Pentadecanoic acid in the French diet: absolute quantitative assessment and contributions of dairy and non-dairy foods using a market basket approach.

Pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0) are odd-chain fatty acids, mainly described in dairy products, as they constitute 1% and 0.5% of total ruminant milk fatty acids. They are thus often considered as plasma biomarkers of dairy intake. Yet, their detection in some non-dairy foods has challenged this exclusivity. To identify the dietary sources of OCFAs, a broad food panel was analyzed by GC-MS, including dairy (cheese, yogurt, butter…), meat (beef, pork, chicken…), different fish species and fish oils, vegetal oils, fruits and vegetables etc. Results confirmed that C15:0 and C17:0 represented on average 1.5% and 0.8% of total fatty acids in dairy products. C15:0 was almost exclusively abundant in dairy, whereas C17:0 also appeared in notable amounts in beef and, to a lesser extent, pork. Low amounts of C15:0 and C17:0 were detected in fish, whereas higher amounts of C17:0 were found in fish oils. Thus, dairy products remain the richest source of C15:0, containing the highest amounts per portion. • C15:0 and C17:0 represent 1.5% and 0.8% of total dairy fatty acids. • C15:0 dietary intake comes mainly from dairy consumption. • C17:0 dietary intake comes from meat and dairy consumption. • C15:0 is very characteristic of dairy products, more than C17:0 • Fish do not appear as main sources of odd-chain fatty acids.