Are you getting enough Vitamin D, B12 and magnesium?

The number of people hospitalised due to a lack of essential vitamins and minerals has soared. Here are ways to ensure you get enough.

In 2024 a review of NHS data by the PA Media news agency reported that the number of people in England admitted to hospital because of a deficiency in vitamins or minerals had soared, with deficiencies of iron increasing ten-fold and of vitamin B12 rising fourfold since the end of the Nineties.

It raises the question of whether we should all be popping pills to make sure our diets are up to scratch but in most cases simple dietary changes suffice, says Dr Linia Patel, a researcher in the department of clinical sciences and community health at the Universita degli Studi di Milano in Italy and a spokesman for the British Dietetic Association (BDA).

“Food is always the best supplier as it comes with a range of vitamins and minerals, fibre and other important compounds for health. If you’ve been diagnosed with a deficiency by a blood test taken by a medical professional, then supplements will be prescribed in tailored doses to offset the shortfall.”

Here are the key nutrients to keep an eye on.

VITAMIN C

How much should we be getting? UK recommendations state that anyone aged 15 and above needs 40mg of vitamin C a day, while those under 15 need 30-35mg daily.

However, a 2021 study by Philippe Hujoel, a professor of oral health sciences at the University of Washington, suggested that intakes of 95mg a day, more than double the recommended amount, are needed to avoid deficiency and improve wound healing for 97.5 per cent of people.

Why we need it: vitamin C plays an important role in supporting immune function and also helps the body to produce collagen, needed for the healing and maintenance of healthy skin. The nutrient is crucial for maintaining healthy blood vessels, bones and cartilage, and is needed to help the body to absorb iron.

Good food sources: If you get your five-a-day of fruit and veg then you are likely to be OK. Citrus fruit (oranges, limes and lemons), Kiwi fruits, new potatoes, broccoli and peppers are among the best suppliers.

Vitamin C is found in fruit and vegies like oranges and capsicum.

Risks of getting too little: Scurvy, a condition caused by a lack of vitamin C, is rare, but your immune function might be affected. “If you seem to be getting more colds and infections, feel tired and sluggish all the time or have bleeding or swollen gums and changes to your hair and nails, then they are signs of low vitamin C,” Patel says.

Will a supplement help? “Only if your intakes of vitamin C are low, or if you have an exceptionally physically demanding lifestyle, will extra vitamin C from a supplement possibly provide some protection against colds,” says Dr Jenna Macciochi, a senior lecturer in immunology at the University of Sussex and author of Your Blueprint for Strong Immunity. Where a supplement might help is in cutting a cold short. A 2023 review of ten published studies reported that vitamin C had “a significant benefit on the duration of severe [cold] symptoms” by up to 1.5 days.

Macciochi says you need to start popping them at the first sign of the sniffles. “Our immune cells need more vitamin C when we are fighting a cold.” Anyone with diabetes should seek medical advice before taking vitamin C supplements.

Can you take too much?

Excess levels are excreted in urine, not stored in the body, so the risk of toxicity is low. Still, high doses, such as those found in megadose supplements, can irritate the stomach lining, causing cramps, diarrhoea and nausea.

VITAMIN D

How much should we be getting? All ages need 10mcg daily.

Why we need it: It’s essential for the health of bones, teeth, muscles and immune function.

As well as helping the body to absorb the bone-building nutrients calcium and phosphorus, it has anti-inflammatory effects.

“From epidemiological studies we know that vitamin D is involved in inflammatory pathways and has a role in systemic inflammation, which links it to many chronic diseases,” Patel says.

“Vitamin D receptors are present in the brain, particularly in areas involved in mood regulation.”

Good food sources: Although found in dairy products, oily fish, cod liver oil, milk and eggs, food is generally not the best supplier. Sunshine is the best source. To boost stores, 15 minutes of daily exposure to sunlight between 10am and 4pm, from April to September, is recommended.

Risks of getting too little: One in six adults in the UK have low levels of vitamin D. Severe deficiency causes rickets and in some adults results in osteomalacia – a condition characterised by pain, muscle weakness and bone fractures. According to the NHS there’s been an increase in rickets.

Although these foods have vitamin d, a better source is the sun.

“Early warning signs include low immunity or low mood,” Patel says. “A blood test can identify a deficiency.”

Is a supplement necessary? Yes, at least from October to April, when it’s recommended that everyone over the age of one takes a 10mcg supplement.

A BMJ study of 449,943 people aged 40 to 69 concluded that “taking supplements was associated with a lower risk of vitamin D deficiency”. Patel says that the D3 form of the supplement is slightly more effective than plain vitamin D. “As vitamin D is fat soluble, make sure you take a supplement with some fat in your tummy for maximum absorption. A little olive oil does the trick.”

Can you take too much? High-strength supplements contain up to ten times the recommended daily intake (100mcg). This is unlikely to cause problems unless you are getting additional vitamin D from other sources, such as fortified foods and multivitamins, Anita Bean, a registered nutritionist, says. “Very high intakes can lead to muscle weakness and increased thirst. Over the longer term it can contribute to high blood pressure and even kidney stones.”

FOLATE AND FOLIC ACID

How much should we be getting? Adults need 200mcg of folate (also known as vitamin B9) daily.

Why we need it: Folate is important for brain health and immune function. It has been shown to reduce the risk of neural defects in unborn babies.

Good food sources: Beans and pulses, oranges, brussels sprouts and leafy greens, oranges, avocados, wholegrains, poultry and pork all contain folate. Folic acid, the synthetic form of the nutrient, is added to many breakfast cereals. From 2026, all UK-milled wheat flour except wholemeal will be fortified with folic acid.

Folic acid is found in beans and pulses, avocado and leafy greens.

Risks of getting too little: It can result in a form of anaemia that causes excessive fatigue. In women, low intake is shown to increase the risk of neural tube defects such as spina bifida in unborn infants. Blood tests are available from the GP.

Is a supplement necessary? Women trying to get pregnant and in the first 12 weeks of pregnancy are advised to take 400mcg of folic acid a day.

Can you take too much? According to the NHS, taking doses of folic acid higher than 1mg can mask the symptoms of vitamin B12 deficiency, which can eventually damage the nervous system if it’s not spotted. Folic acid from supplements and fortified foods is absorbed more easily by the body than natural folate from foods. In extreme cases supplementing can lead to a build-up of unmetabolised folic acid in the blood, which is linked to health concerns including faster age-related mental decline in older adults.

MAGNESIUM

How much should we be getting? Men aged 15 and older, and girls aged 15 to 18, need 300mg per day. Women aged 19 plus need 270mg daily.

Why we need it: It helps the body to activate important enzymes, is needed for the secretion of hormones involved in bone metabolism, and is essential for healthy muscle and nerve function.

Good food sources: Meat and dairy, oat bran, brown rice, pumpkin, sunflower seeds, quinoa and dark leafy green vegetables. Dark chocolate, coffee and nuts are other sources. A 25g serving of sunflower seeds provides about 81mg magnesium and 25g almonds contains roughly 67mg.

Risks of getting too little: Some studies have suggested that a magnesium deficiency disrupts nerve signalling, which adversely affects sleep. “Doctors don’t routinely test for magnesium levels,” Patel says. “Warning signs of suboptimal intakes include muscle cramps and headaches, mood changes and disturbed sleep.”

Is a supplement necessary? According to the NHS you should be able to get all of the magnesium you need from food but a supplement of up to 400mg a day won’t do any harm.

Can you take too much? Yes. It potentially causes digestive issues and an irregular heartbeat.

IRON

How much should we be getting? Men need 8.7mg daily. Women aged 11 to 50 need 14.8mg, while women over 50 need 8.7mg daily.

Why we need it: As a building block for haemoglobin, iron is responsible for ferrying oxygen around the body and supplying energy. It plays a role in metabolic processes including breathing, immune function, and the reduction of tiredness and fatigue.

Good food sources: The most easily absorbed form is the haem iron found in meat, offal, clams and oysters.

The iron found in meat is the most easily absorbed.

Plant sources such as beans, pulses, leafy green vegetables and seeds contain non-haem iron, which is harder for the body to absorb. The registered nutritionist Rhiannon Lambert, author of The Science of Plant Based Nutrition, says that our bodies do get better at absorbing it over time and that eating foods containing vitamin C increases the absorption of non-haem iron. According to the BDA, all white bread sold in the UK is fortified with iron and many cereals have it added.

Risks of getting too little: “People with a mild deficiency often look pale and feel listless,” Lambert says. “Iron supports the immune system and a deficiency can cause itchy skin, heart palpitations and ulcers.”

The National Institute for Health and Care Excellence estimates that 3 per cent of men and 8 per cent of women have iron-deficiency anaemia, leading to 57,000 emergency hospital admissions each year. “If you suspect you are deficient see your GP.”

Is a supplement necessary? If you have an iron deficiency diagnosed by a blood test, a supplement will likely be prescribed by a GP or dietitian at the standard recommended dose of 60-100mg per day for three months to correct the shortfall. Multivitamins often contain at least 100 per cent of the daily requirement or about 14mg, whereas iron-only supplements typically contain 15-20mg. Make sure you don’t take both.

Can you take too much? Taking extra iron if you are not lacking it in the diet can be risky. The NHS warns that “very high doses of iron can be fatal, particularly if taken by children” and iron poisoning can occur after single doses of high amounts of iron.

VITAMIN B12

How much should we be getting? 1.5mcg daily.

Why we need it: “It is estimated that up to 15 per cent of the population has a B12 deficiency,” Lambert says. Vitamin B12 is important for healthy blood and nerve function, and works with folate to synthesise our DNA. It also plays a role in breaking down homocysteine, a protein that is linked to an increased risk of heart disease and strokes. “Blood tests from the GP will detect if levels are low.”

Good food sources: Meat, fish, dairy and eggs. A glass of milk provides 1.24mcg, a 20g slice of cheese 0.4mcg, a pot of yoghurt 1mcg and an egg 0.6mcg. “There are lots of myths about plant-based sources of vitamin B12 but they don’t exist,” Lambert says. “You will find it in fortified yeast extracts and other fortified foods.”

Meat and fish contain B12.

Risks of getting too little: Symptoms include fatigue, muscle pains, poor memory and reduced cognitive function. Although the body stores some B12, there is an increased risk of nerve damage if supplies run out. A deficiency can lead to megaloblastic anaemia, muscle weakness, memory problems and deteriorating brain function. “Another type of anaemia, called pernicious anaemia, can be caused by B12 not being absorbed by the body,” Lambert adds.

Is a supplement necessary? It’s a non-negotiable if you follow a strict plant-based diet. Advice is to take 2-7mcg in supplement form which will ensure you are addressing the shortfall, although always consult a healthcare professional before taking one. “If you have pernicious anaemia, even a high-dose supplement won’t solve the problem,” Lambert says. “A GP will sometimes prescribe injections of B12 into the muscle and the condition must be monitored by a professional.”

Can you take too much? The NHS says that taking more than 2mg a day could be problematic.

The original version of this story appeared on The Times.

Originally published as Are you getting enough Vitamin D, B12 and magnesium?