Eating Fish Can Reduce Risk of Stroke
Oily fish reduces risk of cardiovascular disease, and now it appears to reduce the risk of cerebrovascular disease as well.
-- by Michael Harkin
A new study published today by BMJ shows a reduced risk of cerebrovascular disease among those who eat at least two servings of fish per week, particularly oily fish. Cerebrovascular disease is a collective term that includes both stroke and mini-stroke.
There is a proven connection between consuming fish and long-chain omega-3 fatty acids (which can be found in fish oil, as well as fish oil supplements) and a lessened risk of coronary heart disease. However, the benefits of fish on risk of stroke are less established. Although the difference in risk was relatively minor, it is still a significant finding, and it has great implications for both human health and dietary science.
The Expert Take
Despite the benefits of oily fish, the study found that fish oil supplements did not produce the same outcome. According to the study’s authors, the results “reinforce a potentially modest beneficial role of fish intake in the cause of cerebrovascular disease.” Even though the reduction in risk isn’t enormous, it is nonetheless significant, and the study’s authors make clear that they recommend the consumption of fish oils as is advised by dietitians.
“Our findings are in line with current dietary guidelines (that is, to encourage fish consumption for all; and intake of fish oils, preferably from oily fish, to people with pre-existing or at high risk of coronary heart disease),” said the authors. They also point out that there is a relative lack of studies of examining actual fish intake versus the use of supplements.
Source and Method
Researchers led by Dr. Rajiv Chowdhury of Cambridge University and Professor Oscar H. Franco of Erasmus M.C. Rotterdam took a close look at the outcome of 38 different surveys to get a better idea of the connections between eating fish and the risk of having a stroke or mini-stroke.
Patients included in the researchers’ overview, of which there were nearly 800,000, included people with cardiovascular disease and people without the disease. Consumption was measured by looking at markers of omega-3 fats in the blood, questionnaires about diet, and records kept about use of fish oil supplements. There were 34,817 cerebrovascular events that were recorded in the studies overall.
The risk of cerebrovascular disease was found to be 6 percent lower in those who ate two to four servings of fish per week, compared to those having one or less servings a week. Additionally, those who ate five or more servings of fish a week had a 12 percent lower risk than those who had one or less serving a week.
There is a small, but significant decrease in risk of stroke in people who eat two or more servings of fish per week. Dietitians advise integrating this kind of fish intake into one’s diet in general, especially those at risk of heart disease. Increased fish intake, especially of oily fish like sardines and mackerel, may be helpful for people at risk of stroke as well.
Fish’s effects on the risk of cerebrovascular disease could be due to a number of things, many of which still need to be studied. The vitamins and essential amino acids in fish might be producing interactions that might reduce risk. It’s also possible that people who eat more fish have a healthier diet in general, or eat less of foods that are disadvantageous for the vascular system such as red meat.
This is one of the first studies to find an actual link between a reduction in stroke risk and the consumption of fish oil. A 2007 study by Bandolier, published by Oxford Medical Sciences Division, was unable to establish a real connection between stroke risk and the consumption of fish and omega-3 polyunsaturated fatty acids. However, it did advocate the role of fatty acids in brain function and the transmission of nerve impulses, as well as its ability to help people be more likely to survive heart attacks.
The Mayo Clinic says that some studies of the link between omega-3 fatty acids and stroke risk have suggested benefits, while others have not. They also mention that excessive intake of omega-3 fatty acids might increase the risk of hemorrhagic stroke (bleeding stroke).