THE EFFECT OF QUALITY AND AMOUNT OF DIETARY-FAT ON THE SUSCEPTIBILITYOF LOW-DENSITY-LIPOPROTEIN TO OXIDATION IN SUBJECTS WITH IMPAIRED GLUCOSE-TOLERANCE
U. Schwab et al., THE EFFECT OF QUALITY AND AMOUNT OF DIETARY-FAT ON THE SUSCEPTIBILITYOF LOW-DENSITY-LIPOPROTEIN TO OXIDATION IN SUBJECTS WITH IMPAIRED GLUCOSE-TOLERANCE, European journal of clinical nutrition, 52(6), 1998, pp. 452-458
Objectives: We examined the effects of a high fat diet rich in monouns
aturated fat (MUFA-diet) and a moderate fat diet rich in polyunsaturat
ed fat (PUFA-diet) on the susceptibility of LDL to oxidation. Subjects
: 29 subjects with impaired glucose tolerance. Methods: After consumin
g a run-in diet [37% of energy (E%) fat, is E% saturated fat] for thre
e weeks, subjects were randomly assigned either to a MUFA-diet (40 E%
fat, 19 E% monounsaturated fatty acids) or a PUFA-diet (34 E% fat, 10
E% polyunsaturated fat) for eight weeks. The susceptibility of LDL to
oxidation was measured by challenging LDL with hemin and H2O2 and meas
uring the time for the reaction to reach maximum velocity. Results are
expressed as lag time to oxidation in minutes. Results: In the PUFA-d
iet group (n = 15) lag time tended to decrease during the experimental
diet (97 +/- 28 vs 90 f 25 min, mean +/- s.d., P = 0.073). whereas in
the MUFA-diet group (n = 14) there was no significant change !lag tim
e 96 +/- 24 vs 100 +/- 16 min, P = 0.408). The mean change in lag time
was -7 +/- 14 min (-7.2%) in the PUFA-diet group and +4 +/- 16 min (4.0%) in the MUFA-diet group (P = 0.029, PUFA-diet group vs MUFA-diet
group). The a-tocopherol concentration in LDL increased significantly
(P < 0.01) in both diet groups relative to the run-in diet period, but
LDL particle score did not change in either of the diet groups during
the dietary intervention. Conclusions: In subjects with impaired gluc
ose tolerance a PUFA-rich diet with a moderate amount of fat tended to
increase the susceptibility of LDL to oxidation as compared to a high
er fat diet rich in MUFA. Furthermore, the negative mean change in lag
time to oxidation found in the PUFA-diet group differed significantly
from the slightly positive mean change found in the MUFA-diet group.