Dietary trans alpha-linolenic acid from deodorised rapeseed oil and plasmalipids and lipoproteins in healthy men: the TransLinE Study

Trans isomers of alpha -linolenic acid, which are formed by deodorization o f refined vegetable oils, can be found in significant amounts in edible oil s. Effects of trans ol-linolenic acid on plasma lipoproteins are unknown. W e therefore investigated the effects of trans alpha -linolenic acid on plas ma lipids and lipoproteins in healthy European men. Eighty-eight healthy me n from three European countries (France, Scotland, UK and the Netherlands) first consumed for 6 weeks a diet with experimental oils 'free' of trans fa tty acids (run-in period). For the next 6 weeks, they were randomly allocat ed to a diet with experimental oils 'high' or 'low' in trans alpha -linolen ic acid. Daily total trans alpha -linolenic acid intake in the high trans g roup was 1410 (range 583-2642) mg. Experimental oils were provided as such, or incorporated into margarines, cheeses, muffins and biscuits. The high t rans alpha -linolenic acid diet significantly increased the plasma LDL-:HDL -cholesterol ratio by 8.1 % (95 % CI 1.4, 15.3; P = 0.02), and the total ch olesterol:HDL-cholesterol ratio by 5.1 % (95 % CI 0.4, 9.9; P = 0.03) compa red with the low-trans diet. This was largely explained by an increase in L DL-cholesterol on the high-trans diet, while no change was observed in the low-trans group (mean treatment effect of 4.7 % (95 % CI -0.8, 10.5; P = 0. 10). No effects were found on total cholesterol and HDL-cholesterol, triacy lglycerols, apolipoprotein B and A-1, and lipoprotein(a) concentrations. In conclusion, trans alpha -linolenic acid may increase plasma LDL-:HDL-chole sterol and total cholesterol:HDL-cholesterol ratios. Whether diet-induced c hanges in these ratios truly affects the risk for CHD remains to be establi shed.