Postprandial effect of n-3 polyunsaturated fatty acids on apolipoprotein B-containing lipoproteins and vascular reactivity in type 2 diabetes.
BACKGROUND
Plasma lipoproteins may be classified by their apolipoprotein composition. The lipoprotein subclass containing apolipoproteins B and C (LpB:C) is considered the most atherogenic.


OBJECTIVE
We evaluated the acute effects of individual fatty acids on apolipoprotein B (apo B)-containing lipoproteins in adults with type 2 diabetes (n = 15).


METHODS
We administered 3 meals in a randomized, double-blind, crossover design. Treatments contained skim milk and 50 g fat from high-oleic acid safflower and canola oils (monounsaturated fatty acid; MUFA), MUFA + 3.5 g alpha-linolenic acid (ALA; MUFA + ALA) from high-ALA canola oil, or MUFA + 4.0 g both eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA; MUFA + EPA/DHA) from sardine oil. Apo B, LpB, LpB:C, LpB:E + LpB:C:E, and LpA-II:B:C:D:E were measured at baseline and 2 and 4 h after the meal. Flow-mediated dilation was measured at baseline and 4 h after the meal.


RESULTS
The treatments significantly increased apo B and LpB postprandially (P < 0.03 for both), but the magnitude of the changes did not differ significantly between the treatments. The postprandial change in LpB:C was 23% lower after MUFA + EPA/DHA than after MUFA (treatment x time interaction, P < 0.0001). MUFA + ALA attenuated the increase in LpA-II:B:C:D:E in those with high triacylglycerols (>/=1.69 mmol/L) but was the only treatment to significantly increase this particle in those with low triacylglycerols (treatment x group interaction, P < 0.0001). Examination of change scores did not reveal the source of the interaction of treatment and time (P < 0.007) for LpB:E + LpB:C:E. Furthermore, the subjects with the largest increases in LpB:C exhibited the largest impairment in endothelial function.


CONCLUSIONS
The results suggest that unsaturated fatty acids differentially affect concentrations of apo B-containing lipoprotein subclasses. A rise in LpB:C adversely affects endothelial function. Meals containing MUFA + EPA/DHA attenuated the postprandial rise in LpB:C and the impairment of endothelial function.
Hilpert
Kirsten F
KF
Department of Nutritional Sciences and The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA.
West
Sheila G
SG
Kris-Etherton
Penny M
PM
Hecker
Kari D
KD
Simpson
Nancy M
NM
Alaupovic
Petar
P
D001055:Apolipoproteins B / Q000737:chemistry / Q000378:metabolism*; D001916:Brachial Artery / Q000187:drug effects; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004311:Double-Blind Method; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period / Q000502:physiology*; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects*
D001055:Apolipoproteins B; D015525:Fatty Acids, Omega-3