Effect of fish diets and weight loss on serum leptin concentration in overweight, treated-hypertensive subjects.
BACKGROUND
Leptin, a circulating hormone secreted from adipocytes, is an index of adiposity and is reduced by caloric restriction and weight loss. A recent population study suggested that dietary-derived omega3 fatty acids lower leptin levels independent of body fat.


OBJECTIVE
To examine whether dietary fish enhanced the effects of weight loss on serum leptin levels, in 69 overweight, treated hypertensive men and women.


METHODS
Participants were randomized to a daily fish meal, a weight-reduction regimen, the two regimens combined or a control group for 16 weeks.


RESULTS
A total of 63 individuals completed the study. Weight fell 5.6 +/- 0.8 kg with energy-restriction. Blood pressure (BP) reductions in the combined fish-weight loss group were twice that seen with either intervention alone. At baseline, in all groups combined, serum leptin levels correlated with serum insulin (r = 0.307, P = 0.014), but not with body weight. The greatest change in serum leptin occurred in the fish-weight loss group (control, 0.60 +/- 0.76 ng/ml; fish, 1.20 +/- 0.79 ng/ml; weight loss, -1.40 +/- 1.05 ng/ml; fish-weight loss, -5.08 +/- 1.64 ng/ml). In the fish-weight loss group, the change in serum leptin was predicted by changes in serum insulin (r = 0.488, P = 0.038), 24-h BP (systolic BP (SBP): r = 0.435, P = 0.060; diastolic BP (DBP): r = 0.563, P = 0.018) and 24-h heart rate (0.584, P = 0.028). Using general linear models, there was a significant fish x weight-loss interaction (P = 0.008) on post-intervention serum leptin after adjustment for baseline levels, independent of post-intervention insulin.


CONCLUSIONS
A daily fish meal as part of a weight-reducing regimen was more effective than either measure alone at reducing leptin levels. Reductions in leptin may be related to the substantial fall in BP seen with the fish-weight loss program.
Mori
Trevor A
TA
School of Medicine and Pharmacology, Royal Perth Hospital Unit, University of Western, Australia. tmori@cyllene.uwa.edu.au
Burke
Valerie
V
Puddey
Ian B
IB
Shaw
Jonathan E
JE
Beilin
Lawrence J
LJ
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D001835:Body Weight; D004032:Diet; D004038:Diet, Reducing; D002149:Energy Intake; D005227:Fatty Acids / Q000097:blood; D005260:Female; D005399:Fishes; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000150:complications / Q000473:pathology / Q000503:physiopathology; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood*; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D010743:Phospholipids / Q000097:blood; D015431:Weight Loss
D001786:Blood Glucose; D005227:Fatty Acids; D007328:Insulin; D020738:Leptin; D008055:Lipids; D010743:Phospholipids