Fish oil
From Wikipedia, the free encyclopedia
Fish oil is oil derived from the tissues of oily fish.
Fish oil is recommended for a healthy diet because it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), precursors to eicosanoids that reduce inflammation throughout the body.
However, fish do not actually produce omega-3 fatty acids, but instead accumulate them from consuming microalgae that produce these fatty acids, as well as from eating other fish that have accumulated them. Fatty fish like mackerel, lake trout, herring, sardines, albacore tuna and salmon are high in Omega-3 fatty acids, but these species are often predators, which can accumulate toxic substances due to their position at the top of the food chain (See biomagnification). For this reason, the FDA recommends limiting consumption of fish due to high levels of toxic contaminants such as mercury, dioxin, PCBs and Chlordane.[1] Due to this limitation, many people have turned to fish oil supplements to get adequate omega-3 fatty acids.
Fish oil supplements have sometimes come under scrutiny in recent years. In early 2006, government agencies such as the Food Standards Agency in the UK and the Food Safety Authority of Ireland reported PCB levels that exceeded the strict new European maximum limits in several fish oil brands,[2] [3] which required temporary withdrawal of these brands. To address the growing concern over contaminated fish oil supplements, the International Fish Oil Standards program, a voluntary review process was created at University of Guelph.
[edit] Benefits of fish oil
Some experts believe that taking fish oil (in any form) can help regulate cholesterol in the body, because fish oil has high levels of Omega 3. The regulation occurs through effects of the EPA and DHA constituents on Peroxisome proliferator-activated receptor alpha (PPARα). Besides cholesterol regulation, benefits include anti-inflammatory properties and positive effects on body composition. However, the preferred source of Omega 3 should be from the fish's body, not the liver. The liver and liver products (such as cod liver oil ) of fish and many animals (such as seals and whales) contain Omega-3, but also the active form of Vitamin A. At high levels, this form of the vitamin can be dangerous. Early explorers to the land of the Inuit were given raw liver by the natives, which contained a toxic overdose of Vitamin A for the white explorers; however, the same amount was harmless to the Inuit, who had no other source of Vitamin A except animal livers.
Some studies[4] were conducted on prisoners in England where the inmates were fed seafood which contains Omega-3 Fatty acids. It was observed that the high consumption of these fatty acids led to a drop in the homicide rates. Another study was conducted in Finland where they found that prisoners who were convicted of violence had lower levels of Omega Three Fatty Acids than normal. It was suggested that these kinds of fatty acids are responsible for the neuronal growth of the frontal cortex of the brain which, it is further alleged, is the seat of personal behavior.
The American Heart Association recommends the consumption of 1g of fish oil daily, preferably by eating fish, for patients with coronary heart disease.[5]
The US National Institutes of Health lists three conditions for which fish oil and other omega-3 sources are most highly recommended (Grade A scientific evidence): Hypertriglyceridemia, Secondary cardiovascular disease prevention and High blood pressure. It then lists 27 other conditions for which there is B or C grade evidence. It also lists possible safety concerns: "Intake of 3 grams per day or greater of omega-3 fatty acids may increase the risk of bleeding, although there is little evidence of significant bleeding risk at lower doses... Very large intakes of fish oil/omega-3 fatty acids ("Eskimo" amounts) may increase the risk of hemorrhagic (bleeding) stroke."[6]
According to a study from Louisiana State University in September 2005, fish oil may help protect the brain from cognitive problems associated with Alzheimer's disease. [7]
Fish oil has also been shown to aid in the treatment of people suffering with depression.[8]
For purchasing fish oil dietary supplements, it is often recommended to seek a label certifying the product to be distilled, pharmaceutical grade fish oil, and free of mercury and other toxins.
[edit] References
- ^ EPA (2007-01-31). Fish Consumption Advisories. Retrieved on February 8, 2007.
- ^ Jess Halliday (13/04/2006). Dioxins prompt second UK fish oil withdrawal. Retrieved on February 8, 2007.
- ^ Pollutants found in fish oil capsules (6 April, 2002). Retrieved on February 8, 2007.
- ^ STEPHEN MIHM. "Does Eating Salmon Lower the Murder Rate?", NYTimes, April 16, 2006. Retrieved on February 8, 2007.
- ^ Fish and Omega-3 Fatty Acids. American Heart Association. Retrieved on February 9, 2007.
- ^ NIH Medline Plus. MedlinePlus Herbs and Supplements: Omega-3 fatty acids, fish oil, alpha-linolenic acid. Retrieved on February 14, 2006.
- ^ Walter J. Lukiw (2005-06-28). "A role for docosahexaenoic acid–derived neuroprotectin D1 in neural cell survival and Alzheimer disease". J. Clin. Invest 115: 2774-2783. DOI:10.1172/JCI25420. Retrieved on 2007-02-09.
- ^ John McKenzie. ABC News: Fish Oil Helps Treat Depression. Retrieved on April 1, 2007.
[edit] External links
- EPA Fish Consumption Advisories
- International Fish Oil Standards
- An organization concerned with the quality of omega-3 products as it relates to the international standards established by the World Health Organization and the Council For Responsible Nutrition for purity and concentration.
- Joyce A. Nettleton, ed. PUFA Newsletter. Retrieved on February 20, 2006. Two newsletters, both quarterly, reviewing recent publications in essential fatty acids. One is written for researchers, the second is for consumers. Industry sponsored, academic contributors.
- Clover, Charles. 2004. The End of the Line: How overfishing is changing the world and what we eat. Ebury Press, London. ISBN 0-09-189780-7
