Influence of fish oil supplementation on in vivo and in vitro oxidation resistance of low-density lipoprotein in type 2 diabetes.
OBJECTIVE
Fish oil supplement has been proposed as a non-pharmacological strategy to correct the atherogenic lipid profile associated with type 2 diabetes mellitus. However, fish oil may have deleterious effects on lipid peroxidation and glycemic control.


METHODS
In this study, 44 type 2 diabetic patients were randomized to vitamin E standardized (53.6 mg/day) supplementation (capsules) with 4 g daily of either fish oil (n=23) or corn oil (n=21) for 8 weeks preceded by a 4 week run-in period of corn oil supplementation. LDL was isolated by density gradient ultracentrifugation and oxidized in vitro with Cu(2+). As a marker of in vivo oxidation malondialdehyde concentration in LDL (LDL-MDA) was measured.


RESULTS
Fish oil reduced both mean lag time (before, 57.8; after, 48.8 min, P<0.001) and mean propagation rate (before, 0.018 DeltaOD/min; after, 0.015 DeltaOD/min, P<0.001), whereas corn oil had no influence on lag time and propagation rate. The changes in lag time and propagation rate differed significantly between fish oil and corn oil treatment. LDL-MDA changes differed borderline significantly between groups (FO, 110.4 pmol/mg protein; CO, 6.7 pmol/mg protein; P=0.057). Fish oil supplementation had no influence on glycemic control as assessed from HbA(1c) and fasting blood glucose.


CONCLUSIONS
According to our findings, fish oil supplementation leads to increased in vivo oxidation and increased in vitro oxidation susceptibility of LDL particles. More studies are needed to clarify the clinical importance of this finding.
Pedersen
H
H
Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
Petersen
M
M
Major-Pedersen
A
A
Jensen
T
T
Nielsen
N S
NS
Lauridsen
S T
ST
Marckmann
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D002499:Centrifugation, Density Gradient; D003300:Copper / Q000737:chemistry; D003314:Corn Oil / Q000008:administration & dosage; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005215:Fasting; D005395:Fish Oils / Q000008:administration & dosage*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007700:Kinetics; D015227:Lipid Peroxidation / Q000187:drug effects*; D008077:Lipoproteins, LDL / Q000097:blood*; D008315:Malondialdehyde / Q000032:analysis; D008875:Middle Aged; D010084:Oxidation-Reduction; D010919:Placebos; D014810:Vitamin E / Q000008:administration & dosage
D001786:Blood Glucose; D003300:Copper; D003314:Corn Oil; D005395:Fish Oils; D006442:Glycated Hemoglobin; D008077:Lipoproteins, LDL; D008315:Malondialdehyde; D010919:Placebos; D014810:Vitamin E