DIETARY ALPHA-LINOLENIC ACID ALTERS TISSUE FATTY-ACID COMPOSITION, BUT NOT BLOOD-LIPIDS, LIPOPROTEINS OR COAGULATION STATUS IN HUMANS

We examined the effect of dietary alpha-linolenic acid (ALA) on the in dices of lipid and coagulation status and on the fatty acid compositio n of serum and peripheral blood mononuclear cell (PBMNC) lipids in ten healthy men (age 21-37 yr) who consumed all their meals at the Wester n Human Nutrition Research Center for 126 d. There was a stabilization period of 14 d at the start when all 10 subjects consumed the basal d iet (BD) containing 23.4 energy percent (en%) fat and two intervention periods of 56 d each. During the first intervention period, 5 subject s consumed the BD containing 23.4 en% fat, and 5 subjects consumed a d iet providing 6.3% calories from alpha-linolenic acid [flaxseed oil (F SO) diet containing 28.8 en% fat]. Diets were crossed over between the two groups during the second intervention period. Feeding the FSO die t did not significantly alter serum triglycerides, cholesterol, high-d ensity lipoproteins, low-density lipoproteins, apoprotein A-I and apop rotein B when compared to the corresponding values in the subjects fed the BD, nor was there any effect of the FSO diet on the bleeding time , prothrombin time and partial prothrombin time for these subjects. Fe eding the ALA-containing diet did cause a significant increase in ALA concentration in serum (P < 0.001) and PBMNC lipids (P < 0.05). It als o caused a significant increase (P < 0.05) in the eicosapentaenoic and docosapentaenoic acid contents of PBMNC lipids, and a decrease (P < 0 .01) in linoleic and eicosatrienoic acid contents of serum lipids. Thu s, dietary ALA, fed for 56 d at 6.3% of calories, had no effect on pla sma triglyceride or very low density lipoprotein levels or the common risk factors associated with atherosclerosis, although these parameter s have been reported by others to be influenced by fatty acids, such a s palmitic or linoleic acids, in the diet. Dietary ALA did significant ly alter the fatty acid composition of plasma and PBMNC.