What Are The Benefits of Fish Oil and How Much to Take?

Fish oil and fish oil supplements are extremely popular, but these are the scientifically proven benefits and the risks too.

What are the benefits of fish oil and fish oil supplements? Fish oils deliver an improvement in eye, bone, heart and liver health, they help mood and fight drepression, counter autoimmune diseases, ease menstral pain, improve skin, help sleep and may help prevent cancer amongst other things.

But despite all the positives, fish oil has become a subject of controversy following the publication of a study which linked its contents to a higher risk of prostate cancer. However, more research has now been done and the links are unclear.

So what is fish oil?

Should you be taking it? And if you are, should you stop?

These questions will all be answered in this article.

Fish oil is the general term used to refer to two kinds of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These reduce triglyceride levels (a type of fat in the blood).

Fish oil is oil which comes from the tissues of oily fish. It contains omega-3 fatty acids which can benefit you in many ways including:

  • Improvements in eye, bone, heart and liver health
  • Improvements in symptoms of depression and other mental disorders
  • Fight autoimmune diseases
  • Fight age-related mental decline and Alzheimer’s
  • May help prevent cancer
  • Benefit early development in children
  • Ease menstrual pain
  • Promote healthier skin
  • Improve your sleep

Let’s first, however, address the stigma surrounding fish oil following the links to prostate cancer found in a study.

The study in question, published in The Journal of the National Cancer Institute, made headlines worldwide back in 2013 as it linked higher blood levels of omega-3s with higher risks of prostate cancer.

This study has since been panned by the scientific community pretty much worldwide. Criticisms of the study are as follows:

  • Not showing causation
  • Some of the participants were on prescription medications
  • Many of the participants smoked and drank alcohol
  • Not stated if the participants were taking omega-3 supplements or eating omega-3 rich foods
  • Failure to report one of the most important risk factors for prostate cancer in their data which is having a parent/sibling/child with prostate cancer

Set this against the fact that the occurrence of prostate cancer in Japan (a country with one of the highest intakes of omega-3 fatty acids) is 10 times lower than it is in America.

There is an abundance of research out there which proves the opposite of this study (Omega-3s reducing the risk of prostate cancer):

  • A 2010 review showed a 63% reduction in mortality from prostate cancer in those who eat fish (a natural source of omega-3) but no relation to a reduction in incidence.
  • A 2003 study found that consuming fish more than three times a week was linked with a reduced risk of prostate cancer.
  • A 2001 study on 6,272 Swedish men over 30 years found that those who didn’t eat fish had a twofold to a threefold higher frequency of prostate cancer than those who ate moderate or high amounts.

Where can I get them and how much should I be having?

Omega-3s are named as an “essential fatty acid” due to the fact your body requires them, but can’t produce them.

Therefore you need to get them from foods like fish, or (for vegetarians) seaweed, chia or hemp seeds, walnuts and kidney beans are good alternative sources.

It’s recommended to eat a minimum of two servings of fish each week (or 250–500 mg a day).

The best fish for Omega-3 content are:

  • Herring
  • Mackerel
  • Salmon
  • Trout
  • Sardines
  • Mussels
  • Oysters
  • Krill

You can also take supplements for omega-3 however a 2015 study in Australia and New Zealand found that of 32 shop bought supplements only 3 had the listed amount of EPA and DHA (Omega-3 fats).

Furthermore, two-thirds of the supplements had less than 67% of the listed EPA and DHA amounts.

In 2017 however, a study by GOED (The Global Organization for EPA and DHA Omega-3) found that – after purchasing every fish oil supplement available from online pharmacies in New Zealand – that the majority of the industry does meet regulatory limits for oxidation and label claims about EPA and DHA content.

Contrasting studies are prominent but none more so than in fish oil following the media scandal in 2013. Therefore, we recommend you get your Omega-3 from natural sources as suggested above.

The benefits of Omega-3s could be a list as long as the longest arm. There are so many supposed benefits, whether that’s for old people, young people, men or women, there are studies to suggest it helps with all sorts of health issues. Let’s take a look at them…

Benefits of Fish Oils

Prevent or improve symptoms of depression

People with major depression show lower blood levels of omega-3s and multiple studies show that consuming omega-3s regularly leads to people being less likely to be depressed.

Furthermore in one study when people with depression, started taking omega-3 supplements, found that their symptoms improved.

Improve symptoms of mental disorders

Similarly to depression, lower blood levels of omega-3s are found in people with psychiatric disorders.

Increasing omega-3 can reduce the frequency of mood swings in people with bipolar or schizophrenia and can also decrease violent behaviour.

Improve bone and joint health

Omega-3s can boost the amount of calcium in your bones, reducing the risk of certain types of bone diseases and boosting bone strength.

Arthritis patients taking Omega-3 supplements reported reduced joint pain and increased grip strength.

Improve eye health

DHA is a type of Omega-3 found in fish and other such foods, it is also a major part in the retina of your eye.

When not getting enough DHA vision problems to arise and you are more likely to get eye diseases, getting enough Omega-3 is found to reduce risk of macular degeneration (causes permanent eye damage and blindness).

Improve Heart health

Fish-eating populations such as Greenland Eskimos are found to have much lower rates of heart disease due to the amount of Omega-3 they consume.

Omega 3 acids are related to many benefits for heart health including:

  • Blood pressure – Omega-3s have been found to reduce blood pressure in people with high blood pressure.
  • Blood clots – Omega-3s prevent harmful blood clots from forming by keeping platelets from going together.
  • Triglycerides (a type of fat found in the blood) – Consuming Omega-3s can reduce triglycerides by up to 30%.
  • HDL (‘good’) cholesterol – Consuming Omega-3s can increase the level of ‘good’ cholesterol.

Range of benefits for early development in children

As Omega-3s are important for brain development and growth in infants, consuming them has a range of potential benefits:

  • Better eyesight
  • Better social skills
  • Fewer behavioural issues
  • Decreased risk of ADHD, autism and cerebral palsy
  • Higher intelligence
  • Reduce asthma risk in children

Reduce a range of symptoms which increase the risk of heart disease, stroke and type 2 diabetes

There is a group of conditions which increase the risk of other diseases such as heart disease, stroke and type 2 diabetes – this is called metabolic syndrome.

Omega-3s can help to improve inflammation, insulin resistance and heart disease risk factors.

Reduce liver fat

Excess liver fat (non-alcoholic fatty liver disease) is bad as it can lead to cirrhosis and scarring increasing your risk of getting liver cancer.

Consuming Omega-3s reduces the amount of liver fat and, as mentioned in the last benefit, inflammation as well both of which help to improve liver function and reduce the symptoms of non-alcoholic fatty liver disease.

Fight autoimmune diseases

An autoimmune disease is when your immune system mistakenly attacks healthy cells as it views them as foreign cells.

Examples include:

  • Type 1 diabetes
  • Psoriasis
  • Ulcerative colitis
  • Crohn’s disease
  • Rheumatoid arthritis
  • Multiple sclerosis

Omega-3s can fight some of these diseases. Studies have shown that consuming enough omega-3s during your first year of life is linked to a reduced risk of many autoimmune diseases.

With age comes a slow down in brain function and an increased risk of Alzheimer’s disease.

Eating fish and the Omega-3s in them has been shown to reduce the rate of decline in people’s brain function and reduced the risk of Alzheimer’s disease.

May help prevent cancer

Some studies have linked consumption of Omega-3s to reducing the risk of various cancers. Whether that is colon, prostate or breast cancer.

It’s important to note “some” – not all studies show the same results.

Ease menstrual pain

All women know that menstrual pains can severely affect daily life, the pain is found in the lower abdomen and pelvis, often the feeling spreads to the lower back and thighs also.

Studies have shown that women who consume the most Omega-3s often experience lighter, less severe menstrual pain.

Promotes healthier skin

Your skin contains loads of Omega-3 fatty acids it looks after the health of cell membranes. With age comes a decline in the quality and health of your skin. With the consumption of Omega-3, this increases the health of your cell membrane which leads to wrinkle-free, soft skin.

Skin disorders such as psoriasis and dermatitis or even acne have been shown to be treated/improved through the consumption of Omega-3s.

Improved sleep

As we know, one of if not the easiest things to biohack is sleep and fish oils can help in this.

Lower levels of Omega-3s in both children and adults has been linked to sleeping problems. Low levels of DHA are linked to lower levels of melatonin, which helps you to fall asleep.

Multiple studies have shown that increasing Omega-3 intake can improve the quality of and lengthen your sleep.

Potentially aid in weight loss in a variety of ways

Studies have shown that Omega-3s can improve your body composition, reduce body fat and increase the amount of ‘good’ HDL cholesterol.

Side Effects

There are a wide variety and a large number of benefits that fish oil and in turn Omega-3s are linked to.

The side effects don’t usually occur without consuming too much.

The maximum daily recommended amount of Omega-3s is up to 5000mg, the guideline as previously mentioned is set at 250-500mg. If you experience any of the following symptoms lower your consumption of Omega-3 fatty acids:

  • Insomnia
  • Stroke
  • Acid reflux
  • Diarrhoea
  • Low blood pressure
  • Nosebleeds or bleeding gums

Unrelated to dosage, Omega-3 consumption can lead to:

  • Bad breath
  • Unpleasant smelling sweat
  • Headaches
  • Heartburn


Fish oil and fish oil supplements contain Omega-3 fatty acids which are linked to a number of important health benefits such as improvements in heart, eye and liver health or benefits to development in children.

They are not without controversy however but the studies with which this controversy came about is questionable itself.

Nonetheless, it is recommended that you always read the label to see the amount of Omega-3s (EPA and DHA) are in either supplements or the food you are eating.

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