Fish oils inhibit thrombosis and may thus decrease the risk of ischemic stroke. However, one needs to take at least 1000 mg of EPA + DHA (not just 1000 mg of fish oil) a day to achieve significant cardiovascular benefits.
It may be wise to stop fish oil supplementation 4-7 days prior to major surgery, except in the case of coronary artery bypass surgery where continued supplementation may help prevent post-procedure atrial fibrillation.
Dr. Bays also addressed the question, “Do prescription and/or supplement omega-3 fatty acid products contain excessive vitamin or toxins, such as mercury, polychlorinated biphenyls, dioxin, or other contaminants, in sufficient concentrations to pose a potential health risk?” Again, his answer is negative. This conclusion is largely based on a 2006 ConsumerLab evaluation of 42 commercially available fish oil supplements. All but two were found to contain the amount of EPA and DHA stated on the label, were free of mercury, PCBs and dioxins, and were not oxidized (rancid). Among the brands that passed the ConsumerLab evaluation were Carlson, Coromega, Metagenics, Nordic Naturals, Kirkland and Puritan Pride.
Dr. Bays cautions that a high fish oil intake through the consumption of large amounts of fish may present a risk for environmental toxin exposure, especially methylmercury, PCBs, organochlorine pesticides and dioxins. He points out that oxidized mercury is insoluble in oil, so would not be expected to represent a significant toxicity risk in fish oil supplements.
In an accompanying editorial Dr. William Harris of the University of South Dakota emphatically endorses Dr. Bays’ conclusion that fish oils do not increase bleeding risk even if taken in combination with aspirin or warfarin.
Bays, HE. Safety considerations with omega-3 fatty acid therapy. American Journal of Cardiology, Vol. 99, No. 6A, March 19, 2007, pp. 35C-43C
Harris, WS. Omega-3 fatty acids and bleeding – Cause for concern? American Journal of Cardiology, Vol. 99, No. 6A, March 19, 2007, pp. 44C-46C
Fish oil supplementation does not increase bleeding tendency
OSLO, NORWAY. A group of Norwegian medical researchers reports that fish oil supplementation does not increase the bleeding tendency in heart disease patients receiving aspirin or warfarin. The study involved 511 patients who had undergone coronary artery bypass surgery. On the second day after the operation half the patients were assigned in a random fashion to receive 4 grams of fish oil per day (providing 2 g/day of eicosapentaenoic acid, 1.3 g/day of docosahexaenoic acid, and 14.8 mg/day of vitamin E). At the same time the patients were also randomized to receive either 300 mg of aspirin per day or warfarin aimed at achieving an INR of 2.5-4.2. The patients were evaluated every 3 months and questioned about bleeding episodes for the duration of the 9-month study.
The researchers concluded that fish oil supplementation did not result in a statistically significant increase in bleeding episodes in either the aspirin group or in the warfarin group. They also found no significant long-term effects of fish oil on common parameters of coagulation and fibrinolysis. They noted that the blood levels (serum phospholipid levels) of eicosapentaenoic acid and docosahexaenoic acid increased by 140% and 14% respectively in the patients taking fish oil. The serum triglyceride levels decreased by 19.1% in the fish oil group while no significant change was observed in the remainder of the patients. NOTE: This study was partially funded by Pronova Biocare AS (a fish oil manufacturer) and Nycomed Pharma AS.
Eritsland, J., et al. Long-term effects of n-3 polyunsaturated fatty acids on haemostatic variables and bleeding episodes in patients with coronary artery disease. Blood Coagulation and Fibrinolysis, Vol. 6, 1995, pp. 17-22
Fish oil interaction with warfarin.Buckley MS, Goff AD, Knapp WE.
Shawnee Mission Medical Center, Shawnee Mission, KS of Arizona, Tucson, AZ 85724, USA. [email protected]
OBJECTIVE: To report a case of elevated international normalized ratio (INR) in a patient taking fish oil and warfarin. CASE SUMMARY: A 67-year-old white woman had been taking warfarin for 1(1/2) years due to recurrent transient ischemic attacks. Her medical history included hypothyroidism, hyperlipidemia, osteopenia, hypertension, and coronary artery disease. She also experienced an inferior myocardial infarction in 1995 requiring angioplasty, surgical repair of her femoral artery in 1995, and hernia repair in 1996. This patient has her INR checked in the anticoagulation clinic and is followed monthly by the clinical pharmacist. Prior to the interaction, her INR was therapeutic for 5 months while she was taking warfarin 1.5 mg/d. The patient admitted to doubling her fish oil dose from 1000 to 2000 mg/d. Without dietary, lifestyle, or medication changes, the INR increased from 2.8 to 4.3 within 1 month. The INR decreased to 1.6 one week after subsequent fish oil reduction, necessitating a return to the original warfarin dosing regimen. DISCUSSION: Fish oil supplementation could have provided additional anticoagulation with warfarin therapy. Fish oil, an omega-3 polyunsaturated fatty acid, consists of eicosapentaenoic acid and docosahexaenoic acid. This fatty acid may affect platelet aggregation and/or vitamin K-dependent coagulation factors. Omega-3 fatty acids may lower thromboxane A(2) supplies within the platelet as well as decrease factor VII levels. Although controversial, this case report illustrates that fish oil can provide additive anticoagulant effects when given with warfarin. CONCLUSIONS: This case reveals a significant rise in INR after the dose of concomitant fish oil was doubled. Patients undergoing anticoagulation therapy with warfarin should be educated about and monitored for possible drug-herb interactions. Pharmacists can play a crucial role in identifying possible drug interactions by asking patients taking warfarin about herbal and other alternative medicine product use.
Yours Truly.
That bleeding issue is interesting. By any chance do you have any studies showing those problems?
Thanks
CROWLER