DHA Supplements: Why They’re Critical for Your Brain

Edited and medically reviewed by Patrick Alban, DC | Written by Deane Alban

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It’s critical to supplement with DHA, a key omega-3 fat, to build and preserve brain health and function for babies, children, and adults.

The human brain is largely made of fat — 60% by dry weight.

One particular group of fats, the omega-3 essential fatty acids, is most important for the brain’s structural integrity and performance. (1)

And one omega-3 fatty acid, DHA, may be the single most crucial nutrient you can take for brain health throughout all stages of life.

DHA is a foundational nutrient needed for a healthy, optimally functioning brain.

Trying to build a healthy brain without it is like building a house on a foundation of sand.

DHA: An Essential Building Block of the Brain

Essential fatty acids are those you need for health that your body can’t synthesize — you have to get them from food or supplements.

Of all the essential fatty acids, the omega-3s are the most abundant in the brain.

They are the preferred building blocks of brain cell membranes and nerve cells.

When omega-3s aren’t available, your brain will use whatever fats are available, but this leads to suboptimal brain cells.

There are three main kinds of omega-3s — DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid),  and ALA (alpha-linolenic acid) — with DHA unarguably being the most important for your brain.

DHA accounts for 97% of the omega-3 fatty acids in the brain. (2)

It’s a major structural component of the cerebral cortex, the part of the brain responsible for memory, language, creativity, emotion, and attention. (3)

DHA plays a role in brain cell communication.

It supports optimal levels of many important neurotransmitters including dopamine, serotonin, GABA, norepinephrine, and acetylcholine. (4)

It also improves the function of neurotransmitter receptors, allowing the brain to better utilize these brain chemicals. (5)

Interestingly, fossil evidence suggests that the evolution of our large human brains depended on the availability of DHA from seafood. (6)

Benefits of DHA Supplements During All Stages of Life

DHA has proven helpful for a wide range of diseases including arthritis, atherosclerosis, depression, diabetes, heart disease, and some cancers. (7)

Just as you need calcium for strong bones, you need DHA for a strong central nervous system.

Here’s a look at how DHA is needed throughout all stages of life for a healthy brain and mental well-being.

DHA for Babies’ Brain Development

Optimal levels of DHA are critical for the development of babies’ brains. (8)

New mothers are advised to take supplemental DHA to ensure that there will be adequate amounts available for their baby’s rapidly growing brain; many prenatal vitamins include DHA. (9, 10)

DHA is a natural component of breast milk and is often added to baby formulas to complete its nutritional profile. (11)

It’s not easy to run cognitive tests on babies (!), but formula-fed infants given a DHA supplement perform better on face recognition tests than those babies fed formula without it. (12)


A quality brain supplement can make a big difference.

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DHA Supplement Benefits for Children

DHA isn’t just for newborns, it’s important during childhood too.

Attention deficit hyperactivity disorder (ADHD) is the most common neurological condition in children.

Numerous studies show that when children with ADHD are given supplemental omega-3s (both DHA and EPA), they experience significant improvement in attention, hyperactivity, defiant behavior, and sleep. (13)

One study found that children with major depressive disorder experienced a 40% decrease in depressive symptoms when given DHA supplements. (14)

DHA Supplements for Better Adult Mental Health

There’s an abundance of evidence that taking a DHA supplement can make you a happier, smarter adult.

Preserves Brain Volume

The human brain naturally shrinks with age, but DHA helps to preserve brain volume. (15)

People low in DHA have smaller brains that age faster than those with normal levels. (16)

Unfortunately, this is a large group since 80% of the world’s population has subpar intake of omega-3s. (17)

Increases BDNF

DHA increases brain-derived neurotrophic factor (BDNF). (18)

BDNF is a protein that keeps existing brain cells healthy and stimulates new brain cell formation.

Increases Brain Plasticity

DHA also increases brain plasticity.

Neuroplasticity is your brain’s capacity to form new brain cells and neural connections and improve its capabilities throughout your lifetime.

In one clinical trial, healthy adults were given 800 mg of DHA plus 1600 mg of EPA.

Study participants experienced an increase in vigor and a decrease in anger, anxiety, fatigue, depression, and mental confusion after only 35 days of supplementation. (19)

DHA Deficiency Impairs Cognitive and Mental Health

DHA deficiency impairs functions like memory, problem-solving, the ability to multitask, and thinking capabilities. (20)

Low DHA levels have been linked to depression, ADHD, anger, and hostility. (21)

Serious psychiatric disorders such as major depressive disorder, suicidal behavior, bipolar disorder, and schizophrenia have also been linked to DHA deficiency. (22, 2324)

Sadly, military veterans are at increased risk for depression, anxiety, and suicide and those with low levels of DHA are 62% more likely to commit suicide. (25)

Surprisingly, low DHA is a stronger predictor of suicide than battle-related stress.

But omega-3 and DHA supplementation were found to improve anxiety and depression scores and reduce suicidal thinking by 45%. (26)

Additionally, extra DHA can prevent postpartum depression which affects 1 in 9 women after they give birth. (27, 28)

DHA Supplements Protect Seniors Against Mental Decline

If you could take only one supplement to stay mentally sharp as you age, it should be DHA.

Adequate levels of DHA can improve memory and learning and protect against age-related mental decline in healthy older adults.

Numerous studies show that seniors with higher levels of omega-3s, specifically DHA, have significantly less risk of developing dementia or Alzheimer’s. (29, 30, 3132)

One landmark study that followed a group of seniors for nine years found that those with higher levels of DHA were 47% less likely to develop dementia and 39% less likely to develop Alzheimer’s than those with low levels. (33)

High intake of DHA is also associated with reduced risk of neuroinflammation, macular degeneration, stroke, and Parkinson’s disease. (34)



Why DHA Supplementation Is Necessary

The evidence is clear — DHA is critical for your brain health and function.

But do you really need to supplement?

Or is it possible to get enough from food alone?

According to the US National Institutes of Health, the average North American consumes only 20% of the recommended amounts of DHA and EPA. (35)

This is because few people regularly consume the main dietary sources of DHA and EPA — cold-water fatty fish such as salmon, herring, mackerel, halibut, sardines, and bluefin tuna.

This chart shows the DHA and EPA content of the most commonly eaten seafood items in the United States.

comparison chart showing DHA and EPA in seafood
DHA and EPA content of the most commonly eaten seafood items in the US. (Chart courtesy of AlwaysOmega3s.com)

You can see that salmon stands alone with roughly 4-14 times more DHA per serving than the other items on this list.

Unfortunately for vegetarians, there are no good plant food sources of DHA.

Only small amounts of omega-3s are found in nuts, flax, seeds, and sea vegetables, and always in the form of ALA rather than DHA.

Research shows that even large amounts of dietary ALA have little effect on blood levels of DHA.

This is because the process that converts ALA into DHA is extremely inefficient. (36)

In fact, less than 0.5% of ALA found in plants gets converted into the DHA your brain needs. (37)

The bottom line is that unless you eat fatty fish several times a week, it’s impossible to get adequate DHA through diet alone.

But you can remedy this by taking a DHA supplement or an omega-3 supplement.


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DHA Supplement Sources Compared

DHA is most commonly found in fish oil supplements.

You can get DHA from supplements in two ways:

  • You can buy a single-ingredient DHA supplement. These are almost always extracted from fish oil.
  • You can buy a supplement that contains DHA as one of the main ingredients.

Here’s a look at various other sources of DHA.

Each has its own set of benefits and drawbacks.

Why Krill Oil Is an Excellent Source of DHA

Krill oil is an alternative to fish oil that is growing in popularity.

Krill are small shrimp-like crustaceans found in all the world’s oceans.

If you check the label of a krill oil supplement, you’ll notice that it contains less DHA than comparable fish oil supplements.

However, krill oil is more bioavailable and more readily absorbed than fish oil. (38)

The DHA molecules in krill oil are attached to phospholipids, which facilitate the passage of DHA through the intestinal wall and increasing uptake into the brain. (39)

Since krill oil is absorbed more efficiently, you can achieve benefits similar to fish oil from lower doses. (40)

However, krill oil supplements usually cost more per dose than fish oil.


A quality brain supplement can make a big difference.

See our review of MIND LAB PRO

Dr. Pat | Be Brain Fit

The Benefits of Algal DHA Supplements

Some DHA supplements are made from algae.

Algal DHA supplements are a good option for people who don’t eat seafood due to food allergies or dietary preference.

But are they as good as DHA sourced from fish oil?

Fish get their DHA from eating smaller fish which, eventually down the food chain, get their DHA from algae.

By getting your DHA from algae directly, you are simply cutting out the middleman (middlefish?).

food chain that makes fish a good source of DHA
The DHA food chain.

One benefit of algal DHA is that it may contain fewer contaminants like mercury. (41)

And while it seems likely that algal DHA will deliver the same health benefits as DHA from fish oil, this is not known for sure and the experts agree that more studies are needed.

Flaxseed Oil Is Not a Good Source of DHA

Like all vegetable sources of omega-3s, flaxseed oil contains ALA which is poorly converted to DHA.

Furthermore, studies show that flaxseed oil does not increase blood levels of DHA. (4243)

So flaxseed oil really is not a viable source of DHA.

Beware of Foods Fortified with DHA

Hundreds of food items from energy bars to orange juice are now fortified with DHA.

But be forewarned that unless the label specifically states the source, these foods almost certainly contain ALA from inferior sources that will not raise your blood levels of DHA like flaxseed, canola oil, or soybean oil. (44)

The Benefits of DHA Compared to EPA

If you read the labels of fish or krill oil supplements, you’ll see that besides DHA, they contain EPA.

EPA is often recommended for heart health but brings its own set of brain benefits to the table.

While both DHA and EPA are anti-inflammatory, EPA is superior to DHA at calming inflammation, including brain inflammation. (45, 46, 47)

Chronic inflammation of the brain can lead to brain fog, ADHD, anxiety, depression, and memory loss. (48, 49)

And EPA is specifically helpful for treating borderline personality disorder. (50)

You need both EPA and DHA, but many experts believe you should look for a supplement that contains a high proportion of DHA or take extra DHA separately for optimal brain function.

For example, award-winning Harvard researcher Datis Kharrazian, PhD, DHSc, author of Why Isn’t My Brain Working?, recommends supplementing with a DHA to EPA ratio as high as 20 to 1 for issues like depression, bipolar disorder, or memory loss.

DHA Supplement Dosages

There is no Recommended Dietary Allowance (RDA) for DHA and recommended dosages vary widely depending on where you look and who you listen to.

However, experts generally recommend 500-1000 mg of total omega-3s per day to maintain health and avoid deficiency, but therapeutic doses up to 3 grams are generally considered safe. (51, 52, 53)

A National Institutes of Health workshop that included omega-3 experts from around the world determined that a minimum adequate intake (AI) of 220 mg each of DHA and EPA is required for optimal health in adults. (54)

If you want to learn more about recommended DHA or EPA dosages, the Global Organization for EPA and DHA has published a comprehensive guide, Global Recommendations for EPA and DHA Intake.

If you are pregnant, talk to your doctor about a DHA supplement and stick with products designed for pregnant women.

How to Read an Omega-3 Supplement Label

It’s not always crystal clear which numbers are important when looking at an omega-3 supplement label.

Here’s a typical label:

fish oil supplement label
Typical omega-3 supplement label.

First, you’ll see that there is 2200 mg of total fish oil and 2000 mg of total omega-3 fatty acids.

And, of that, 1400 mg is EPA while only 480 is DHA.

This means only 22% of this supplement is DHA.

This low percentage of DHA is pretty standard.

DHA Side Effects and Interactions

DHA supplements are generally safe but can cause digestive upset.

Taking them with meals can help.

DHA can increase blood sugar levels in type 2 diabetics and can decrease the effectiveness of diabetes medications. (55)

DHA can decrease blood pressure, so taking DHA along with medications for high blood pressure could cause your blood pressure to drop too low. (56)

One common warning for fish oil supplements is that they are not to be taken with blood-thinning medications like warfarin or aspirin.

But it seems that EPA is largely responsible for the blood-thinning effects of fish oil and that taking DHA alone does not have the same effect.

And of course, don’t take fish oil or krill oil if you are allergic to seafood.

DHA for Children

If you are planning to take DHA during pregnancy or give it to your kids, I recommend the DHA/EPA Omega-3 Institute as a source of information.

They have an excellent “frequently asked questions” area that discusses many things including dosages for children.

Talk to your doctor if you are pregnant or nursing, or talk to your pediatrician before giving your child a DHA supplement.

The Benefits of DHA Supplements: Take the Next Step

DHA is one of the main omega-3 essential fatty acids and may be the single most important nutrient for overall brain health and function.

It’s a major building block of brain cells and enhances brain cell communication.

It’s essential for prenatal brain development, good mental health through all stages of life, and protection against age-related mental decline.

It’s found mainly in seafood, particularly cold-water, oily fish like salmon and sardines — foods that few of us eat frequently.

Virtually every brain can benefit from supplementation either in the form of fish oil, krill oil, algal oil, or a single-ingredient DHA supplement.