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

BACKGROUND

The effect of long-term increased intakes of alpha-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.