Association between interaction and ratio of ω-3 and ω-6 polyunsaturated fatty acid and the metabolic syndrome in adults.

OBJECTIVE: To investigate the association of the intakes of ω-3 (including α-linolenic acid [ALA], eicosapentaenoic acid [EPA] plus docosahexaenoic acid [DHA]) and ω-6 polyunsaturated fatty acids (PUFAs), the interaction, and the ratio of these PUFAs with the metabolic syndrome (MetS) in adults.

METHODS: This cross-sectional study was conducted in a random sample of participants (n = 2451, 19-84 y old) in the Tehran Lipid Glucose Study. Dietary intake was assessed using a validated semiquantitative food-frequency questionnaire. Anthropometric characteristics, blood pressure, and fasting plasma concentrations of glucose and lipids were measured. The MetS was defined according to the Adult Treatment Panel III guidelines.

RESULTS: Among the PUFAs, the ALA and ω-6 PUFA intakes were inversely associated with the MetS. Subjects in the highest quartile of ALA and ω-6 fatty acid intakes had a 38% (odds ratio 0.62, 95% confidence interval 0.41-0.95) and a 0.47% (odds ratio 0.53, 95% confidence interval 0.31-0.89) lower prevalence of MetS, respectively, compared with those in the lowest quartile. The dietary ratio of ω-6 to ω-3 fatty acids was not associated with the MetS. When the interaction between ALA and ω-6 fatty acid was assessed, the ALA intake was associated with a lower prevalence of the MetS, without modification by the ω-6 PUFA intake. Subjects with at least the median ALA intake (1084 mg/d) had a lower prevalence of the MetS, irrespective of an ω-6 PUFA intake lower or higher than the median compared with subjects with intakes below the median for both.

CONCLUSION: The ALA intake was inversely associated with the MetS, irrespective of the background intake of ω-6 PUFAs, in adults.