Pure omega 3 polyunsaturated fatty acids (EPA, DPA or DHA) are associated with increased plasma levels of 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) in a short-term study in women

3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF) is a metabolite of furan fatty acids found in plasma and urine of humans after consumption of foods containing these fatty acids. Recently, CMPF has been identified as a prominent metabolite following the consumption of either fish oil, fish oil fatty acid-ethyl esters or diets rich in fish. As furan fatty acids are known to occur in fish and fish oil (at a low level), it is possible that in these studies the CMPF in plasma originated from furan fatty acids. We report the plasma CMPF levels in 10 healthy women who consumed 1 gram daily for 6 days of pure eicosapentaenoic acid (EPA), or docosapentaenoic acid (DPA) or docosahexaenoic acid (DHA), or olive oil, in a cross-over study. The supplemented omega 3 fatty acids contained no detectable levels of furan fatty acids. Plasma CMPF and the omega 3 fatty acids levels were measured by LC-MS/MS. Consuming the pure omega 3 fatty acids led to significant increases in plasma CMPF levels, but not with olive oil (from 1.6 to 2.5-fold compared with baseline). Plasma free fatty acid levels of EPA, DPA and DHA also increased significantly when they were supplemented (p<0.05). There were significant positive correlations between plasma free fatty acid DPA and DHA levels (p<0.05, r=+0.35 to +0.81), but not for EPA and CMPF. These data suggest that purified long chain omega 3 fatty acids may be precursors of CMPF, however the metabolic pathway(s) from omega 3 fatty acids to CMPF remain to be elucidated