Omega-3 essential fatty acids: What they do and why most Australians need more

Discover why omega-3s are essential, how EPA & DHA support heart, brain, joint & eye health, and how most Australians can close the intake gap with diet or supplements.

Three out of four people globally are not meeting recommended intakes of the omega-3 fatty acids EPA and DHA, according to a 2025 review published in Nutrition Research Reviews. In Australia, the picture is similar: analysis of the 2011–12 National Nutrition and Physical Activity Survey found that fewer than one in four adults met the NHMRC’s Suggested Dietary Target for long chain omega-3s, and median intakes sat well below the mean, indicating that most Australians consume far less than the average figure suggests.

Omega-3 fatty acids are classified as essential because the body cannot produce them in adequate amounts. They must come from food or supplementation. This article explains what omega-3s do in the body, how they contribute to the function of multiple organ systems, and what the current evidence says about dietary intake and supplementation in Australia.

What makes omega-3 an essential nutrient

The term “essential” in nutrition has a specific meaning: the body requires a nutrient for normal function but cannot synthesise enough of it internally. Omega-3 fatty acids fall into this category. The three main forms are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

ALA is found in plant sources like flaxseed, chia seeds, and walnuts. EPA and DHA, the long chain forms, are found primarily in oily fish, seafood, and marine algae. The body can convert ALA into EPA and DHA, but the process is limited. A review published in the International Journal for Vitamin and Nutrition Research found that conversion of ALA to EPA is approximately 6%, while conversion to DHA is around 3.8%. A later analysis from the same research group confirmed these low rates, particularly in men. This means that relying on plant sources of omega-3 alone may not provide sufficient EPA and DHA for most people.

EPA and DHA are structural components of cell membranes throughout the body. They contribute to membrane fluidity, which affects how efficiently cells communicate and respond to signals. This structural role is why omega-3s are relevant to so many different organ systems rather than being limited to one area of health.

How omega-3 supports multiple systems in the body

Heart and cardiovascular health

EPA and DHA contribute to cardiovascular system health through several pathways. They are incorporated into cell membranes of cardiac tissue, where they influence cellular signalling and help maintain the structure of blood vessels. A 2025 review in Current Atherosclerosis Report noted that updated cohort data and recent meta-analyses consistently link higher intake or circulating levels of EPA and DHA with cardiovascular health outcomes. The omega-3 fatty acids also play a role in maintaining healthy blood lipid levels. The NHMRC Suggested Dietary Targets for long chain omega-3s (610 mg/day for men, 430 mg/day for women) were established with cardiovascular health as a key consideration.

Brain and cognitive function

DHA is the most abundant omega-3 in the brain, comprising approximately 40% of total polyunsaturated fatty acids in brain tissue. It concentrates in the cerebral cortex and plays a structural role in neuronal cell membranes, where it influences membrane fluidity, neurotransmitter function, and signal transmission.

A 2025 systematic review and dose-response meta-analysis published in Scientific Reports examined 58 randomised controlled trials and found that omega-3 supplementation was associated with improvements across multiple cognitive domains, including attention, perceptual speed, and primary memory. The review found effects were present in cognitively healthy individuals and were evident in studies with intervention periods under 48 weeks. EPA contributes through a different pathway, helping to regulate inflammatory processes in the brain and supporting neurotransmitter balance.

Joints and mild inflammation

Omega-3 fatty acids, particularly EPA, are involved in the body’s inflammatory response pathways. EPA competes with omega-6 fatty acids for incorporation into cell membranes, and when present in sufficient quantities, it shifts the balance toward the production of less inflammatory compounds. This mechanism underpins the role of omega-3s in maintaining joint comfort and mobility.

For people with mild joint stiffness or mild arthritis symptoms, the research supports a role for omega-3 supplementation as part of a broader approach to joint health. Higher doses are typically studied in this context, with most trials using 2,000 mg or more of combined EPA and DHA daily.

Eye health

DHA is highly concentrated in the retina, where it contributes to the structure and function of photoreceptor cells. Adequate DHA intake throughout life may support healthy eye function and visual health. A 2024 literature review in the Asian Journal of Food Research and Nutrition noted that omega-3 fatty acids play a role in maintaining eye health, with DHA being particularly relevant to retinal cell membrane integrity.

Skin health

Omega-3 fatty acids contribute to the lipid content of the skin’s outer layer, helping to maintain its barrier function. EPA’s role in modulating inflammatory pathways may also play a part in maintaining healthy skin when dietary intake is adequate. Skin is one of the body’s largest organs and responds to nutritional status over time, making consistent omega-3 intake relevant to ongoing skin health.

Key benefits of omega-3 for everyday health

The broad relevance of omega-3s comes from their structural role in cell membranes. Because EPA and DHA are incorporated into cells across the cardiovascular, nervous, musculoskeletal, and visual systems, their influence is not confined to one health area. For an everyday nutrient, this is significant. A single dietary component that contributes to the maintenance of heart health, brain function, joint comfort, eye health, and skin integrity represents a practical target for anyone looking to support their general wellbeing.

The evidence also reinforces that omega-3s work gradually and cumulatively. They are not a quick-acting supplement; rather, they integrate into cell membranes over weeks and months of consistent intake. This aligns with a preventative health approach: small, daily actions that compound over time.

Why many Australians don’t get enough omega-3 from diet alone

The NHMRC’s Nutrient Reference Values set a Suggested Dietary Target of 610 mg/day of long chain omega-3s for men and 430 mg/day for women. The Heart Foundation recommends 250–500 mg of combined EPA and DHA daily for general cardiovascular health. Meeting these targets requires regular consumption of oily fish.

The challenge is that most Australians do not eat enough fish. Meyer’s 2016 analysis of the national survey data found that median daily omega-3 intakes were less than half of the mean, revealing a pattern where a small group consumes high amounts (often through supplementation) while the majority consumes far less. Only about 20% of the adult population met the NHMRC’s Suggested Dietary Target, and among those not taking supplements, the figure dropped to around 10%.

Several factors contribute to this gap. Fish is not a daily staple for many Australian households. Cost, taste preferences, convenience, and concerns about sustainability all play a role. The average adult consumes roughly 24–28 grams of fish per day, which is well below the two to three serves of oily fish per week that most dietary guidelines recommend. Plant sources of omega-3 (ALA) do not compensate effectively, given the low conversion rates to EPA and DHA discussed earlier.

This intake gap is nutritional rather than clinical. It does not mean most Australians are clinically deficient, but it does indicate that a large proportion of the population has omega-3 intakes below the levels associated with long term health maintenance.

Food sources of omega-3

Oily fish remains the richest dietary source of EPA and DHA. Salmon, sardines, mackerel, and anchovies are among the highest in omega-3 content per serve. A 150g serve of Atlantic salmon provides roughly 1,500–2,500 mg of combined EPA and DHA, depending on whether it is farmed or wild caught. Sardines and mackerel offer 1,000–1,500 mg per serve.

Other marine sources include oysters, mussels, and prawns, though these contain lower amounts per serve. Canned tuna is widely consumed in Australia but provides less EPA and DHA than oily fish varieties, with approximately 200–400 mg per serve depending on the type.

For plant based sources, flaxseed (linseed) is the richest in ALA, followed by chia seeds, hemp seeds, and walnuts. As noted, the body’s limited capacity to convert ALA into EPA and DHA means these sources are complementary to, rather than a replacement for, marine omega-3 intake.

Omega-3 enriched eggs, milk, and bread products are available in Australia and contribute modest amounts to dietary intake. These can be useful additions but are unlikely to close the gap on their own for people who eat little or no fish.

Incorporating omega-3 into a daily wellness routine

For people who eat oily fish two to three times a week, dietary intake alone may be sufficient to meet recommended targets. For everyone else, and that includes the majority of Australians based on the survey data, supplementation offers a practical way to close the gap.

When choosing a fish oil supplement, the EPA and DHA content per capsule matters more than the total fish oil amount listed on the front of the label. A product labelled “1,000 mg fish oil” may contain only 300 mg of combined omega-3s, while a concentrated formula delivers significantly more per capsule. Concentration affects both the daily dose required and the overall convenience of the routine.

Purity and freshness are also worth considering. Quality fish oil should be tested for heavy metals (mercury, lead), PCBs, and oxidation levels. Reputable manufacturers use third party testing and publish their results. Fish oil in triglyceride form is the natural form found in fish and is generally well absorbed when taken with a meal that contains some dietary fat.

Blackmores Omega Triple Super Strength Fish Oil contains 1,500 mg of concentrated fish omega-3 triglycerides per capsule, providing 540 mg EPA and 360 mg DHA (900 mg total omega-3s). It is extracted from 100% wild caught small fish (anchovies and sardines) and undergoes molecular distillation for purity. For those who prefer a standard strength option, Blackmores Fish Oil 1000 provides 180 mg EPA and 120 mg DHA per capsule and may suit people who are also getting some omega-3 from their diet.

Consistency matters more than timing. Whether you take fish oil in the morning or evening makes little difference to absorption, but taking it with food and making it part of a daily habit helps maintain steady omega-3 levels over time. The benefits of omega-3 supplementation are cumulative, reflecting the gradual incorporation of these fatty acids into cell membranes throughout the body.

When to talk to a health professional

Fish oil is generally well tolerated, but some situations call for professional guidance. If you are taking blood thinning medications, preparing for surgery, pregnant or breastfeeding, or managing multiple health conditions, speak with your doctor or pharmacist before starting or changing your omega-3 supplementation.

A healthcare professional can also help you assess whether your current diet is meeting your omega-3 needs and advise on the appropriate dose for your individual circumstances.

Frequently asked questions

Why is omega-3 called an essential fatty acid?

Omega-3 is classified as essential because the human body cannot produce sufficient amounts on its own. EPA and DHA must be obtained through diet (primarily oily fish and seafood) or supplementation. The body can convert the plant based form, ALA, into EPA and DHA, but at very low rates (approximately 6% and 3.8% respectively).

What does omega-3 do for the body?

EPA and DHA are structural components of cell membranes in the heart, brain, joints, eyes, and skin. They contribute to membrane fluidity and cellular signalling, and EPA plays a role in the body’s inflammatory response pathways. Their involvement across multiple organ systems is why omega-3s are considered relevant to whole body health rather than a single function.

Should you take omega-3 every day?

Yes. Omega-3 fatty acids work through gradual incorporation into cell membranes, so consistent daily intake is more effective than occasional use. Most Australians do not get enough omega-3 from diet alone, making daily supplementation a practical option for many people.

How much omega-3 do Australians need?

The NHMRC’s Suggested Dietary Targets are 610 mg/day for men and 430 mg/day for women of combined long chain omega-3s (EPA, DPA, and DHA). The Heart Foundation recommends 250–500 mg of EPA and DHA daily for general cardiovascular health. Most guidelines recommend two to three serves of oily fish per week as the primary dietary strategy.

Can I get enough omega-3 from plant foods?

Plant foods like flaxseed, chia seeds, and walnuts provide ALA, but the body converts only a small fraction of ALA into the long chain forms EPA and DHA. For most people, marine sources (fish, seafood) or fish oil supplementation are needed to meet recommended intakes of EPA and DHA.

Key takeaways

Omega-3 fatty acids are essential nutrients that the body cannot produce in adequate amounts. EPA and DHA, the long chain forms found in fish oil, are structural components of cell membranes across the cardiovascular, neurological, musculoskeletal, and visual systems. Their relevance to whole body health is well supported by decades of research, including recent large scale meta-analyses.

Most Australians are not meeting recommended omega-3 intakes through diet alone. Fewer than one in four adults reach the NHMRC’s Suggested Dietary Target, and the majority of the population consumes well below the levels associated with long term health maintenance. Eating oily fish two to three times per week is the most direct dietary strategy; for those who fall short, a quality fish oil supplement can help close the gap.

The benefits are gradual and cumulative. Omega-3s are not a quick fix but a foundational nutrient that supports health over time when consumed consistently. Quality, concentration, and purity matter when choosing a supplement, and healthcare professional advice is recommended for anyone with specific health conditions or taking medications.

Always read the label and follow the directions for use.

Disclaimer: This article provides general information only and is not intended to diagnose, treat, cure, or prevent any disease. The information presented is not a substitute for professional medical advice. If you have concerns about your health, please consult your GP or healthcare provider for a personalised assessment and recommendations. Supplements should not replace a balanced diet.