There are a number of ways Omega-3 fatty acids are known to benefit heart health:

• Decreasing triglycerides
• Lowering blood pressure slightly
• Decreasing the risk of strokes and heart failure
• Reducing blood clotting
• Reducing irregular heart beats

Decreasing Triglycerides 

The most consistent evidence for omega-3s and heart health is their ability to lower triglyceride levels. Triglycerides are a type of fat found in your blood and are stored as body fat. High levels of triglycerides have been linked with fatty build-up in the artery walls, which increases your risk of heart attack and stroke.

High triglycerides are often a sign of other conditions that increase the risk of heart disease and stroke, including obesity and metabolic syndrome — a cluster of conditions that includes too much fat around the waist, high blood pressure, high triglycerides, high blood sugar and abnormal cholesterol levels. There’s strong evidence that omega-3 fatty acids, particularly DHA, can significantly reduce blood triglyceride levels.

Lowering Blood Pressure

High blood pressure can lead to heart attack and stroke.  The effects of Omega-3s on blood pressure can be favourable.  The amount of pressure in your arteries during the contraction of your heart muscle and the amount of pressure in your arteries between beats have both been shown to be reduced when individuals have been given higher doses of Omega-3s.

Decreasing Risk of Stroke and Heart Failure

Most strokes occur when the arteries to the brain become narrowed or blocked, severely reducing blood flow to the brain. This is commonly caused when a blood clot forms in one of the arteries that supplies blood to the brain or when a blood clot forms outside of the brain (usually in the heart) and is then carried through the bloodstream and lodges in a narrower brain artery. A clot is formed by fatty deposits or plaque, which build up in the arteries, also known as atherosclerosis, and cause reduced blood flow. Studies have shown that Omega-3s slow the build-up of plaque.

Reducing Blood Clotting

Plaque, a substance comprising of fat, cholesterol, and calcium can accumulate and harden in your arteries.  Plaque formations can grow large enough to significantly limit the flow of oxygen-rich blood throughout your body.   When a plaque formation becomes brittle or inflamed, it may rupture, triggering a blood clot to form. A clot may either further narrow the artery, or completely block it. Preventing plaque build-up will lessen the chance of blood clotting.

Reducing Irregular Heart Beat (arrhythmia)

When your heart beats abnormally, it is referred to as an arrhythmia.  Heart rhythm problems (heart arrhythmias) occur when the electrical signals that coordinate the heart’s beats don’t work properly. The faulty signalling causes the heart to beat too fast (tachycardia), too slow (bradycardia) or irregularly.

Heart arrhythmias may feel like a fluttering or racing heart and may be harmless. However, some heart arrhythmias may cause bothersome — sometimes even life-threatening — signs and symptoms, and may increase the risk of stroke or other serious heart issues. Studies have shown a link between increased intake of omega-3s and reduced risk of arrhythmia.