Omega-3 fatty acids or omega-3s achieved widespread news coverage because of their impressive ability to reduce deaths from heart disease, particularly sudden deaths. Research has shown that survivors of a heart attack, who consume as little as one gram a day of the omega-3s found in fish, have half the mortality from heart disease as people who do not consume these fatty acids. More recently, evidence from Japan and elsewhere indicates that where seafood consumption is frequent, essentially every day, heart disease is extremely low. For these reasons, the American Heart Association urges everyone to consume fish, especially fatty species such as salmon, rainbow trout, herring, mackerel, and sardines at least twice a week. For people who already have the condition, eating seafood more often, or consuming marine omega-3s from supplements, is just as important. Here are the ways marine omega-3s benefit heart health:
Lower risk of mortality from heart disease. In western countries, heart disease claims more lives than any other cause. You can lower your chance of dying from this disease by eating fish regularly or consuming marine omega-3 fatty acids. These fatty acids can reduce the chance of uncontrolled heart rhythms and developing fatal blood clots, two major causes of heart disease deaths. Omega-3s, therefore, lower the chances that heart attacks will be fatal.
Improved heart rhythms. Dangerously fast heartbeats or disordered heart rhythms can be fatal. Omega-3s from fish help maintain stable heart rhythms by affecting the electrical activity of the heart. Thus, it is more difficult for uncontrolled heart rhythms to develop. Unstable and uncontrolled heart rhythms underlie sudden death, the cause of nearly half of all cardiac mortality. By stabilizing heart rhythms, marine omega-3s reduce the chance of dying suddenly.
Improved heart rate. Heart rate is the number of beats a minute your heart pumps at rest. It accelerates to increase the amount of blood ejected by the heart. Heart rate is lower in people who are physically fit and higher in the obese. Usual heart rate is between 60 and 80 beats per minute and usually increases with age. Heart rate adapts to changing conditions and generally speaking, the greater adaptability of the heart, the better its condition. Consumption of marine omega-3s is associated with lower heart rate and with greater heart rate variability, conditions that reflect better heart health and lower the chance of heart attack.
Less chance of having a first heart attack. There is evidence that people who do not have signs of heart disease may be able to avoid having a first heart attack if they eat fish or marine omega-3 fatty acids often. For people who have had a heart attack, risk of another is also substantially reduced. Consuming these fatty acids regularly improves heart rhythms, reduces the likelihood of blood clots forming, reduces the low-grade inflammation that accompanies heart disease, and improves blood lipid patterns – all effects that discourage heart failure.
Less chance of stroke. A stroke results from a blood clot blocking an artery in the brain. Clots may develop there or be carried to the brain from elsewhere. Non-fatal strokes can cause serious disability. In most western countries, ischemic strokes, the kind caused by blood clots or lack of oxygen, are the most common type. It has been shown in several studies that people who eat fish once or more per week have about a 30% less chance of having a stroke compared with people who eat fish less than once a month.
Improved blood lipids. The blood carries different types of lipids, including fats and cholesterol, throughout the body. High levels of blood lipids lead to deposits in the walls of arteries called plaques. These reduce blood flow and the supply of oxygen to the heart. Marine omega-3s, in doses that can only be achieved with supplementation (i.e., 3-4 gm/day), improve blood lipids by lowering the amount of triglycerides or fats and increasing the amount of HDL or “good” cholesterol that removes cholesterol from the blood. They do not, however, lower total or LDL (“bad”) cholesterol levels. These improvements in blood lipids are especially important in people with type 2 diabetes who have high triglycerides and low HDL.
Reduced blood clotting. Some blood clotting is essential for life, but an excessive tendency towards clotting increases the risk of blocked arteries. These can be fatal when a clot completely closes a blood vessel in the heart, lungs, or brain. Marine omega-3 fatty acids reduce platelet clumping and affect certain clotting factors reducing the tendency for blood to clot. Marine omega-3s also improve blood flow and make red blood cells more flexible so they pass through tiny blood vessels more easily. Omega-3s do not pose a serious risk to blood clotting unless a person consumes very large amounts of them (roughly 10 grams a day) or is already taking blood thinners (anti-coagulants) and consuming large amounts of omega-3s.
Less inflammation. Although you can’t feel it, the development of heart disease includes low-level inflammation of the blood vessels. Responses to this condition increase the risk of heart disease and impair blood vessel function. High blood levels of the protein CRP are linked to the inflammation observed in heart disease. High CRP predicts greater risk of new coronary events. Some studies, but not all, have reported that consumption of omega-3s reduces CRP in people with heart disease. Omega-3s are well known for their anti-inflammatory properties.