What Are Omega-3s, Actually? Here's The Lowdown On These Healthy Fats
Even during the days of low-fat everything, one specific type of fat maintained its "good for you" status: omega-3s. And though nutrition science and health trends have since brought all sorts of dietary fats back into the mainstream's good graces, omega-3s still deserve some extra attention.
The bottom line is: you need your fair share of these high-profile fats in order to feel your best.*
Though they're most famous for heart health, omega-3s fuel a slurry of important processes in the body, supporting everything from your brain to your eyes.*
If that's the extent of your knowledge about omega-3s, don't sweat it; you've come to the right place.
Consider this your one-stop guide to all things omega-3s, from what they really are and what the difference between EPA and DHA is to why they're so important for your body and how to get more of them (because, nope, eating fish isn't your only option).
What are omega-3s?
"Omega-3s [EPA and DHA] are a family of fatty acids that are primarily found in higher-fat fish," says William Harris, Ph.D., FASN, FAHA, co-creator of the omega-3 index1 (a blood test that measures the amount of EPA and DHA in your red blood cell membranes).
Salmon, anchovies, herring, sardines, mackerel, and albacore tuna all land in the higher-fat fish category, delivering a great source of marine omega-3s EPA and DHA.
Harris goes on to say this about EPA and DHA: "These are fatty acids that our bodies are very inefficient at making and so are best supplied directly through the diet." (For this reason, they're known as "essential" [ALA] or "conditionally essential" [EPA and DHA] fatty acids by many renowned lipid researchers, including Harris.)
Specifically, omega-3s fall into a category of long-chain unsaturated fats called polyunsaturated fatty acids2 (aka PUFAs) that are found in fish and a variety of plant foods (but that's ALA; more on that later).
Types of omega-3s
Within this family of omega-3s, there are three specific fats you've probably heard of before—and that are praised far and wide for their various health benefits: EPA, DHA, and ALA.*
You can't really compare them apples to apples, though. "They are simply different chemical compounds with different biological actions," explains Harris. On a chemical level, ALA is 18 carbons long whereas EPA and DHA are 20 and 22 carbons long, respectively.
ALA (alpha-linolenic acid)
A shorter-chain PUFA, ALA is the parent fatty acid of the omega-3s and found in plants. It can be metabolized into EPA and DHA in the liver3, but only at an inefficient and highly variable rate (that differs between women and men and as we age) of 5 to 20 percent4.
Because of this, consuming foods high in ALA is not an effective way to get the EPA and DHA we need, Harris says. In fact, he believes it's nearly impossible to achieve optimal EPA and DHA levels by consuming ALA alone.* And that belief is rooted in published clinical evidence5.
That said, ALA has its own benefits independent of its ability to transform into EPA and DHA. In addition to supporting the body's anti-inflammatory pathways and promoting brain health and mood, research has even recently linked ALA with longevity.*
EPA (eicosapentaenoic acid)
EPA is a long-chain PUFA produced by water plants (like algae)6, but we typically get it from fish (which consume said algae).
It contributes to the often-talked-about health benefits of omega-3s, including but not limited to supporting immune function, cardiovascular and joint health, and fetal development7.*
DHA (docosahexaenoic acid)
Similarly, DHA is also a long-chain PUFA found in algae and fish. This particular omega-3 is found in high concentrations in the retina and brain8 (i.e., the central nervous system), making it essential for the development of our brain and eyes, as well as vision and cognitive function throughout life.*
In terms of reproductive and perinatal health, it is important for a healthy pregnancy9 and supports male fertility.* Research also suggests that DHA is the omega-3 that interacts most with cholesterol10.*
The health benefits of omega-3s
Omega-3s serve plenty of important purposes throughout the body (and the lifespan).* Though research continues to develop, there are a few specific health perks that have been well-established:
Eye health & vision
DHA, in particular, helps to regenerate rhodopsin11, a visual pigment involved in converting the light that hits your retina into the visual images you see.* Because of this, it's crucial for retina development and function9.*
Plus, consumption of omega-3s, in general, is also associated with eye health later in life12.*
You've already heard time and time again that omega-3s are heart healthy.* Research shows that higher concentrations of omega-3s are associated with optimal cardiovascular function13, including healthy circulation and blood pressure regulation.*
In fact, consuming EPA and DHA combined may reduce the risk of CHD (coronary heart disease) by helping to lower blood pressure.† One serving of omega-3 potency+ provides 1.5 grams of EPA and DHA, an amount ample enough to contribute to this cardiovascular role.
Mood & brain health
Omega-3s are important for pathways that contribute to synaptic plasticity and memory14, both of which support learning.* Diets high in these fats are also associated with healthy cognitive function15.*
They may also support various aspects of mood and mental well-being.* Some research, for example, suggests that omega-3s support the body's ability to respond to and cope with feelings of stress16.*
One report17 even suggests that health care practitioners who help clients' optimize their mental well-being consume enough omega-3s.*
Pregnancy & fetal development
Adequate omega-3s are essential during pregnancy and the postpartum period for the development of the baby's eyes and brain.* Research also shows that they promote a healthy gestational duration18 and birth weight18.*
Research also indicates19 that omega-3s support joints, specifically comfort during movement (i.e., mobility), in large part due to the anti-inflammatory actions and buffering against oxidative stress that omega-3s provide.*
The best sources of omega-3s
Fish are our most obvious source of omega-3s and provide the body with the long-chain omega-3 fatty acids EPA and DHA.*
Not sure which fish to turn to? Functional physician Mark Hyman, M.D., recommends using the acronym SMASH (which stands for "salmon, mackerel, anchovies, sardines, herring") when stocking your fridge with fresh filets and pantry with canned and tinned fish.
That doesn't mean that people who don't consume animal products are out of luck, though. Since sea plants like algae are the original source of omega-3s for fish, you can get EPA and DHA by consuming them as well.
In fact, many algal oils available these days are great sources of DHA20, in particular.
You can get ALA, meanwhile, from a variety of plant foods, including walnuts, flaxseeds, flaxseed oil, and edamame21.
Of course, many people turn to supplements in order to up their intake of omega-3s, whether from fish or plant sources. The most popular options out there: fish oils for omnivores and algae (algal oils) for strict vegans. For specific recommendations, check out our omega-3 supplement roundup.
How many omega-3s do we need?
Research has long shown that Americans don't consume much fish. "Typical intakes of EPA and DHA in the U.S. (a low fish-eating country) are about 100 to 150 milligrams per day, on average," Harris explains. "In countries like Japan or Korea, where fish is eaten nearly every day, though, intakes are between 750 and 1,000 milligrams per day."
As a result, "the typical American has an omega-3 index of 4 to 6%, whereas the typical Japanese and Korean person falls between 8 and 12%," he says. (A level equal to or greater than 8% is considered optimal.)*
Achieving an optimal omega-3 index, Harris says, would require most Americans to consume about 1,000 to 1,500 milligrams of EPA+DHA per day—a far cry from the average current intakes in this country.
Indeed, mbg's vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN, shares that, "Nationally representative data proves how low our fish intake truly is, with more than 90% of Americans22 failing to consume the recommended (baseline starting point) two servings of fish per week, which equates to roughly 500 mg of EPA plus DHA daily. On average, as a country, we're actually eating less than 90 mg of these marine omega-3s23 per day."
She goes on to say, "Mind you, we actually need a 1,000 milligram-plus to optimize heart and whole-body health throughout life. That superior amount of omega-3s is the equivalent of eating a fish a day."*
Bottom line: Unless you plan on incorporating fish into your daily meal plan, a high-quality omega-3 supplement (that contains a potent, science-backed dose of EPA and DHA) is a must.*
A note about our omega-6 to omega-3 ratio...
Fun fact: Omega-3s aren't the only omegas out there. Omega-6 fats, which are found in many plant foods (most notably vegetable oils, with canola and soybean oils being some of the worst offenders), are another component to consider when evaluating your omega-3 intake.
Here's the deal: While omega-6s play a role in brain development and function (among other things), they also promote inflammatory pathways in the body.
This isn't a bad thing, as long as we maintain the proper balance of omega-6s and omega-3s. That's where things get a little hairy.
While research suggests the optimal balance is a 2:117 ratio of omega-6s to omega-3s, the average American diet has a ratio closer to 10:1 or even as high as 20:117, highlighting that many Americans could benefit from cutting back on omega-6s and seriously boosting their consumption of omega-3s.*
As Ferira puts it: "Striking a balance of these PUFAs is critical. Pro tip: You'll want to dial down the omega-6 fats, and dial up the omega-3s. Our nation's health would be greatly benefited if Americans tipped the fats equation in this way."*
What's at stake when we don't get enough omega-3s?
Given all of the good things omega-3s do throughout the body, it's no shock that falling short on them isn't exactly ideal for our health.
According to Harris, having too little omega-3 in your diet (and therefore in your blood and tissues, organs, systems, and whole-body) contributes to suboptimal cardioprotection, cognition, (musculoskeletal health, vision, etc.) and overall vitality.*
Feel a little more fluent in the language of omega-3s? These healthy fats are important for maintaining a number of areas of health, including everything from your cardiovascular system to your mood.*
And though ALA, EPA, and DHA all offer individual benefits, it's important to keep in mind that loading up on ALA is certainly not a replacement for getting your EPA and DHA in, too. In many cases, supplementing with a properly dosed fish oil is important for getting ample amounts of EPA and DHA into the cells and tissues in your body that need them on the daily.*
If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.
Josey Murray is a freelance writer focused on inclusive wellness, joyful movement, mental health, and the like. A graduate of Wellesley College, where she studied English and Creative Writing, her work appears in Women’s Health, Cook & Culture, and more. By expressing her own vulnerability, she writes with warmth and empathy to help readers find self-compassion and true wellness that’s sustainable for body, mind, and planet.