Effect of synthetic triglycerides of myristic, palmitic, and stearic acid on serum lipoprotein metabolism.
OBJECTIVE
To determine relative effects of diets high in synthetic sources of myristic (14:0), palmitic (16:0) or stearic (18:0) acid on concentrations and metabolism of serum lipoproteins.


METHODS
Eighteen healthy women participated in a three-way cross-over study for five week periods separated by seven week washout periods, diets were assigned in random order.


METHODS
Premenopausal women, not on medication, were from three races (Caucasian, African-American, Asian) and four apolipoprotein E phenotype groups (3/3, 3/2, 4/3, and 4/2).


METHODS
During the first week the subjects consumed a baseline diet providing 11 energy (en)% saturated fat, 10en% polyunsaturated fat and 14en% monounsaturated fat. Followed by test diets with 19en% saturated fat (including 14en% test saturated fatty acid), 3en% polyunsaturated fat, and 14en% monounsaturated fat for four weeks. Synthetic fats (trimyristin, tripalmitin, and tristearin) were used in blends with natural fats and oils.


RESULTS
Mean concentrations of serum total, esterified and LDL cholesterol were significantly lower after 18:0 than after 16:0 (n = 16-18, P < 0.01 for treatment effect). Myristic acid (14:0) had an intermediate effect. Receptor-mediated degradation of 125I-LDL in mononuclear cells obtained from the subjects was lower after 16:0 than after 14:0 and 18:0 (n = 16-18, P=0.05 for treatment effect). Differences in the digestibilities of the fats were not a major factor in the results. Strong cholesterolemic responses to the 16:0 diet were partly explained by apoE phenotype.


CONCLUSIONS
As noted previously, stearic acid was neutral compared to 14:0 and 16:0. In contrast to studies involving natural fats, 14:0, fed as a synthetic triglyceride, was less cholesterolemic than 16:0 in a majority of subjects. ApoE phenotype influenced the cholesterolemic response particularly when diets high in 16:0 were eaten.
Snook
J T
JT
Department of Human Nutrition and Food Management, The Ohio State University, Columbus 43210, USA. snook.3@osu.edu
Park
S
S
Williams
G
G
Tsai Y-H
Lee
N
N
D000328:Adult; D001057:Apolipoproteins E / Q000235:genetics; D002784:Cholesterol / Q000097:blood* / Q000378:metabolism; D018592:Cross-Over Studies; D004041:Dietary Fats / Q000378:metabolism*; D019358:Fat Substitutes / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008074:Lipoproteins / Q000097:blood / Q000378:metabolism*; D019814:Myristic Acid / Q000378:metabolism; D019308:Palmitic Acid / Q000378:metabolism; D010641:Phenotype; D011973:Receptors, LDL / Q000378:metabolism; D013229:Stearic Acids / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
D001057:Apolipoproteins E; D004041:Dietary Fats; D019358:Fat Substitutes; D005227:Fatty Acids; D008074:Lipoproteins; D011973:Receptors, LDL; D013229:Stearic Acids; D014280:Triglycerides; D019814:Myristic Acid; C036694:trimyristin; D019308:Palmitic Acid; C031183:stearic acid; D002784:Cholesterol; C005859:tripalmitin; C022618:tristearin