Inhibition of experimental colorectal carcinogenesis by dietary N-6 polyunsaturated fats.
The influence of dietary fats on azoxymethane-induced colorectal carcinogenesis and erythrocyte, adipose, colon mucosa and tumour tissue fatty acids was investigated in 228 Wistar rats. The two main diets compared were beef suet rich in saturated fatty acids and corn oil rich in a linoleic acid, an N-6 polyunsaturated fatty acid. The animals were placed in one of four dietary groups: A = 5% saturated fat, B = 20% saturated fat, C = 5% N-6 fat and D = 20% N-6 fat. There was no difference in the number of adenomas between any of the dietary groups. The mean (+/- SEM) carcinoma yield per rat was A = 0.93 +/- 0.28, B = 1.93 +/- 0.50, C = 0.70 +/- 0.07, D = 0.13 +/- 0.04; the tumour yields in rats fed the saturated fat diets were significantly different from each other and from those fed the N-6 fat diets. The fatty acid profiles in all tissues were dependent upon the type and level of dietary fat and the tissue type. Arachidonate was higher in tumours compared to normal mucosa. Significant correlations were found between adipose linoleate (reflecting dietary intake) and tumour oleate and tumour arachidonate but not with the colorectal mucosa of control animals. This is the first in vivo study to show reduced colorectal carcinogenesis by N-6 polyunsaturated fatty acids.
Nicholson
M L
ML
University Department of Surgery, Leicester Royal Infirmary, UK.
Neoptolemos
J P
JP
Clayton
H A
HA
Talbot
I C
IC
Bell
P R
PR
D000236:Adenoma / Q000139:chemically induced / Q000517:prevention & control*; D000273:Adipose Tissue / Q000737:chemistry; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000032:analysis; D001397:Azoxymethane; D002277:Carcinoma / Q000737:chemistry / Q000178:diet therapy*; D002462:Cell Membrane / Q000737:chemistry; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D005224:Fats, Unsaturated / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis / Q000627:therapeutic use; D007413:Intestinal Mucosa / Q000737:chemistry; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D019301:Oleic Acid; D009829:Oleic Acids / Q000032:analysis; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013229:Stearic Acids / Q000032:analysis; D015430:Weight Gain / Q000187:drug effects
D001095:Arachidonic Acids; D005224:Fats, Unsaturated; D005227:Fatty Acids; D008041:Linoleic Acids; D009829:Oleic Acids; D010169:Palmitic Acids; D013229:Stearic Acids; D016718:Arachidonic Acid; D019301:Oleic Acid; D019308:Palmitic Acid; C031183:stearic acid; D019787:Linoleic Acid; D001397:Azoxymethane