Fish oil supplements are increasingly popular amongst UK parents seeking to support their children's health and development. Derived from oily fish such as salmon and mackerel, fish oil is rich in omega-3 fatty acids—particularly EPA and DHA—which play important roles in brain development, visual function, and overall growth. Whilst the NHS recommends children eat oily fish regularly, many fall short of these targets, prompting consideration of supplementation. However, evidence for benefits beyond addressing dietary deficiency remains mixed, and not all products are suitable for children. Understanding appropriate use, dosing, and safety considerations is essential for parents considering fish oil for their child.

What Is Fish Oil and Why Is It Given to Children?

Fish oil is a dietary supplement derived from the tissues of oily fish such as mackerel, salmon, sardines, and anchovies. It is rich in omega-3 polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While alpha-linolenic acid (ALA) is the essential omega-3 fatty acid that must be obtained through diet, EPA and DHA are conditionally essential as the body can only convert ALA to these long-chain fatty acids in limited amounts.

Omega-3 fatty acids play crucial roles in children's growth and development. DHA is an important structural component of the brain and retina, contributing significantly to their fatty acid composition. During childhood, the brain undergoes rapid development, and adequate omega-3 intake supports neurological maturation, cognitive function, and visual development.

Many parents consider fish oil supplementation because children in the UK often do not consume sufficient oily fish to meet recommended intakes. The NHS advises that children should eat at least two portions of fish per week, including one portion of oily fish. However, there are specific limits: girls should have no more than two portions of oily fish weekly, while boys can have up to four portions. Children should avoid shark, swordfish and marlin due to potential mercury contamination. National Diet and Nutrition Survey data consistently shows that most UK children fall short of recommended fish intake targets.

It's important to distinguish between fish body oil supplements and cod liver oil, as the latter also contains vitamins A and D. Excessive vitamin A can be harmful to children, so parents should be cautious about cod liver oil products.

Whilst omega-3 fatty acids are recognised as important nutrients for child health, it is essential to understand that supplementation should complement, rather than replace, a balanced diet. Parents considering fish oil for their children should be aware of both the potential benefits and the importance of appropriate dosing and product selection.

Health Benefits of Fish Oil for Kids

Research into omega-3 supplementation in children has explored various health outcomes, though the strength of evidence varies across different conditions. Adequate omega-3 intake is important for general growth and development, particularly during critical developmental periods, but benefits of supplementation in well-nourished children remain uncertain.

Cognitive and behavioural development: Some studies suggest that adequate omega-3 intake may support cognitive performance, including memory, attention, and learning abilities. However, evidence remains mixed, and whilst observational studies often show associations between higher omega-3 levels and better cognitive outcomes, randomised controlled trials have produced inconsistent results. There is no official link definitively established between fish oil supplementation and improved academic performance in typically developing children.

Attention and behaviour: Fish oil has been investigated as a complementary approach for children with attention deficit hyperactivity disorder (ADHD) and related behavioural difficulties. Some research indicates modest improvements in attention, hyperactivity, and impulsivity with omega-3 supplementation, though effects are generally small. Importantly, NICE guidance (NG87) explicitly states that omega-3 supplements should not be offered to treat ADHD in children and young people. Fish oil supplements should not replace evidence-based treatments for ADHD.

Immune function and inflammation: Omega-3 fatty acids possess anti-inflammatory properties and may support immune system development. Some evidence suggests potential benefits for children with asthma or allergic conditions, though findings are not conclusive and UK guidelines do not currently recommend omega-3 supplementation for prevention or treatment of these conditions. The anti-inflammatory effects of EPA and DHA work through multiple mechanisms, including the production of specialised pro-resolving mediators that help regulate immune responses.

Visual development: DHA is important for retinal health and visual function. Adequate intake during infancy and early childhood supports normal visual development, though there is limited evidence that supplementation beyond recommended dietary intakes provides additional benefits in children without deficiency.

Recommended Dosage and How to Give Fish Oil to Children

There is no single universally agreed dosage of fish oil for children, as recommendations vary depending on age, health status, and the specific product formulation. The European Food Safety Authority (EFSA) has established adequate intake levels for omega-3 fatty acids, suggesting that children aged 2–18 years should consume approximately 250 mg of combined EPA and DHA daily for general health maintenance.

When selecting a fish oil supplement, parents should pay attention to the actual EPA and DHA content rather than the total fish oil amount, as these can differ significantly between products. A typical children's fish oil supplement might contain 200–500 mg of combined EPA and DHA per dose. For children with specific health conditions, different doses may sometimes be recommended under medical supervision.

It is essential to follow the dosage instructions on the product label and not exceed the recommended daily amount without healthcare professional guidance. If considering higher doses for specific conditions, always consult with a GP or specialist first.

Practical administration tips:

• Liquid formulations are often easier for younger children and can be mixed with food or drinks. Many products are flavoured (commonly with lemon or orange) to mask the fishy taste. These must be refrigerated after opening.

• Chewable capsules or gummies may be more acceptable for older children who can safely chew and swallow them. Always follow the age guidance on the product label to avoid choking risks. These products may contain added sugars or sweeteners.

• Standard capsules can be used for older children and adolescents. Only pierce capsules for mixing with food if the product label specifically states this is safe.

• Timing: Fish oil can be taken with meals to improve absorption and reduce the likelihood of gastrointestinal discomfort or fishy aftertaste.

Consistency is important for any potential benefits to be realised. Parents should establish a regular routine, such as giving fish oil with breakfast or dinner. It is advisable to start with a lower dose and gradually increase to the recommended amount, particularly if the child is new to supplementation, to allow the digestive system to adjust.

Note that prescription omega-3 medicines (omega-3-acid ethyl esters) are different from food supplements and are licensed for specific conditions in adults, not for routine use in children.

Safety Considerations and Potential Side Effects

Fish oil supplements are generally considered safe for children when used appropriately, but parents should be aware of potential side effects and important safety considerations. The most common adverse effects are mild and gastrointestinal in nature.

Common side effects include:

• Fishy aftertaste or burping

• Mild nausea or stomach upset

• Loose stools or diarrhoea

• Fishy-smelling breath

These effects are usually mild and often resolve with continued use or can be minimised by taking the supplement with food, using enteric-coated capsules, or refrigerating liquid formulations.

Important safety considerations:

Allergic reactions: Children with fish or shellfish allergies should use fish oil supplements with caution. Whilst highly purified fish oils typically contain minimal allergenic proteins, allergic reactions remain possible. If your child experiences signs of a severe allergic reaction (such as wheezing, swelling of the face/lips/tongue, breathing difficulty, or collapse), stop giving the supplement immediately and seek emergency medical help by calling 999 or 112. Alternative omega-3 sources such as algal oil (derived from algae) may be more appropriate for children with fish allergies.

Bleeding risk: Omega-3 fatty acids have mild anticoagulant properties. While clinically significant bleeding is uncommon at standard supplement doses, parents should inform their GP or specialist if their child is taking fish oil supplements before any surgical procedures or if the child has a bleeding disorder or is taking anticoagulant or antiplatelet medications.

Vitamin A content: Cod liver oil products contain vitamin A, which can be harmful in excessive amounts. Check product labels and avoid high vitamin A intake, particularly if your child takes other supplements containing vitamin A.

Contaminants: Fish can accumulate environmental contaminants such as mercury, polychlorinated biphenyls (PCBs), and dioxins. Reputable manufacturers use purification processes to remove these substances, but product quality varies. Parents should choose supplements that have been independently tested for purity and contaminants.

When to contact your GP:

• If your child experiences persistent gastrointestinal symptoms

• Before starting fish oil if your child has a bleeding disorder, takes anticoagulant medication, or has upcoming surgery

• If your child has a known fish allergy

• If you are considering doses higher than standard recommendations

• If your child develops any unexpected symptoms after starting supplementation

Fish oil supplements should not replace prescribed medications or recommended treatments for any medical condition without discussion with a healthcare professional. If you suspect your child has experienced a side effect from a fish oil supplement, you can report this through the MHRA Yellow Card scheme.

Choosing the Right Fish Oil Supplement for Your Child

The UK supplement market offers numerous fish oil products marketed for children, but quality and composition vary considerably. Parents should consider several factors when selecting an appropriate supplement to ensure safety, efficacy, and acceptability.

Key selection criteria:

Purity and quality standards: Look for products that have been independently tested and certified by third-party organisations. Products bearing certification from organisations such as IFOS (International Fish Oil Standards) or similar bodies provide assurance regarding purity, potency, and absence of contaminants. Ensure the product complies with UK and EU regulations for food supplements.

EPA and DHA content: Examine the supplement facts label carefully to determine the actual amounts of EPA and DHA per serving, not just the total fish oil content. Products should clearly state these amounts in milligrams. For general health maintenance in children, look for supplements providing approximately 200–500 mg of combined EPA and DHA per dose.

Vitamin A content: If considering cod liver oil products, check the vitamin A content to avoid exceeding age-appropriate intake levels, particularly if your child takes other supplements containing vitamin A.

Form and palatability: Consider your child's age and preferences. Liquid formulations work well for younger children but must be refrigerated after opening. Chewable capsules or gummies are often more acceptable to children but may contain added sugars or sweeteners. Check ingredient lists for potential allergens (fish, soy in vitamin E) or additives you wish to avoid, including gelatine for vegetarian or religious dietary preferences.

Sustainability: Where possible, choose products from manufacturers committed to sustainable fishing practices. Look for certifications from organisations such as the Marine Stewardship Council (MSC), which indicate that the fish source is sustainably managed.

Freshness: Omega-3 fatty acids are susceptible to oxidation, which reduces their effectiveness and can cause rancidity. Check expiration dates and, for liquid products, smell the oil before use—it should have a mild, fresh scent rather than a strong, unpleasant fishy odour.

Alternative sources: For children who cannot tolerate fish oil or have fish allergies, algal oil supplements provide a vegetarian source of DHA and are increasingly available. These products are derived from marine algae and offer similar benefits without fish-derived ingredients.

Parents should discuss supplementation with their GP or a registered dietitian, particularly if their child has existing health conditions, takes regular medications, or follows a restricted diet. Professional guidance can help ensure that fish oil supplementation is appropriate and that the chosen product and dosage are suitable for the individual child's needs.

Frequently Asked Questions