Omega-3 Fish Oil: Everything You Need To Know

Health Watch

7 min readJul 7, 2021

Fish oil is the most popular supplement, either in liquid or capsule form.

But what is omega-3? Why is it “essential”? What is the proper dosage?

This article offers a comprehensive guide to omega-3 fish oil, based on current scientific evidence.

What is omega-3?

Omega-3 is a group of polyunsaturated fatty acids considered “essential” for the human body.

The fatty acids are natural components of fats and are classified as:

Saturated : They are found in meats such as pork, beef and poultry, as well as in butter or coconut oil.
Monounsaturated : Walnuts, avocado, and some plant-based oils contain monounsaturated fatty acids.
Polyunsaturated : Omega-3 falls into this group. Certain fish (so-called “blue fish”) such as salmon contain high amounts of these types of fatty acids.

Fat is necessary for the synthesis of certain vitamins and for the proper functioning of the body’s metabolic functions.

In the case of omega-3, it is considered an essential fatty acid because the human body needs it and is not capable of producing it on its own , so it must be ingested through the diet.

Omega-3 is divided into several types.

Omega-3 types: ALA, EPA, DHA

There are several types of omega-3s, but the ones that are most relevant to health are:

ALA (alpha-linoleic acid)

Alpha-linoleic acid, better known as ALA for its acronym in English, is the most common of the omega-3 fatty acids.

It is found in many plant-based foods such as kale, spinach, walnuts, and in seeds such as chia, flaxseed, or hemp.

However, the body cannot use it directly; you must convert it to EPA or DHA first , two other forms of omega-3 explained later.

The problem is that this conversion process is extremely inefficient; in fact, it is estimated that less than 10% of the ALA consumed is converted to EPA or DHA.

If ALA is not converted into either of the other two forms mentioned above, it remains inactive and the body simply stores it or uses it for energy, just like any other fat.

EPA (eicosapentaenoic acid)

Eicosapentaenoic acid (EPA) is another type of fatty acid in the omega-3 family.

Its main function is to synthesize molecules called “eicosanoids”.

Eicosanoids are essential for the proper functioning of the immune system , for regulating the inflammatory response, and for overall cardiovascular health .

Its intake has even been linked to the reduction of depressive symptoms.

Part of the eicosapentaenoic acid can in turn be converted to DHA.

DHA (docosahexaenoic acid)

Docosahexaenoic acid (DHA) is considered the most important of the omega-3 fatty acids due to its importance for the body.

DHA is a fundamental component for the formation and development of the nervous system (specifically for the brain and retina), its deficiency at an early age is linked to learning problems.

EPA and DHA are found in high amounts in fish oil.

Omega-3 Fish Oil Benefits

A diet high in omega-3 fatty acids from fish oil offers multiple health benefits:

Helps cardiovascular health

Omega-3 is proven to greatly benefit cardiovascular health: it lowers triglycerides, controls blood pressure, and prevents blood clots, among other things.

Decreases chronic inflammation

Chronic inflammation is linked to a wide variety of diseases such as arteriosclerosis, diabetes, heart disease, irritable bowel, and even various types of cancer.

It can help you lose weight

Consuming fish oil can increase metabolism, which in turn increases the number of calories burned by the body.

Reduces symptoms of depression and anxiety

Evidence indicates that, in these cases, EPA is more effective than DHA in combating symptoms of depression and anxiety.

May delay the onset of Alzheimer’s symptoms

Increasing your intake of DHA can decrease mental decline and reduce the risk of Alzheimer’s.

May improve memory loss related to old age

DHA in particular can improve cognition in individuals with memory loss associated with old age. However, it does not have the same effect in healthy people.

Omega-3 sources

There are two ways to ingest omega-3 fatty acids; through food or supplements.

In the case of diet , the greatest source of EPA and DHA is from oily fish such as herring, salmon, eel, shrimp or sturgeon.

Some algae also contain EPA and DHA.

Certain dairy and meat also contain EPA.

ALA is found in seeds such as flaxseed, chia, hemp and soy, but they are not recommended sources since they are inefficient and the percentage that the body manages to convert into EPA and DHA is very small.

In the case of supplementation, the most popular source is fish oil as it contains large amounts of EPA and DHA.

However, it is important to read the nutritional information on the supplement carefully to know exactly how much EPA and DHA are in each dose.

Depending on the concentration of fatty acids in each dose, it may be necessary to take several capsules or tablespoons of fish oil.

It is preferable to look for a supplement that has a high concentration of EPA and DHA in each dose.

Among the most common fish oil options are:

Natural fish oil

Although it contains less percentage of EPA and DHA than processed, its oxidative process is slower, the body digests it more easily and it contains vitamins A and D.

It usually comes from salmon, sardines or cod liver.

Processed fish oil

The process purifies and concentrates the fish oil, increasing the percentage of EPA and DHA.

However, when processed, the human body does not digest it as easily as the natural one and it oxidizes easily.

For vegetarians or vegans, there are also microalgae supplements that contain DHA.

How much omega-3 do you need?

There is currently no agreement on what is the necessary daily dose of omega 3 to maintain optimal health.

However, according to the World Health Organization, a daily intake of 250–500 mg of a combination of EPA and DHA is recommended for a healthy adult.

The easiest way to achieve this is to include oily fish in your diet, at least twice a week.

The daily limit of the combination of EPA and DHA in a healthy adult is around 5000 mg, according to the EFSA.

The daily recommendation may vary depending on each case:

During pregnancy , an additional 200 mg dose of DHA is recommended .
For children between 6 and 24 months of age , 10–12 mg per kilogram of weight is recommended . This is vital to optimize the baby’s brain development.
For patients with coronary heart disease , it is recommended to take 1000 mg.
For patients with symptoms of depression and anxiety , 200 to 2,200 mg is recommended.
For patients with personality disorders , doses of up to 000 mg daily are recommended .

Another important factor related to dosage is maintaining a balance between the ratio of omega 6 and omega 3 .

Omega 6 is another group of polyunsaturated fatty acids, but its excessive intake is linked, among other things, to the development of diseases and increased cardiovascular risk.

Experts recommend that the proper ratio should be 2: 1 (omega-6: omega-3), however, the current Western diet contains 10 to 15 times more omega 6 than omega 3.

Omega-3: side effects

The most common side effects are:

Fishy breath.
Stomach ache.
Diarrhea.
Flatulence
Sickness.
Gastroesophageal reflux.
Bleeding gums
Nosebleeds

In general, if there are negative symptoms, it is recommended to reduce the dose of omega-3.

However, consuming too much omega-3 can:

Increase the risk of bleeding, due to its anticoagulant properties.
Increase blood sugar levels in people with diabetes.
Lower the tension, so it is not recommended in people with hypotension.
Contribute to weight gain.
Cause vitamin A poisoning; Each tablespoon of cod liver oil contains an average of 270% of the daily requirement of vitamin A.
Cause insomnia.

Summary: Omega-3 Fish Oil

Omega-3s are essential polyunsaturated fatty acids that the body is unable to create, so they must be included in the diet.

The main omega-3s are: ALA, EPA and DHA.

The most important are EPA and DHA, since they can be synthesized directly by the body and offer many health benefits.

Among the benefits are cardiovascular health, decreased chronic inflammation, and increased cognitive abilities.

Fish oil is the most popular omega-3 supplement as it contains high amounts of EPA and DHA.

The recommended dose for an average adult is 250–500 mg of the combination of EPA and DHA.

It is not advisable to consume fish oil prior to surgery due to its anticoagulant properties.

In case of side effects such as nausea or indigestion, it is recommended to divide the dose into small portions and consume them during the day.