Nutrition - DHA side effects

Mar 2014   Side effects of DHA
DHA supplements can cause minor side effects. However, if high doses of the supplement are taken, serious side effects can develop.
The signs of internal bleeding, giddiness and allergic reactions require immediate discontinuance of the supplement and seeking medical help.

Common side effects of DHA

  • Nausea
  • Belching
  • Bloating
  • Fishy aftertaste
  • Fishy burps
  • Halitosis
  • Acid reflux
  • Abdominal discomfort
  • Flatulence
  • Constipation
  • Gastrointestinal upset
  • Diarrhea
  • Nosebleeds
  • Bruising
The side effects of DHA can be due to docosahexaenoic acid itself. Some people may develop nausea and belching while taking DHA supplement. Taking DHA with food may help prevent or lessen these side effects. DHA can cause blood thinning. Eicosapentaenoic acid (EPA) can cause greater blood thinning. As most of DHA supplements have EPA also in them, there may be occasional bruising and nosebleeds. Cuts and wounds may take longer time to stop bleeding and wound healing may get prolonged.

Some of the serious side effects include, gastrointestinal bleeding, bleeding in the brain and allergic reactions.
If the stool is dark or bloody or if there is blood in the vomit, the supplement must be discontinued immediately. Severe headache, numbness in the limbs and changes in the vision and speech may indicate hemorrhage in the brain.

Allergic reactions like rash, urticaria, angioedema, wheezing, difficulty in breathing or swallowing and asthmatic attack may occur in some persons. In all such situations one has to discontinue the supplement and seek immediate medical help.

The side effects may also be relative to the type of supplement consumed. Fishy aftertaste is a very common problem while taking fish oil. To reduce this side effect one may take the supplement along with food. In fish oil supplement, if it is not purified properly, there is a possibility of contamination with toxins or heavy metals. Fish oil supplements may cause slight increases in fasting blood glucose levels, particularly in those with Type 2 diabetes.

Interacting DHA side effects


DHA supplements have the tendency to decrease the blood pressure. Persons with hypertension are prescribed antihypertensives like enalapril, atenolol, doxazosin, bucindolol, valsartan, furosemide, amlodipine and clonidine. Taking DHA along with these medicines can cause the blood pressure to go too low. Sudden giddiness, blurred vision, shallow breathing and cold, clammy, pale skin are the signs of low blood pressure (hypotension).

Anticoagulant medication

Certain cardiovascular and inflammatory conditions require the use of medications such as heparin, warfarin or aspirin to slow down blood clotting (anticoagulant). As omega-3 fatty acids, including DHA have blood thinning actions, taking them along with the anticoagulant medication can increase the risk of bruising and bleeding. At higher doses there may be internal bleeding and the risk of edema and even stroke.


In persons with aspirin intolerance and sensitivity, the intake of DHA supplements can worsen the condition with side effects like persistent cough, asthma and other breathing difficulties.


DHA supplement has anti-inflammatory function and may suppress the inflammatory responses of the immune system. In persons suffering from immunodeficiency diseases, such immunosuppression can have severe consequences.
Related topics in Nutritional deficiency diseases:
Scurvy causes.
Excess vitamin C.
Ascorbic acid functions.
Vitamin C fruits.
Carbohydrate deficiency diseases.
Fat deficiency diseases.
Mineral deficiency diseases.
Protein energy malnutrition in children.
DHA benefits.
DHA fatty acid.
Current topic in Nutritional deficiency diseases:
Side effects of DHA

No comments: