People are sometimes fearful of the blood-thinning effects of fish oil. Fish oil does indeed inhibit platelets (a blood-clotting cell) and reduce blood clotting factors like fibrinogen. However, bleeding problems from fish oil are exceptionally rare. I have never witnessed an adverse bleeding effect from fish oil in thousands of patients. Fish oil remains very safe even if taken with aspirin. In fact, the modest blood thinning effects of fish oil are desirable, since the majority of heart attacks and strokes are based on an increased tendency to form blood clots (on ruptured atherosclerotic plaques).
The only time there may be some concern over excessive blood thinning is if you take warfarin (CoumadinTM), a full-strength blood thinner, or if you have an abnormal bleeding tendency like sickle cell anemia or other clotting factor deficiency. In these instances, discuss the use of fish oil with your doctor. But in the huge majority, fish oil is safe and does not expose you to excessive risk of bleeding.
All in all, in my view, the benefits of fish oil far, far outweigh the risks─if any. The omega-3 fatty acids are a critical ingredient in any heart disease prevention program. Judging from the best information we have from unbiased sources, there is no reason to deprive ourselves of this wonderful health tool.
