Docosahexaenoic acid (DHA) is an omega-3 fatty acid — and it’s one of the most important. Its found in various seafoods and is important for brain growth and function.

Docosahexaenoic acid (DHA) is one of the most important omega-3 fatty acids.

Like most omega-3 fats, it’s linked to many health benefits.

Part of every cell in your body, DHA plays a vital role in your brain and is absolutely crucial during pregnancy and infancy.

Since your body can’t produce it in adequate amounts, you need to obtain it from your diet.

This article explains everything you need to know about DHA.

DHA is mainly found in seafood, such as fish, shellfish, and fish oils. It also occurs in some types of algae.

It’s a component of every cell in your body and a vital structural component of your skin, eyes, and brain (1Trusted Source, 2Trusted Source, 3Trusted Source, 4Trusted Source).

In fact, DHA comprises over 90% of the omega-3 fatty acids in your brain and up to 25% of its total fat content (3Trusted Source, 5Trusted Source).

While it can be synthesized from alpha-linolenic acid (ALA), another plant-based omega-3 fatty acid, this process is very inefficient. Only 0.1–0.5% of ALA is converted into DHA in your body (6Trusted Source, 7Trusted Source, 8Trusted Source, 9Trusted Source, 10Trusted Source).

What’s more, the conversion also relies on adequate levels of other vitamins and minerals, as well as the amount of omega-6 fatty acids in your diet (11Trusted Source, 12Trusted Source, 13Trusted Source).

Because your body can’t make DHA in significant amounts, you need to get it from your diet or take supplements.

SUMMARY

DHA is vital for your skin, eyes, and brain. Your body can’t produce it in adequate amounts, so you need to obtain it from your diet.

DHA is mainly located in cell membranes, where it makes the membranes and gaps between cells more fluid. This makes it easier for nerve cells to send and receive electrical signals (14Trusted Source, 15Trusted Source).

Therefore, adequate levels of DHA seem to make it easier, quicker, and more efficient for your nerve cells to communicate.

Having low levels in your brain or eyes may slow the signaling between cells, resulting in poor eyesight or altered brain function.

SUMMARY

DHA makes the membranes and gaps between nerve cells more fluid, making it easier for cells to communicate.

DHA is mainly found in seafood, such as fish, shellfish, and algae.

Several types of fish and fish products are excellent sources, providing up to several grams per serving. These include mackerel, salmon, herring, sardines, and caviar (16Trusted Source).

Some fish oils, such as cod liver oil, can provide as much as 1 gram of DHA in a single tablespoon (15 ml) (17).

Just keep in mind that some fish oils may also be high in vitamin A, which can be harmful in large amounts.

What’s more, DHA may occur in small amounts in meat and dairy from grass-fed animals, as well as omega-3-enriched or pastured eggs.

However, it may be hard to get enough from your diet alone. If you don’t regularly eat these foods, taking a supplement may be a good idea.

SUMMARY

DHA is mostly found in fatty fish, shellfish, fish oils, and algae. Grass-fed meat, dairy, and omega-3-enriched eggs may also contain small amounts.

DHA is the most abundant omega-3 in your brain and plays a critical role in its development and function.

Brain levels of other omega-3 fatty acids, such as EPA, are typically 250–300 times lower (3Trusted Source, 4Trusted Source, 18Trusted Source).

Plays a major role in brain development

DHA is extremely important for brain tissue growth and function, especially during development and infancy (19Trusted Source, 20Trusted Source).

It needs to accumulate in the central nervous system for your eyes and brain to develop normally (3Trusted Source, 4Trusted Source).

DHA intake during the third trimester of pregnancy determines the baby’s levels, with the greatest accumulation occurring in the brain during the first few months of life (3Trusted Source).

DHA is mainly found in the gray matter of the brain, and the frontal lobes are particularly dependent on it during development (21Trusted Source, 22Trusted Source).

These parts of the brain are responsible for processing information, memories, and emotions. They are also important for sustained attention, planning, problem solving, and social, emotional, and behavioral development (4Trusted Source, 5Trusted Source, 23Trusted Source).

In animals, decreased DHA in a developing brain leads to a reduced amount of new nerve cells and altered nerve function. It also impairs learning and eyesight (24Trusted Source).

In humans, DHA deficiency in early life has been associated with learning disabilities, ADHD, aggressive hostility, and several other disorders (25Trusted Source, 26Trusted Source).

Furthermore, low levels in mothers are linked to an increased risk of poor visual and neural development in the child (3Trusted Source, 24Trusted Source, 27Trusted Source).

Studies show that babies of mothers who consumed 200 mg per day from the 24th week of pregnancy until delivery had improvements in vision and problem solving (3Trusted Source, 28Trusted Source).

May have benefits for the aging brain

DHA is also critical for healthy brain aging (29Trusted Source, 30Trusted Source, 31Trusted Source, 32Trusted Source).

As you age, your brain goes through natural changes, characterized by increased oxidative stress, altered energy metabolism, and DNA damage (33Trusted Source, 34Trusted Source, 35Trusted Source).

The structure of your brain also changes, which reduces its size, weight, and fat content (36Trusted Source, 37Trusted Source).

Interestingly, many of these changes are also seen when DHA levels decrease.

These include altered membrane properties, memory function, enzyme activity, and neuron function (38Trusted Source, 39Trusted Source, 40Trusted Source, 41Trusted Source, 42Trusted Source).

Taking a supplement may help, as DHA supplements have been linked to significant improvements in memory, learning, and verbal fluency in those with mild memory complaints (43Trusted Source, 44Trusted Source, 45Trusted Source, 46Trusted Source, 47Trusted Source, 48Trusted Source).

Low levels are linked to brain diseases

Alzheimer’s disease is the most common form of dementia in older adults.

It affects about 4.4% of people over age 65 and alters brain function, mood, and behavior (49Trusted Source, 50Trusted Source).

Reduced episodic memory is among the earliest signs of brain changes in older adults. Poor episodic memory is associated with difficulties recalling events that occurred at a specific time and place (44Trusted Source, 51Trusted Source, 52Trusted Source, 53Trusted Source).

Interestingly, Alzheimer’s disease patients have lower amounts of DHA in the brain and liver, while EPA and docosapentaenoic acid (DPA) levels are elevated (54Trusted Source, 55Trusted Source).

Studies show that higher blood DHA levels are linked to a reduced risk of dementia and Alzheimer’s (56Trusted Source).

SUMMARY

DHA is essential for brain and eye development. As such, low levels may disrupt brain function and are linked to an increased risk of memory complaints, dementia, and Alzheimer’s disease.

DHA helps activate rhodopsin, a membrane protein in the rods of your eyes.

Rhodopsin helps your brain receive images by changing the permeability, fluidity, and thickness of your eye membranes (57Trusted Source, 58Trusted Source).

A DHA deficiency can cause vision problems, especially in children (3Trusted Source, 24Trusted Source, 27Trusted Source).

Therefore, baby formulas are now generally fortified with it, which helps prevent vision impairment in babies (59Trusted Source, 60Trusted Source).

SUMMARY

DHA is important for vision and various functions inside your eye. A deficiency may cause vision problems in children.

Omega-3 fatty acids are generally linked to a reduced risk of heart disease.

Low levels are associated with an increased risk of heart disease and death, and some studies show that supplements reduce your risk (61Trusted Source, 62Trusted Source, 63Trusted Source, 64Trusted Source).

This applies especially to the long-chain omega-3 fatty acids found in fatty fish and fish oils, such as EPA and DHA.

Their intake can improve many risk factors for heart disease, including:

While some studies are promising, many don’t report any significant effects.

Two large analyses of controlled studies concluded that omega-3 fatty acids have minimal effects on your risk of heart attacks, strokes, or dying from heart disease (80Trusted Source, 81Trusted Source).

SUMMARY

DHA may reduce your risk of heart disease by lowering blood triglycerides and blood pressure, among other effects. However, its role in heart disease prevention is controversial.

DHA may also protect against other diseases, including:

SUMMARY

DHA may relieve conditions like arthritis and asthma, as well as prevent the growth of cancer cells.

DHA is critical during the last months of pregnancy and early in a baby’s life.

Babies up to the age of 2 have a greater need for it than older children and adults (3Trusted Source, 91Trusted Source, 92Trusted Source).

As their brains are growing rapidly, they need high amounts of DHA to form vital cell membrane structures in their brains and eyes (3Trusted Source, 93Trusted Source).

Therefore, DHA intake can dramatically affect brain development (27Trusted Source, 94Trusted Source).

Animal studies show that DHA-deficient diets during pregnancy, breastfeeding, and weaning limit the supply of this omega-3 fat to the infant’s brain to only about 20% of normal levels (95Trusted Source).

Deficiency is associated with changes in brain function, including learning disabilities, alterations in gene expression, and impaired vision (24Trusted Source).

SUMMARY

During pregnancy and early life, DHA is vital for the formation of structures in the brain and eyes.

Most guidelines for healthy adults recommend at least 250–500 mg of combined EPA and DHA per day (96Trusted Source, 97Trusted Source, 98Trusted Source, 99, 100Trusted Source).

Studies show the average DHA intake is closer to 100 mg per day (101Trusted Source, 102Trusted Source, 103Trusted Source).

Children up to the age of 2 may need 4.5–5.5 mg per pound of body weight (10–12 mg/kg), while older children may need up to 250 mg per day (104).

Pregnant or breastfeeding mothers are advised to get at least 200 mg of DHA, or 300–900 mg of combined EPA and DHA, per day (94Trusted Source, 98Trusted Source).

People with mild memory complaints or cognitive impairments may benefit from 500–1,700 mg of DHA per day to improve brain function (43Trusted Source, 44Trusted Source, 45Trusted Source, 46Trusted Source, 47Trusted Source, 48Trusted Source).

Vegetarians and vegans are often lacking in DHA and should consider taking microalgae supplements that contain it (11Trusted Source, 105Trusted Source).

DHA supplements are usually safe. However, taking more than 2 grams per day does not have any added benefits and is not recommended (106Trusted Source, 107).

Interestingly, curcumin, the active compound in turmeric, may enhance your body’s DHA absorption. It’s linked to many health benefits, and animal studies suggest that it may boost DHA levels in the brain (108Trusted Source, 109Trusted Source).

Therefore, curcumin may be helpful when supplementing with DHA.

SUMMARY

Adults should get 250–500 mg of combined EPA and DHA daily, while children should get 4.5–5.5 mg per pound of body weight (10–12 mg/kg).

DHA supplements are usually well tolerated, even in large doses.

However, omega-3s are generally anti-inflammatory and may thin your blood. Consequently, too much omega-3 may cause blood thinning or excessive bleeding (110Trusted Source).

If you are planning surgery, you should stop supplementing with omega-3 fatty acids a week or two beforehand.

Additionally, consult with your healthcare practitioner before taking omega-3s if you have a blood clotting disorder or take blood thinners.

SUMMARY

Like other omega-3 fatty acids, DHA may cause blood thinning. You should avoid taking omega-3 supplements 1–2 weeks before surgery.

DHA is a vital component of every cell in your body.

It’s essential for brain development and function, as it may affect the speed and quality of communication between nerve cells.

Furthermore, DHA is important for your eyes and may reduce many risk factors for heart disease.

If you suspect you’re not getting enough in your diet, consider taking an omega-3 supplement.