The effect of dietary trans α-linolenic acid on plasma lipids and platelet fatty acid composition: the TransLinE study

Abstract

; on behalf of the investigators of the TransLineE project { Objective: To collect (i) baseline data and (ii) execute a large multicentre study examining the effect of trans a-linolenic acid on its incorporation into plasma lipids and on risk factors for coronary heart disease. Design: Male volunteers were recruited and the habitual diet assessed by a 4-d weighed record. Fatty acid composition of plasma and platelet lipids were determined by gas chromatography at baseline. After a 6 week run-in period on a trans`free' diet, male volunteers were randomised to consume 0.6 % of energy trans a-linolenic acid or to continue with a diet`low' in trans a-linolenic acid for 6 weeks. Setting: Three European university research departments supported by the research and development departments of the food industry. Subjects: Male volunteers (88) recruited by local advertisement. Methods: Replacement of 30 % of the fat of the habitual diet by margarine, oil and foods. Rapeseed oil was deodorised especially to produce the trans`free' and`high' trans foods for this study. The incorporation and conversion of trans a-linolenic acid into plasma lipids and platelets was assessed by gas chromatography and dietary compliance was veri®ed by 4-d weighed record. Results: Less trans a-linolenic acid isomers are incorporated into human plasma lipids in French volunteers than in Dutch or Scottish volunteers consuming their habitual diets. Trans`free' a-linolenic acid-rich oil can be produced by careful deodorization during re®ning. The`high' trans diet provided 1410AE 42 mg/d trans isomers of a-linolenic acid, whilst the`low' trans group consumed 60 AE 75 mg/d. The change in plasma lipid and platelet fatty acid composition documented that trans linolenic isomers are incorporated and converted to a trans isomer of eicosapentaenoic acid. Only the 15-trans a-linolenic acid is incorporated into plasma cholesteryl esters. The group consuming low trans diet had a slightly higher intake of fat, especially saturated and monounsaturated fat. Conclusions: Trans`free' rapeseed oil, rich in a-linolenic acid, can be produced by careful deodorization. Dietary records show good compliance. Dietary trans isomers of a-linolenic acid are incorporated in plasma lipids and converted to long-chain polyunsaturated fatty acids. Their effects on risk factors for coronary heart disease and their metabolism will be reported elsewhere. Sponsorship: European Commission (FAIR 95-0594 grant).

Trans Fatty Acids: Properties, Benefits and Risks.

“…Trans fatty acids compete with the essential fatty acids for the enzyme systems involved in these reactions. [38][39][40][41][42][43][44] With regard to the immune system, the splenic production of prostaglandin E 2 was reduced, while both plasma IgG and CD 4 + :CD 8 + T-lymphocytes ratio were increased by dietary trans fatty acids.…”

Trans fatty acids in diets act as a precipitating factor for gut inflammation?

“…21,23 The association between dietary TFAs and risk for CHD has strongly been suggested in many studies. [24][25][26][27][28] Willet et al reported that consumption of TFAs generated by partially hydrogenated vegetable oils including margarine indicated significant correlation with CHD onset. 29 Hu et al demonstrated that replacing saturated and TFAs with unhydrogenated monounsaturated and polyunsaturated fats is more effective in preventing CHD in women than reducing overall fat intake.…”

Dietary intake of α-linolenic acid and risk of age-related macular degeneration ,

“…Based on a few US food samples (e.g., mayonnaise, white bread, muffins), we crudely estimated the ratio of trans ALA to cis ALA was 1:7.5. By assuming that this ratio is generalizable to other trans ALA-containing foods, this translates into an intake of 0.2 g trans ALA/d on the basis of a mean intake of 1.5 g ALA/d in the US population (17), which is slightly lower but in the same magnitude as the estimated intake among Dutch and Scottish (0.5-0.7 g/d) and French participants (0.2-0.4 g/d) (24). Our study and the European study (24) both suggested a low concentration of erythrocyte trans ALA (w0.05% of total fatty acids) under a habitual diet.…”

“…Up to 40% of ALA can be present as trans isomers (19,20). trans ALA also occurs in human serum (24) and maternal milk (25,26).…”