Erythrocyte cell membrane phospholipid levels compared against reported dietary intakes of polyunsaturated fatty acids in pregnant Mexican women

Abstract

AbstractObjective:To evaluate the validity of a food-frequency questionnaire (FFQ) for assessment of the dietary intakes of polyunsaturated fatty acids (PUFAs) against a biochemical marker of fat intake, erythrocyte cell membrane phospholipid levels, during pregnancy.Design:Cross-sectional analysis.Setting:Developmental Neurobiology Department, National Institute of Perinatology, Mexico City.Subjects:One hundred forty-six healthy pregnant women during the last trimester of pregnancy. Among women enrolled, the first 35 pregnant women (24%) had their erythrocytes analysed for fatty acid status.Methods:We administered an FFQ and compared intakes of PUFAs against their erythrocyte cell membrane concentrations, processed by gas chromatography.Results:Pearson correlation coefficients among α-linolenic acid (ALN), docosahexaenoic acid (DHA) and eicosapentaenoic acid in erythrocyte cell membranes against their crude dietary counterparts were 0.32, 0.35 and 0.36 (each P < 0.05). In a simple linear regression, erythrocyte DHA and arachidonic acid (AA) were significantly related to their respective dietary intakes (β = 0.30, 95% confidence interval (CI): 0.007–0.60, P = 0.045 for DHA; β = 0.49, 95% CI: 0.010–0.98, P = 0.044 for AA). Erythrocyte cell membrane ALN concentration (%/total) was only marginally related to ALN dietary intake (mg day−1) (β = 0.52, 95% CI: −0.020–1.10, P = 0.061). However, after adjustment for long-chain n–3 PUFA/AA, this association reached significance (β = 0.44, 95% CI: 0.026–0.825, P = 0.038). Main dietary sources for n–3 PUFAs were canned tuna fish and fresh catfish; for n–6 these were eggs and cow's milk. The use of this FFQ in these pregnant Mexican women provided estimates of average long-term intakes of PUFAs and correlated reasonably well with their erythrocyte cell membrane phospholipid status. However, we need to consider that, during pregnancy, there is a faster turnover of PUFAs from fat storage that may modify the profile of erythrocyte PUFAs and lower the correlation between dietary intake and erythrocyte PUFAs.