There are numerous health benefits associated with the consumption of oily fish. Research indicates that it can reduce the risk of death from heart disease, improve mental ability, ward off cancer, prevent alcohol-related dementia, and lower your risk of rheumatoid arthritis.
Oily fish is very rich in omega-3 polyunsaturated fatty acids. While white fish also contains these fatty acids, levels are much lower.
As well as being a super source of omega-3 oils, oily fish contains plenty of lean protein.
Having sufficient levels of these fatty fish oils is important for good health. In fact, eating oily fish during pregnancy and while breastfeeding may help the fetus develop - babies need omega-3 fatty acids for proper nervous system development.
This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular foods. It highlights the health benefits of eating oily fish, includes a section on which fish are oily, mentions the limit to the amount of oily fish that should be consumed, and why eating too much can be bad.
Health benefits of oily fish
People are advised to eat one portion (140 grams) of oily fish per week. The National Health Service1, UK, advises people to eat at least two portions of fish a week, including one of oily fish.
Eating one portion of fatty fish, such as mackerel or salmon, could cut your risk of developing rheumatoid arthritis by 50%
The health benefits of eating oily fish include:
Prevention of cardiovascular disease - a study published in the American Journal of Physiology - Regulatory, Integrative, and Comparative Physiology showed that fatty fish oils can "counteract the detrimental effects of mental stress on the heart."
Reduced risk of rheumatoid arthritis - research published in the journal Annals of the Rheumatic Diseases found that one weekly portion of fatty fish may reduce rheumatoid arthritis risk by over 50%.
Protect against alcohol-related dementia - a team of investigators at Loyola University Chicago Stritch School of Medicine found that eating oily fish may protect alcohol abusers from dementia. Their study demonstrated that brain cells exposed to a mix of fish oil and alcohol had 95% less neuroinflammation and neuronal death compared to brain cells that were only exposed to alcohol.
Prevention of oral and skin cancers - oily fish consumption may protect from early- and late-stage oral and skin cancers, a study published in the journal Carcinogenesis reported. The authors wrote "We found that the omega-3 fatty acid selectively inhibited the growth of the malignant and pre-malignant cells at doses which did not affect the normal cells."
Boosting infant sensory, cognitive, and motor development - consuming oily fish during the last months of pregnancy can have positive effects on a child's sensory, cognitive, and motor development.
Protecting vision - DHA can protect elderly people from vision loss. DHA is an omega-3 fatty acid found in fish. Scientists at the University of Alberta's Faculty of Medicine & Dentistry identified a link between oily fish consumption and a lower risk of vision loss in elderly individuals.
Improving memory - a team of researchers at the University of Pittsburgh published a study in PLOS One which suggested that eating oily fish may improve working memory.
What are oily fish?
Oily fish are species of fish that contain significant amounts of oil throughout their body tissues and in their belly cavity. In contrast, whitefish only contain oil in their liver - and much less of it than oily fish.
Examples of oily fish include:
All these fish, with the exception of tuna, are rich in omega-3 fatty acids, regardless of whether they are canned, fresh or frozen. Tuna is only rich in omega-3 when it is fresh - not when canned.
Is there a limit to how much oily fish I can eat?
Despite the significant health benefits of eating oily fish, eating too much may be bad for you.
If you are pregnant or planning to have a baby, you should limit your oily fish intake to two portions each week. The rest of the population should eat no more than four portions per week.
The advice on farmed salmon is the same as for all other oily fish.
Why is eating too much oily fish bad?
According to the Food Standards Agency2, oily fish contain pollutants called PCBs (polychlorinated biphenyls) and dioxins. These pollutants do not have an immediate effect on health, but they do after long term exposure.
Dioxins are highly toxic compounds that are persistent environmental pollutants. The World Health Organization said that over 90% of human exposure to these pollutants is through meat and dairy products, fish and shellfish. High exposure to dioxins can cause skin lesions, and impairment of the immune and reproductive systems.
Can I eat oily fish if I'm pregnant or breastfeeding?
Yes. You can and should eat oily fish if you are pregnant or breastfeeding, because it is good for your child's health.
Just make sure you do not eat more than the recommended limit of two portions of oily fish per week.