Potential Toxicities of Fish Oil
Concerns have been raised about the potential toxicity or side effects that might result from the prolonged consumption of fish oil by humans. One such possibility is excessive bleeding, since the Eskimos were said to have frequent epistaxis and easy bruisability. Mild to moderate thrombocytopenia was also found in the Eskimos, two of Dyerbergs subjects having platelet counts of fewer than 100,000/cu mm. In the United States, when high doses of salmon oil were fed to normal subjects, one volunteer developed a platelet count fall to 90,000/cu mm, which rapidly rose to normal following cessation of the fish oil feeding. Platelet survival studies during a subsequent trial of salmon oil showed that platelet survival was normal. Hugh Sinclair, who ingested a “Eskimo diet” of seal and fish for 4 months, also developed a fall in his platelet count to 50,000/cu mm, which was associated with a markedly prolonged bleeding time. So far, clinically significant thrombocytopenia has occurred only when very large doses of fish oil were used, so that the lower doses of oil being administered in current clinical studies are unlikely to produce significant thrombocytopenia. Furthermore, thrombocytopenia has not been reported following the use of more purified preparations of fish oil that are currently under study. www.asthma-inhalers-online.com
An important consequence of an increased bleeding tendency is the possible increase in stroke reported in the Eskimos of Greenland. However, it should be noted that the type (eg, thrombotic, hemorrhagic) of the CNS events in these subjects has not been well characterized. In the study recently reported by Hollander et al, the cynomologus monkeys fed fish oil in an effort to retard atherogenesis developed increases in focal atherosclerotic lesions at the bifurcation of the internal and external carotid artery, although common carotid artery atherosclerosis was reduced. However, in contrast to the report on the Eskimos, a decreased incidence of stroke was found in a Japanese fishing village.