Couple of weekly portions of oily fish can help ward off stroke

Eating at least two servings of oily fish a week is moderately but significantly associated with a reduced risk of stroke, finds a study published in British Medical Journal .

But taking fish oil supplements doesn't seem to have the same effect, say the researchers.

Regular consumption of fish and long chain omega 3 fatty acids has been linked with a reduced risk of coronary heart disease and current guidelines recommend eating at least two portions of fish a week, preferably like mackerel and .  But evidence supporting a similar benefit for stroke remains unclear.

So an international team of researchers, led by Dr. Rajiv Chowdhury at Cambridge University and Professor Oscar H. Franco at Erasmus MC Rotterdam, analysed the results of 38 studies to help clarify the association between fish consumption and risk of stroke or mini-stroke (transient ischaemic attack or TIA). Collectively, these conditions are known as cerebrovascular disease.

The 38 studies involved nearly 800,000 individuals in 15 countries and included patients with established cardiovascular disease (secondary prevention studies) as well as lower risk people without the disease (primary prevention studies). Differences in study quality were taken into account to identify and minimise bias.

Fish and long chain omega 3 fatty acid consumption was assessed using dietary questionnaires, identifying markers of omega 3 fats in the blood, and recording use of fish oil supplements. A total of 34,817 cerebrovascular events were recorded during the studies.

After adjusting for several risk factors, participants eating two to four servings a week had a moderate but significant 6% lower risk of cerebrovascular disease compared with those eating one or fewer servings of fish a week, while participants eating five or more servings a week had a 12% lower risk.

An increment of two servings per week of any fish was associated with a 4% reduced risk of cerebrovascular disease. In contrast, levels of omega 3 fats in the blood and fish oil supplements were not significantly associated with a reduced risk.

Several reasons could explain the beneficial impact of eating fish on vascular health, say the authors. For example, it may be due to interactions between a wide range of nutrients, like vitamins and essential amino acids, commonly found in fish. Alternatively, eating more fish may lead to a reduction in other foods, like red meat, that are detrimental to vascular health. Or higher fish intake may simply be an indicator of a generally healthier diet or higher socioeconomic status, both associated with better vascular health.

The differences seen between white and oily fish may be explained by the way they are typically cooked (white fish is generally battered and deep fried, adding potentially damaging fats).

Although there's a possibility that some other unmeasured (confounding) factor may explain their results, the authors conclude that "they reinforce a potentially modest beneficial role of fish intake in the cause of cerebrovascular disease."

In addition, they say their findings are in line with current dietary guidelines that encourage for all; and intake of fish oils to people with pre-existing or at high risk of heart disease. They also support the view that future nutritional guidelines should be principally "food based."

In an accompanying editorial, authors from the Division of Human Nutrition at Wageningen University suggest that although it is "reasonable" to advise patients that eating one or two portions of per week could reduce the risk of and stroke, any benefit of long chain omega 3 fatty acid supplementation is likely to be small. They say it is possible, however, that patients with additional risk factors such as diabetes may benefit.

More information: www.bmj.com/cgi/doi/10.1136/bmj.e6698

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Can YouTube save your life?

6 hours ago

Only a handful of CPR and basic life support (BLS) videos available on YouTube provide instructions which are consistent with recent health guidelines, according to a new study published in Emergency Medicine Australasia, the jo ...

Doctors frequently experience ethical dilemmas

7 hours ago

(HealthDay)—For physicians trying to balance various financial and time pressures, ethical dilemmas are common, according to an article published Aug. 7 in Medical Economics.

AMGA: Physician turnover still high in 2013

7 hours ago

(HealthDay)—For the second year running, physician turnover remains at the highest rate since 2005, according to a report published by the American Medical Group Association (AMGA).

Obese or overweight teens more likely to become smokers

8 hours ago

A study examining whether overweight or obese teens are at higher risk for substance abuse finds both good and bad news: weight status has no correlation with alcohol or marijuana use but is linked to regular ...

Taking preventive health care into community spaces

9 hours ago

A church. A city park. An office. These are not the typical settings for a medical checkup. But a new nationwide study by the UCLA Center for Health Policy Research shows that providing health services in ...

User comments