Omega-3 fatty acids are essential nutrients that children cannot produce themselves and must obtain through diet or supplementation. These polyunsaturated fats, particularly DHA and EPA, play vital roles in brain development, visual function, and overall growth during childhood. Whilst UK guidance recommends two portions of fish weekly (one oily), most children fall short of this target. This article examines the evidence for omega-3 in paediatric health, explores dietary sources versus supplements, and provides practical guidance on safe use. Parents seeking to optimise their child's nutrition will find clear, evidence-based information on when omega-3 supplementation may be appropriate and how to implement it safely.

What Is Omega-3 and Why Do Children Need It?

Omega-3 fatty acids are essential polyunsaturated fats that the human body cannot synthesise independently, meaning they must be obtained through diet. The three main types are alpha-linolenic acid (ALA), found primarily in plant sources, and the long-chain fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), predominantly found in marine sources. DHA is particularly important during childhood as it is a major structural component of the brain and retina, with studies suggesting it comprises a significant proportion of polyunsaturated fatty acids in these tissues.

Children require adequate omega-3 intake to support critical developmental processes. During the first few years of life, the brain undergoes rapid growth and maturation, with neural pathways forming at an extraordinary rate. DHA plays a role in neuronal membrane fluidity, synaptic plasticity, and neurotransmitter function. EPA, whilst present in lower concentrations in neural tissue, contributes to anti-inflammatory processes and may influence mood regulation and cognitive function.

The UK does not have specific recommended nutrient intake (RNI) values for omega-3 fatty acids for children. UK Government and NHS Eatwell guidance advises that everyone, including children, should aim to eat two portions of fish per week, one of which should be oily. Child portions are smaller than adult portions and should be appropriate for their age. National Diet and Nutrition Survey (NDNS) data consistently shows that most UK children fall short of this target, with average fish consumption well below recommended levels. While dietary sources remain the preferred approach where feasible, this nutritional gap has prompted increased interest in omega-3 supplementation.

Health Benefits of Omega-3 for Kids

Cognitive development and academic performance represent one of the most extensively studied areas of omega-3 research in children. Systematic reviews have examined the relationship between omega-3 status and cognitive outcomes, with mixed findings. Some studies suggest that DHA intake may support aspects of cognitive function, particularly in children with lower baseline omega-3 levels. However, the evidence remains inconsistent, with generally small effect sizes in typically developing children. There is no established link between omega-3 supplementation and enhanced intelligence or academic achievement in most children.

Visual development is another area where omega-3, specifically DHA, plays a recognised physiological role. The retina contains high concentrations of DHA, which is incorporated into photoreceptor membranes. Adequate DHA status during infancy and early childhood supports normal visual acuity development. Breast milk naturally contains DHA (though levels vary with maternal diet), and infant formulas in the UK are now routinely fortified with this fatty acid following retained EU regulations.

Behavioural and neurodevelopmental conditions have been investigated in relation to omega-3 status. Some research suggests modest improvements in attention, hyperactivity, and impulsivity in certain trials involving children with attention deficit hyperactivity disorder (ADHD). However, NICE guidance (NG87) specifically advises not to offer fatty acid supplements to treat ADHD. The evidence for autism spectrum disorder is limited and insufficient to support recommendations for supplementation.

Immune function and inflammation may also be influenced by omega-3 intake. EPA and DHA serve as precursors to specialised pro-resolving mediators that help regulate inflammatory responses. Whilst this has theoretical implications for conditions such as asthma and allergic disease, clinical evidence in paediatric populations remains limited and further research is needed before any conclusions can be drawn.

Food Sources vs Supplements: Getting Omega-3 for Your Child

Dietary sources should always be the first-line approach to meeting omega-3 requirements in children. Oily fish remains the richest source of EPA and DHA, with options including:

• Salmon (fresh or tinned): rich in omega-3

• Mackerel: excellent source of omega-3

• Sardines: good omega-3 content

• Fresh tuna (not tinned, which contains significantly reduced omega-3 during processing)

Parents should be aware of mercury content in certain fish species. The NHS advises that children should avoid eating shark, swordfish, and marlin due to mercury levels. Girls and women who may become pregnant in the future should have no more than two portions of oily fish per week, while boys and men can have up to four portions weekly. It's important to note that tinned tuna does not count as an oily fish in UK dietary guidance.

Plant-based sources provide ALA, which the body can convert to EPA and DHA, though this conversion is inefficient. Useful plant sources include flaxseeds, chia seeds, walnuts, and rapeseed oil. Vegetarian and vegan children may benefit from algal oil supplements, which provide DHA derived from microalgae.

Omega-3 supplements are available in various formulations including fish oil, cod liver oil, and algal oil. When considering supplementation, parents should:

• Choose products specifically formulated for children with age-appropriate dosing

• Look for products with independent testing for purity and absence of contaminants

• Check EPA and DHA content rather than total fish oil volume

• Consider liquid formulations or chewable capsules for younger children who cannot swallow tablets

Cod liver oil contains omega-3 but also vitamins A and D. The UK Department of Health recommends that all children aged 1-4 years should take a daily supplement containing 10 micrograms of vitamin D. However, parents should ensure total vitamin A (retinol) intake from all sources remains within safe limits according to UK Expert Group on Vitamins and Minerals guidance, as excessive vitamin A can be harmful.

There is no official NHS or NICE recommendation for routine omega-3 supplementation in healthy children who consume adequate dietary sources. Supplementation may be considered for children with restricted diets, those who refuse fish, or in specific clinical contexts under healthcare professional guidance.

Safety and Side Effects of Omega-3 in Children

Omega-3 supplementation is generally well-tolerated in children when used at appropriate doses, though parents should be aware of potential side effects and safety considerations. Common adverse effects are typically mild and gastrointestinal in nature, including:

• Fishy aftertaste or burping (particularly with fish oil supplements)

• Mild nausea or stomach upset

• Loose stools or diarrhoea at higher doses

• Fishy body odour (rare)

These effects can often be minimised by taking supplements with food, choosing high-quality products, or refrigerating liquid formulations. Enteric-coated capsules may reduce gastrointestinal symptoms in some children.

Bleeding risk is a theoretical concern with omega-3 supplementation due to effects on platelet function and blood clotting. However, at appropriate paediatric doses (as directed on product labels), clinically significant bleeding complications are extremely rare. Parents should inform healthcare providers about omega-3 supplementation before any surgical procedures and follow local guidance regarding whether to continue or pause supplements.

Allergic reactions to fish oil supplements can occur in children with fish allergies. Children with known fish allergies should generally avoid fish oil supplements and consider algal oil alternatives after checking with a healthcare professional. Allergic reactions may include rash, itching, or respiratory symptoms.

Contaminant concerns including mercury, polychlorinated biphenyls (PCBs), and dioxins have been raised regarding fish oil supplements. Reputable manufacturers use purification processes to remove these contaminants to levels below regulatory limits. Parents should choose products from established brands that comply with UK and EU standards for contaminants.

When to seek medical advice: Parents should contact their GP if their child experiences persistent gastrointestinal symptoms, signs of allergic reaction, unusual bruising or bleeding, or any other concerning symptoms after starting omega-3 supplementation. Children with bleeding disorders, those taking anticoagulant medications, or with other significant medical conditions should only use omega-3 supplements under medical supervision. Always inform healthcare providers about all supplements your child is taking, as omega-3 may interact with certain medications including anticoagulants and antiplatelet agents.

Suspected adverse reactions to omega-3 supplements should be reported through the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Frequently Asked Questions