Effects of fish oil on rectal cell proliferation, mucosal fatty acids, and prostaglandin E2 release in healthy subjects.
BACKGROUND
Experimental studies have indicated dietary fish oil as a protective agent in colon carcinogenesis. Prostaglandins have been suggested to be involved in this process. In the present study, the effects of fish oil on rectal cell proliferation (i.e., intermediate biomarker of cancer risk), mucosal membrane fatty acids, and prostaglandin E2 (PGE2) release were investigated in 12 healthy volunteers.


METHODS
In addition to a controlled basal diet, the test subjects received either fish oil (4.4 g omega-3 fatty acids/day) or corn oil supplements for two 4-week periods in a double-blind, crossover trial. Rectal cell proliferation was determined by bromodeoxyuridine immunohistochemistry and ornithine decarboxylase activity. After 2-hour incubation with bromodeoxyuridine, PGE2 concentration in the incubation medium was measured by radioimmunoassay. Mucosal membrane fatty acids were analyzed by gas chromatography.


RESULTS
Bromodeoxyuridine labeling index (9.2% vs. 10.9%; P < 0.05), ornithine decarboxylase activity (19.7 vs. 36.4 pmol.mg protein-1.h-1; P < 0.005), and PGE2 release from rectal biopsy specimens (435.5 vs. 671.5 pg/mg wet tissue; P < 0.05) were significantly lower during the fish oil than the corn oil period, whereas membrane fatty acids were not statistically different.


CONCLUSIONS
The results support the hypothesis that dietary fish oil may protect against colon cancer.
Bartram
H P
HP
Department of Medicine, University of Würzburg, Germany.
Gostner
A
A
Scheppach
W
W
Reddy
B S
BS
Rao
C V
CV
Dusel
G
G
Richter
F
F
Richter
A
A
Kasper
H
H
D000328:Adult; D002455:Cell Division / Q000187:drug effects; D003110:Colonic Neoplasms / Q000517:prevention & control; D003314:Corn Oil / Q000494:pharmacology; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000494:pharmacology*; D015232:Dinoprostone / Q000378:metabolism*; D004311:Double-Blind Method; D005227:Fatty Acids / Q000032:analysis*; D005260:Female; D005395:Fish Oils / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009955:Ornithine Decarboxylase / Q000378:metabolism; D012007:Rectum / Q000166:cytology* / Q000378:metabolism*
D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005395:Fish Oils; D003314:Corn Oil; D009955:Ornithine Decarboxylase; D015232:Dinoprostone