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.
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.
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.
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.
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.
DHA may have anti-inflammatory effects in the skin and reduce severity of atopic dermatitis. Further research is needed to confirm these results.
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.
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.
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.
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.
Baby formula containing DHA may prevent lung infection during the first year of life. More research is needed before firm conclusions may be made.
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.
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.
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 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.
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.
DHA has been studied for potential benefits in supporting pregnancy and newborn health. Further well-designed research is required before conclusions are made.
Preliminary findings showed that omega-3 fatty acids may improve eye health, although the results are mixed. Further research is necessary in this field.
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.
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.
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.
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.
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
A: Strong scientific evidence for this use B: Good scientific evidence for this use C: Unclear scientific evidence for this use D: Fair scientific evidence for this use (it may not work) F: Strong scientific evidence against this use (it likley does not work)
Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. 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 healthcare provider. There may be other proposed uses that are not listed below.
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.
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.
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.
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.
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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.