Fish oil side effects

Fish oil and Fish oil containig products has a lot of benefits. But what about the fish oil side effects?
Vitamin A and D toxicity (fish liver oil only). The unpleasant taste of fish liver oil liquids may be masked by mixing with fruit juice or milk. Fish oil omega 3 supplements are generally safe, and in one prospective study involving 295 people aged 18–76 years, 10–20 ml of fish oil providing 1.8–3.6 g EPA/DHA for 7 years was not associated with any serious adverse effects. The safety of n-3 fatty acids from fish oil (derived from menhaden) was reviewed by the US Food and Drug Administration (FDA) in 1997. After reviewing more than 2600 articles, the FDA concluded that dietary intakes of up to 3 g daily of the 2 fish oil omega 3 (EPA/DHA) from menhaden oil were generally regarded as safe (GRAS). The FDA came to this conclusion after considering three main issues related to the safety of fish oils:
- firstly, the risk of deteriorating glycaemic control in type 2 diabetes;
- secondly, prolonged bleeding times;
- thirdly, the risk of increasing LDL levels in patients with hypertriglyceridaemia.
Many fish oil supplements (e.g. cod liver oil, halibut liver oil) contain vitamin A and vitamin D – that are fat-soluble vitamins that can be toxic in excessive amounts. However, the amount of these vitamins contained, for example, in an average multivitamin supplement containing no more than 100% of the RDAs together with the amounts in a recommended dose of, say, ordinary cod liver oil are unlikely to be harmful. However, care should be taken in pregnancy not to take excessive amounts of vitamin A, and product labels should be checked. Other safety concerns expressed in relation to fish oils include the potential to increase bleeding time (a beneficial effect in relation to prevention of CHD) and the possibly of altering glycaemic control in diabetes. However, it is unlikely that any of these effects is a problem, particularly with intakes of <3g EPA/DHA daily. Nevertheless, patients taking anticoagulant medication or those with blood clotting disorders should be monitored while taking fish oils. This does not mean that such patients have to avoid fish oils – just that their doctor should be aware of it. There is also concern about industrial contaminants in fish oil supplements. These include dioxins and polychlorinated biphenyls (PCBs). There is no immediate danger to health, but risks come from long exposure to high levels. In 2001, the UK Committee on Toxicity (COT) set a tolerable daily intake for dioxins and dioxin-like PCBs of 2 pg TEQ/kg/bw/day. (For comparison the EU Scientific Committee on Food (SCF) set a tolerable weekly intake of 14 pg/kg/body weight). Since July 2002 it has been an offence to place on the market any fish oil supplements containing higher contaminant levels.