Colon cancer prevention with a small amount of dietary perilla oil high in alpha-linolenic acid in an animal model.
BACKGROUND
Epidemiologic and experimental studies suggest that dietary fish oil and vegetable oil high in omega-3 polyunsaturated fatty acids (PUFAs) suppress the risk of colon cancer. The optimal amount to prevent colon carcinogenesis with perilla oil high in omega-3 PUFA alpha-linolenic acid in a 12% medium-fat diet was investigated in female F344 rats. For comparison, safflower oil high in omega-6 PUFA linoleic acid was used.


METHODS
Thirty or 25 rats at 7 weeks of age in each group received an intrarectal dose of 2 mg N-methyl-N-nitrosourea 3 times weekly in weeks 1 and 2 and were fed the diets with various levels of perilla oil and safflower oil throughout the experiment.


RESULTS
The incidence of colon cancer at the termination of the experiment at week 35 was 40%, 48% and 32% in the rats fed the diets with 3% perilla oil plus 9% safflower oil, 6% perilla oil plus 6% safflower oil, and 12% perilla oil plus 0% safflower oil, respectively, whereas it was 67% in the rats fed the control diet with 0% perilla oil plus 12% safflower oil. The amount of diet consumed and the body weight gain were identical in all of the dietary groups. The ratios of omega-3 PUFA to omega-6 PUFA in the serum and the colonic mucosa at week 35 were increased in parallel to the increased intake of perilla oil.


CONCLUSIONS
The results suggest that a relatively small fraction of perilla oil, 25% of total dietary fat, may provide an appreciable beneficial effect in lowering the risk of colon cancer.
Narisawa
T
T
Akita University College of Allied Medical Science, Japan.
Fukaura
Y
Y
Yazawa
K
K
Ishikawa
C
C
Isoda
Y
Y
Nishizawa
Y
Y
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000097:blood; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D003110:Colonic Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D004041:Dietary Fats / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004435:Eating / Q000187:drug effects; D005227:Fatty Acids / Q000097:blood / Q000378:metabolism; D005260:Female; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008041:Linoleic Acids / Q000737:chemistry* / Q000627:therapeutic use*; D008055:Lipids / Q000097:blood; D008770:Methylnitrosourea; D010743:Phospholipids / Q000097:blood; D010938:Plant Oils / Q000737:chemistry* / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344; D012450:Safflower Oil / Q000627:therapeutic use; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D017962:alpha-Linolenic Acid / Q000032:analysis*
D004041:Dietary Fats; D005227:Fatty Acids; D008041:Linoleic Acids; D008055:Lipids; D010743:Phospholipids; D010938:Plant Oils; D014280:Triglycerides; D017962:alpha-Linolenic Acid; C058216:perilla seed oil; D008770:Methylnitrosourea; D012450:Safflower Oil; D002784:Cholesterol