Effect of an increased intake of α-linolenic acid and group nutritional education on cardiovascular risk factors: the Mediterranean Alpha-linolenic Enriched Groningen Dietary Intervention (MARGARIN) study

Abstract

Background: The effect of long-term increased intakes of α-linolenic acid (ALA; 18:3n−3) on cardiovascular risk factors is unknown. Objectives: Our objectives were to assess the effect of increased ALA intakes on cardiovascular risk factors and the estimated risk of ischemic heart disease (IHD) at 2 y and the effect of nutritional education on dietary habits. Design: Subjects with multiple cardiovascular risk factors (124 men and 158 women) were randomly assigned in a double-blind fashion to consume a margarine rich in either ALA [46% linoleic acid (LA; 18:2n−6) and 15% ALA; n = 114] or LA (58% LA and 0.3% ALA; n = 168). An intervention group (n = 110; 50% ALA) obtained group nutritional education, and a control group (n = 172; 34% ALA) received a posted leaflet containing the standard Dutch dietary guidelines. Results: Average ALA intakes were 6.3 and 1.0 g/d in the ALA and LA groups, respectively. After 2 y, the ALA group had a higher ratio of total to HDL cholesterol (+0.34; 95% CI: 0.12, 0.56), lower HDL cholesterol (−0.05 mmol/L; −0.10, 0), higher serum triacylglycerol (+0.24 mmol/L; 0.02, 0.46), and lower plasma fibrinogen (−0.18 g/L; −0.31, −0.04; after 1 y) than did the LA group (adjusted for baseline values, sex, and lipid-lowering drugs). No significant difference existed in 10-y estimated IHD risk. After 2 y, the intervention group had lower saturated fat intakes and higher fish intakes than did the control group. Conclusions: Increased ALA intakes decrease the estimated IHD risk to an extent similar to that found with increased LA intakes. Group nutritional education can effectively increase fish intake.