Docosahexaenoic acid, better known as DHA, is one of the main components of fish oil that is touted for its health benefits. DHA, along with Eicosapentaenoic acid, or EPA, are said to help in the prevention of heart disease, cancer, depression and arthritis, and are also very important for proper brain function. Due to the fact that many people don't get enough DHA from their diet, fish oil supplementation has become common. Even with all of its health benefits, there are some known side effects to taking fish oil--including a possible elevation in blood sugar levels, upset stomach and increased risk of bleeding.
Possible Elevated Blood Sugar Levels
A possible increase in blood sugar levels is particularly important for those with Type 2 diabetes, as slight increases in fasting blood glucose levels have been noted for this group, according to the National Institutes of Health's MedlinePlus site. Still, it notes that there are no significant effects of fish oil over the long term in patients suffering from diabetes, so minimal caution can be taken.
Possible Stomach Upset
Symptoms may include diarrhea, increased burping, acid reflux, heartburn or indigestion, according to MedlinePlus. A fishy aftertaste may be another unpleasant side effect. Ways to minimize these side effects include taking DHA with meals, and taking lower doses.
Possible Increased Risk of Bleeding
The Mayo Clinic says there is little evidence of bleeding risk at lower doses, but a large intake of fish oil increases the risk of a bleeding stroke. High intake has also been shown to increase the possibility of nosebleeds and blood in the urine.