Plaques—not good for the arteries

Atherosclerosis, or hardening of the arteries, is characterised by plaque formation in the artery walls. These plaques are thought to be the result of cholesterol build-up, oxidative damage, and inflammation.

The cap of an atherosclerotic plaque can break away from the vessel wall, travel in the blood, and become lodged in a smaller artery: travelling plaques within the coronary arteries can cause a heart attack. Breakaway plaques from the carotid arteries tend to block small arteries in the brain, leading to vision loss, a condition that sometimes precedes a stroke, known as transient ischemic attack, or a stroke.

Low omega-3s associated with more symptoms

Carotid artery plaques from 41 people having surgery to have them removed were analysed for signs of inflammation and for their fatty acid makeup. Plaques from people with symptoms of vision loss, transient ischemic attack, or stroke, had a higher degree of inflammation and lower levels of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), the two major omega-3 fatty acids from fish, than plaques from people with no symptoms. Levels of omega-6 fatty acids, which are generally considered to be inflammatory, were the same in symptomatic and asymptomatic people.

“Recommendations have previously been made regarding the amount of omega-3 content which may prove to be beneficial for cardiac protection, especially in those at risk,” the study’s authors said.

More might be the answer

These current results suggest that omega-3 fatty acids from fish might prevent stroke, adding to the evidence from a number of previous studies showing that omega-3 fatty acid consumption prevents cardiovascular disease. Here are some ways to get more in your diet:

• Follow the advice of the American Heart Association: eat two 3-ounce servings of fatty fish per week. These include salmon, tuna, herring, and mackerel.
• Include plant sources of omega-3 fatty acids such as non-defatted linseed meal, walnuts, and oils from soya, canola, walnut, and linseed. These foods can increase levels of the beneficial EPA, and, unlike fish, are generally free of heavy metals and PCBs (polychlorinated biphenyl).
• If you have heart disease or a high risk of heart disease, consider taking a daily fish oil supplement that provides 1 to 1.8 grams of omega-3 fatty acids.

(Vascul Pharmacol 2009; doi:10.1016/j.vph.2009.08.003)