Fatty acid composition of erythrocytes reflects CLA intake in a depletion‐repletion study with healthy subjects

Abstract

We studied fatty acid (FA) composition of erythrocytes in response to CLA depletion (8 w) and CLA repletion (8 w), in 27 men and women, aged 23 to 36 years. During the depletion phase all participants excluded sources of dairy fat from their diets and in the repletion phase they returned to their habitual diets and received 20 g of CLA‐biofortified butter, resulting in the intake of 1 g CLA/d. The FA composition of erythrocytes was determined by GC after lipid extraction and FA transesterification. Twenty‐seven FA were detected in the erythrocytes. The CLA contents (g/100g FA) in erythrocytes decreased significantly (p<0.01) in the depletion phase (0.18±0.03) when compared to baseline (0.31±0.05) and increased in the repletion phase (0.34±0.06). In addition, the CLA contents in erythrocytes were positively correlated with the habitual intake of CLA food sources obtained from a food‐frequency questionnaire. The ratio between 20:4n‐6 and 20:3 n‐6 was used as indicator of Δ5‐desaturase activity and reduced (p<0.05) in the CLA repletion phase. In addition, arachidonic acid was negatively correlated (r= 0.49; p<0.05) with CLA in erythrocytes. Our results are suggestive of erythrocyte composition as marker of CLA intake and of effects of CLA on Δ5‐desaturase activity, which could mediate some of the observed biological effects of CLA.Grant Funding Source: FAPERJ, CAPES, CNPq (Brazil).