was associated with a change in serum C15: 0 (n = 59; r = 0.27; p = 0.04).

Conclusions: C15: 0 is a useful biomarker of dairy fat intake in children and can detect short-term changes in the absolute intake of dairy fat.