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FISH OIL
Genes Boost Fish Oils' Effect Against Breast Cancer
Fri Sep 24, 2004 7:03 PM ET
FRIDAY, Sept. 24 (HealthDayNews) -- Women with certain genes get an extra protective boost when they take fish oils called marine n-3 fatty acids that may reduce the risk of breast cancer.
That's the conclusion of a study by researchers at the University of Southern California and the National University of Singapore.
The study found that women whose bodies do a poor job of eliminating the fish oils' byproducts seem to derive the most benefit from taking them. It's believed the fish oils' byproducts provide the cancer-fighting properties.
"In this study, we found that women with certain common DNA patterns experienced more breast cancer protection from marine n-3 fatty acids than women with other common patterns," study author Dr. Manuela Gago-Dominguez, an assistant professor of preventive medicine at USC's Keck School of Medicine, said in a prepared statement.
Researchers examined data from the Singapore Chinese Health Study of diet and cancer risk in more than 63,000 Chinese women and men who live in Singapore.
The findings could help scientists better understand how fish oils may protect against cancer.
The study appeared in the Sept. 21 online issue of Carcinogenesis.
Potential Side Effects of Fish Oil Capsules
 General: Fishy odor, gastrointestinal upset
 Coagulation: Increased bleeding time may result in nosebleeds, easy bruising
 Metabolism: Can increase cholesterol in those with combined hyperlipidemia
 Can increase calorie intake and hence weight gain
 Some preparations have added cholesterol
 Some lack vitamin E (alpha tocopherol); concern for oxidation
 Immune response: Various parameters are decreased (uncertain significance)
 Toxicity: Vitamin A and D toxicity with some preparations
 Some fish oils (not highly refined) may contain pesticide
 Concerns regarding effects on immune response
 Cost: Expensive compared with dietary fish intake
Medscape Medical News
Omega-3 Fatty Acids Improve Systemic Arterial Compliance
Laurie Barclay, MD
Medscape Medical News 2002. © 2002 Medscape
July 26, 2002 — Two omega-3 fatty acids contained in fish, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), significantly improve systemic arterial compliance, according to the results of a double-blind, placebo-controlled trial reported in the August issue of the American Journal of Clinical Nutrition. As a result, systolic and pulse pressure and total vascular resistance tended to decrease, while triglyceride levels dropped significantly.
"Substantial epidemiologic and other evidence shows that eating fish may benefit people at high risk for ischemic heart disease (IHD), [and] sudden cardiac deaths occur less frequently in individuals who habitually [eat] fish," write Paul Nestel, from Baker Medical Research Institute in Melbourne, Australia, and colleagues. "Because of increasing evidence linking heightened pulse pressure, a reflection of increased arterial stiffness, to increased coronary risk, interventions that improve arterial compliance are thought likely to reduce risk for IHD."
During a seven-week dietary intervention, 38 middle-aged men and women with elevated plasma total cholesterol were randomized to treatment with an EPA supplement (3 g/day), a DHA supplement (3 g/day), or placebo.
Systemic arterial compliance was unchanged in the placebo group, rose 36% in the EPA group and 27% in the DHA group (P=.043), and there was a trend toward reduced systolic and pulse pressure in the omega-3 fatty acid groups. Plasma total and very low density lipoprotein triacylglycerol concentrations were significantly lower in the treatment groups than in the placebo group (P=.026 and .006, respectively).
"EPA and DHA increase systemic arterial compliance and tend to reduce pulse pressure and total vascular resistance, effects that may reduce the risk of adverse cardiovascular events," the authors write.
Am J Clin Nutr. 2002;76:326-330
Reviewed by Gary D. Vogin, MD
Laurie Barclay, MD, is a staff writer with WebMD.
Medscape Medical News is edited by Deborah Flapan, an associate editor at Medscape. Please send press releases and comments to news@webmd.net.
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Fish Oil Reduces Body Fat Mass
Obesity is not only widespread in world populations, but has been designated by the World Health Organization as an important risk factor for heart disease, diabetes, certain cancers and a number of other disorders. As a result, many scientists are currently focusing on ways to combat this growing problem. New research, as reported in the March 1998 issue of PUFA Newsletter, suggests that omega-3 fatty acid supplementation may reduce body fat mass.
Data from animal studies has indicated that omega-3 fatty acids, which are found in fish and fish oil, may modulate the balance between the proportion of fat that is burned up as energy and the amount that is stored. For example, feeding rodents fish oil reduces weight gain and the deposit of body fat.
In a recent study at Bretonneau Hospital, Tours, in France, a group of six healthy volunteers (five men and one woman) were given tests with two types of diet. First, they spent three weeks on a conventional French diet, with no restrictions on quantity, eating meals prepared by a dietitian and comprising 52 per cent carbohydrates, 16 per cent protein and 32 per cent fat. Then, between 10 and 12 weeks later, the volunteers ate the same diet for a further three weeks except that 6 g of fat (such as butter, olive oil and sunflower oil) was replaced by 6 g of fish oil each day.
The latter was administered as capsules containing 1.8 g per day of fish oil, which, depending on the species, is equivalent to between 100 and 200 g of fish. At various times the researchers measured energy intake, physical activity, weight, metabolic rate, and other indicators including body composition.
Substituting fish oil for the same amount of visible fat appeared to stimulate the resting metabolic rate by some four per cent, reports Dr C. Couet, who led the investigation. Over the three weeks, subjects eating the control diet showed a 0.30 kg reduction in body fat. However, while eating the fish oil diet the decrease in body fat almost tripled to 0.88 kg, even though there was no change in weight. The absence of weight loss may have been due to the very short period of the tests.
The number of participants in the study was too small to draw conclusions about the usefulness of fish oil supplements in management of obesity, the investigators noted. However, further research with larger numbers and including obese patients is now envisaged.
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Both Fish Oil and Vitamin E Improve ALT (liver function test) in Study
Jules Levin, NATAP
VITAMIN E OR OMEGA-3 FATTY ACID CONCENTRATE (OMACOR‚) AS SUPPRESSIVE TREATMENT FOR PATIENTS WITH CHRONIC HEPATITIS C.
John B Gross, Laurie A Czaplewski, David J Brandhagen, Albert J Czaja, John J Poterucha, Terry M Therneau, Mayo Clin, Rochester, MN
For patients with chronic hepatitis C who are not candidates for interferon-based treatment, an alternative might be suppressive treatment with a well-tolerated agent that reduces inflammation and might therefore slow progression of fibrosis. Vitamin E has previously been shown to reduce ALT levels among a small group of patients with chronic hepatitis C. Omega-3 fatty acid (O3FA) concentrate (Omacor‚) has been shown to reduce disease activity in chronic conditions such as arthritis and IBD. AIM: to determine whether short-term treatment with vit E or O3FA reduces serum ALT levels among patients with chronic hepatitis C.
METHODS: Patients had histological evidence of chronic hepatitis, detectable serum HCV RNA, and ALT at least 2X normal. They had received no antiviral, herbal, or vitamin treatment within 30 days of entry. In random order, they were given vit E 400 IU BID x 12 wk, then O3FA 2 g BID x 12 wk, or vice versa, with 12-wk observation after each. Blood tests were monitored at 0, 2, 4, 8, and 12 wk of treatment, and at 12 wk after treatment.
RESULTS: 20 patients were enrolled, most having failed interferon; 13 have completed treatment and follow-up on vit E, and 10 on O3FA. On vit E, median ALT was ~60% of baseline, starting at 2 wk; 11 of 13 patients had a reduction in ALT. On O3FA, median ALT gradually declined to ~60% of baseline at 12 wk; 7 of 10 had reduced ALT. Median ALT relapsed toward baseline after each treatment. Median ALT (% of baseline): see table. Among 7 patients on vit E with paired PCR results available thus far (Chiron bDNA assay), we found no significant changes in RNA levels on treatment compared to baseline.
CONCLUSIONS: 1) Both vitamin E and O3FA (Omacor‚) can reduce ALT levels among patients with chronic hepatitis C. 2) The progressive decline in ALT over 12 weeks on O3FA suggests that longer treatment might be beneficial. 3) These agents warrant further study as alternative suppressive treatments for patients who are not candidates for conventional therapy. Grant support was received from Mayo Foundation and from Pronova a.s. (Norway
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