There is recently a considerable development in the understanding of lipids and their associations with disease, through disease etiology, biomarkers, treatment and prevention. To the present date, there have been over 150 different diseases connected with lipids, ranging from high blood pressure and artery plaques, obesity, type II diabetes, cancer and neurological disorders
[1].
Fatty acids are the basic building blocks of more complex lipids
[2] and their composition in different lipid species are often used as a means for comparison within a lipid class when examining disease and physiological perturbations in lipid metabolism. It has been shown that saturated fatty acids
[3] are associated with increased relative risks for diseases such as coronary heart disease, atherosclerosis, fatty liver disease, inflammatory diseases and Alzheimer’s disease. In contrast many unsaturated fatty acids including both mono-unsaturated and poly-unsaturated, have been associated with a reduced risk for each of the previously described disorders in certain studies
[4]. Fatty acid chain length is also used for the diagnosis and prognosis of disease with respect to adrenoleukodystrophy, Refsum disease and Zellweger Syndrome where the propagation of very long chain fatty acids (>22 Carbon length chain
[5]) is indicative of these disorders
[6].
Pentadecanoic acid (15:0), which originate from rumen microbial fermentation, is a kind of minor saturated fatty acid (FAs) in ruminant fat
[7]. Its concentration in conventionally produced cow milk are on average 1.2% of total FAs, respectively. Concentrations in organically produced milk are somewhat higher
[8]. 15:0 is accepted biomarkers for dairy fat intake
[9], because its concentration in human plasma and RBCs increase with higher intake of dairy fat
[10–13].
For instance, in the EPIC (European Prospective Investigation into Cancer and Nutrition)-InterAct case-cohort study, concentration of 15:0 in plasma phospholipids were on average 0.21% of total FAs, respectively
[5]. Interestingly, 17:0 is present in plasma at approximately twice the concentration of 15:0 [reviewed in
[14]] or even more in RBCs
[4], the association with dairy fat intake is stronger for 15:0 than for 17:0
[10, 12, 13].
Figure 1 the chemical structure of Pentadecanoic acid
