Js. Volek et al., Fasting lipoprotein and postprandial triacylglycerol responses to a low-carbohydrate diet supplemented with n-3 fatty acids, J AM COL N, 19(3), 2000, pp. 383-391
Background: The effects of a prolonged low-carbohydrate diet rich in n-3 fa
tty acids on blood lipid profiles have not been addressed in the scientific
literature.
Objective: This study examined the effects of an eight-week ketogenic diet
rich in n-3 fatty acids on fasting serum lipoproteins and postprandial tria
cylglycerol (TG) responses.
Design: Ten men consumed a low-carbohydrate diet rich in monounsaturated fa
t (MUFA) and supplemented with n-3 fatty acids for eight weeks. Fasting blo
od samples were collected before and after one week of habitual diet and on
two consecutive days after 2, 4, 6 and 8 weeks of the intervention diet. P
ostprandial TG responses to a fat-rich test meal were measured prior to and
after the intervention diet.
Results: Compared to the habitual diet, subjects consumed significantly (p
less than or equal to 0.05) greater quantities of protein, fat, MUFA and n-
3 fatty acids and significantly less total energy, carbohydrate and dietary
fiber Body weight significantly declined over the experimental period (-4.
2 +/- 2.7 kg). Compared to baseline, fasting total cholesterol, LDL cholest
erol and HDL cholesterol were not significantly different after the interve
ntion diet (+1.5%, +9.7% and +10.0%, respectively). Fasting TG were signifi
cantly reduced after the intervention diet (-55%). There was a significant
reduction in peak postprandial TG (-42%) and TG area under the curve (-48%)
after the intervention diet.
Conclusions: A hypocaloric low-carbohydrate diet rich in MUFA and supplemen
ted with n-3 fatty acids significantly reduced postabsorptive and postprand
ial TG in men that were not hypertriglyceridemic as a group before the diet
. This may be viewed as a clinically significant positive adaptation in ter
ms of cardiovascular risk status. However, transient increases in total cho
lesterol and LDL cholesterol were also evident and should be examined furth
er in regard to which particular subfractions are elevated.