Dietary linolenic acid is inversely associated with plasma triacylglycerol: The National Heart, Lung, and Blood Institute Family Heart Study

Background: Dietary intake of linolenic acid is associated with a decreased risk of cardiovascular disease mortality. However, the mechanisms by which dietary linolenic acid affects cardiovascular disease risk are not clearly understood. Objective: We examined the association between dietary linolenic acid and plasma triacylglycerol concentrations. Design: In a cross-sectional design, we studied 4440 white subjects (2036 men and 2404 women) aged 25-93 y who participated in the National Heart, Lung, and Blood Institute Family Heart Study. We used generalized linear models to estimate adjusted mean triacylglycerol concentrations according to categories of total dietary linolenic acid (α- and γ-linolenic acid) intake. Results: The mean dietary linolenic acid intakes were 0.81 and 0.69 g/d for the men and the women, respectively. High consumption of dietary linolenic acid was associated with young age; high intakes of energy, fat, carbohydrates, fruit, vegetables, and fish; low HDL cholesterol; current smoking; and frequent consumption of creamy salad dressing. High consumption of dietary linolenic acid was also associated with low plasma triacylglycerol concentrations. From the lowest to the highest quintile of linolenic acid intake, the multivariate-adjusted mean triacylglycerol concentrations were 1.75 (95% CI: 1.65, 1.85), 1.74 (1.66, 1.82), 1.69 (1.61, 1.77), 1.66 (1.58, 1.74), and 1.54 (1.44, 1.64) mmol/L, respectively (P for linear trend = 0.007). When linolenic acid was used as a continuous variable, the corresponding regression coefficient was -0.2811 (-0.4922, -0.07001). Conclusions: Consumption of total linolenic acid is inversely related to plasma triacylglycerol concentrations in both white men and white women. This suggests a pathway by which dietary linolenic acid might reduce cardiovascular disease risk.