Recommended dairy product intake modulates circulating fatty acid profile in healthy adults: a multi-centre cross-over study.

Dairy products are rich sources of an array of fatty acids (FA) that have been shown individually and in certain clusters to exert varying effects on cardiovascular health, for which the circulating lipid profile is a powerful biomarker. Whether the profile of these FA is reflected in blood upon short terms of intake, possibly contributing to the lipid-related health impacts of dairy products, remains to be fully established. The objectives of the present study were to assess a recommended dairy product consumption in relation to circulating FA and lipid profiles, and to evaluate certain FA in dairy fat as potential biomarkers of intake. In a free-living, multi-centre, cross-over design, 124 healthy individuals consumed 3 servings/d of commercial dairy (DAIRY; 1% fat milk, 1·5% fat yogurt and 34% fat cheese) or energy-equivalent control (CONTROL; fruit and vegetable juice, cashews and a cookie) products for 4 weeks each, separated by a 4-week washout period. Plasma FA and serum lipid profiles were assessed by standard methods at the end of each dietary phase. After 4 weeks of intake, plasma levels of FA pentadecanoic acid (15 : 0) and heptadecanoic acid (17 : 0) were higher (0·26 v. 0·22% and 0·42 v. 0·39% of the total identified FA, respectively) after the DAIRY phase than after the CONTROL phase (P< 0·0001). This was accompanied by a small but significant increase in serum LDL-cholesterol levels after the DAIRY phase compared with the CONTROL phase (+0·08 mmol/l; P= 0·04). In conclusion, intake of 3 servings/d of conventional dairy products may modify certain circulating FA and lipid profiles within 4 weeks, where 15 : 0 and 17 : 0 may be potential short-term biomarkers of intake.