Written by in section: Medicine > Supplements
Medically Reviewed by Dr. Aj Thomas MS, MBA & Updated on Apr 22, 2016
Omega-3 Fish Oil Supplement Benefits and Side Effects
Omega-3 Fish Oil Supplement

With all the media hype about the benefits of Omega 3 fatty acids, there has been an ever growing demand for fish oil supplements.

There are countless manufactures and websites promoting fish oil supplements, the question that often comes to our minds is: What are the actual benefits of fish oil supplements over natural sources of omega-3? Are there any side effects to taking omega-3 supplements?

To know more about Omega-3 types, read: Omega-3 vs Omega-6 - Knowing how to balance them is important


Advantages and Benefits of Fish Oil Supplements

Our body needs Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) for various important functions.

Very limited and specific types of natural food items contain sufficient quantities of EPA and DHA. It may not be an easy task to properly plan our diet to include these food items on a regular basis for various reasons.

Fish oil supplements can provide sufficient amounts of EPA and DHA as per daily nutrition requirements in a capsule form. Most high quality fish oil supplements do not have any unpleasant odor and do not cause any irritation in stomach or throat.

Researchers have observed that nations where, there is a higher consumption of fish as a part of their regular diets tends to have a lower risk of heart related diseases even if their diet contains high amount of fats. E.g. Diets of Finnish, Japanese and Greenland Inuit people. The possible explanation for this observation is that the sea food they consume may contain beneficial EPA and DHA.


So what is fish oil?

Fish oil is a form of fatty acid extracted from the tissues of fatty fish that is rich in EPA and DHA.


Does everyone need to take fish oil supplements?

The simple answer is No! Individuals who consume a lot of fatty fishes like salmon, mackerel, herring, tuna, halibut etc. regularly in their diet, usually do not need to any more supplements in the form of fish oil.

However, it is important to note that many of these fishes may contain high levels of mercury in their tissues. Mercury is toxic for human beings, therefore it’s important to limit the intake of fishes that may contain high amount of mercury.

It would be safe to conclude that consuming fish items at least two times a week can keep the possibility of mercury intake to bare minimum while giving all the benefits of a diet rich in seafood. Commonly eaten fishes like salmon and canned light tuna are low in mercury contamination. It is important to note than white albacore tuna has more mercury content than canned light tuna.

Women who are planning to get pregnant or are pregnant should be careful while eating seafood or fishes in order to limit the intake of mercury. Mercury can affect the unborn child by having negative effects on brain development and the nervous system.

Young children and nursing mothers should also try to limit seafoods or fishes they may contain mercury.

One of the healthiest diet in the world is Mediterranean diet and seafood is an important component of this diet.

Read more: 11 Secrets of the Mediterranean Diet for a healthy and longer life


Fish oil vs Cod liver oil vs krill oil vs vegetable-based omega-3

This is a broad and debatable topic. In short all these are good sources of Omega-3 fatty acids, unfortunately they are not all the same and the benefits they deliver could be different.

Vegetable oil based Omega-3 from plant sources like flax oil may not be an ideal source to get your recommended dose of useful omega-3 fatty acids because these plant based oils contain Alpha-linolenic Acid (ALA) which has to be converted to EPA and DHA inside the human body for it to be useful.

Read more about this: Omega-3 vs Omega-6 - Knowing how to balance them is important


Therefore, animal based Omega-3 is superior to plant based omega-3 and fish oil, cod liver oil and krill oil are better alternatives. Taking supplements based on these sources may be good alternative for people who do not consume fish products.

Out of the three animal-based omega-3 fatty acids, krill oil may be a better source of EPA and DHA.

Read more: Krill oil, Is this the best source of Omeag-3 fatty acids?


Disadvantages and side effects of Fish Oil Supplements

Any healthy nutrition, if abused may cause have its own set of undesired consequences. Excess intake of Omega-3 fatty acids is not an exception for this rule.

The concentration of EPA and DHA in animal based foods is much lower than the effective dosage of commercial supplements. Therefore, it is important to make sure that the correct dosage is followed and these supplements are not abused.

To get very high amounts of EPA and DHA from natural diet, you will need to over indulge in fish products rich in omega-3 fatty acids. Most people will never exceed this limit. On the other hand, going overboard with omega-3 supplements is just too easy.


Some side effects of too much EPA and DHA in the system

Fish oil is safe in most cases when taken in low doses of 3 grams (3,000 mg) or less per day. If you increase the daily dose above the 3 grams’ threshold, you are elevating certain risk factors.

Here are some side effects of taking too much fish oil supplements:

Blood sugar: People who are on medication for high blood sugar should be careful while using omega-3 supplements because of the ability of the supplements to make the effects of Diabetes medication even more stronger, thus increasing the risk of lowering blood sugar level below normal.

Blood pressure: Omega-3 has many benefits for maintain a healthy heart and circulatory system. It can be effective in lowering high blood pressure, but people who are already on medication for lowering high blood pressure should be careful with taking supplements rich in Omega-3, because they may make the effects of blood pressure medications even more stronger.

Bleeding risk: Certain medication like warfarin, clopidogrel, and aspirin used to prevent heart attacks, strokes, and blood clots may have the side effect of increased risk of internal bleeding and this risk is further increased in the presence of EPA. Individuals not on medication, may also run the risk of bleeding if there is excess EPA in their system.

Risk for children: Omega-3 supplements should not be given to children without specific recommendation from the child’s pediatrician. These supplements can alter the EPA and DHA balance in the child’s body during early developmental years.

Pregnant and Breast feeding women: DHA is very important during the first 6 months of pregnancy. New born children also require DHA for their brain development and a healthy mother on a balanced diet is able to provide this through the breast milk. Supplementing omega-3 may disrupt the required balance between EPA and DHA.

Other side effects: Nausea, Stomach upset, Loose stools and fishy odor in breath.



Before starting any types of Omega-3 supplements, it is best to consult your doctor so that they can take your individual health condition into consideration and recommended the appropriate dosage of the supplement if at all necessary.

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  • Last Reviewed on:Apr 22, 2016
  • Medically Reviewed by:Dr. Aj Thomas MS MBA
  • References:


    1. Why not flaxseed oil? - Harvard Health. http://www.health.harvard.edu/staying-healthy/why-not-flaxseed-oil.
    2. Omega-3 fatty acids, fish oil, alpha-linolenic acid Safety - Mayo Clinic. http://www.mayoclinic.org/drugs-supplements/omega-3-fatty-acids-fish-oil-alpha-linolenic-acid/safety/hrb-20059372.
    3. Omega-3 Supplements: In Depth | NCCIH. https://nccih.nih.gov/health/omega3/introduction.htm.

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