The effect of dietary trans alpha-linolenic acid on plasma lipids and platelet fatty acid composition: the TransLinE study.
OBJECTIVE
To collect (i) baseline data and (ii) execute a large multicentre study examining the effect of trans alpha-linolenic acid on its incorporation into plasma lipids and on risk factors for coronary heart disease.


METHODS
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 alpha-linolenic acid or to continue with a diet 'low' in trans alpha-linolenic acid for 6 weeks.


METHODS
Three European university research departments supported by the research and development departments of the food industry.


METHODS
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 alpha-linolenic acid into plasma lipids and platelets was assessed by gas chromatography and dietary compliance was verified by 4-d weighed record.


RESULTS
Less trans alpha-linolenic acid isomers are incorporated into human plasma lipids in French volunteers than in Dutch or Scottish volunteers consuming their habitual diets. Trans 'free' alpha-linolenic acid-rich oil can be produced by careful deodorization during refining. The 'high' trans diet provided 1410+/-42 mg/d trans isomers of alpha-linolenic acid, whilst the 'low' trans group consumed 60+/-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 alpha-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 alpha-linolenic acid, can be produced by careful deodorization. Dietary records show good compliance. Dietary trans isomers of alpha-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.


BACKGROUND
European Commission (FAIR 95-0594 grant). European Journal of Clinical Nutrition (2000) 54, 104-113
Sébédio
J L
JL
INRA, Unité de Nutrition Lipidique, Dijon, France.
Vermunt
S H
SH
Chardigny
J M
JM
Beaufrère
B
B
Mensink
R P
RP
Armstrong
R A
RA
Christie
W W
WW
Niemelä
J
J
Hénon
G
G
Riemersma
R A
RA
D000328:Adult; D001792:Blood Platelets / Q000737:chemistry*; D002849:Chromatography, Gas; D003327:Coronary Disease / Q000209:etiology; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D002149:Energy Intake; D005227:Fatty Acids / Q000097:blood*; D005229:Fatty Acids, Monounsaturated; D005602:France; D006801:Humans; D007536:Isomerism; D008055:Lipids / Q000097:blood*; D008297:Male; D009426:Netherlands; D000074262:Rapeseed Oil; D012307:Risk Factors; D012606:Scotland; D017962:alpha-Linolenic Acid / Q000008:administration & dosage / Q000494:pharmacology*
D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D008055:Lipids; D000074262:Rapeseed Oil; D017962:alpha-Linolenic Acid