Docosahexaenoic acid (dha)
Docosahexaenoic acid (dha)

Background

Docosahexaenoic acid (DHA) is an omega-3 fatty acid that is found along with eicosapentaenoic acid (EPA) in cold-water fish, including tuna and salmon.

DHA plays a key role in the development of eye and nerve tissues. DHA might also reduce the risk of heart and circulatory disease by decreasing the thickness of the blood, reducing swelling (inflammation), and lowering blood levels of triglycerides.

People commonly use DHA for high levels of cholesterol or other fats in the blood. It is also used for boosting memory and thinking skills, for helping infant and child development, for certain eye disorders, and many other conditions, but there is no good scientific evidence to support many of these uses.

Don't confuse DHA with EPA. They are both in fish oil, but they are not the same. DHA can be converted into EPA in the body in very small amounts. See separate listings for algal oil, cod liver oil, fish oil, EPA, and krill oil.
When taken by mouth: DHA is likely safe for most people. It's been used safely for up to 4 years. Most side effects are mild and involve stomach and intestine issues. But people shouldn't take more than 3 grams of DHA or other omega-3 fatty acids daily, and no more than 2 grams daily should come from a dietary supplement. Taking more than 3 grams daily of DHA and other omega-3 fatty acids is possibly unsafe. Doing so might slow blood clotting and increase the chance of bleeding.

Special Precautions & Warnings:

Pregnancy and breast-feeding: DHA is likely safe when taken by mouth in appropriate amounts during pregnancy and breast-feeding. DHA is commonly used during pregnancy and is an ingredient in some prenatal vitamins. DHA is also a normal part of breast milk and added to some infant formulas. It's recommended that 200-300 mg of DHA are consumed daily during pregnancy and breast-feeding, either from supplements or food sources.

Children: DHA is likely safe when used appropriately. DHA is included in some infant formulas. Also, DHA has been safely given to children 7 years and older at doses of 30 mg/kg daily for up to 4 years. It has also been safely given to children 4 years and older at doses of 0.4-1 gram daily for up to 1 year. But DHA is possibly unsafe when used in preterm infants born at less than 29 weeks. It might worsen breathing in these infants.

Diabetes: DHA seems to increase blood sugar in some people with type 2 diabetes.

Effectiveness

NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
Likely effective Effectiveness definitions
Possibly effective Effectiveness definitions
  • High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia). Taking DHA with or without eicosapentaenoic acid (EPA) by mouth daily seems to somewhat lower triglyceride levels. But it doesn't seem to lower total cholesterol and might increase low-density lipoprotein (LDL or "bad") cholesterol.
  • Preterm birth. In people who get less DHA from their diet, taking DHA by mouth during pregnancy seems to lower the risk of having a baby very early.
Likely ineffective Effectiveness definitions
Possibly ineffective Effectiveness definitions
  • Decline in memory and thinking skills that occurs normally with age. Taking DHA supplements by mouth alone or with other ingredients doesn't improve memory, forgetfulness, or learning ability in people with age-related memory changes.
  • Alzheimer disease. People who get more DHA from their diet might have a lower risk of Alzheimer disease. But taking DHA supplements by mouth doesn't seem to slow the progression of the disease.
  • Attention deficit-hyperactivity disorder (ADHD). Taking DHA supplements by mouth doesn't seem to improve ADHD symptoms in children.
  • A lung disease that affects newborns (bronchopulmonary dysplasia). Giving DHA to preterm infants by mouth or taking DHA by mouth while breast-feeding doesn't reduce the infant's risk for this lung disease. In fact, DHA might increase the risk for this disease in some infants.
  • Memory and thinking skills (cognitive function). Taking DHA supplements by mouth doesn't improve mental performance in healthy adults.
  • Cystic fibrosis. Taking DHA supplements by mouth doesn't improve symptoms of cystic fibrosis.
  • Depression. Taking DHA supplements by mouth doesn't seem to improve symptoms of depression or prevent depression in most people.
  • Infants born weighing more than 4000 grams (8 pounds, 13.1 ounces). Taking DHA supplements by mouth during pregnancy doesn't seem to reduce the chance of having a large baby.
There is interest in using DHA for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Insufficient evidence Effectiveness definitions

Dosing & administration

DHA is commonly consumed in the diet. Sources include cold-water fish, including mackerel, herring, tuna, halibut, salmon, cod liver, whale blubber, and seal blubber.

In supplements, DHA has most often been used by adults in doses of 400-800 mg by mouth daily for up to 6 months.

Interactions with pharmaceuticals

Medications for diabetes (Antidiabetes drugs)

Interaction Rating=Moderate Be cautious with this combination.

DHA might increase blood sugar levels. Taking DHA along with diabetes medications might reduce the effects of these medications. Monitor your blood sugar closely.

Medications for high blood pressure (Antihypertensive drugs)

Interaction Rating=Moderate Be cautious with this combination.

DHA might lower blood pressure. Taking DHA along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Taking DHA might slow blood clotting. Taking DHA along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Interactions with herbs & supplements

Herbs and supplements that might lower blood pressure: DHA might lower blood pressure. Taking it with other supplements that have the same effect might cause blood pressure to drop too much. Examples of supplements with this effect include andrographis, casein peptides, L-arginine, niacin, and stinging nettle.
Herbs and supplements that might slow blood clotting: DHA might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.

Interactions with foods

There are no known interactions with foods.
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This monograph was last reviewed on 08/03/2024 11:00:00 and last updated on 17/11/2022 10:25:32. Monographs are reviewed and/or updated multiple times per month and at least once per year.
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