Summary Background Both
hempseed oil (HO) and flaxseed
oil (FO) contain high amounts of
essential fatty acids (FAs); i.e.
linoleic acid (LA, 18:2n-6) and
alpha-linolenic acid (ALA, 18:3n-
3), but almost in opposite ratios.
An excessive intake of one essential
FA over the other may interfere
with the metabolism of the
other while the metabolisms of LA
and ALA compete for the same
enzymes. It is not known whether
there is a difference between n-3
and n-6 FA of plant origin in the
effects on serum lipid profile. Aim
of the study To compare the
effects of HO and FO on the profile
of serum lipids and fasting concentrations
of serum total and
lipoprotein lipids, plasma glucose
and insulin, and haemostatic factors
in healthy humans. Methods
Fourteen healthy volunteers participated
in the study. A randomised,
double-blind crossover
design was used. The volunteers
consumed HO and FO (30 ml/day)
for 4 weeks each. The periods
were separated by a 4-week washout
period. Results The HO
period resulted in higher proportions
of both LA and gammalinolenic
acid in serum cholesteryl
esters (CE) and triglycerides (TG)
as compared with the FO period
(P < 0.001), whereas the FO period
resulted in a higher proportion
of ALA in both serum CE and TG
as compared with the HO period
(P < 0.001). The proportion of
arachidonic acid in CE was lower
after the FO period than after the
HO period (P < 0.05). The HO
period resulted in a lower total-to-
HDL cholesterol ratio compared
with the FO period (P = 0.065).
No significant differences were
found between the periods in
measured values of fasting serum
total or lipoprotein lipids, plasma
glucose, insulin or hemostatic
factors. Conclusions The effects of
HO and FO on the profile of serum
lipids differed significantly, with
only minor effects on concentrations
of fasting serum total or
lipoprotein lipids, and no significant
changes in concentrations of
plasma glucose or insulin or in
haemostatic factors.