Effect of a low-fat diet on fatty acid composition in red cells, plasma phospholipids, and cholesterol esters: investigation of a biomarker of total fat intake

• Published in: The American journal of clinical nutrition 2006-02, Vol.83 (2), p.227-236
• Main Authors: King, Irena B, Lemaitre, Rozenn N, Kestin, Mark
• Format: Article
• Language: English
• Subjects: Aged; Biological and medical sciences; Biomarkers - blood; blood lipids; Cholesterol; Cholesterol Esters - blood; Cholesterol Esters - chemistry; cholesteryl esters; Chromatography, Gas; Diet; Diet Records; Diet, Fat-Restricted; dietary fat; Erythrocytes - chemistry; fat intake; fatty acid composition; Fatty acids; Fatty Acids - analysis; Fatty Acids, Omega-3 - analysis; Fatty Acids, Omega-6 - analysis; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Humans; Isomerism; Lipids; lipolysis; Logistic Models; low fat diet; menopause; Middle Aged; Oils & fats; phospholipids; Phospholipids - blood; Phospholipids - chemistry; Plasma; Postmenopause; Predictive Value of Tests; reticulocytes; ROC Curve; Sensitivity and Specificity; Vertebrates: anatomy and physiology, studies on body, several organs or systems; women
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/83.2.227

BACKGROUND: The utility of fatty acids (FAs) as biomarkers of total fat intake is unknown. OBJECTIVE: We compared FA changes in red cells (RCs), plasma phospholipids (PLs), and cholesterol esters (CEs) in response to a low-fat diet (LFD) and a moderate-fat diet (MFD) and assessed whether individual or combination of FAs predict LFD. DESIGN: Postmenopausal women (n = 66) were randomly assigned to receive an LFD (17% of energy from fat) or an MFD (34% of energy from fat) for 6 wk. All foods were provided. FAs in diets and blood were determined by gas-liquid chromatography. FA changes between baseline and end of study were compared across diets by using t tests. FA predictors of an LFD were selected by logistic regression. RESULTS: Many FAs in RCs, PLs, and CEs responded differently to the 2 diets. Changes from baseline with an LFD for palmitic acid (16:0) (3-11% increase), behenic (22:0) and lignoceric (24:0) acids (3-20% decrease, in RCs and PLs only), cis-monounsaturated FA (MUFA) (25-35% increase), linoleic acid (18:2n-6) (11-13% decrease), trans octadecanoic acids (trans 18:1) (7-20% decrease), and n-6 highly unsaturated FA (HUFA) (2-8% increase) were significantly different from changes with an MFD. Individually, 18:2n-6 and trans 18:1 were strong predictors of an LFD [receiver operating characteristic (ROC) curves: 0.92-0.80). A logistic regression model with trans 18:1, 18:2n-6, and vaccenic acid (18:1n-7) predicted an LFD with high specificity and sensitivity (ROC curves: 0.99). CONCLUSIONS: Saturated FA, cisMUFA, n-6 HUFA, and exogenous FAs greatly differed in their response to the LFD and MFD. Parallel responses were observed in RCs, PLs, and CEs. A model with a combination of FAs almost perfectly differentiated the consumption of 34% fat from that of 17% fat.