The human body can make most of the types of fats it needs from other fats or raw materials. That isn’t the case for omega-3 fatty acids (also called omega-3 fats and n-3 fats). These are essential fats—the body can’t make them from scratch but must get them from food. Foods high in Omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.
What makes omega-3 fats special? They are an integral part of cell membranes throughout the body and affect the function of the cell receptors in these membranes. They provide the starting point for making hormones that regulate blood clotting, contraction and relaxation of artery walls, and inflammation. They also bind to receptors in cells that regulate genetic function. Likely due to these effects, omega-3 fats have been shown to help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may play protective roles in cancer and other conditions.
Omega-3 fats are a key family of polyunsaturated fats. There are three main omega-3s:
The strongest evidence for a beneficial effect of omega-3 fats has to do with heart disease. These fats appear to help the heart beat at a steady clip and not veer into a dangerous or potentially fatal erratic rhythm. Such arrhythmias cause most of the 500,000-plus cardiac deaths that occur each year in the United States. Omega-3 fats also lower blood pressure and heart rate, improve blood vessel function, and, at higher doses, lower triglycerides and may ease inflammation, which plays a role in the development of atherosclerosis.
Heart attacks and strokes are the world’s leading causes of death Decades ago, researchers observed that fish-eating communities had very low rates of these diseases. This was later linked to omega-3 consumption.
Since then, omega-3 fatty acids have been tied to numerous benefits for heart health. These benefits address:
For some people, omega-3s can also lower “bad” LDL cholesterol. However, evidence is mixed — some studies find increases in LDL.
Despite these beneficial effects on heart disease risk factors, there is no convincing evidence that omega-3 supplements can prevent heart attacks or strokes. Many studies find no benefit.
A decline in brain function is one of the unavoidable consequences of aging.
Several studies link higher omega-3 intake to decreased age-related mental decline and a reduced risk of Alzheimer’s disease.
One review of controlled studies suggests that omega-3 supplements may be beneficial at disease onset, when the symptoms of AD are very mild. Keep in mind that more research is needed on omega-3s and brain health.
DHA, a type of omega-3, is a major structural component of the retina of your eye. When you don’t get enough DHA, vision problems may arise.
Interestingly, getting enough omega-3 is linked to a reduced risk of macular degeneration, one of the world’s leading causes of permanent eye damage and blindness.
In addition to their powerful health benefits, these fats may benefit your hair and skin. Though research is limited, they appear to boost your skin’s resistance to sunburns, reduce acne, and protect against dry, red, and itchy skin.
Some fish oils contain other nutrients, such as vitamin A, vitamin D, and selenium. Vitamin A is an antioxidant related to retinol, a popular ingredient in skin care products and a treatment for skin disorders.