'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 either consuming
microalgae that produce these fatty acids, as is the case with prey fish like
herring and
sardines, or, as is the case with fatty predatory fish, by eating prey fish that have accumulated
omega-3 fatty acids from microalgae. Such fatty predatory fish like
mackerel,
lake trout,
albacore tuna and
salmon may be high in omega-3 fatty acids, but due to their position at the top of the
food chain, these species can accumulate
toxic substances (See
biomagnification). For this reason, the FDA recommends limiting consumption of certain (predatory) fish species (e.g. albacore tuna) due to high levels of toxic contaminants such as
mercury,
dioxin,
PCBs and
chlordane.
[ Fish Consumption Advisories EPA ]
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,
[ Dioxins prompt second UK fish oil withdrawal Jess Halliday ]
[ Pollutants found in fish oil capsules ]
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.
Benefits of fish oil
: ''See also
Coronary heart disease (Omega-3_fatty_acids)''
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 fatty acids. The regulation occurs through effects of the EPA and DHA constituents on
Peroxisome proliferator-activated receptor alpha (PPAR'α'). 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.
Studies
[ Does Eating Salmon Lower the Murder Rate? ][1]
were conducted on prisoners in England where the inmates were fed seafood which contains Omega-3 Fatty acids. The higher consumption of these fatty acids led to a drop in the assault rates. Another Finnish study found that prisoners who were convicted of violence had lower levels of omega–3 fatty acids than prisoners convicted of nonviolent offenses. 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 1
g of fish oil daily, preferably by
eating fish, for patients with
coronary heart disease.
[ Fish and Omega-3 Fatty Acids ]
The US
National Institutes of Health lists three conditions for which fish oil and other omega-3 sources are most highly recommended:
hypertriglyceridemia, secondary
cardiovascular disease prevention and
high blood pressure. It then lists 27 other conditions for which there less 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."
[ MedlinePlus Herbs and Supplements: Omega-3 fatty acids, fish oil, alpha-linolenic acid NIH Medline Plus ]
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.
[ A role for docosahexaenoic acid–derived neuroprotectin D1 in neural cell survival and Alzheimer disease, Walter J. Lukiw, , , J. Clin. Invest, ]
Fish oil has also been shown to aid in the treatment of people suffering with depression.
[ ABC News: Fish Oil Helps Treat Depression John McKenzie ]
For purchasing fish oil dietary supplements, it is highly recommended to seek a label certifying the product to be "molecularly distilled",
USP Certified, and therefore free of mercury and other metal toxins.
References
1. Influence of supplementary vitamins, minerals and essential fatty acids on the antisocial behaviour of young adult prisoners. Randomised, placebo-controlled trial, Gesch CB, Hammond SM, Hampson SE, Eves A, Crowder MJ, , , The British journal of psychiatry : the journal of mental science, 2002
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.
★
PUFA Newsletter Joyce A. Nettleton, ed 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