7 Fish Oil Side Effects and How to Avoid Them

fish oil soft gels spilling out of amber glass bottle

Are you currently experiencing fish oil side effects and looking for a way to reduce or eliminate them?

This article will take a closer look at each fish oil side effect and offer effective ways to help you reduce or eliminate them.

Fish oils are an excellent source of the omega 3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

While they offer many health benefits, you may be concerned about possible side effects from taking them.

The most common side effects from fish oils are:

  1. Fish burps and bad breath
  2. Diarrhea and upset stomach
  3. Possible mercury exposure
  4. Allergic reactions
  5. Possible drug interactions
  6. Reduced risk for blood clots
  7. Blood pressure reduction

1. Fish Burps and Bad Breath

– Fish oil burps and gas are usually caused by either rapid digestion of the fatty acids or ingesting rancid, low-quality oils.

– Using enteric-coated fish oil pills can help delay absorption in the small intestine, reducing gas and fish burps.

– Choosing pharmaceutical grade fish oils that can provide higher purity levels can reduce possible side effects.

– Taking digestive enzymes with your fish oils can help improve digestion of the fatty acids.

2. Diarrhea and Upset Stomach

– A large scale study published in 2013 issue of Biomed Central and Geriatrics looked over 994 adults taking fish oils and found the most common side effect was gastrointestinal (at less than 8%).

– As stated above, upset stomach issues can be caused by ingesting rancid fish oils. Fish oils can become rancid when they’re exposed to excessive heat, light exposure and oxidation or due to poor manufacturing practices.

– Try to use only fish oils packaged in dark opaque bottles that prevent light exposure.

– Some manufacturers may also use nitrogen to flush the air from the bottles during packaging to limit air exposure. These types of packaging techniques may help reduce your exposure to oxidation and rancid fish oils.

– Always store your bottles in cool dark places or keep them in the refrigerator after opening to reduce heat exposure.

3. Mercury Exposure

– A common fish oil side effect is exposure to traces of mercury, PCB’s, dioxins and other contaminants.

– Infants and small children are particularly vulnerable to mercury and their exposure should be kept to a bare minimum.

– You can reduce mercury exposure by choosing products Certified or tested by a 3rd party laboratory.

4. Allergic Reactions

– Allergic reactions can include skin hives, itching and anaphylactic shock.

– Food experts claim that most fish allergies are due to the fish proteins.

– You can lower your exposure to fish proteins by using only highly-purified oils where the fish proteins should be completely removed.

– Using only products with plant-based soft gel or capsules can also help you reduce exposure to proteins found in many gelatin-based soft gels.

– There are also alternative omega 3 supplements that don’t may not have fish proteins,  including flaxseed oil and krill oil.

5. Possible Drug Interactions

Blood Thinning Medications:

– People diagnosed with cardiovascular disease such as high blood pressure or high cholesterol may be on certain medications, such as warfarin, which can affect blood clotting and bleeding times.

– Researchers at The University of Texas Health Sciences Center found patients on blood thinners taking 3 to 6 grams of fish oil a day showed no negative effects on bleeding or clotting times.

Diabetic Medications:

– Studies show that omega 3 fatty acids may alter your insulin sensitivity which could lead to a possible increase in blood sugar. People using blood sugar medications (Metformin, Glucotrol, Micronase) should consult with their doctors before taking fish oil supplements.

Corticosteroids and NSAIDs:

– Prednisone and topical steroid creams work by reducing inflammation. Many of these drugs are prescribed using a specific dosage schedule.

– studies show that omega 3 fatty acids have an anti-inflammatory effect which may require altering your prescribed dosage.

6. Reduced Risk for Blood Clots

– Fish oils don’t increase the risk for bleeding, but they can reduce the tendency to form blood clots.

– A study from Scotland where 28 healthy males ate 500 mg of mackerel a week (equaling 1 gram of the omega 3 fatty acids, EPA and DHA) showed a 35% reduction in the tendency to form blood clots. Researchers concluded that regular consumption of oily fish or EPA and DHA reduces the risk for thrombosis and atherosclerotic plaque.

– Another study published in the International Journal of Haemostasis and Thrombosis showed 4 grams a day of fish oil did not cause any increase in bleeding episodes in patients also taking aspirin or blood thinning medications. They also found no long term effects on bleeding time and blood coagulation measures.

7. Fish Oils May Lower Blood Pressure

– Scientists at the Harvard School of Public Health analyzed 31 placebo-controlled studies and concluded that fish oils can reduce blood pressure. Patients taking less than 3 grams a day of fish oil reduced their blood pressure by -1.3/-0.5 mmHg and dosages greater than 15 grams a day saw reductions up to -8.1/-5.8 mmHg.

How to Avoid Fish Oil Side Effects

Depending on your overall health and product choices, you may not be able to completely eliminate all side effects from fish oil. However, there are many things you can do to help reduce your risk for them.

How to Reduce Fish Burps, Gas and Upset Stomach:

Try freezing the fish oil pills before you need to take them
Take fish oils with food or digestive enzymes to enhance digestion
Try using enteric coated fish oils
Reduce your fish oil dosage to see if it lessens the symptoms

How to Limit Mercury and Contaminant Exposure:
Use only pharmaceutical-grade fish oils
Choose products that come with a Certificate of Analysis to ensure it contains the lowest amount of contaminants allowed

How to Avoid Allergic Reactions caused by Fish Proteins:
Try using an algae or plant-based omega 3 sources (flaxseed oil)
Avoid soft gels and pills made with fish proteins.

How to Avoid Drug Interactions:
Always consult with your doctor before taking any nutritional supplement, such as fish oil


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