Fish Oil And Cancer

Fish Oil And Cancer

Effects of different doses of fish oil on rectal cell proliferation in patients with sporadic colonic adenomas

GASTROENTEROLOGY (USA) , 1994, 107/6 (1709-1718)

Background/Aims: Fish oil supplementation can reduce cytokinetic anomalies in the flat rectal mucosa of patients with sporadic colorectal adenoma. This study attempted to identify an optimum dose for fish oil supplementation and evaluate the persistence of its effects during long-term administration. Methods: In a double-blind study, 60 patients with sporadic adenomas received 2.5, 5.1, or 7.7 g of fish oil per day or placebo for 30 days. (3H)thymidine autoradiographic labeling indices were calculated in flat rectal mucosal biopsy specimens collected before and after supplementation. In a subsequent study, 15 patients with polyps received 2.5 g of fish oil per day. Proliferative parameters, mucosal fatty acids, and mucosal and plasma alpha- tocopherol levels were evaluated before, during, and after 6 months of supplementation. Results: Mean proliferative indices and mucosal arachidonic acid levels decreased significantly (and to similar degrees) in all treated groups, whereas mucosal eicosapentaenoic and docosa-hexaenoic acid levels increased. Significantly reduced proliferation was observed only in patients with abnormal baseline patterns. These effects persisted during long-term, low-dose treatment. A transient reduction in mucosal (but not plasma) alpha- tocopherol levels was observed after 1 month of treatment. Side effects were insignificant. Conclusions: Low-dose fish oil supplementation has short-term and long-term normalizing effects on the abnormal rectal proliferation patterns associated with increased colon cancer risk.

Omega-3 fatty acids can improve radioresponse modifying tumor interstitial pressure, blood rheology and membrane peroxidability

ANTICANCER RES. (Greece) , 1994, 14/3 A (1145-1154)

Several studies provide evidence that hypoxic cells present in animal and human solid tumors, may be critical for the successful treatment of cancer. In particular hypoxic cells are resistant to ionizing radiation, photodynamic treatment and the large majority of chemotherapeutic drugs. Hypoxia is generally due to the inadequacy of vascular beds supporting the tumor and to an abnormal microcirculation. Three parameters, tumor interstitial fluid, hemorheological factors and lipoperoxidation, are considered and tentatively associated as playing a role in hypoxic cell treatment. Omega three fatty acids modify these factors and are discussed for their possible ability to enhance tumor cells susceptibility to radiotherapy.

Effects of dietary omega-3 fatty acids on human breast cancer growth and metastases in nude mice

J. NATL. CANCER INST. (USA) , 1993, 85/21 (1743-1747)

Background: Diets rich in omega-6 polyunsaturated fatty acids stimulate the growth and metastases of transplantable mammary carcinomas in rodents, whereas fish oil-containing diets, rich in omega-3 fatty acids, suppress the growth of these mammary tumor cells. Purpose: This study was performed to evaluate the effect of a diet rich in menhaden fish oil on the growth and metastases of MDA-MB-435 human breast cancer cells in a mouse model system. Methods: Ninety female athymic nude mice (Ncr-nu/nu) were fed a 23% (wt/wt) corn oil, omega-6 fatty acid-rich diet; after 7 days, 1 x 106 estrogen- independent MDA-MB-435 human breast cancer ceils were injected into a thoracic mammary fat pad. The 23% corn oil diet was continued for a further 7 days, after which the mice were assigned randomly to one of three diets containing a total of 23% fat, but different proportions of corn oil and menhaden oil (diet Cm: 18% corn oil and 5% menhaden oil, diet CM: 11.5% corn oil and 11.5% menhaden oil, and diet cM: 5% corn oil and 18% menhaden oil). Animal body weights and the surface area of the mammary fat pad tumors were recorded weekly. The mice were killed after 12 weeks on the experimental diets. Primary tumor surface areas and body weights were compared by unpaired Student's t tests, the incidence of lung metastases by the chi-square test, and differences in the total volumes of lung metastases by the nonparametric Mann-Whitney U test. Results: Tumor growth rates in the mice of the group fed diet Cm were significantly greater than for mice of either of the two groups fed diets containing higher levels of menhaden oil. Of the mice with primary tumors, the incidence of macroscopic lung metastases was greater in those fed diet Cm, compared with those fed diet cM (57.7% versus 22.2%; P<.01), but not significantly different from the mice fed diet CM. When metastases did occur, their extent was significantly greater in mice fed diet Cm, compared with those fed diet cM (P<.001). C onclusion: These results indicate that a high- fat diet rich in omega-3 fatty acids can suppress human breast cancer cell growth and metastases in this mouse model system. Implication: Dietary intervention trials to reduce recurrence risk in the postsurgical breast cancer patient should take account not only of the level of fat consumed, but also its fatty acid composition.

Fish-oil supplementation reduces intestinal hyperproliferation in persons at risk for colon cancer

NUTR. REV. (USA) , 1993, 51/8 (241-243) CODEN: NUREA ISSN: 0029-6643

Hyperproliferation in the upper compartments of colonic crypts is associated with an increased risk for colon cancer. A recent short-term, double-blind, placebo-controlled study found that fish-oil supplementation (8 g/day) reduced the rate of proliferation in the upper crypt cells of patients with a history of colonic polyps.

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