Considering how vital the healthy fat docosahexaenoic acid (DHA) is, it’s no wonder more people are taking DHA supplements to support their nervous system, heart and brain than ever before.
Fortunately, as studies continue to demonstrate the importance of DHA for both adults and children, supplements and foods that provide docosahexaenoic acid are becoming more widely available. This means it’s now relatively easy to include sources of DHA in your diet regularly, especially the richest food sources of omega-3s like wild-caught fish, such as salmon, sardines and herring.
If you’ve ever tried to buy fish oil or algae supplements before, you’re probably aware of just how many options there now are to choose from. In addition to eating oily fish, DHA supplements are recommended for most people — whether you’re pregnant, looking to give docosahexaenoic acid to your child or you’re an adult who wants to maintain healthy cognitive function as you age.
Below we’ll cover the benefits of DHA, the best food sources and what types of DHA/fish oil supplements to look for.
What Is DHA?
Docosahexaenoic acid is a polyunsaturated omega-3 fatty acid found throughout the body that is important for normal brain function, including growth and development of the infant brain.
It is a major structural fat, making up 97 percent of the omega-3s found in the brain and 93 percent of the omega-3s found in the retina of the eyes. It is also a key component of the heart.
Docosahexaenoic acid is the prominent structural fatty acid found in the grey matter of the brain and retinal tissues in humans. Granule neurons in the hippocampus (the part of the brain that is primarily associated with memory) continue to proliferate throughout life. The formation of these newly proliferated cells in the hippocampus helps explain why dietary DHA is crucial for the maintenance of learning and brain function in older age.
How exactly does DHA impact our health, and what are the benefits of obtaining it from supplements and foods?
1. Supports the Nervous System
Having adequate intake of DHA is important in adults when it comes to the health and function of the brain. It is also needed for proper brain growth and development in infants, as well as maintaining normal cognitive function into older age.
Humans obtain DHA primarily from their diets because we only have the capacity to synthesize a limited amount. The brain actually prefers DHA to other fatty acids, so uptake of it is higher than other fats. DHA turnover is also very fast, which means the brain needs a steady supply.
2. Supports Fetal/Infant Development
Why is DHA good for babies? Infants acquire it in utero during pregnancy and from breast milk. Neural function and integrity can be damaged permanently by deficits of omega-3 essential fatty acids during fetal and neonatal development. The DHA in the cerebral cortex starts to increase with age, primarily due to the length of breastfeeding.
Studies suggest that one long-term benefit of infants with higher levels of DHA is faster development of behavioral functions. Specific DHA deficits may lead to learning impairment because docosahexaenoic acid is involved in cell signaling.
If a mother is healthy and consumed dietary docosahexaenoic acid or DHA supplements, a breastfed baby should be able to get enough DHA from the mother’s breast milk. Infant formulas may or may not supply DHA, so it’s important to read labels carefully if you plan to formula-feed your infant.
During the last 50 years, many infants who were formula-fed lacked DHA and other omega-3 fatty acids. Some speculate that this has contributed to the rise in learning disabilities, including ADHD, though more research is needed to verify this.
3. Supports Vision and Eye Health
DHA plays a major role in the development of proper visual function in infants. Studies with both premature and full-term infants suggest that an adequate supply of docosahexaenoic acid, sourced either from breast milk or DHA-fortified formula, is associated with better visual function and more rapid visual development, which is why docosahexaenoic acid is an important eye vitamin.
The retina contains a high concentration of DHA, which enhances visual function, fluidity of photoreceptor membranes and retinal integrity. Many studies demonstrate that docosahexaenoic acid has a protective role in the retina.
Experts now tell us that from a nutritional standpoint, older individuals who tend to have a higher than optimal omega-6/omega-3 ratio should make an effort to increase DHA consumption (from food and/or fish oils) to help protect their vision.
4. Treats Rheumatoid Arthritis Symptoms
Low DHA levels have been found to be associated with development of rheumatoid arthritis, an autoimmune inflammatory disease that negatively affects joints and leads to the destruction of bone and cartilage. DHA reduces inflammation in the body, so it may help decrease damage, swelling and pain in the joints of people with rheumatoid arthritis.
Studies have found that the Japanese population, which eats a larger quantity of DHA-rich foods compared to many other countries, has a lower incidence of rheumatoid arthritis. One case-controlled study showed that subjects who consumed two or more fish meals per week had a 43 percent reduced risk of developing rheumatoid arthritis as compared to those who consumed less than one serving of fish per week.
5. Improves Memory
In the journal Applied Physiology, Nutrition, and Metabolism, findings from one study conducted with mice showed that memory cells in the hippocampus could better communicate with each other and perform faster relay messages when DHA levels in that region of the brain were increased. This make foods with docosahexaenoic acid strong brain foods.
Researchers believe that DHA supplements may facilitate synaptic plasticity (the ability of synapses in the brain to strengthen or weaken over time, which affects learning and memory). This could explain why a diet enriched with docosahexaenoic acid is able to improve memory.
When the diet is supplemented with DHA or fish intake is increased, additional stores of the omega-3 fatty acid are deposited into the brain. This may help prevent declining DHA levels in the brain and changes in cognitive function that can occur with advanced age.
6. Lowers Risk for Heart Disease
Docosahexaenoic acid has been linked to a reduced risk of cardiovascular disease. DHA has anti-inflammatory effects, and higher intake may reduce blood triglycerides, risk of clots, blood pressure and cholesterol levels.
Fish oil containing DHA has been shown to help reduce triglycerides in the blood and decrease thrombosis, plus help prevent cardiac arrhythmias. DHA may also protect against endothelial dysfunction, which is a catalyst to cardiovascular disease. The American Heart Association recommends consuming fish, particularly fatty fish, at least two times per week to support overall heart health.
7. Improves Acne
According to the American Academy of Dermatology, acne is considered the most common skin condition in the U.S., affecting more than 50 million Americans annually. Acne breakouts can be painful and unpleasant to deal with, but fortunately DHA supplements and foods may be able to help.
Surprisingly, acne is considered a rare condition in non-Westernized countries, where a higher dietary intake of omega-3s compared to omega-6s is more common. In a case study conducted in Korea, individuals with acne consumed a diet that included more junk food and less fish oil than the control group. In Italy, it was discovered that the consumption of fish was correlated with protective properties against moderate to severe form of acne.
8. Exhibits Anticancer Effects
Docosahexaenoic acid taken alone or used in combination with chemotherapy can exert anticancer activity by causing apoptosis in human cancer cells. One study out of Italy reported that supplementation with two grams per day of fish oil for the first nine weeks of chemotherapy contributed to delay in tumor progression in colorectal patients.
Further research is needed to verify the cancer-fighting effects of DHA, but the results thus far are promising.
9. Eases Asthma Symptoms
Asthma is a chronic lung condition characterized by inflammation, airway hyper-responsiveness and obstruction. Allergic asthma is triggered by allergens, such as dust or pollen. Non-allergic asthma may be induced by exercise or may be occupational. Certain studies have found that children who eat fresh oily fish more than once per week have a reduced risk of developing asthma.
One study followed 4,162 American children for 20 years, documenting intake of omega-3 fatty acids as well as those who developed asthma. As a result, those with the highest intake of omega-3 fatty acids were 54 percent less likely to have asthma.
It was also observed that DHA was the most beneficial omega-3 for fighting asthma. Docosahexaenoic acid is known for regulating inflammatory processes and reducing the degree of inflammation. It is therefore not surprising to find that higher intake of DHA could prevent respiratory inflammation and the risk for asthma.
10. Boosts Immunity
In a study published in the Journal of Leukocyte Biology, researchers observed that omega-3 fatty acids enhanced B cells (a type of white blood cell) activity and could potentially increase gut immunity. Before this study, fish oil was thought to have a different effect on the immune system. This study challenges the notion that fish oil is only immunosuppressive, according to the authors.
The research was performed in mice, in which half were given a DHA-rich fish oil supplement for five weeks. As a result, the mice who were on the DHA supplement showed enhanced antibody production and cell activation.
DHA has also been shown to have protective effects against many chronic diseases related to immune dysfunction and inflammation, including “hypertension, arthritis, atherosclerosis, depression, adult-onset diabetes mellitus, myocardial infarction, thrombosis and some cancers.”
11. May Help Treat Depression
DHA may be able to help reduce development of mood-related issues, including depression. Certain studies have found an association between depression and lower intakes of essential omega-3 fatty acids.
In a study where depressed patients were instructed to increase consumption of fish over a five-year period, occurrence of aggressive hostility and depression were reduced. In societies where the consumption of fish is increased, the rate of depression is typically lower.
Overall, the correlation between the prevalence of major depression and the fish consumption in different countries suggests that people tend to suffer from less depression when they consume more fish.
What foods are high in DHA? Docosahexaenoic acid is primarily found in fatty, cold-water fish. It is also present in mother’s milk and available in lower amounts in meat and eggs.
Below are the best dietary sources of DHA:
- Salmon — 2,477 milligrams per serving
- Herring — 2,150 milligrams per serving
- Tuna — 1,940 milligrams per serving
- Mackerel — 1,673 milligrams per serving
- Sardines — 1,463 mg per serving
- Rainbow trout — 1,251 milligrams per serving
- Halibut — 520 milligrams per serving
- Oysters — 425 milligrams per serving
- Mussels — 430 milligrams per serving
- Anchovies — 411 milligrams per serving
- Atlantic cod — 277 milligrams per serving
- Egg yolks — 160 milligrams per serving
Women who are pregnant or planning to become pregnant should not eat high quantities of white albacore tuna, shark, tilefish, swordfish or king mackerel due to concerns about mercury consumption. It’s recommended that pregnant women consume no more than six ounces per week of these fish and instead get omega-3s from fish like salmon and sardines.
Supplements and Dosage
- Fish oil capsules (as well as cod liver oil and krill oil) provide both docosahexaenoic acid and eicosapentaenoic acid (EPA). When considering a fish oil supplement, the first thing to look at is the amount of total omega-3 contained per serving. It is important to consider the percentage of EPA and DHA in the supplement. The greater the percentage of EPA and DHA, the greater the benefits the supplement will have. The concentration per serving is superior in higher-quality supplements compared to those that are lower quality.
- Algae contains docosahexaenoic acid but doesn’t contain EPA. Supplements sourced from algae should be considered for vegans and vegetarians who lack DHA in their diets but don’t want to consume fish oil.
How much omega-3s do you need per day? The recommended intake of omega-3 fatty acids (DHA and EPA combined) can be achieved through supplementation and/or increasing consumption of oily fish.
If you regularly eat oily fish several times per week, this lowers or eliminates the need for omega-3 supplements. Women who are pregnant or breastfeeding should also consume at least eight and up to 12 ounces of a variety of seafood per week, especially those with low mercury content (like salmon or sardines).
When it comes to supplements, the dosage of omega-3s that you should take each day depends on your age and current health.
- The general recommended guidelines for taking a combined DHA and EPA supplement per day in healthy adults is 250 milligrams/day. The beneficial upper limit intake per day is approximately 500 milligrams.
- Even though DHA supplements are considered to be safe, taking more than two grams/2,000 milligrams a day is not recommended and does provide added benefits.
- For prevention of cardiovascular disease, 300–600 milligrams of DHA and EPA per day is recommended.
- For pregnant women or breastfeeding moms, it’s recommended to consume between 300–900 milligrams of combined DHA and EPA per day. Certain prenatal vitamins include DHA/EPA but not all. During pregnancy, women need about 200 milligrams of docosahexaenoic acid each day to support a growing fetus.
- For people who are experiencing memory loss, trauma or other cognitive impairments, research shows that 900–1,700 milligrams of docosahexaenoic acid per day may help support cognitive health.
DHA vs. EPA vs. ALA
- Even though there are several different omega-3s, the vast majority of scientific research has focused on three: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is the type of omega-3 found in flaxseeds and walnuts; it cannot be converted easily to DHA and therefore has less beneficial effects.
- The form of omega-3 fatty acids found in fish are either docosahexaenoic acid or eicosapentaenoic acid — or a combination of the two.
- Most fish oil capsules contain both DHA and EPA.
- How much EPA and DHA do you need daily? A typical fish oil supplement provides about 1,000 milligrams of fish oil, usually containing about 180 milligrams of EPA and 120 milligrams of docosahexaenoic acid.
- Supplements with EPA may not be recommended for infants or small children because of the risk of upsetting the balance between DHA and EPA during early development.
DHA in Baby Formula
In the past, DHA was not usually found in infant formulas, but almost all brands of formula sold in the U.S. are now fortified with docosahexaenoic acid and arachidonic acid (ARA). This is good news considering that these fatty acids are an important part of baby nutrition.
What is ARA and what does it do? ARA is a long-chain polyunsaturated fatty acid that is usually obtained from foods, including fish (or fish oils), algae and fungi, eggs, and human breast milk. Like DHA, ARA accumulates in the brains and eyes of infants, helping with development.
What does DHA in formula do? Docosahexaenoic acid in baby formula is meant to help support cognitive development, protect against learning disabilities, aid in visual development and support healthy immune function.
Risks and Side Effects
Fish oil capsules that contain docosahexaenoic acid may potentially cause omega 3 side effects, such as loose stools, stomach upset, belching, unpleasant taste, bad breath, heartburn, nausea, gastrointestinal discomfort, diarrhea, headache and bad-smelling sweat.
Fish oil supplements may also increase the risk of excess bleeding and lower blood pressure. Omega-3 dietary supplements, including fish oil, have the potential to interact with medications, especially Warfarin (Coumadin®) and similar anticoagulants.
If taking blood-thinners or medication, a health care provider should be consulted before considering taking fish oil. Pregnant women should talk to their health care providers before taking fish oil supplements if they have any concerns about quality or adverse reactions.
- Docosahexaenoic acid is a polyunsaturated omega-3 fatty acid that is critical for optimal brain health and function at all ages of life. Having a healthy nervous system, healthy hair and skin, reduced cardiovascular and cancer risk and stronger immune system are few of the many benefits of DHA.
- Symptoms of docosahexaenoic acid deficiency can include fatigue, dry skin, poor memory, poor circulation, hair loss, heart problems, learning impairment, mood-related issues and behavioral problems.
- The best way to boost DHA consumption is by eating cold-water, fatty fish each week and by taking high quality supplements (fish oil).
- If you’re taking omega-3 supplements that contain DHA and EPA, take a daily dose that provides about 250–500 milligrams of DHA/EPA combined.