Omega-3s: What You Need to Know
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Omega-3s: What You Need to Know

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If you’re on a Keto or low-carb diet, you’ll be used to the idea that your body can burn fat for fuel. You’ve also probably heard that omega-3 fats are particularly important for your health. Today, we’re going to dig into how and why that is, as well as how to ensure you’re getting enough omega-3s for optimum health. Let’s dive in.

Fat: More Than Just Fuel

We often get caught up in thinking of our food as just a source of calories or energy. Even once we’re used to the idea that different macronutrients (fat, carbohydrate and protein) can fuel our bodies in different ways, we often still forget that we use our food to build our bodies as well as to run them.

Fats, or fatty acids, aren’t only a source of fuel. Your body also uses the fatty acids to – among other things – build cell membranes, produce hormones, absorb fat-soluble vitamins, cushion your organs and regulate inflammation. 

The type and quality of the fats you eat determines how effectively your body is able to perform these functions – for example, omega-6 fatty acids help your body create inflammation, and omega-3s help reduce it. You need enough of both, in balance, to keep your immune system running at its best.

Here’s something else to ponder before we get into the nitty-gritty: your brain itself is 60% fat. Would you rather be doing your thinking with extra virgin olive oil, fresh salmon and chia seeds -or the crumb-coated oil at the bottom of the deep fryer?

Good Things Come in Threes

The group of fatty acids called “omega-3s” are fundamental to your health. They’re used in cell membranes throughout your body, but they’re found in the highest concentrations in tissues in your eyes, brain and heart.[*

These omega-3 fatty acids are what’s known as an “essential” fatty acid, which means that you need them to survive, but your body can’t make them on its own – you have to get them from your diet.

Omega-3 fatty acids have been found to:

  • Reduce the risk of heart disease[*]
  • Improve high blood pressure[*]
  • Be as effective as an antidepressant in treating depression[*]
  • Protect against dementia and Alzheimer’s disease[*][*]
  • Lead to higher IQs in 4-year-olds when taken by their mothers during pregnancy[*], as well as possibly reducing the risk of autism spectrum disorder, ADHD and cerebral palsy[*]
  • Improve ADHD symptoms in children[*][*]
  • Prevent and reduce inflammation in people with metabolic syndrome[*][*]
  • Help to treat autoimmune disease[*][*][*]
  • Reduce the risk of colorectal cancer[*] and breast cancer[*]
  • Lower the incidence of asthma in young adults[*]

However, most of the world’s population is deficient in omega-3 fatty acids[*] – one study even found that low dietary omega-3 fatty acids were the sixth biggest cause of preventable deaths per year in the US.[*]

Let’s talk about six

Before we dive into how to get enough omega-3s, we need to briefly talk about omega-6 fatty acids.

Omega-6 fatty acids work in balance with omega-3s in your body. The ideal ratio of omega-6 to omega-3 is between 1 and 3 to 1. Unfortunately for us, omega-6 fatty acids are much more common in modern diets, so our ratios are often up to as much as 20:1. Simopoulos AP.**

Omega-6 fatty acids are found in:

  • Vegetable oils
  • Deep fried foods
  • Processed foods
  • Nuts and seeds
  • Soybeans and corn

Consuming too many omega-6 fatty acids and not enough omega-3s may lead to inflammation and an increased risk of certain cancers, cardiovascular disease, autoimmune and inflammatory disorders[*], fertility issues[*], anxiety and depression.[*]

Getting Enough Omega-3 Fatty Acids

The most important types of omega-3 fatty acids are:

ALA is found in plants, and EPA and DHA are most abundant in seafood. Your body can make EPA and DHA from ALA if it has to – but the conversion rate is below 5%[*], and it has to use the same enzymes that your body uses to process omega-6 fatty acids. If you’re consuming plant sources of omega-3s and also getting too many omega-6s, the odds are that you’re likely deficient in EPA and DHA.

Signs that you might be deficient in omega-3s can include:

  • Skin complaints, including dry, itchy or flaky skin[*], acne[*], or little bumps on the backs of your arms
  • Depression or mood swings[*]
  • Dry eyes[*]
  • Joint pain[*]
  • Fatigue***

The adequate intake (AI) for ALA is 1.6g per day for men and 1g per day for women.[*] At least 250mg per day of combined DHA and EPA is generally recommended – higher if you’re pregnant or have a health condition.[*]

The Best Food Sources of Omega-3 Fatty Acids

1. SMASH fish – salmon, mackerel, anchovies, sardines and herrings

SMASH fish are small, oily fish that are high in DHA and EPA – salmon (2.2g of omega-3s in a 3-ounce serving), mackerel (1.9g), anchovies (1.7g), sardines (2.2g) and herring (2.1g).

Because omega-3s are easily damaged by heat or processing, it’s best to buy fresh or frozen fish when you can. If you choose to buy canned, choose fish in olive oil or spring water instead of soy or canola oil, which are very high in omega-6s.

2. Caviar, fish eggs and krill oil

Fish eggs (roe) and krill oil contain a superpowered form of DHA called lyso-DHA, which is more bioavailable and gets privileged transport to your brain.[*]

A tablespoon of caviar contains 1g of omega-3s and more than 35% of those are lyso-DHA. Next time you’re at a fancy party, remember that tucking into the hor d'oeuvres might actually be making you smarter.

3. Cod liver oil

One tablespoon of cod liver oil has 2.6g of omega-3s, mainly in the form of DHA and EPA.  

Cod liver oil comes from – surprise! – the livers of codfish. You can choose to eat the livers, but most people take cod liver oil as a supplement, in either liquid or capsule form. Many people choose to take cod liver oil over fish oil because cod liver oil is also very high in vitamins A and D.

4. Mollusks

Mollusks might have a funny name, but they’re not playing around when it comes to nutrition. 6oz of mussels contain 1.3g of omega-3s, and 6oz of oysters contain 1.2mg. They’re also loaded with iron, zinc, B vitamins and copper.

5. Algae oil

Algae oil is an excellent option for vegetarians and vegans. Algae oil contains EPA and DHA in roughly the same amount and bioavailability as in fish[*][*] – probably because fish get most of their EPA and DHA from eating algae.

You can buy algae oil as a supplement, or find it in many omega-3 fortified foods. It’s also a good choice if you get indigestion or a fishy aftertaste from taking fish oil.[*]

6. Eggs 

An omega-3 enriched egg can contain up to 250mg of omega-3s[*]. The omega-3 content of an egg increases based on the hen’s diet – so buy free-range, pasture-raised eggs when you can.

7. Flaxseeds

When it comes to plant-based sources of omega-3s, flaxseeds are the clear winner. Not only do they top the list at 2.3g of omega-3s per tablespoon (or 7.3g per tablespoon of flaxseed oil) – they also have almost four times as many omega-3s as they do omega-6s. 

Worth noting that other nuts and seeds may be good sources of omega-3 fatty acids – but are even better sources of omega-6. For example, walnuts have a decent amount of omega-3 fatty acids, but an omega-6 to omega-3 ratio of 4.5:1. Hazelnuts have a ratio of 90:1, and peanuts come in at a whopping 1720:1!

8. Chia seeds

Our second choice plant source of omega-3s is chia seeds. Chia seeds are a good source of antioxidants, minerals, B-vitamins and fiber. They contain about 18g of ALA per 100g and have three times as many omega-3 fatty acids as omega-6.

Tip: Consuming some turmeric and black pepper with plant sources of omega-3s may help to convert ALA into DHA and EPA.[*]

9. Hemp seeds

Hemp seeds contain 25% protein, include all nine essential amino acids, and are a good source of fiber, minerals and vitamins. Hemp seeds contain 22g of ALA per 100 grams – and an omega-6 to omega-3 ratio of about 2.5:1.[*]

10. Grass-finished beef 

All meat contains some omega-3s, but the amounts increase vastly when the animals are fed grass instead of grain. One study found an omega-6 to omega-3 ratio of 1.5:1 for grass-fed and grass-finished beef, vs almost 8:1 for cattle finished on grain.[*]

When To Supplement

It’s worth considering an omega-3 supplement if you’re a vegetarian or vegan, you don’t eat fish, or you eat a lot of processed or fried foods. Your doctor may also recommend a supplement if you have a health condition or are pregnant or breastfeeding.

Because omega-3s are easily damaged by heat or exposure to oxygen, it’s important to purchase a high-quality supplement. Check out Thrive Market’s range of fish oil and cod liver oil supplements for adults and children. For vegans and vegetarians, try flax oil or algae oil.

Note: if you have high triglycerides or a bleeding condition (or take medication that makes you more prone to bleeding), check with your doctor before taking an omega-3 supplement. It’s also best to consult with your physician regarding appropriate dosing for omega-3 supplementation.

Can You Take an Omega-3 Supplement While Fasting?

The short answer is: it’s up to you.

Some intermittent fasting protocols allow you to have some fat while you’re fasting - as long as you don’t also consume protein or carbohydrates. This is because, although fat contains calories, ingesting a small quantity on its own shouldn't affect your insulin levels or turn off autophagy. Omega-3 supplements are pure fat, so if you’re following this kind of protocol, you may choose to take an omega-3 supplement in your fasting window.

However, if you’re a fasting purist – or if taking supplements on an empty stomach makes you feel queasy – you may want to wait until your eating window. Waiting until you eat also ensures your body will be making lots of digestive enzymes to ensure the omega-3s in the supplement can be fully broken down and absorbed.

The Final Word

Omega-3 fatty acids are critical to good health, and you need to get them from food. Plant sources of omega-3s are harder for your body to use and will compete for the same conversion enzymes as omega-6 fatty acids in our body.

Your body does also need some omega-6 fatty acids, but most people need far fewer than they’re already getting. 

To ensure you’re getting enough omega-3s each day:

  1. Eat small, oily fish twice a week, or add flax or chia seeds to smoothies, baking, yogurt, or salads. Purchase the best quality fish, eggs and meat you can afford for an omega-3 boost.
  2. Reduce your omega-6 consumption by eating fewer processed or fried foods and cooking with olive or coconut oil instead of vegetable oil 
  3. Consider an omega-3 supplement.

Disclaimer: This article contains affiliate links. Carb Manager may earn a commission for qualifying purchases made through these links.

** Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med (Maywood). 2008 Jun;233(6):674-88. doi: 10.3181/0711-MR-311. Epub 2008 Apr 11. PMID: 18408140.

*** (Maes M, Mihaylova I, Leunis JC. In chronic fatigue syndrome, the decreased levels of omega-3 poly-unsaturated fatty acids are related to lowered serum zinc and defects in T cell activation. Neuro Endocrinol Lett. 2005 Dec;26(6):745-51. PMID: 16380690.)

Comments 10

  • UpbeatCauliflower246078

    UpbeatCauliflower246078 a month ago

    Thank you!

    • OutstandingKetone353160

      OutstandingKetone353160 a year ago

      Was just advised by my Dr. That I should be taking Omega 3s now I understand why.

      • AmazingMacadamia817001

        AmazingMacadamia817001 a year ago

        Great information!

        • ExcellentKale625184

          ExcellentKale625184 a year ago

          I was looking for information about Omega 3 and Omega 6s and this gave me more than I expected Thank You!

          • FortuitousAvocado700986

            FortuitousAvocado700986 a year ago

            Very good information.

            • Sandraqx10

              Sandraqx10 a year ago

              Great information thank everyone

              • GodsGirl

                GodsGirl 2 years ago

                Good article

                • JohnnyR2

                  JohnnyR2 2 years ago

                  Good information.

                  • PropitiousArugula135147

                    PropitiousArugula135147 2 years ago


                    • YaseminDeniz

                      YaseminDeniz 2 years ago

                      This is so insightful, Thank you!