Sunday, September 24, 2023

Omega–3 oils: A complete guide

Everything you needed to know about omega-3 oils and fish oils, their benefits, dosages, sources, and other important concerns.

Executive Summary

Omega-3 oils and their supplements help the heart, vascular health, brain, skin, eyes, liver, lungs, reproductive system, and bones. They are useful in pregnancy, for infants, children, and the elderly.

Our diets have become high in omega-6 oils, which are pro-inflammatory. Omega-3 oils help counterbalance that effect by acting as anti-inflammatories.

It is difficult to get adequate omega-3 oils from vegetarian sources unless you use algal oils. Consuming flaxseed and other ALA-rich oils is not enough.

Take 1,000 mg of EPA+DHA omega-3 oils a day. Depending on medical needs, you may need a higher amount. Read the article for more details.

Disclaimer: The information, including but not limited to, text, graphics, images, and other material, contained on this website is for informational and educational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified healthcare provider with any questions you may have regarding a medical condition or treatment before undertaking a new healthcare regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Omega-3 oils are important for our health. However, these days, for certain dietary reasons that we will discuss in this article, they have become far more vital. In fact, over the last fifty years, our need for omega-3 oils has gone up multifolds.

What are Omega–3 Oils?

Omega–3 fats are healthy oils that are required by our bodies.

There are nearly a dozen omega–3 oils, but the three main ones are:

  1. Alpha-linolenic acid (ALA),
  2. Eicosapentaenoic acid (EPA), and
  3. Docosahexaenoic acid (DHA).

Of course, there is no need to remember the long names—even I don’t—but just remember the acronyms.

ALA is found mainly in plant sources, such as flaxseed, walnuts, soybean oil, and canola oil. EPA and DHA are mostly found in cold-water fatty fish and other seafood.

ALA is an essential fat. The word essential means your body needs it for its functioning, but cannot synthesize it. So you must get ALA from the food you eat.

In strictly technical terms, EPA and DHA are not essential oils because your body can make them from ALA. The problem, though, is that the conversions of ALA to EPA and DHA in the body are very inefficient. About 5% of ALA is converted to EPA and just about 0.5% of ALA is converted to DHA.

The other option is to get EPA and DHA through foods, which are mostly fish sources. These days, though, some vegetarian sources of EPA and DHA are becoming available.

Besides these two ways, there is no other option for your body to get the required EPA and DHA.

Functions of Omega-3 Oils

Omega–3s are important components of the cell membranes in your body.

ALA mainly provides energy.

EPA is very useful for heart and vascular health.

Your eye retina, brain, and sperm cells have very high DHA levels. The shortfall of DHA may hamper their proper functioning.

Overall, omega–3 oils have many functions in blood vessels, heart, lungs, immune system, and hormone production.

Daily Requirement of ALA Oil

Table 1 below gives recommended ALA amounts at various stages of life. Note that these are not the values of the oils containing ALA, but rather the actual ALA contents of them.

Table 1. Recommended daily ALA intake at various stages of life
Life StageRecommended Amount of ALA
Birth to 12 months*500 mg
Children 1–3 years700 mg
Children 4–8 years900 mg
Boys 9–13 years1,200 mg
Girls 9–13 years1,000 mg
Teen boys 14–18 years1,600 mg
Teen girls 14–18 years1,100 mg
Men1,600 mg
Women1,100 mg
Pregnant teens and women1,400 mg
Breastfeeding teens and women1,300 mg

*As total omega-3s. All other values are for ALA alone. Source: National Institutes of Health (NIH), USA.

Daily Requirement of DHA and EPA Oils

The minimum daily required values of DHA and EPA are not established. Many organisations recommend a combined total of 500 mg of EPA and DHA a day for a person without any health challenges. However, there are five factors to be kept in mind.

1. Special Health Conditions

In many medical conditions, a higher level of omega–3 oil consumption is advised to maintain health.

For example, American Heart Association advises a daily combined EPA and DHA intake of:
1,000 mg, for heart disease patients, and
2,000—4,000 mg, for high triglyceride patients.

Now, stay with me for some rough calculations:

Let us see what it would take to get 1,000 mg of omega-3 oils daily. Generally, EPA and DHA oils are taken in 60:40 proportion. So we are looking at 600 mg of EPA and 800 mg of DHA on a daily basis.

As I mentioned earlier, the vegetarian sources of EPA and DHA are still not widely available. So let’s assume we wish to get all DHA and EPA through the other vegetarian route that many people follow: Consuming ALA, the best source of which is flaxseeds.

That means we will need to consume 12 g of ALA for getting adequate EPA. And 80 g of ALA for getting sufficient DHA. Since the DHA-related ALA need is higher, we will need to consume 80 g of ALA a day.

For the sake of completeness, the specific gravity of omega-3 oils is 0.92. So we would need 86 mL of ALA. Imagine drinking 12 tablespoons of flaxseed oil. Or worse, 54 tablespoons of ground flaxseed powder. Every single day!

So in my opinion, fulfilling your daily omega-3 need through ALA supplementation (flaxseed oil, etc) is very difficult. What about getting ALA through the food we eat?

2. Low Dietary Intake

In the USA, ALA consumption from food is about 1,590 mg in females and 2,060 mg in males, which looks adequate. However, if you consider an average 5% conversion to EPA, and 0.5% conversion to DHA, women would get about 80 mg EPA and 8 mg DHA in women. Similarly, men would get 103 mg EPA and 10 g DHA.

Besides, in the USA, the amount of DHA and EPA an adult gets from the food is 90 mg (combined) a day.

Thus, a back-of-the-envelope calculation suggests that in the USA, men get (113 + 90) mg = 203 mg of EPA and DHA combined, while women get (88 + 90) mg = 178 mg of EPA and DHA together.

Thus, even considering ALA conversions, most people get far less than the recommended amounts of 500 to 2,000 mg a day.

And this is the average intake. That means, fifty percent of men and women will be getting less than these amounts.

To add to the woes, the conversions from ALA depend on the composition of our diet. If there is more ALA in the diet, the conversion percentage drops by 40%–50%. So, a healthy ALA-rich diet will give lesser DHA and EPA than the numbers above.

In many developing countries, these numbers would be even lesser. In essence, many people may have a shortfall of EPA and DHA, if they do not resort to direct EPA + DHA supplementation. There is just no way around it.

3. Minimal Requirements

Five hundred milligrams a day is the minimum requirement for a healthy person. Neither is it an optimal one for such a person nor is it the minimal one for an already unhealthy person.

They are equivalent of passing marks or grades in school. But we never tell our children to barely pass; we encourage them to excel. So why should it be different for omega-3 oils?

4. Your Omega–6 Oils Consumption Decides Omega–3 Requirements

Nearly fifty years ago, we started worrying about saturated fats for heart reasons. Along the way, even trans fats were flagged as unhealthy.

The substitutes that became popular were seed oils such as sunflower oil, safflower oil, peanut oil, and corn oil. They were called Healthy Oils and they indeed were far better than trans fats.

But they had one shortcoming: they were predominantly omega-6 oils. Omega–6 oils compete for the same enzymes in the body as omega–3 oils do. So when you consume omega–6 oils, they block some beneficial actions of omega–3 oils.

Omega–3 oils reduce inflammation in the body and prevent disease. So they are considered anti-inflammatory. Since omega-6 oils prevent the anti-inflammatory actions of omega-3 oils by competing for the same enzymes, they act as pro-inflammatory foods. They can increase inflammation in the body and lead to many lifestyle disorders if taken in excess. So when does their consumption become excessive?

Our ancestors ate diets that had omega–6 and omega–3 in the ratio of 1:1. As the omega-6 oil proportion started rising in our diets, it did not matter until the ratios become 4:1—four parts omega-6 to one part omega-3. That is the rough cutoff for excess intake of omega-6 oils.

These days, our consumption of omega–6 has increased so much that our modern diets have omega–6 to omega–3 ratios of 10:1 to 20:1. Here is a list of different foods and their omega-6 to omega-3 ratios. Try to guess what your diet’s ratio would be.

The omega–6 oils we consume in excess are refined vegetable oils of sunflower, corn, cottonseed, soybean, rapeseed, sesame, canola, and rice bran.

The oils that have fewer omega–6 oils—and so are safer—are butter, coconut oil, palm oil, olive oil, and even lard.

The highly inflammatory diet we currently take is the main cause of many lifestyle disorders such as heart disease, diabetes, and cancer. Here is an article on this website about inflammatory foods to avoid.

If we cannot reduce the consumption of omega–6 oils, we should at least increase the intake of omega–3 oils so that the ratio stays near 4:1 or lower. If our modern diet has the omega-6 to omega-3 ratio of 20:1, we will need to increase our omega-3 intake to five times that of our ancestors.

Here is an article on this website discussing this point: Why must we consume more omega-3 oils? Below is a short video on the same theme:

That is why those who claim that they can get enough omega-3 by consuming home-cooked meals like their forefathers are wrong. They would get enough for their forefathers’ needs; not enough for their own.

Here is an article that explains why the omega–6 to omega–3 ratio matters a lot.

5. Starting Levels versus Ongoing Requirements

The excess omega–6 fats we consume is stored in the cell membranes of our bodies. The task of replacing so much stored omega–6 will take months, even if we provide adequate omega-3 oils to the body.

So the starting levels of omega–3 oils should be much higher when we start to raise omega–3 intakes, as against our ongoing requirements. Start with a higher intake than you normally should and then bring down the amount after 3 months.

EPA + DHA Supplementation

If you consider the five points discussed above, the optimal amount of daily EPA + DHA oil consumption should be higher than the recommendations of various associations. Also, it will be almost impossible to acquire your omega-3 requirements by just consuming ALA through flaxseed or similar oils. I hope this clarifies my stand that everyone needs omega-3 oil supplementation.

If one wants to stick to vegetarian sources, one should look for algae-based (algal oil) EPA+DHA supplements. Otherwise, one should take a high-quality fish oil supplement containing EPA and DHA.

Typically, standard fish oil or algal oil soft gel is 1,500 mg in weight. It contains 1,000 mg of fish oil (plus some other stuff like gelatin, glycerin, etc),. Such a soft gel will give 180 mg of EPA and 120 mg of DHA, a total of 300 mg of omega-3 oils.

Upper Limit on Omega-3 Oils Consumption

The U.S. Food and Drug Administration (US FDA) advises not to exceed 5,000 mg of (EPA + DHA) per day. European Food Safety Authority (EFSA) also puts the safe limit at 5,000 mg of (EPA + DHA) a day.

In other words, FDA and EFSA are saying that one should not take more than 17 standard fish oil or algal oil soft gels a day. These are high enough limits that most people will not exceed them, anyway.

Fish Oils versus Omega-3 Oils

Fish oil is extracted from the tissues of fatty fish, such as salmon, tuna, and anchovies. Fish oil contains thirty percent omega–3 fats, seventy percent other fats, as well as vitamins A and D.

Interestingly, fish themselves do not produce omega–3 oils. So where do those fatty fish get their omega-3 oils from? From their own food.

Here is a summary video about the difference between omega-3 oils and fish oils.

Most of the fatty fish eat phytoplanktons or marine microalgae. These algae produce omega-3 oils. So if the diet of the fish does not include these marine microalgae, tough luck: you will have fish oil but it will not have omega-3 oils.

This is always a risk in buying cheap fish oil supplements. If they come from farmed fish, it is quite likely that they are not so high in omega-3 oils. Such fish oil needs to be refined and concentrated first.

In my opinion, many clinical trials use cheap fish oils since conducting such trials for a long duration is a costly affair. Most such trials don’t do their independent testing of the fish oil contents. They go by what is claimed by the manufacturers of the fish oils.

However, considering that the fish oil industry is not strongly regulated, it is quite likely that the cheaper versions of fish oils fall through the quality cracks. They may give inadequate amounts of omega-3 oils to the participants.

Here is an article that details the multitude of problems with fish farming.

Fish Oils and Heavy Metal Toxicity

One claim against fish oil is it may contain heavy metals such as mercury. The fish from which such oils are extracted are higher up in the food chain. They eat smaller fish and plankton.

Such fish may be contaminated by industrial sources such as waste incinerators, coal-fired power plants, and factories. Typically, emissions from these sources produce airborne mercury and cadmium contaminants that eventually contaminate the water after falling to the ground.

As a result, many fish such as swordfish and sharks contain high amounts of toxic heavy metals. In fact, even fish such as salmon and tuna from which omega-3 oils are extracted have some amount of such toxins. But most of the fish oils are distilled and filtered and their heavy metal contamination is removed. So almost none of the fish oil supplements in the market have such toxins.

So here we have an interesting situation: Many organisations recommend eating fish instead of taking fish oil supplements. But some fish are found to contain heavy metal toxins while none of the popular fish oil supplements on the market have any toxic metal contamination.

Benefits of Fish Oil Supplementation

Here are some of the main benefits of fish oil and fish oil supplements (numerous references in the article for each of the claims below). You can get similar benefits from algal oil supplements, too.

Heart Health

  • Increase levels of HDL (good) cholesterol;
  • Lower triglycerides by 15-30%;
  • Reduce blood pressure, even with small amount of fish oil;
  • Prevent plaques that harden arteries;
  • Stabilise plaques that are already formed, making them safer;
  • Reduce abnormal heart rhythms that can cause heart attacks.

Here is an article on this website that explains how omega-3 fish oil helps after a heart attack.

Eye Health

  • Reduce risk of age-related macular degeneration (AMD), which is a major cause of vision loss among older adults. People who get higher amounts of omega–3s may have a lower risk of developing AMD;
  • Improve vision in AMD.

Here is an article on this website that explains how to protect your eyes from blue rays, which can damage the retina.

There are other nutrients that also help with AMD. Read on this website: Supplements for macular degeneration.

Inflammation Reduction

  • Help treat conditions caused by chronic inflammation;
  • In stressed or obese individuals, reduce production of cytokines (inflammatory molecules);
  • Fish oil supplements significantly reduce joint pain, stiffness, and medicinal needs in rheumatoid arthritis (RA). Some clinical trials show that taking omega–3 supplements may help manage RA when taken together with standard RA medications and other treatments;
  • Keep skin healthy; help in many skin conditions such as psoriasis and dermatitis.

Weight Loss

  • Fish oil supplements improve body composition and reduce risk factors for heart disease in obese people;
  • Fish oil supplements, in combination with diet or exercise, help in losing weight;
  • A meta-analysis of 21 studies showed that fish oil supplements reduced waist circumference and waist-to-hip ratio in obese individuals.


  • Some studies suggest that people who get more omega-3s from foods and dietary supplements may have a lower risk of breast cancer, and perhaps colorectal cancer.

Liver Function

  • Fish oil supplements improve liver function;
  • They reduce inflammation, reducing symptoms of non-alcoholic fatty liver disease (NAFLD) and the amount of fat in the liver.


  • During pregnancy and breastfeeding, eating 250 to 350 grams per week of fatty fish may improve the baby’s health;
  • Choose fish that is lower in mercury.

Children’s Developmental Issues

  • Fish oil supplements improve hyperactivity, inattention, impulsiveness, and aggression in children. This helps in attention deficit and hyperactivity disorder (ADHD);
  • Fish oil supplements, when taken by pregnant or breastfeeding women, improve hand-eye coordination and visual development in infants, and reduce the infants’ risk of allergies.

Here is a short video about the role of omega-3 oils in ADHD.

Brain Ageing and Memory

  • People who eat more fish experience a slower decline in brain function in old age;
  • Some very small studies have shown that fish oil may improve memory in healthy, older adults;
  • Slow down the progress of Alzheimer’s disease (memory loss).

Read on this website: Do fish oil supplements help in Alzheimer’s disease and other dementias?

Mental Disorders

  • People with major depression have lower omega-3 blood levels;
  • Omega-3 supplements improve symptoms of depression;
  • Reduce the chances of psychotic disorders;
  • High dose of fish oil can reduce symptoms of Schizophrenia and bipolar disorders.

Read on Harvard Medical School website: Omega-3 fatty acids for mood disorders.

Asthma and Respiratory Problems

  • Fish oil may reduce asthma symptoms, especially in early childhood;
  • Researchers are studying whether taking omega–3 dietary supplements may help lessen some of the symptoms of childhood allergies, and cystic fibrosis.

Read a very comprehensive article on this website: Benefits of omega–3 fish oil in asthma and allergies.

Bone Health

  • People with higher omega–3 intakes and blood levels have better bone mineral density (BMD);
  • Fish oil supplements reduce markers of bone breakdown, which may prevent osteoporosis.

If you really want to keep your bones healthy, there is no substitute for knowledge. Blindly swallowing calcium tablets don’t make bones stronger. Read a long, long article on this website: Everything you want to know about strong bones.

Joint Health

Osteoarthritis causes inflammation in the knee joint. It increases the levels of inflammatory markers in the synovial fluid, the liquid that surrounds the knee joint.

Omega–3 fish oils neutralise the inflammatory molecules, such as Leukotriene B4. This reduces inflammation and helps keep the joint healthy.

Read on this website: Healthy diet for osteoarthritis.

There are other nutrients that help with osteoarthritis. Read on this website: Supplements for osteoarthritis.

To Read More

Articles in Nutrients Series

  1. Omega–3 Oils: A Complete Guide
  2. Vitamin D: A Complete Guide
  3. Vitamin A: A Complete Guide
  4. Coenzyme Q10: A Complete Guide
  5. Turmeric (Curcumin): A Complete Guide
  6. Lutein: A Complete Guide

Articles in Supplementation Series

  1. Why Do We Need Supplements?
  2. Supplements for Various Age Groups
  3. Supplements for Preventing Ageing & Age-Related Diseases
  4. Supplements for Type 2 Diabetes
  5. Supplements for Osteoarthritis
  6. Supplements for Hair Loss
  7. Supplements for Fatty Liver
  8. Supplements for Autoimmune Disorders
  9. Supplements for Anemia
  10. Supplements for Prostate Enlargement
  11. Supplements for Macular Degeneration
  12. Supplements for PCOS
  13. Supplements for Parkinson’s Disease
  14. Supplements for Gout
  15. Supplements for Eczema

Articles in Supplementation Series

  1. Why Do We Need Supplements?
  2. Supplements for Various Age Groups
  3. Supplements for Preventing Ageing & Age-Related Diseases
  4. Supplements for Type 2 Diabetes
  5. Supplements for Osteoarthritis
  6. Supplements for Hair Loss
  7. Supplements for Fatty Liver
  8. Supplements for Autoimmune Disorders
  9. Supplements for Anemia
  10. Supplements for Prostate Enlargement
  11. Supplements for Macular Degeneration
  12. Supplements for PCOS
  13. Supplements for Parkinson’s Disease
  14. Supplements for Gout
  15. Supplements for Eczema

First published on: 25th December 2018
Image credit: Malidate Van on
Last edited on: 29th August 2022


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