You’ve probably heard of “good” fats and “bad” fats — the ones that support heart health and the ones that don’t. But fat isn’t the enemy it’s often made out to be. In fact, some types of fat are not only beneficial but essential to your health.
These are known as essential fatty acids, or EFAs — fats your body needs but can’t make on its own. That means you have to get them through the food you eat. So, what exactly are essential fatty acids, and why are they so important?
Just as proteins[1] are made up of amino acids, fats are made up of fatty acids. When you eat fat, your body breaks it down during digestion into smaller units — fatty acids — which can then be absorbed and used.
Fatty acids serve many important roles in the body. They provide energy, help with the absorption of fat-soluble vitamins (like vitamins A[2], D[3], E[4], and K[5]), support organ function, and are involved in hormone production. Some types of fatty acids may even help protect against certain diseases[6].
There are four general categories of fatty acids:
Chemically speaking, fatty acids are chains of carbon atoms bonded to hydrogen atoms[7], with a carboxyl group at one end. The structure of the chain determines the type of fat:
There are more than 20 different fatty acids found in food[8], including those in vegetable oils, nuts, seeds, fruits, animal fats, and fish oils.
Essential fatty acids — often called EFAs — are types of fatty acids that your body can’t produce on its own, or at least not in sufficient amounts. That means you have to get them from the food you eat.
EFAs were first identified in 1929[9], when researchers discovered that certain fats are necessary for growth, development, and overall health. Since then, scientists have confirmed that these fats play a vital role in everything from building cell membranes to supporting brain and heart function.
There are two essential fatty acids that the body must get from food:
ALA is an omega-3 fatty acid, a type of polyunsaturated fat. Omega-3s play several key roles[10] in the body: they help form cell membranes, provide energy, and support the health of your blood vessels, lungs, immune system[11], and endocrine system.
ALA is found in plant-based foods. Once consumed, the body can convert a small portion of ALA into two other important omega-3 fats: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, the conversion process is not very efficient — which is why it’s also important to get EPA and DHA directly from food or supplements if possible.
Good sources of ALA include:
ALA is also available as a dietary supplement, especially for people who don’t eat much fish.
Linoleic acid, or LA, is a type of omega-6 fatty acid — a category of polyunsaturated fats that, like omega-3s, plays an important role in health. LA has been shown to help lower LDL (“bad”) cholesterol[12], raise HDL (“good”) cholesterol[13], and may also support healthy blood pressure[14] and insulin sensitivity.
Omega-6 fatty acids sometimes get a bad rap. That’s because linoleic acid can be converted in the body into arachidonic acid, a compound involved in inflammation[15], blood clotting, and blood vessel constriction. However, arachidonic acid also has beneficial roles, such as aiding in the healing process and preventing excessive clotting.
In fact, a 2019 review[16] published in the journal Circulation found that higher intakes of omega-6 fatty acids, especially linoleic acid, were linked with a lower risk of heart disease[17] — countering the idea that omega-6 fats are harmful when consumed in appropriate amounts.
Good sources of LA include:
Most people in the U.S. consume about 10 times more omega-6 fats[18] than omega-3s. While both are essential, experts recommend shifting the balance by increasing omega-3 intake rather than cutting omega-6s.
Research from Harvard’s T.H. Chan School of Public Health supports this approach, showing that replacing saturated fat and refined carbs with LA-rich foods like nuts, seeds, and vegetable oils can lower heart disease risk. The American Heart Association recommends[19] getting 5% to 10% of your daily calories from linoleic acid — about 100 to 200 calories (or 11 to 22 grams of fat) for someone eating 2,000 calories per day.
In addition to supporting heart health, essential fatty acids — especially omega-3s — have been linked to a wide range of benefits throughout the body. These may include:
Although it’s rare, not getting enough essential fatty acids can lead to a range of symptoms, including:
EFA deficiency is uncommon in healthy adults and typically occurs in cases of severe malnutrition or medical conditions that limit fat absorption. It’s most often seen in infants who are fed diets extremely low in fat or lacking sources of essential fatty acids. According to the Merck Manual[21], a deficiency in infants can lead to serious outcomes, including developmental delays and intellectual disability.
While it might be tempting to reach for an essential fatty acid supplement, most people don’t need one — unless recommended by a healthcare provider. You can usually meet your EFA needs through a balanced eating pattern that includes:
Some people who don’t eat fish — or who have higher omega-3 needs — may benefit from a supplement. If you go this route, keep in mind:
Essential fatty acids may be small in size, but they have a big impact on your health — from supporting your heart and brain to keeping your skin and immune system strong. The good news? With a few simple food choices, you can get the omega-3 and omega-6 fats your body needs without turning to supplements. A balanced, varied diet that includes healthy oils, nuts, seeds, and fatty fish is often the best place to start.
Want to learn more about dietary fat and diabetes? Read “Essential Fatty Acids in Health and Disease.”[23]
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