What Happens to Your Brain When You Take an Omega-3s

Your brain works tirelessly to store memories, process thoughts and emotions, coordinate movement and keep your body functioning normally. To carry out these vital tasks, it needs the right nutrients to run smoothly. Among them is a group of healthy fats called omega-3 fatty acids, which play a critical role in supporting brain health. 

While a diet rich in fatty fish and certain plant foods can help boost your omega-3 intake, many people turn to supplements to meet their daily needs. But do they actually support brain health? We spoke with dietitians to break down what really happens to your brain when you consistently take an omega-3 supplement.

Why We Love Omega-3s for Brain Health

They Are Brain Building Blocks

Nearly half of the fat that makes up the brain is made of polyunsaturated fatty acids, and omega-3s are a key part of that foundation, says Meghan Pendleton, M.S., RD. 

“Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and alpha-linolenic acid (ALA) are of the most interest for cognitive function and brain health, and all take on different levels of importance depending on life stage,” says Pendleton. She notes that ALA and DHA are especially important for brain growth and development in infancy, while EPA and DHA help protect the brain as we age.,, Among these, Pendleton emphasizes that DHA is particularly crucial because it’s rapidly incorporated into brain tissue to support both structure and function.

They May Preserve Cognitive Function

Omega-3 fatty acids may also help preserve and protect long-term cognitive health. Research suggests that higher levels of omega-3s—whether through targeted supplementation or greater fish intake—may help to lower the risk of Alzheimer’s disease, reduce depressive symptoms associated with dementia and protect against structural changes in key regions of the brain. 

Pendleton highlights that EPA and DHA, in particular, support cognitive health through anti-inflammatory pathways that help to maintain healthy nerve function.

They May Improve Memory and Visuospatial Function

When it comes to omega-3 supplements, EPA and DHA are the most widely studied forms for their effects on memory and visuospatial function—the ability to understand and use visual and spatial information. More specifically, “research shows omega-3 supplements are reliably associated with improved short-term memory and visuospatial function, which helps us drive to familiar places without a map and picture doing things,” shares Maggie Moon, M.S., RDN. “When visuospatial memory degrades, you may bump into things and get lost more often.” 

These findings are promising, as they suggest omega-3 supplements may help protect against age-related declines in memory and visuospatial ability.

They May Support Brain Energy Metabolism

The brain requires a steady and substantial supply of glucose to function properly. While DHA and EPA supplements often get the spotlight in brain health discussions, new studies suggest that ALA deserves more attention. Traditionally viewed as mainly a precursor to EPA and DHA, Moon points to research showing that ALA may independently support glucose metabolism in the brain, helping to support the brain’s high energy needs. 

Because most plant-based omega-3 sources provide ALA, this finding is especially reassuring to those who follow plant-based eating patterns. 

Omega-3 Deficiency

Omega-3 fatty acid deficiency is rare among otherwise-healthy individuals in the United States. This is partly because, during periods of inadequate intake or malabsorption, the body can release essential fatty acids from fat tissue reserves.

“Assessing inadequacy or deficiency is somewhat arbitrary as there have been no cut-off values of DHA or EPA present in plasma or tissues where bodily functions are specifically impaired,” says Pendleton. In cases of prolonged inadequate intake, the most common symptoms may include rough, scaly skin or dermatitis, according to Moon and Pendleton. However, for most people, the concern isn’t a true deficiency, but whether their intake is enough to support optimal health. 

How Much You Need

Omega-3 needs aren’t one-size-fits-all. Instead, they vary based on the omega-3 type and your current life stage. “We technically only require plant-based omega-3 ALA, since it converts to EPA and DHA, and that recommendation for ALA is 1.6 grams per day for men and 1.1 grams per day for women,” says Moon. She adds that those who are pregnant or lactating should aim for a higher ALA intake of 1.4 grams and 1.3 grams per day, respectively.

However, Pendleton notes that the conversion rate from ALA to EPA and DHA is quite limited. As a result, most people benefit from consuming EPA and DHA through food—and supplements when needed. While there are no formal intake guidelines in the United States, experts commonly recommend aiming for two servings of fatty fish per week, which equates to roughly 250 to 500 milligrams of EPA and DHA per day, says Moon. For heart disease prevention, the American Heart Association recommends about 1,000 mg per day from food or supplements.,

“The optimal amount for a person may be higher if they are at risk for heart disease, if dementia runs in their family or if they are starting out with very low levels of omega-3s. Often, these complications and concerns become more pressing with age,” says Moon. Ultimately, she emphasizes that individual omega-3 needs are best discussed with a health care professional.

Food Sources of Omega-3s

While supplementation can help fill nutritional gaps, whole foods provide omega-3s in their most natural form. EPA and DHA are naturally found in fatty fish, while plant foods like nuts and seeds deliver ALA.

The top sources of EPA and DHA include:

• Salmon
• Herring
• Sardines
• Mackerel
• Trout

The top sources of ALA include:

• Flaxseed and flaxseed oil
• Chia seeds
• Hemp seeds
• Walnuts
• Canola oil
• Soybean oil

Are Omega-3 Supplements Safe for Everyone?

For most healthy adults, omega-3 supplements are generally considered safe at doses up to 5 grams per day. However, exceeding recommended doses may carry certain risks. Moon shares that taking high-dose DHA and EPA supplements may reduce immune function due to their ability to suppress inflammation.

The risk of adverse effects can also increase when omega-3 supplements are taken alongside specific medications. “Omega-3 supplements may moderately magnify the effect of drugs that lower blood pressure, leading to undesirably low blood pressure,” says Moon. 

Though less common, she also shares that omega-3s could potentially increase bleeding risk when taken with anticoagulants or interfere with the effectiveness of blood sugar–lowering medications in people with diabetes.,, For these reasons, it’s important to talk to a health care professional before beginning supplementation, especially if you take prescription medications.

What to Look For in an Omega-3 Supplement

When choosing an omega-3 supplement, Moon shares that three factors matter most: safety, quality assurance and effective dose.

• Safety: Moon recommends choosing supplements from companies that undergo independent verification to ensure quality and safety. She also advises checking the label for inactive ingredients that you may be allergic or sensitive to. Additionally, if a supplement contains nutrients beyond omega-3s, make sure you’re not exceeding the recommended daily amounts of those nutrients.
•  Quality: “Look for the good manufacturing practices stamp, or GMP, and be sure to buy a product that’s in an opaque or dark container and hasn’t expired, which helps you avoid rancid oil,” Moon explains.
•  Effective dose: Moon shares that most people will want to look for at least 500 mg of combined EPA and DHA per serving. However, you should talk to a health care professional, such as a doctor, dietitian or pharmacist, to determine what’s right for you.

“Beyond these core areas, you may want to look for sustainable sources of omega-3s, like krill oil or fish oil with MSC or ASC certifications,” Moon adds. For those who are vegan, she suggests opting for algae-based omega-3 supplements.

Another key consideration is the form of omega-3 in the supplement. “Triglyceride forms of omega-3 supplements are better absorbed than the more common ethyl ester form. But all forms are well-absorbed when taken with a balanced meal, which triggers the release of digestive enzymes,” Moon explains.

Once you’ve chosen your supplement, she suggests storing it away from heat and light and refrigerating it after opening. If your supplement has a strong fishy odor, it may have already gone rancid and should be discarded and replaced.

Our Expert Take

Your brain relies on a steady supply of nutrients to function at its best, and omega-3 fatty acids are among the most important for supporting brain health. While whole foods like fatty fish, nuts and seeds naturally provide these fats, supplements can help maintain optimal levels for your brain. Taking an omega-3 supplement supplies your brain with the nutrients it needs to support cell membranes, preserve cognitive function and improve memory and visuospatial abilities. Before adding omega-3s to your routine, however, it’s important to consult your health care provider to ensure supplementation is safe and appropriate for you.