Docosahexaenoic acid (DHA)

While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.

Related Terms

  • 20:6n-3,22:6 Omega-3, ALA, algal DHA, ALNA, alpha-linolenic acid, CA, cervonic acid, DCHA, DHA Gold™, DHA-S, DHASCO®, eicosapentaenoic acid, EPA, fish oil, impact, K85, life’s DHA™, Lovaza®, marine oil, MaxEPA™, Neuromins™, Omacor®, omegavenous, salmon, Schizochytrium sp., seal oil, single-cell source DHA, tuna, Ulkenia sp.

Background

  • Docosahexaenoic acid (DHA) is an omega-3 fatty acid found in salmon, tuna, and other types of fish. It is in the same family as other omega-3 fatty acids found in plant foods like flax, soy, and walnuts. In the human body, the highest levels of DHA are found in the brain, eyes, and sperm.

  • DHA has been studied for preventing heart attack risk factors such as high cholesterol. However, some research found that DHA may increase levels of “bad” cholesterol.

  • DHA has also been studied for improving brain and eye function, infant development, health during pregnancy, and mental disorders. Low levels of DHA have been linked to a higher risk of some conditions such as attention-deficit hyperactivity disorder (ADHD), Alzheimer’s disease, and depression. However, more research is needed.

  • DHA is now added to infant formula in many countries. It is believed to have health and development benefits.

Scientific Evidence

Uses

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Heart disease

Previous research has shown that omega-3 fatty acids may help improve heart health, heart rate, and blood pressure. Some studies reported that high DHA levels may reduce the risk of clogged arteries, while other studies found that DHA may increase “good” cholesterol. However, some evidence is conflicting. More studies on the effects of DHA are needed before a conclusion can be made.

Infant development / neonatal care

Much research has highlighted the importance of DHA in infant nutrition for proper brain development. Most studies looked at the effects of DHA in combination with other therapies. These studies suggest benefits of high-DHA fish oil in supplements or foods during pregnancy or in baby formula. Some studies looked at the effects of DHA in increasing children’s IQ. However, more research is needed before conclusions can be made.

Age-related macular degeneration (eye disease)

Initial research suggests that DHA supplementation may benefit people who have this age-related eye disease. Studies have found that certain omega-3 fatty acids such as DHA may help improve eye health. However, there is conflicting evidence. Therefore, more studies are needed before conclusions can be made.

Atopic dermatitis (chronic skin disease)

DHA may have anti-inflammatory effects in the skin and reduce severity of atopic dermatitis. Further research is needed to confirm these results.

Bipolar disorder

DHA is found in high levels in the brain, and its role in brain function is being studied. The effect of DHA in people with bipolar disorder has been studied in preliminary research. The effect of DHA in this population still needs to be determined.

Cystic fibrosis (lung disease)

Preliminary research has shown that people with cystic fibrosis tend to have low DHA levels. DHA supplementation may be safe for these patients, although some studies found no benefits for lung function. Further research is required in this field.

Dementia (loss of brain function)

DHA has been studied for potential benefits in people with Alzheimer’s disease. Some preliminary research found that DHA reduced dementia risk by as much as 50 percent. Other studies reported that low DHA led to worsened behavior changes. Further research is required to determine the effects of DHA alone.

High cholesterol

The benefits of omega-3 fatty acids on heart health are well known. Some studies suggest that DHA may increase levels of “good” cholesterol in patients with high cholesterol. However, the results are still unclear. The use of DHA should be carefully monitored by doctors. Further research is required before conclusions are made.

Infection prevention (infants)

Baby formula containing DHA may prevent lung infection during the first year of life. More research is needed before firm conclusions may be made.

Liver disease

Preliminary studies suggest that DHA may benefit people with liver disease. This includes liver disease in children that is not caused by alcohol use. Further research is needed.

Male infertility

DHA is found in high levels in the sperm of healthy men. Some trials suggest that DHA supplementation may help improve fertility, although there is conflicting evidence. Further research is needed.

Metabolic abnormalities (increased risk of disease)

One trial compared a supplement containing DHA to soybean oil and found no difference between the two treatments. Further research examining the effect of DHA alone is needed.

Phenylketonuria (infant disorder)

Phenylketonuria is a disorder that causes a certain amino acid to build up in the body. A formula containing DHA may benefit babies with this disease. Treatment with DHA may improve motor function and coordination. However, benefits are still unclear. More research is needed.

Pneumonia

Human research found that DHA-rich oil may benefit people with immune-based illnesses like pneumonia. Some studies found that DHA helped improve appetite in children with pneumonia. Further research is required in this field.

Pregnancy support

DHA has been studied for potential benefits in supporting pregnancy and newborn health. Further well-designed research is required before conclusions are made.

Retinitis pigmentosa (eye disease)

Preliminary findings showed that omega-3 fatty acids may improve eye health, although the results are mixed. Further research is necessary in this field.

Sepsis (infant infection)

DHA-rich oil may support babies’ immune systems, according to preliminary studies. DHA appeared to increase body mass and fat mass in infants with this life-threatening infection. Further research is required in this field.

Attention deficit disorder

DHA has been studied for its potential benefits in helping children with ADHD. DHA appeared to improve attention span in healthy boys and protect nervous system function. However, there are conflicting results. More well-designed research is required.

Cognitive improvement

One study reported that DHA intake resulted in a 50 percent reduction in dementia risk. However, other trials did not find benefits of DHA supplementation on brain function in healthy patients. Further research is required in this field.

Depression

DHA is found in high levels in the brain, and its role in brain function is being studied. The effects of DHA on depression have been studied, but results suggest that it has no effect in patients with major depression or postpartum depression. The benefits of DHA alone are not clear.

Diabetes

Preliminary studies found that DHA does not appear to have an effect on insulin or glucose levels in healthy people. In diabetics, however, DHA increased fasting glucose levels. Until further results are found in this field, people with diabetes should use DHA under the care of a doctor only.

*Key to grades:

Tradition

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

  • Abnormal heart rhythms, adrenoleukodystrophy (brain disease), aggression, Alzheimer’s disease, anti-inflammatory, anxiety, arthritis, asthma, autism, cancer, dry eyes, dyslexia (reading disability), epilepsy (seizures), high blood pressure, high blood pressure associated with pregnancy, immunomodulation (affects the immune system), kidney disease (lupus), kidney transplant, memory, menstrual pain, miscarriage, multiple acyl-coenzyme A dehydrogenase deficiency (genetic disease), nerve damage, obesity, osteoporosis, skin conditions (psoriasis), schizophrenia, sickle cell anemia pain, substance abuse.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

  • General: Experts suggest that women consume 1.1 grams of alpha-linolenic acid (the material that will be changed into DHA in the body) and men consume 1.6 grams daily. Many researchers suggest that 10 percent of this dose could come from preformed eicosapentaenoic acid (EPA) plus DHA. The American Heart Association (AHA) recommends 1,000 milligrams of EPA plus DHA daily for people who have heart disease and four grams of EPA plus DHA daily for people with high cholesterol. Many studies support the addition of DHA and arachidonic acid (AA) to both term and preterm infant formula. Most expert groups suggest taking DHA at levels of 0.2-0.4 percent and AA at levels of 0.35-0.7%. Most infant formulas sold in North America contain 0.6 percent fat as AA and 0.3-0.35 percent of fat as DHA. The DHA mostly comes from algal oil but sometimes comes from fish oil. One study advised that EPA plus DHA should not exceed 1% of total fatty acids in infant formula. Another study suggested a target intake of 400-500 milligrams of EPA plus DHA daily, equivalent to two oily fish dishes per week, as recommended by the American Heart Association. Others reported that the optimal dose to maintain normal DHA levels is 11 milligrams per kilogram daily after birth.

  • To treat eye disease (age-related macular degeneration), 800 milligrams of DHA has been taken by mouth daily for four months.

  • To treat bipolar disorder, 2,000 milligrams of DHA has been taken by mouth daily for 13 months.

  • To reduce heart disease risk, up to four grams of DHA has been taken by mouth daily for up to 16 weeks. Doses of 1.25-2.5 grams of DHA have been taken by mouth daily for six weeks. A total of 10 DHA-rich eggs (147 milligrams of DHA per egg) have been taken by mouth weekly.

  • To improve brain function in healthy people, 800 milligrams of DHA has been taken by mouth daily for four months.

  • To treat dementia, 0.72 grams of DHA has been taken by mouth daily for one year. A dose of two grams of DHA has been taken by mouth daily for 18 months.

  • To treat depression after giving birth, 200 milligrams of DHA has been taken by mouth daily for the first four months after childbirth. To treat major depression, two grams of DHA has been taken by mouth daily for six weeks.

  • To support infant development and care, 200 milligrams of DHA as DHASCO® has been taken by mouth by the breastfeeding mother for four months after giving birth. A dose of 400 milligrams of DHA has been taken by mouth daily from week 20 of pregnancy through childbirth.

  • To treat male infertility, 400-800 milligrams of DHA as Neuromins® has been taken by mouth daily for three months.

  • To support pregnancy, up to 12 DHA-enriched eggs weekly (133 milligrams of DHA per egg) have been taken by mouth starting at 24-28 weeks of pregnancy until childbirth.

  • To treat eye damage (retinitis pigmentosa), 1,200 milligrams of DHA has been taken by mouth daily for up to four years.

Children (under 18 years old)

  • To treat attention-deficit hyperactivity disorder (ADHD), 345 milligrams of DHA as DHASCO® has been taken daily for four months.

  • To improve brain function in healthy children, 400-1,000 milligrams of DHA has been taken daily for up to four months.

  • To treat cystic fibrosis, a dose of 70 milligrams of DHA per kilogram of body weight has been taken for six weeks.

  • To treat high cholesterol, 1.2 grams of DHA has been taken daily for six weeks.

  • To support infant development and care, DHA has been added to formula at levels of 0.14-0.76 percent energy for up to four months. A dose of 20 milligrams of DHA in liquid form has been taken daily for one year.

  • To treat liver disease, 250-500 milligrams of DHA has been taken daily for six months.

  • To treat methylmalonic acidemia (protein and fat breakdown disorder), 25 milligrams of DHA per kilogram has been taken daily.

  • To treat pneumonia, DHA has been taken from hospitalization until discharge.

  • To treat eye damage (retinitis pigmentosa), 1,200 milligrams of DHA has been taken daily for up to four years.

  • To treat sepsis, 100 milligrams of DHA has been taken daily for 14 days.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

  • Avoid using if allergic or sensitive to DHA, fish, fish oils, or any products from the sea or ocean.

Side Effects and Warnings

  • DHA is considered safe for babies in levels that are commonly found in infant formulas and for adults in doses of up to 14 grams daily for 15 weeks. DHA is also considered safe for breastfeeding women in a dose of 200 milligrams of DHASCO® for four months after giving birth and for pregnant women in the second trimester through consumption of 12 eggs weekly or a dose of 0.57 grams daily for up to 20 weeks. DHA is considered safe for children in a dose of ≤400 milligrams daily for four months or ≤1,000 milligrams daily for up to eight weeks.

  • Avoid using if allergic or sensitive to DHA, fish, fish oils, or any marine products.

  • DHA may increase the risk of bleeding. Caution is advised in people with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

  • DHA may lower blood sugar levels. Caution is advised in people with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist, and medication adjustments may be necessary.

  • DHA may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure.

  • Use cautiously in people who have abnormal heart rate, anxiety, autoimmune disorders, high cholesterol, low sperm count, or sexual dysfunction.

  • Use cautiously in people who are taking cholesterol-lowering agents, heart rate-regulating agents, or immunosuppressants.

  • Avoid using DHA in the absence of AA in pregnant women during the first two trimesters of pregnancy.

  • DHA may cause other side effects, including anorexia, anxiety, bad breath, belching, bloating, decreased antioxidant status, decreased insulin response, dizziness, dry mouth, fatigue, fishy aftertaste, gas, headaches, heartburn, increased fasting glucose levels, increased cholesterol levels, increased protein levels in the blood, lightheadedness, loose stools, nausea, reduced sex drive, skin rash, sleep problems, upset stomach, and warmth in hands.

Pregnancy and Breastfeeding

  • General: It is well known that DHA is essential for brain function and that babies’ brains grow fastest during the final three months of pregnancy. DHA has been studied before pregnancy, during pregnancy, and during early infant development. Researchers suggest that pregnant women avoid using DHA without AA supplementation during the first two trimesters of pregnancy.

  • Intakes in pregnant women: In Canadian pregnant women, dietary AA intake was increased compared to dietary EPA and DHA intake due to low fish consumption. Most DHA intake comes from consuming 1-2 servings of fish weekly. In Europe, DHA intake tends to be higher in Spanish women (155-160 milligrams daily) compared to Hungarian and German women (119-125 milligrams daily).

  • Breast milk DHA: The highest concentrations of DHA are found in populations that eat more seafood. Increasing breast milk DHA levels increased breastfed babies’ DHA status. After giving birth, mothers’ DHA status became lower. DHA levels tend to be low in donor milk and in American Indian women in New Mexico.

  • DHA supplementation of the mother: Some research found that DHA supplementation in pregnant and breastfeeding women may reduce babies’ body mass index (BMI). Mothers’ DHA status increased after eating DHA-rich eggs and taking algal DHA supplements. Preliminary results also show that DHA may result in fewer low-birthweight or preterm infants, larger placentas, improved cognitive performance in children, and a lower risk of diabetes during pregnancy.

  • Infant and child development: Some studies looked at the benefits of omega-3 fatty acid supplementation during pregnancy on children’s IQ, attention, and eye health. More research is needed.

  • Breastfeeding vs. formula feeding: Studies suggest that brain and plasma DHA levels are higher in breastfed infants compared to formula-fed infants.

  • Alpha-linolenic acid levels in formula: Higher levels of alpha-linolenic acid in baby formula resulted in higher DHA in plasma and red blood cells, but DHA levels were still lower than those of breastfed babies.

  • DHA in formula: Some studies have looked at the effects of DHA alone in infant formula, but most looked at the combined effects of DHA with AA. Adding DHA to formula of preterm and term babies may help keep up blood DHA levels. Experts suggest taking DHA at levels of 0.2-0.4 percent and AA at levels of 0.35-0.7 percent. Some studies have found that supplementing formula with AA and DHA may prevent immune system problems, intestinal tissue death, and lung problems, while increasing body mass and decreasing fat mass in babies.

  • Toxicity: DHA toxicity has been studied, but there were no differences found in weight, length, or head circumference of babies after consuming a formula enriched with 0.1-1 percent DHA.

  • Fertility: DHA levels were lower in the sperm of men who had fertility problems, according to some studies.

  • Reviews: Some studies looked at the potential benefits of increasing omega-3 fatty acid intake for health during pregnancy and breastfeeding. Preliminary research found that DHA status decreases with each pregnancy a woman has.

  • Other: Studies looked at the effects of a vitamin-mineral supplement with added DHA on nutrition in women. More evidence is needed.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

  • DHA may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

  • DHA may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

  • DHA may cause low blood pressure. Caution is advised in people taking drugs that lower blood pressure.

  • DHA may also interact with agents that may widen blood vessels, alcohol, anticancer agents, anti-inflammatories, antiseizure agents, cholesterol-lowering agents, folic acid, heart rate-regulating agents, hormonal agents, immunosuppressants, iron salts, mood stabilizers, peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists, and tobacco.

Interactions with Herbs and Dietary Supplements

  • DHA may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

  • DHA may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

  • DHA may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.

  • DHA may also interact with alpha-linolenic acid, anticancer herbs and supplements, anti-inflammatories, antiseizure herbs and supplements, arachidonic acid, carnitine, cholesterol-lowering herbs and supplements, cod liver oil, conjugated linolenic acid, copper, echium oil, EPA, essential fatty acids, evening primrose oil, folate, gamma-linolenic acid, herbs and supplements that may affect the immune system, herbs and supplements that may promote heart health, herbs and supplements that may widen blood vessels, hormonal agents, iron, lutein, mood stabilizers, myristic acid, seal oil, stearidonic acid, vitamin A, vitamin C, vitamin E, and zinc.

Author Information

  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

  1. Agren JJ, Hanninen O, Julkunen A, et al. Fish diet, fish oil and docosahexaenoic acid rich oil lower fasting and postprandial plasma lipid levels. Eur.J.Clin.Nutr. 1996;50(11):765-771. View Abstract
  2. Auestad N, Montalto MB, Hall RT, et al. Visual acuity, erythrocyte fatty acid composition, and growth in term infants fed formulas with long chain polyunsaturated fatty acids for one year. Ross Pediatric Lipid Study. Pediatr Res 1997;41(1):1-10. View Abstract
  3. Birch EE, Hoffman DR, Uauy R, et al. Visual acuity and the essentiality of docosahexaenoic acid and arachidonic acid in the diet of term infants. Pediatr.Res. 1998;44(2):201-209. View Abstract
  4. Carlson SE, Ford AJ, Werkman SH, et al. Visual acuity and fatty acid status of term infants fed human milk and formulas with and without docosahexaenoate and arachidonate from egg yolk lecithin. Pediatr Res 1996;39(5):882-888. View Abstract
  5. Clandinin MT, Van Aerde JE, Parrott A, et al. Assessment of the efficacious dose of arachidonic and docosahexaenoic acids in preterm infant formulas: fatty acid composition of erythrocyte membrane lipids. Pediatr Res 1997;42(6):819-825. View Abstract
  6. Conquer JA, Holub BJ. Supplementation with an algae source of docosahexaenoic acid increases (n-3) fatty acid status and alters selected risk factors for heart disease in vegetarian subjects. J.Nutr. 1996;126(12):3032-3039. View Abstract
  7. Courage ML, McCloy UR, Herzberg GR, et al. Visual acuity development and fatty acid composition of erythrocytes in full-term infants fed breast milk, commercial formula, or evaporated milk. J Dev.Behav Pediatr 1998;19(1):9-17. View Abstract
  8. Egert S, Kannenberg F, Somoza V, et al. Dietary alpha-linolenic acid, EPA, and DHA have differential effects on LDL fatty acid composition but similar effects on serum lipid profiles in normolipidemic humans. J Nutr 2009;139(5):861-868. View Abstract
  9. Geppert J, Kraft V, Demmelmair H, et al. Microalgal docosahexaenoic acid decreases plasma triacylglycerol in normolipidaemic vegetarians: a randomised trial. Br J Nutr 2006;95(4):779-786. View Abstract
  10. Grimsgaard S, Bonaa KH, Hansen JB, et al. Highly purified eicosapentaenoic acid and docosahexaenoic acid in humans have similar triacylglycerol-lowering effects but divergent effects on serum fatty acids. Am.J.Clin.Nutr. 1997;66(3):649-659. View Abstract
  11. Innis SM, Akrabawi SS, Diersen-Schade DA, et al. Visual acuity and blood lipids in term infants fed human milk or formulae. Lipids 1997;32(1):63-72. View Abstract
  12. Kelley DS, Siegel D, Vemuri M, et al. Docosahexaenoic acid supplementation improves fasting and postprandial lipid profiles in hypertriglyceridemic men. Am J Clin Nutr 2007;86(2):324-333. View Abstract
  13. SanGiovanni JP, Berkey CS, Dwyer JT, et al. Dietary essential fatty acids, long-chain polyunsaturated fatty acids, and visual resolution acuity in healthy fullterm infants: a systematic review. Early Hum Dev. 2000;57(3):165-188. View Abstract
  14. Stark KD, Holub BJ. Differential eicosapentaenoic acid elevations and altered cardiovascular disease risk factor responses after supplementation with docosahexaenoic acid in postmenopausal women receiving and not receiving hormone replacement therapy. Am.J.Clin.Nutr. 2004;79(5):765-773. View Abstract
  15. Wu WH, Lu SC, Wang TF, et al. Effects of docosahexaenoic acid supplementation on blood lipids, estrogen metabolism, and in vivo oxidative stress in postmenopausal vegetarian women. Eur J Clin Nutr 2006;60(3):386-392. View Abstract

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.