The mean RBC percentage of 22:0 (behenic acid) in this cohort was 0.23%. Very little 22:0 is consumed directly from the few foods that contain it (e.g., canola oil, peanuts, and macadamia nuts). The primary source of 22:0 is via metabolism of 18:0 by elongases 1 and 3 (38). Our results are in agreement with reports in which higher percentages of VLCFAs in RBC were associated with lower risk of coronary heart disease (39, 40) or sudden cardiac arrest (41). VLCFAs are important constituent of sphingolipids, such as ceramides and sphingomyelins. The high correlation between 22:0 and 24:0 and 24:1 observed here confirms that this FA is a surrogate of a suite of these complex lipid molecules. In a previous study in Framingham Offspring (examination 8, the same as in the current study), Walker et al. (42) found an inverse relation between the 22:0/16:0 ratio in plasma ceramides with both CV and total mortality. Zhao et al. (43) reported an inverse relation between plasma VLCFA, including 22:0, and risk of metabolic syndrome. Although the relation between VLCFAs in RBC and plasma has not been thoroughly explored, a higher RBC 22:0 could reasonably reflect a lower risk milieu.
