Oily fish

Health benefits

Dementia

A 1997 study published in Annals of Neurology followed 5,386 elderly participants in Rotterdam. It found that fish consumption decreased the risk of dementia.{{Cite journal | hdl-access = free

French research published in 2002 in the British Medical Journal (BMJ) followed 1,674 elderly residents of southern France for seven years, studying their consumption of meat versus seafood and the presence of dementia symptoms. The conclusion was that people who ate fish at least once a week had a significantly lower risk of being diagnosed with dementia over a seven-year period. This study reinforced the Annals of Neurology findings. Because of the longer term, the BMJ study provided stronger evidence of a genuine protective effect.{{Cite journal

Cardiovascular health

Consuming 200–400 g of oily fish twice per week may also help prevent sudden death due to myocardial infarction by preventing cardiac arrhythmia. The eicosapentaenoic acid found in fish oils appears to dramatically reduce inflammation through conversion within the body to resolvins, with beneficial effects for the cardiovascular system and arthritis.

Recommended consumption

In 1994, the UK Committee on Medical Aspects of Food and Nutrition Policy recommended that people eat at least two portions of fish per week, one of which should be oily fish.

In 2004 the UK Food Standards Agency published advice on the recommended minimum and maximum quantities of oily fish to be eaten per week, to balance the beneficial qualities of the omega-3 fatty acids against the potential dangers of ingesting polychlorinated biphenyls and dioxins. It reiterated the 1994 guideline of two portions of fish per week including one portion of oily fish, but advised eating no more than four portions per week, and no more than two portions for people who are pregnant, may become pregnant or who are breastfeeding.

The United States Environmental Protection Agency's (EPA) Exposure Reference Dose (RfI) for methylmercury (MeHg) is 0.1 micrograms per kg body weight per day. The corresponding limit of blood mercury is 5.8 micrograms per liter. The restrictions apply to certain oily fish – "marlin, swordfish, shark and, to a lesser extent, tuna". The recommendations on maximum consumption of oily fish were up to four portions (1 portion = 140g, or approx 4.9 ounces) a week for men, boys, and women past childbearing age, and up to two portions a week for women of childbearing age, including pregnant and breastfeeding women, and girls. There is no recommended limit on the consumption of white fish.

The EPA and 2007 U.S. Department of Agriculture guidelines sets a limit only on consumption of fatty fish with greater than one part per million of methylmercury, specifically tilefish, king mackerel, shark and swordfish. There are limits, however, for nursing/pregnant women and children under the age of six. This population should completely avoid fish with high risk of mercury contamination (those listed above) and limit consumption of moderate and low-mercury fish to 12 ounces or less per week. Albacore tuna should be limited to six ounces or less per week.

Omega-3 content

Concerns about contamination, diet or supply have led to investigation of plant sources of omega-3 fatty acids, notably flax, hempseed and perilla oils. Lactating women who supplemented their diet with flaxseed oil showed increases in blood and breastmilk concentration of alpha-linolenic acid and eicosapentaenoic acid but no changes to concentrations of docosahexaenoic acid.

References

References

1. (4 July 2024). "Types of fish: Bluefish, Whitefish and Semi-fatty fish".
2. (24 June 2004). "What's an oily fish?".
3. (7 October 1989). "Oily fish helps heart attack victims to live longer - 07 October 1989". New Scientist.
4. Kremer JM. (2017). "Fish Oil and Inflammation — A Fresh Look". The Journal of Rheumatology.
5. Wilkinson, Emma. (9 March 2009). "Oily fish dementia boosts queried".
6. (2003). "Clinical prevention of sudden cardiac death by n-3 polyunsaturated fatty acids and mechanism of prevention of arrhythmias by n-3 fish oils". Circulation.
7. Arita, M.. (2005). "Stereochemical assignment, antiinflammatory properties, and receptor for the Omega-3 lipid mediator Resolvin E1". [[J. Exp. Med..
8. (23 June 2004). "Oily fish advice: your questions answered".
9. SACN (2004) [https://cot.food.gov.uk/sites/default/files/cot/fishreport200401.pdf ''Advice on fish consumption: benefits and risks''], 20 May 2014, Committee on Toxicity. {{ISBN. 011243083X.
10. (1 January 2003). "Supplementing lactating women with flaxseed oil does not increase docosahexaenoic acid in their milk". American Journal of Clinical Nutrition.