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What does fish oil do for the body?

On by , Digestive Care Advisor

What does fish oil do for the body?

Fish oil is often recommended for a healthy diet because it contains the omega-3 fatty acids that are said to have many health benefits. It has became very popular and is widely used especially in the form of supplements. But do you know that fish oil may do more harm than good? Let’s explore what studies reveal regarding the effects of fish oil on the body.

Updated on June 24, 2013

What good does fish oil do?

Fish oil contains omega-3 fatty acids, which have been shown in research to hold numerous health benefits. These Omega-3 fatty acids - called eicosapentaenic acid (EPA) and docosahexaenoic (DHA) - are vital nutrients and do a lot of different things. 

According to Medline Plus a service of the US National Library of Medicine, the intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements:
  • lowers blood triglyceride levels
  • reduces the risk of heart attack
  • reduces the risk of dangerous abnormal heart rhythms
  • reduces the risk of strokes
  • slows the buildup of atherosclerotic plaques
  • lowers blood pressure
Omega-3 fatty acids play a very important role with the function of our bodies and are used for a wide range of conditions. 

Importance of fish oil for brain power and memory

Researchers have found positive associations between fish oil supplements and cognitive functioning. It is believed that a diet lacking in omega-3 fatty acids may cause the brain to age faster and lose some of its memory and thinking abilities. DHA plays a very important role during fetal development, as well as early infancy and old age. High concentrations of DHA are found in the brain and increases 300-500% in an infant's brain during the last trimester of pregnancy! Indeed adding DHA to a pregnant mothers diet may be beneficial for the fetus' brain development. 

What fish oil does in terms of inflammation

Omega-3 fatty acids have a reputation as potent anti-inflammatory agents. Fish oil is widely believed to help prevent disease by reducing inflammation.

Has fish oil anti-cancer effects?

Several studies report possible anti-cancer effects of Omega−3 fatty acids found in fish oil (particularly breast, colon and prostate cancer). Although some research supports the anti-cancer claims made for omega-3 fatty acids from foods, some does not... Some studies even show an increase in disease when omega-3 supplements are used. The relationship between omega-3 fatty acids and cancer is not as well known.

Effect of fish oil on mental stress and depression

Taking fish oil pills seemed to be protective against the effects of mental stress on the heart, particularly heart rate and muscle sympathetic nerve activity. 
Also, fish oil supplements may help ease symptoms of depression in some people. A few studies in adults suggest that omega-3 fatty acids may be beneficial in the treatment of mild to moderate depression. However, studies using fish oil as the primary treatment for severe depression haven't been done. 

What does fish oil do for your skin?

Fish oil may help prevent skin cancer

A study by dermatology researchers at Hope Hospital in Manchester, England, revealed that oily fish in our diets helps prevent skin cancer because essential fatty acids protect the skin against the DNA damage that can cause skin cancer. 

Is fish oil beneficial for chronic skin conditions?

There is some evidence that administering fish oil intravenously (by IV) can decrease severe psoriasis symptoms. But taking fish oil by mouth doesn’t seem to have any effect on psoriasis. In fact most studies on the intake of Omega-3 for chronic skin conditions such as eczema and psoriasis do not provide enough reliable evidence to form a clear conclusion. 

Can fish oil harm your body?

Be careful with the consumption of fish

It's healthy to eat fish but you should choose it carefully. Fatty predatory fish like mackerel, lake trout, flounder, albacore tuna and salmon may be high in omega-3 fatty acids, but due to their position at the top of the food chain, these species can accumulate toxic substances. Therefore try to limit your consumption of fish species that are at the top of the food chain to avoid high mercury exposure. The concern with regularly eating high-mercury fish is that the metal can build up in your body and lead to health problems such as birth defects in newborns, learning disabilities in children and even diabetes in adults.

Are fish oil supplements safe?

  • Fish oil supplements and mercury
Instead of consuming fish every day, taking a fish oil supplement on a regular basis appears to be a safer choice nowadays. A report by researchers at Harvard Medical School and at Massachusetts General Hospital studied five popular brands of fish oil, including Nordic Ultimate, Kirkland and CVS. They found that the brands had negligible amounts of mercury, suggesting either that mercury is removed during the manufacturing of purified fish oil or that the fish sources used in these commercial preparations are relatively mercury-free.

  • Risk of becoming rancid
Fish oil is primarily EPA and DHA, both of which are extremely unsaturated. The greater the degree of unsaturation, the greater the propensity to go rancid. When these oils go rancid, they convert to harmful oxidized fats called lipid peroxides which can damage fatty cellular membranes. How to avoid fish oil to go rancid? Keep your capsules in glass bottles because they are impervious to air, and put the glass bottle in the refrigerator. The cold will markedly slow down the oxidation process even if a little air gets in the bottle.

  • Safety concerns when fish oil is taken in high doses
High doses may have harmful effects, such as an increased risk of bleeding. It is believed that the intake of 3 grams per day or greater of omega-3 fatty acids may increase the risk of bleeding, although there is little evidence of significant bleeding risk at lower doses. 
High doses of fish oil might also reduce the immune system’s activity, reducing the body’s ability to fight infection. This is a special concern for people taking medications to reduce their immune system’s activity (organ transplant patients, for example) and the elderly.

Fish oil does a lot of good things for your body when taken in recommended amounts. This is why you should ask your practitioner for safe dosage depending on your condition. However there is no magic pill that fixes a bad diet. A healthy balanced diet is paramount. There are also studies that show the benefits of omega 3 oils are actually based on eating fish not pills. Luckily there are some options for people who don't want to eat fish, such as ground chia and flax seeds. Even if they contain lower amounts of Omega-3, they are great and safer options to consider!

Other interesting articles related to Omega-3

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Resources and useful links about fish oil

If you think this article may be useful for others and want to link to it, please use the following format: Beck, Josephine. "What does fish oil do for the body" Jan 9, 2010. Updated on June 24, 2013. 

Important: The information provided on this page about fish oil is for educational and informational purposes only and should not be used as a substitute for the advice of an appropriately qualified practitioner.

Tell us what you think about fish oil and leave a comment below!

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Comments from the community (1)

"Musher" on 2010-01-10 at 00:00:00
Very nice article, thanks! But can anyone explain to me what's the point of killing fish to feed cattle? Isn't it a bit illogical? :)
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