Vitamins and Supplements: Who May Need Them and How to Use Them Safely

Vitamins and minerals are nutrients the body needs in relatively small amounts. They support functions including bones, muscles, blood, nerves, immunity, vision and the release of energy from food.^[1]NHS

A multivitamin normally combines several vitamins, and sometimes minerals, in one tablet, capsule, liquid, powder, spray or gummy. A multivitamin is not automatically necessary or suitable for everyone. Whether a supplement helps depends on what your body actually needs, not on how the product is marketed.

A varied diet can provide most of the nutrients most people need. Useful everyday foods include:^[9]NHS

• Fruit and vegetables — fresh, frozen, tinned or dried all count
• Beans, peas and lentils
• Wholegrain and fortified foods, such as wholemeal bread and fortified cereals
• Dairy products, or suitable fortified alternatives
• Eggs
• Fish and meat
• Nuts and seeds

Eating a varied diet is not always straightforward. It may be difficult because of disability, illness, swallowing problems, allergies, sensory difficulties, low income, reduced appetite or limited access to food and cooking facilities. None of that is a personal failing.

If you are struggling to eat properly, eating a very narrow range of foods, or losing weight without meaning to, speak to a GP, pharmacist or registered dietitian rather than trying to make up the difference with supplements alone.

Practical help with food costs is covered on our Food Banks and Emergency Food Help page.

Supplements may be recommended for:

• People with a diagnosed vitamin or mineral deficiency
• People who are pregnant, trying for a baby or could become pregnant
• Babies and young children
• People who receive little sunlight
• People who are housebound or spend most of their time indoors
• People who usually cover most of their skin when outdoors
• People with black or brown skin, who may not make as much vitamin D from sunlight
• Vegans and people following other restricted diets
• People with conditions that affect digestion or nutrient absorption
• People who have undergone certain forms of weight-loss surgery
• People advised to take supplements by a GP, dietitian or specialist

Individual needs differ. Blood tests or a professional assessment are sometimes needed before it is clear whether a supplement is appropriate, and at what amount.

Vitamin D helps the body absorb calcium and phosphate, and supports healthy bones, teeth and muscles.^[2]NHS

Do not take high-dose vitamin D unless it has been prescribed or recommended for you by an appropriate healthcare professional. Taking too much vitamin D over a long period can cause too much calcium to build up in the body, which can damage the kidneys, bones and heart.^[2]NHS

People who are pregnant, trying for a baby or could become pregnant are normally advised to take 400 micrograms of folic acid every day before pregnancy and during the first 12 weeks of pregnancy.^[3]NHS

Some people are advised to take a higher, prescribed dose because of their individual circumstances. If you think that might apply to you, speak to a GP, midwife or pharmacist rather than selecting a high-dose product yourself.

Current NHS guidance, in plain English:^[4]NHS

• Children aged 6 months to 5 years are generally advised to have supplements containing vitamins A, C and D each day.
• Babies having more than 500ml of infant formula a day usually do not need these supplements, because formula is already fortified.
• Breastfed babies may need vitamin D from birth.
• Parents and carers should use age-appropriate products and follow NHS or health-visitor advice on amounts.

People following a vegan diet need a reliable source of vitamin B12, either from fortified foods or from a supplement.^[8]NHS

Other nutrients that may need attention on a vegan diet include:

• Vitamin D
• Iodine
• Calcium
• Iron
• Selenium
• Omega-3 fats

This does not mean every vegan needs every supplement. A well-planned vegan diet can provide most nutrients from food. It is worth checking reliable dietary guidance or speaking to a registered dietitian, particularly for children, in pregnancy, or alongside a health condition.

Diets can also be restricted for reasons that are not a choice — allergies, coeliac disease, sensory difficulties, eating disorders or other medical conditions. If your diet is narrow for any of these reasons, ask for a proper assessment rather than guessing which products to buy.

Supplements are not automatically needed simply because someone is older or disabled. Many older and disabled people eat well and need nothing extra beyond the general vitamin D advice.

Some people may be at greater risk because they:

• Spend little time outdoors
• Have difficulty shopping, cooking or eating
• Have a reduced appetite
• Take medicines that affect nutrient absorption
• Have swallowing difficulties
• Have digestive or absorption problems
• Eat a very restricted range of foods

Please do not start several supplements simply because you feel tired or unwell. Tiredness, weakness, memory difficulties and poor balance can have many causes, including conditions that need treatment, and may need medical assessment.

Iron is needed to make healthy red blood cells, which carry oxygen around the body. Low iron can cause iron-deficiency anaemia — but tiredness does not automatically mean someone is short of iron.^[6]NHS

Iron supplements can cause side effects such as constipation, stomach discomfort and dark stools, and can be dangerous in excessive amounts. People should not take high-dose iron long-term without appropriate advice or evidence of deficiency, and a blood test is the usual way to confirm it.

Vitamin B12 supports the production of red blood cells and the healthy working of the nervous system.^[7]NHS

People at greater risk of B12 deficiency may include:

• Vegans without a reliable dietary source
• Some older people
• People with pernicious anaemia
• People with digestive or absorption conditions
• People taking certain medicines
• People who have had particular stomach or bowel operations

B12 deficiency can cause neurological problems, including tingling, numbness, balance difficulties and memory or concentration changes. It should be properly assessed and treated — some people need injections rather than tablets — so speak to a GP rather than self-treating.

Vitamin A supports vision, skin and the immune system, but excessive amounts can be harmful, particularly to bones and the liver.^[1]NHS

Many multivitamins and fish-liver-oil products contain vitamin A. People who regularly eat liver or liver products should take particular care not to add more vitamin A from supplements, because liver is very high in it.

Calcium supports bones and teeth, and also helps muscles and nerves to work properly. Most people should obtain calcium through food, such as dairy products, fortified plant drinks, tinned fish with bones, and some green vegetables.^[1]NHS

Some people do need supplements, for example because of their diet, osteoporosis treatment or a medical condition. That should be decided with a professional rather than assumed.

Calcium can affect the absorption of certain medicines, including some thyroid medicines and some antibiotics. A pharmacist can advise on safe timing — often simply leaving a gap between the medicine and the supplement.

See also our Osteoporosis and Bone Health page.

Magnesium helps turn food into energy and supports the working of muscles and nerves. Zinc helps with wound healing, the immune system and making new cells. Vitamin C helps protect cells and supports healthy skin, blood vessels and connective tissue, and helps the body absorb iron from food.^[1]NHS

Most people can obtain enough of all three from food. There is no good evidence that these supplements cure colds, anxiety, cramps, tiredness or sleep problems, and they should not be sold or taken on that basis.

High amounts can cause side effects, including diarrhoea, stomach pain and other digestive problems, and can interact with medicines. High-dose zinc taken over a long period can also affect copper levels.

Supplements come in many forms. Attractive packaging, a pleasant flavour or a higher price does not prove that a product is more effective.

• Gummies may contain sugar and can easily be mistaken for sweets.
• Effervescent products may contain significant amounts of salt.
• Powders can make it easier to accidentally take too much.
• Sprays and drops still require careful measuring.
• Keep every supplement away from children and pets.

Some supplements can alter medical-test results, which can lead to unnecessary worry, repeated tests or the wrong conclusion.

High-dose biotin, often sold for hair, skin or nails, can interfere with certain blood tests, including some thyroid tests and some heart-related tests.

Tell the person arranging or taking your blood test about every vitamin and supplement you use, and follow their instructions about whether anything needs to be paused beforehand.

The same nutrient may appear in more than one thing you take, such as:

• A daily multivitamin
• A separate single-vitamin tablet
• Fish-liver oil
• Fortified foods or drinks
• Hair, skin and nail products
• Energy or fitness supplements
• Pregnancy supplements

Compare labels and add up the total amount of each nutrient, rather than assuming that each separate product is safe to combine with the others.

Sixpence Support UK CIC does not recommend, rank or sell any brand or product.

Food supplements are not medicines. They should not be advertised as preventing, treating or curing medical conditions, and UK rules restrict the claims a seller may make.^[5]GOV.UK

A celebrity endorsement, an online review, an influencer video or the word “natural” is not proof that a product is safe or effective. “Natural” substances can still be strong, and can still interact with medicines.

Products sold online, particularly from overseas sellers, may not meet UK requirements on ingredients, amounts or labelling. Use reputable UK retailers and ask a pharmacist if you are unsure.

Contact a GP, or NHS 111 where appropriate, if you or someone you care for has:

• Persistent or unexplained tiredness
• Unexplained weight loss
• Ongoing vomiting or diarrhoea
• Difficulty swallowing or eating
• Tingling, numbness or balance problems
• Unusual weakness
• Pale skin, breathlessness or a racing heartbeat
• Symptoms that began after starting a supplement
• Concerns about pregnancy, a child or a possible deficiency

These symptoms can have many different causes. They should be assessed rather than self-treated with several supplements at once.