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What is Omega-3? | Benefits, Side Effects & Dosage

What is Omega-3? | Benefits, Side Effects & Dosage
Jamie Wright
Qualified Nutritionist11 months ago
View Jamie Wright's profile

Omega-3 has been investigated by scientists extensively for its many potential health benefits along with how it could impact fitness goals. What exactly is omega-3 and does the science live up to the hype? This article will go through what omega-3 is, what the health benefits are, including how it could impact your training, and how much is safe to use.

What are omega-3 fatty acids?

Many of us know that omega-3 is good for us. Not-so-fond childhood memories of a daily spoonful of cod liver are hard to forget. But what exactly is it, and what does it do?

Omega-3 fatty acids are essential polyunsaturated fats that are crucial for supporting overall health and wellbeing. Often referred to as “good fats”, they’re found in foods like fish, nuts, and seeds, and play a vital role in supporting heart, brain and joint health.1,2


What is omega-3?

Omega-3 is a type of polyunsaturated fat, and is classified as an essential fatty acid, meaning that it has to be sourced from our diets as it cannot be produced by our bodies.8

Omega-3 comes in many different forms that vary in both length and chemical structure. There are short-chain omega-3 fatty acids which can come from plant-based sources such as leafy green vegetables, walnuts, and flaxseed. If you see the name ALA or alpha-linolenic acid, this is a plant-based omega-3 fatty acid.8

Long-chain fatty acids are the other common form of omega-3. These omega-3 fatty acids contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are linked to brain and eye health and are important structural components of cells in the body.13 They’re naturally found in algae, which are eaten by fish and other sea life. These fatty acids are often referred to as marine-source omega-3, or fish oils.8

It’s worth noting that the body doesn’t absorb both sources of omega-3 in the same way. Our metabolism can only convert around 5% of plant-based ALA omega-3 into EPA, so this is worth keeping in mind when considering which type to go for, as well as dosage. 8

What is the difference between fish oil and omega-3?

Although fish oil and omega-3 are often used interchangeably, they’re not quite the same thing.

Omega-3s are a type of fatty acid considered essential, meaning the body needs it but cannot produce it on its own.

Fish oil, on the other hand, is a supplement rich in omega-3s extracted from oily fish such as salmon, mackerel, sardines. It contains two of the main types of omega-3s: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which has health benefits including reducing inflammation, supporting brain health and promoting heart health.3,4,5

So, fish oil is a supplement that’s high in omega-3 fatty acids, but omega-3s can also be found in sources other than fish oil.

Flaxseeds, chia seeds, walnuts, algae and certain plant oils like rapeseed and soybean are all good sources of omega-3s.

So, if you're looking to increase your intake of omega-3s but not in the mood for fish oil, there are other options available, including algae-based omega-3 supplements.


What are the three types of omega-3 fatty acids?

There are three main types of omega-3 fatty acids: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

ALA is a plant-based omega-3 fatty acid. It can be found in flaxseeds, chia seeds, and walnuts. It’s considered an essential fatty acid because the body cannot produce it on its own, so we must get it from the food we eat. Once consumed, ALA is converted into EPA and DHA (although this conversion process is not very efficient).6

EPA and DHA are mainly found in fatty fish, including salmon, mackerel, and sardines, and are highly beneficial for health. They have been extensively studied for their anti-inflammatory properties and other potential health benefits. DHA is also vital for brain and eye health, making it particularly important for pregnant women and young children.7


Sources of omega-3

Fatty fish: Salmon, mackerel, sardines and trout are all excellent sources of omega-3. Not only are they packed with these healthy fats, but they also contain important nutrients like vitamin D and selenium as well as being a rich source of high-quality protein.

Flaxseeds: These tiny seeds are a powerhouse of omega-3. Sprinkle them on your cereal or yoghurt or add them to smoothies.

Chia seeds: Like flaxseeds, chia seeds are also rich in omega-3. Try adding them to baked treats, oatmeal, or even making chia seed pudding.

Walnuts: These crunchy nuts not only make a delicious snack but are also a great source of omega-3. You can enjoy them on their own or add them to salads, oatmeal, or even baked goods for added nutrition.

Hemp seeds: These nutty-tasting seeds are becoming an increasingly popular source of omega-3. They can be sprinkled on salads, added to smoothies, or used as a topping for roasted vegetables.

Omega-3 health benefits

Omega 3, especially fish oil, has been associated with many different health benefits, but does the science support the claims? Let’s take a look at the different health benefits of omega-3:

Fish oil and insulin sensitivity

Being sensitive to insulin is one of the markers of good health and is often the result of a healthy lifestyle, good nutrition, and being active. A study by Gao investigated all the research on fish oil supplementation and the positive effects on insulin sensitivity. As a whole, the study showed that fish oil didn’t improve insulin sensitivity, however, on further investigation, it did appear that it might be of some benefit to those who already exhibited at least one symptom of a metabolic disorder. 5


Fish oil and hypertension

Fish oils have been thought of by many health practitioners to help reduce blood pressure and therefore lower cardiovascular risk.  A study has investigated these claims, alongside scientific evidence, and found that fish oils showed a very modest, real-life effect. The study determined that there was an effect of fish oils on blood pressure, and ruled out the possibility of pure chance. 3

There can be no argument that any reduction in high blood pressure is a good thing, but not at the expense of blood pressure medication. If you’re using blood pressure medication to treat high blood pressure, then it’s recommended to consult a medical professional before considering using or switching to fish oils to help further reduce your risk.


Supports your immune system

Omega-3 can provide the immune system with the nutrients it needs to fight off infection and disease.

One way it does this is by reducing inflammation.8 While inflammation is a natural response that occurs when the body is trying to heal itself, chronic inflammation can weaken the immune system over time.

Omega-3's anti-inflammatory properties help regulate the inflammatory response, ensuring the immune system can focus on fighting harmful germs instead of being overwhelmed by excessive inflammation.

Additionally, omega-3s enhance the function of immune cells.8 They help improve the activity of white blood cells, which are responsible for identifying and destroying foreign invaders in our body.

Omega-3s have also been found to improve the production and activity of certain molecules involved in immune function, such as cytokines and antibodies.8 These molecules play a crucial role in coordinating the immune response and fighting off infections. By optimising the performance of these immune cells, omega-3s help strengthen the immune system's response to infection and disease.

omega 3

Promotes a healthy heart

Omega-3 fatty acids are good for a healthy heart. They have been shown to improve overall cardiovascular health.4

One of the main ways omega-3s benefit the heart is by reducing inflammation. Chronic inflammation is a major contributor to poor heart health, and omega-3s help to counteract it.

Omega-3s have also been found to lower blood pressure and triglyceride levels, both of which are risk factors for heart disease.

By incorporating omega-3-rich foods into your diet or taking supplements, you can help keep your heart healthy and strong.


Improves bone and joint health

Omega-3 fatty acids have been shown to have a big effect on the strength and flexibility of bones and joints. By reducing inflammation in the body, a major factor in conditions like arthritis and osteoporosis, omega-3-rich food or supplements may be able to help address the symptoms of these conditions.2,9

Omega-3s may also improve bone and joint health by increasing calcium absorption.10 Calcium is vital for strong bones, but it must be properly absorbed by the body to be effective. Calcium absorption tends to decrease with age, so omega-3 is especially important for older people.

Studies have also shown that omega-3s promote formation and enhance bone density, which is also important for strong, healthy bones and joints.9


A better night’s sleep

Omega-3s have been shown to help regulate the production of some hormones involved in sleep regulation.11 For example, they can regulate the production of melatonin, a hormone that helps regulate the sleep-wake cycle. By doing this, omega-3s can help improve sleep quality.

Omega-3 fatty acids also help produce serotonin, a neurotransmitter that helps regulate mood and sleep.12 By increasing the levels of serotonin in your brain, omega-3 can help promote a more balanced sleep-wake cycle, making it easier for you to fall asleep and stay asleep throughout the night.

Finally, as already mentioned, omega-3s have anti-inflammatory properties that may help reduce the symptoms of certain sleep disorders, such as sleep apnoea and restless leg syndrome.

These conditions can cause disrupted sleep, leading to fatigue and reduced productivity. By incorporating more omega 3-rich foods into your diet or taking a high-quality omega-3 supplement, you may be able to relieve some of these symptoms and enjoy a more restful night's sleep.


Promotes healthy skin

While there are countless skincare products on the market promising miraculous results, sometimes the key to improving your skin health lies within your diet. Enter omega-3 fatty acids, which have been shown to have a multitude of benefits, including for our skin.

Omega-3 plays a crucial role in maintaining the integrity of cell membranes, which in turn helps to keep our skin hydrated and protected from external aggressors. By nourishing our skin cells from within, omega-3 can effectively reduce inflammation, minimise redness, and even reduce symptoms of conditions like eczema and psoriasis.13

Omega-3 has also been found to boost collagen production, the protein responsible for maintaining the elasticity and firmness of our skin.13 As we get older, collagen production naturally declines, leading to fine lines, wrinkles, and sagging skin. By incorporating omega 3-rich foods into your diet or taking supplements, you can help stimulate collagen synthesis and improve the overall appearance of your skin.

In addition to their anti-inflammatory and collagen-boosting properties, omega-3 also has antioxidant effects. This means they can help protect your skin from free radicals, which are unstable molecules that can damage cells and accelerate the ageing process. By neutralising these harmful molecules, omega-3 contributes to a healthier complexion and a more youthful appearance.

Reaching fitness goals with Omega-3?

Omega-3 and fat loss

It may seem counterintuitive that consuming fat can actually aid in losing fat, but omega-3s are different. Uniquely, omega 3s have been shown to increase metabolism, boost the body's ability to burn calories, and even reduce appetite.14,15

One of the reasons omega-3s are effective for fat loss is because they help regulate the hormone leptin.14 Leptin is responsible for controlling hunger and signalling to the brain when you're full. When your body lacks omega-3 fatty acids, leptin levels can become disrupted, leading to increased hunger and overeating. By incorporating omega-3-rich foods or supplements into your diet, you can ensure that leptin levels are properly regulated, reducing the risk of overeating and promoting fat loss.

In addition to regulating appetite, omega-3s also play a role in reducing inflammation in the body. Chronic inflammation has been linked to obesity and other metabolic disorders.16 By consuming omega-3 fatty acids, you can help reduce inflammation and promote a healthier metabolism, which in turn can aid in fat loss.

Furthermore, omega-3s have been shown to improve insulin sensitivity.1 Insulin is a hormone that helps regulate blood sugar levels and plays a crucial role in metabolism. When your body becomes resistant to insulin, it can lead to weight gain and difficulty losing fat. Omega-3s can help improve insulin sensitivity, allowing your body to effectively utilise glucose for energy and preventing excess sugar from being stored as fat.


Omega-3 and muscle gain

When it comes to building muscle, most people immediately think of protein as the key nutrient. And while protein is critically important for muscle growth, there are many other nutrients that are often overlooked, including omega-3 fatty acids.17

One way omega-3s help with muscle gain is by reducing inflammation after intense workouts. Excessive inflammation can hinder muscle recovery and growth.

Omega-3's anti-inflammatory properties can help reduce this inflammation, allowing for faster recovery and better muscle growth. Additionally, omega-3s can improve blood flow to the muscles, delivering more oxygen and essential nutrients for muscle repair and growth.

Omega-3 can also support muscle growth by increasing protein synthesis. Protein synthesis is the process by which our bodies build new proteins. Omega-3 has been shown to enhance protein synthesis, meaning that they can help our bodies build more muscle tissue. This is especially important for people who are engaging in strength training or resistance exercises to build muscle mass.


Omega-3 supplements

Supplements should always be just that, a supplement, to your diet. So supplementation all depends on what kind of diet you have. If you choose to eat a plant-based diet, then you’ll probably need to supplement with omega-3 from high-quality plant-based sources as traditional fish or krill oils are not suitable. By using a supplement, you can easily ensure that you’re consuming the correct quantity of high-quality omega-3.

Even if you don’t follow a vegetarian or vegan diet, you still may have asked yourself whether it’s best to consume oily fish in meals or opt for supplements like omega-3. Whilst supplements will make it much easier to consume larger quantities of omega-3 you can choose either supplements or eating more oily fish and will reap the benefits with both.

If you’re eating a calorie deficit, then you can miss out on valuable nutrition as you cut down on what you eat — this might also be a good time to consider an omega-3 supplement. A supplement can be a convenient way of getting enough omega-3 in your diet, without negatively affecting your daily calories.


Omega-3 dosage

While there’s no one-size-fits-all answer or recognised daily dosage for omega 3s, it is generally recommended a daily dose of at least 250-500 milligrams of combined EPA and DHA, the two primary types of omega-3s found in fish oil.14 However, for people with specific health concerns, higher doses may be necessary.

It's important to note that if you’re getting your omega-3s from food sources, the current government recommendations are to aim for two portions of a fatty fish (like salmon, mackerel, or sardines) twice per week.

However, if you're not a fan of fish or have dietary restrictions that limit your intake, omega-3 supplements can be a convenient alternative. When choosing a supplement, look for one that provides a minimum of 500 milligrams of combined EPA and DHA per serving.

It's also worth mentioning that the quality of the omega-3 supplement you choose is important. Look for products that have been carefully tested for purity and potency to ensure you're getting a reliable and effective product. It’s also incredibly important to read the label too so you know exactly what you’re getting (in terms of dose per capsule and serving size).


Is it good to take omega-3 every day?

The answer is a resounding yes!

In fact, many health experts recommend taking omega-3 supplements on a daily basis to ensure you're getting enough of these essential fats. Omega-3s are not produced by the body, so it's important to obtain them through your diet or supplementation. Whether you choose to incorporate them into your meals or take them in capsule form, consistency is key when it comes to reaping the benefits of omega-3s.

Now, can you have too much of a good thing? It's certainly possible.

While omega-3s are generally safe, excessive intake can lead to some side effects. Taking extremely high doses of omega-3 supplements can increase the risk of bleeding, especially in people on blood-thinning medications. It can also cause gastrointestinal issues like diarrhoea and an upset stomach. However, these side effects are rare and usually only occur when consuming extremely high amounts of omega-3.


Recipe ideas to add more Omega-3 to your diet


Delicious Creamy Tomato Salmon Pasta

Just try and stop us from making this one.

2 years agoBy Emily Wilcock




Vegan Chickpea Blondies

The perfect simple sweet treat for your weekend.

1 year agoBy Lauren Dawes



10-Minute Chickpea Salad Meal Prep

Tasty meal prep doesn't have to take all night to prepare.

2 years agoBy Lauren Dawes



Sweet Chilli Glazed Salmon

Light on calories, heavy on flavour.

12 months agoBy Lauren Dawes


Potential side effects of taking omega-3

Omega-3 is a low-risk supplement to use. As long as you don’t use fish oils to substitute medication, then there’s no problems associated with them when consuming the recommended daily dosage.12


Take home message

Omega-3 is an essential part of a healthy, balanced diet. It’s important to consume adequate amounts of these essential fatty acids on a daily basis for good health and wellbeing.

Omega-3 can be found in both marine- and plant-based sources, though there’s a difference in strength between the two. A marine-based source is much more absorbable within the body and seems to have a considerably more potent effect when taken in smaller doses.

Omega-3 has been linked to a variety of health- and fitness-related benefits, including weight loss and muscle gain. Though some of these benefits may actually only be marginal, they could still be beneficial.

There are very few side effects associated with taking omega-3’s and they should be an important part of a daily supplement routine to provide the best health and wellbeing.

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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

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Jamie Wright
Qualified Nutritionist
View Jamie Wright's profile
Jamie Wright has a bachelor's of science in Sports and exercise science and a Master's degree in Human Nutrition (specialising in obesity and weight management). Jamie specialises in nutrition centred around body composition change, sports nutrition and helping people improve their relationship with food. His company Balance are one of Ireland's leading nutritionist and dietetics services and he has worked with hundreds if not thousands of clients to help them solve all manner of nutrition related problems and achieve a vast range of diet related goals. They have recently launched the life changing course Be Binge Free, the first of its kind, and are continuing ongoing works on a range of projects. Jamie has worked with a range of industry leaders and featured as a nutritionist expert for Myprotein for over five years and with other brands like Insider, Adidas, Women's Health and more. Jamie's experience ranges from working in research trials to advising on product formulations, working with clients one to one, in group settings and presenting to public and private companies. He continues his professional development to this day and is currently undergoing his personal training qualifications. Having recently become a Dad, his spare time is filled spending time with his family, training, running, socialising and spending time cooking.