Selenium and zinc are essential trace minerals that support immune function, cellular metabolism, and protection against oxidative stress. Whilst required only in small amounts, these nutrients play critical roles in over 300 enzymatic reactions, thyroid hormone regulation, wound healing, and DNA synthesis. Most people in the UK can meet their selenium and zinc requirements through a balanced, varied diet incorporating both animal and plant-based sources. Understanding which foods are richest in these minerals—and how to incorporate them into daily meals—helps ensure adequate intake without relying on supplements unless medically indicated.

Why Selenium and Zinc Are Essential for Your Health

Selenium and zinc are trace minerals that play vital roles in maintaining optimal health, despite being required only in small amounts. Both minerals function as essential cofactors for numerous enzymatic processes throughout the body, supporting immune function, cellular metabolism, and protection against oxidative stress.

Selenium is a critical component of selenoproteins, which include glutathione peroxidases and thioredoxin reductases. These enzymes protect cells from oxidative damage by neutralising harmful free radicals. Selenium also supports thyroid hormone metabolism, as iodothyronine deiodinases (selenium-dependent enzymes) convert thyroxine (T4) to its active form, triiodothyronine (T3). Additionally, selenium contributes to DNA synthesis, reproductive health, and may play a role in reducing inflammation.

Zinc is involved in over 300 enzymatic reactions and is essential for immune cell development and function. It supports wound healing, protein synthesis, and DNA production. Zinc is particularly important for maintaining the integrity of skin and mucous membranes, which serve as the body's first line of defence against pathogens. The mineral also plays a crucial role in taste and smell perception, growth and development during childhood and adolescence, and male reproductive health.

Both minerals support immune function, with deficiencies in either potentially compromising the body's ability to fight infections. Adequate intake through diet is generally preferred over supplementation, as food sources provide these minerals in bioavailable forms alongside other beneficial nutrients. The UK's National Health Service (NHS) emphasises obtaining vitamins and minerals primarily through a balanced, varied diet rather than relying on supplements unless medically indicated.

Top Food Sources Rich in Selenium and Zinc

A varied diet incorporating both animal and plant-based foods can provide adequate selenium and zinc. Understanding which foods are richest in these minerals helps ensure sufficient intake without requiring supplementation.

Excellent sources of selenium include:

• Brazil nuts – exceptionally high in selenium, though content can vary significantly. Just 1-2 nuts may provide the daily requirement, but should not be consumed in large quantities daily due to risk of excessive intake

• Fish and seafood – particularly tuna, sardines, salmon, and shellfish such as oysters and mussels

• Meat and poultry – beef, lamb, chicken, and turkey provide moderate amounts

• Eggs – a convenient source, with selenium concentrated in the yolk

• Wholegrains – brown rice, wholemeal bread, and oats (selenium content varies depending on soil levels where crops are grown)

Top sources of zinc include:

• Shellfish – oysters contain more zinc per serving than any other food, with crab and mussels also being excellent sources

• Red meat – beef and lamb are particularly rich in bioavailable zinc

• Poultry – chicken and turkey provide good amounts

• Dairy products – cheese, milk, and yoghurt contribute to zinc intake

• Legumes – chickpeas, lentils, and beans (though phytates in legumes can reduce zinc absorption)

• Nuts and seeds – particularly pumpkin seeds, cashews, and almonds

• Wholegrains – wholemeal bread, quinoa, and oats

It is worth noting that animal-based sources generally provide zinc in more bioavailable forms compared to plant sources, as phytates in plant foods can reduce zinc absorption. For selenium, bioavailability varies by form, but plant-derived selenomethionine is generally well absorbed. For those following vegetarian or vegan diets, consuming a wider variety of plant-based sources and employing preparation methods such as soaking legumes can enhance mineral absorption.

Note for pregnant women: If including fish and shellfish, follow NHS guidance on safe consumption during pregnancy – limit oily fish to 2 portions weekly, avoid shark, swordfish and marlin, limit tuna to 2 steaks or 4 medium cans weekly, and ensure all shellfish is thoroughly cooked.

Daily Requirements and Recommended Intake in the UK

The UK's Department of Health and Social Care provides Reference Nutrient Intakes (RNIs) for selenium and zinc, which represent the amount sufficient to meet the needs of approximately 97% of the population. Understanding these recommendations helps individuals assess whether their dietary intake is adequate.

Selenium requirements:

• Adult men (19-64 years): 75 micrograms (µg) per day

• Adult women (19-64 years): 60 µg per day

• Pregnant women: 60 µg per day

• Breastfeeding women: 75 µg per day

• Children's requirements vary by age: 10 µg (1-3 years), 15 µg (4-6 years), 30 µg (7-10 years), 45 µg (11-14 years), and 60-75 µg (15-18 years)

The European Food Safety Authority (EFSA) sets a tolerable upper intake level for selenium at 300 µg per day from all sources. The NHS advises not exceeding 350 µg per day from supplements. Exceeding these limits regularly may lead to selenosis, characterised by hair loss, nail brittleness, and neurological symptoms.

Zinc requirements:

• Adult men: 9.5 milligrams (mg) per day

• Adult women: 7 mg per day

• Pregnant women: 7 mg per day

• Breastfeeding women: 13 mg per day (0-4 months), 9.5 mg per day (4+ months)

• Children's requirements: 5 mg (1-3 years), 6.5 mg (4-6 years), 7 mg (7-10 years), and 9 mg (11-14 years)

The safe upper limit for zinc from supplements is 25 mg per day. Excessive zinc intake can interfere with copper absorption and may suppress immune function paradoxically.

Most individuals in the UK can meet these requirements through diet alone. The NHS advises that supplements should only be taken if recommended by a healthcare professional, as excessive intake of either mineral can cause adverse effects. Those at higher risk of deficiency—including individuals with malabsorption conditions, strict vegetarians, or those with increased requirements—should discuss their needs with their GP.

Signs of Selenium and Zinc Deficiency

Whilst severe deficiencies of selenium and zinc are relatively uncommon in the UK, suboptimal intake can occur in certain populations and may manifest through various clinical signs. Recognising these symptoms is important for timely intervention, though many are non-specific and may have other causes.

Selenium deficiency may present with:

• Fatigue and generalised weakness

• Mental fog or difficulty concentrating

• Weakened immune function, leading to recurrent infections

• Hair loss or thinning

• Muscle weakness or discomfort

• Thyroid dysfunction, as selenium is essential for thyroid hormone metabolism

• In severe cases (rare in the UK): Keshan disease (a form of cardiomyopathy) or Kashin-Beck disease (osteoarthropathy)

Certain groups are at higher risk, including those with gastrointestinal disorders affecting absorption (such as Crohn's disease or coeliac disease), individuals undergoing dialysis, and those with HIV infection.

Zinc deficiency may manifest as:

• Impaired immune function with increased susceptibility to infections

• Loss of appetite

• Altered sense of taste or smell

• Slow wound healing

• Hair loss

• Skin lesions, particularly around the mouth and extremities

• Diarrhoea

• In children: growth retardation and delayed sexual maturation

• In men: reduced testosterone levels and fertility issues

• In severe cases: acrodermatitis enteropathica (a distinctive rash)

Risk factors for zinc deficiency include vegetarian or vegan diets (due to lower bioavailability from plant sources), pregnancy and lactation, chronic liver or kidney disease, inflammatory bowel disease, and excessive alcohol consumption.

When to seek medical advice:

If you experience persistent symptoms suggestive of deficiency, contact your GP. Blood tests can assess selenium and zinc levels, though interpretation requires clinical context as serum levels may not always reflect tissue stores accurately. Serum zinc, in particular, is influenced by inflammation and fasting state. Self-prescribing high-dose supplements is not recommended, as excessive intake can cause toxicity. Your GP can arrange appropriate investigations and, if deficiency is confirmed, recommend evidence-based treatment, which may include dietary modification or supervised supplementation.

How to Incorporate These Foods into Your Diet

Achieving adequate selenium and zinc intake through diet is straightforward with thoughtful meal planning. The following practical strategies can help you incorporate selenium- and zinc-rich foods into your daily routine without requiring major dietary changes.

Practical tips for increasing selenium intake:

• Add 1-2 Brazil nuts occasionally to your morning porridge or yoghurt—this can provide a significant amount of selenium, but avoid consuming them daily due to their highly variable selenium content and risk of exceeding safe intake levels

• Include fish or seafood 2-3 times weekly; tinned tuna or salmon on wholemeal toast makes a convenient, selenium-rich lunch

• Choose wholegrain varieties of bread, pasta, and rice over refined versions

• Incorporate eggs into breakfast or use them in salads and sandwiches

• For meat-eaters, include poultry or lean meat several times weekly

Strategies for boosting zinc intake:

• Add pumpkin seeds to salads, soups, or homemade granola

• Include lean red meat 1-2 times weekly, choosing cuts like sirloin or extra-lean mince, while keeping within the NHS recommendation of around 70g per day on average

• Consume dairy products daily—cheese on wholemeal crackers, milk in tea or coffee, or yoghurt as a snack

• For plant-based diets, regularly eat legumes (chickpeas, lentils, beans); soaking them overnight and cooking thoroughly can reduce phytates and improve zinc absorption

• Snack on nuts, particularly cashews and almonds

• Choose wholegrain breakfast cereals, some of which are fortified with additional minerals

Meal ideas combining both minerals:

• Grilled salmon with quinoa and roasted vegetables

• Chicken and chickpea curry with brown rice

• Wholemeal pasta with tuna, spinach, and pine nuts

• Beef stir-fry with cashews and mixed vegetables

• Porridge topped with a Brazil nut, pumpkin seeds, and yoghurt

For those following vegetarian or vegan diets, focus on combining multiple plant sources throughout the day, as plant-based zinc is less bioavailable than animal sources. Techniques such as soaking, sprouting, and fermenting legumes and grains can enhance mineral absorption.

If you have concerns about meeting your requirements through diet alone—particularly if you have increased needs, absorption issues, or dietary restrictions—consult your GP or request a referral to a registered dietitian for personalised advice. The NHS Eatwell Guide provides additional guidance on achieving a balanced diet that naturally provides essential micronutrients.

If you experience any suspected side effects from supplements, report them through the MHRA Yellow Card scheme.

Frequently Asked Questions