Vitamins and minerals in a healthy diet

Vitamins and minerals are also known as ‘micronutrients’, because they are needed by the body in much smaller amounts [milligrams (mg) or micrograms (µg) per day] than the other nutrients that make up a healthy diet, such as carbohydrate, protein and fat (called macronutrients). Vitamins and minerals are essential nutrients, which means that we cannot make them in our body and so we must get them from our diet, although there are a couple of exceptions, such as vitamin D, which we can make in our skin when exposed to sunlight.

Vitamins are usually grouped into two categories:

• Water-soluble vitamins: These are not stored in the body and so we must get them regularly from our diet. Examples include vitamin C and the B vitamins.
• Fat-soluble vitamins: These can be stored by the body in the liver and fat tissues. Examples include vitamins E and D.

What do vitamins and minerals do in the body?

Vitamins perform a wide variety of functions in our bodies, such as helping to release energy from the foods that we eat, playing a role in DNA synthesis, and acting as antioxidants to protect our cells from damage.  

Minerals such as calcium and iron also have a range of essential functions, such as the formation of bones and teeth, and are needed for the normal function of our nervous system. Some vitamins and minerals may be absorbed more efficiently by the body from the foods that we eat, rather than from food supplements (such as the iron in red meat).

The tables below provide more information about the various roles of vitamins and minerals in the body, and which foods you can find them in. The reference intake (RI) for vitamins and minerals are used for food labelling can be found on the back of pack for some products. RIs are for adults and show the amount most of us need per day of each vitamin and mineral for good health.  Some RI values are given in milligrams (mg), while others are in micrograms (µg). A thousand micrograms is equivalent to 1 milligram.

Water-soluble vitamins

Fat-soluble vitamins

Minerals

How much of the different vitamins and minerals do I need?

We may need different amounts of vitamins and minerals depending on our age, sex, and also for women during pregnancy or breastfeeding. For food labelling in Europe, we have values for each vitamin and mineral called reference intakes (RIs – shown in the Table 1 above), which give an average figure for adults. These are what you can see on the nutritional information on packaged foods and drinks.

The UK government has also published a set of dietary reference values (DRVs) for different vitamins and minerals. These provide an estimate of the amounts required each day by different groups of healthy people in the general population to support growth and development, and to maintain good health.

The most common type of DRV for vitamins and minerals is the reference nutrient intake (RNI). This is the amount that is considered to be enough to meet the needs of nearly everyone in the population (97.5% of people). Below is an example of the RNIs for calcium (in mg per day) recommended throughout life for males and females. Calcium needs are highest during adolescence because young peoples’ bones are growing rapidly at this time.

For more information on nutrient requirements see the Nutrition Requirements resource below.

Reference nutrient intakes (RNIs) for calcium

What is the best way to get enough vitamins and minerals?

There is no single ‘superfood’ that can provide everything we need and so the key is the balance of our diet overall. A varied and balanced diet with the right proportions of foods from the main food groups, should provide enough vitamins and minerals (except for vitamin D) to meet the needs of most people. However, supplementation is recommended in certain situations (see below for more information). Find out more by reading our pages on a healthy, balanced diet.

A healthy and balanced diet also provides other important food components, such as fibre and potentially beneficial compounds (such as polyphenols). If we get the vitamins and minerals we need from the foods in our diet,

The National Diet and Nutrition Survey gathers information on the average diet of people in the UK. Results from the survey show that there are low intakes of some vitamins (such as vitamin A) and minerals (such as iron for women) in the UK population, especially among teenage girls, who on average eat a poor-quality diet. A low intake does not necessarily mean that someone is deficient in a particular nutrient, as requirements vary according to age, sex and our life stage. However, very low intakes of a vitamin or mineral over time can result in symptoms of deficiency, such iron deficiency anaemia, which is estimated to affect 9% of girls aged 11-18 years.

Which foods are a good source of vitamins and minerals?

Different foods provide different vitamins and minerals in varying amounts. Therefore, it is important to aim for a varied and balanced diet that includes foods from all food groups shown in the Eatwell Guide in appropriate amounts. Some micronutrients can be found in a relatively wide range of foods (such as vitamin B6 and potassium), while others, such as vitamin D, are found in a smaller number of foods. In the average UK diet, animal-based foods such as meat, fish, eggs, milk and other dairy products, make an important contribution to intakes of several vitamins (such as vitamin B12 and vitamin D) and minerals (such as calcium and iodine in dairy foods, iron and zinc in meat). Therefore, if you are following a diet which restricts or cuts out animal products altogether, such as a vegetarian or vegan diet, it may be important to think about which foods can provide key nutrients such as iron, calcium, iodine and vitamin B12. For more information read our pages on healthy vegetarian and vegan diets.

You can find out more information about which foods different vitamins and minerals are found in, and what they do in the body, from our resource below Vitamins and minerals in our foods.

Do I need to take a vitamin or mineral supplement?

Most people should be able to get all the vitamins and minerals they need (except for vitamin D) by eating a healthy, varied diet. Supplements are not a substitute for a healthy diet, which provides other important dietary components such as fibre, which helps maintain gut health and reduces the risk of diseases such as type 2 diabetes, heart disease and bowel cancer.

However, the government recommends certain supplements in some instances:

• Folic acid: Women who are pregnant, trying to conceive or could become pregnant, are recommended to take a 400µg (microgram) folic acid supplement daily from preconception until 12 weeks of pregnancy. Women at higher risk of having a pregnancy affected by a neural tube defect may be advised by their doctor to take a higher dose of folic acid.
• Vitamin D: Adults and children aged 5 years and older should take (or should be given) a daily 10µg (microgram) vitamin D supplement during the autumn and winter months (from October to March) to protect bone and muscle health.
• The government recommends that people who are not able to go outside often, or who cover their skin while outside, should take a daily 10µg (microgram) vitamin D supplement all year round.
• People with dark skin, including those from and African, African-Caribbean or South Asian background, should consider take a daily 10µg (microgram) vitamin D supplement all year round.
• Vitamins A, C and D: All children aged 6 months to 5 years should be given a vitamin supplement containing vitamins A, C and D every day.

Aside from the situations described above, if you are worried that you are not getting enough vitamins and minerals from your diet it is important to speak to your GP or another health professional (such as dietitian or pharmacist) who can advise you on whether it is necessary for your specific needs and any issues you should be aware of (such as interactions with any medication you might be taking). Buy from a reputable retailer (such as a pharmacist or high-street retailer), always read the label and make sure not to exceed the recommended dose.

Can I get enough vitamins and minerals from a vegetarian or vegan diet?

Well-planned vegetarian and vegan diets can provide most essential nutrients but, there are some nutrients that you might want to give more consideration to if you are following a vegetarian or vegan diet, or if you are reducing the amount of meat, fish and dairy foods that you eat. This is because it may be more difficult to get enough of some vitamins or minerals from plant-based foods alone (like vitamin B12), or they may not be absorbed as easily by the body (referred to as ‘bioavailability’).

For example, the iron found in plant foods such as beans, lentils, nuts and green vegetables (called ‘non-haem’ iron) is less readily absorbed by the body than the iron from animal sources (known as ‘haem iron’). Some plant foods also contain compounds called phytates and oxalate that can bind to minerals such as iron, zinc and calcium, meaning that they are less bioavailable.

Below are some of the nutrients that may require more consideration if you are following a vegetarian or vegan diet:

• Vitamin B12: If you are vegan, you should include foods fortified with vitamin B12 in your diet (such as fortified breakfast cereals). You may also wish to consider taking a vitamin B12 supplement to ensure an adequate intake but speak to your GP or another health professional before taking any supplements if you are on any medication or have any health issues.
• Iron: Plant-based sources of iron, such as beans, lentils, nuts, wholemeal bread and dried fruit provide ‘non-haem’ iron that is less bioavailable than the ‘haem’ iron provided by meat. Including a source of vitamin C with meals, such as glass of orange juice, citrus fruits or peppers, can increase the absorption of non-haem iron from the diet.
• Calcium: Plant-based sources include fortified dairy alternatives, dried fruits, some green leafy vegetables (such as kale and watercress), bread and calcium-set tofu.
• Iodine: Milk and milk products are the main provider of iodine in the UK diet. Iodine can be found at a low level in plant foods although the amount varies depending on the levels in the soil where the plants were grown. Some plant-based milk alternatives (such as oat and soya drinks) are fortified with iodine, but it is important to check the label.
• Vitamin D: Plant-based sources of vitamin D include fortified foods, such as some vegetable spreads, breakfast cereals and some plant-based dairy alternatives (check the label), as well as UV-irradiated mushrooms. Most vitamin D supplements contain vitamin D3, which is typically produced from a wax called lanolin, extracted from sheep’s wool, and so may not be suitable for vegans or those who do not consume dairy. When choosing vitamin D supplements, read the label to ensure they are suitable for vegans. Vitamin D2 and vitamin D3 from lichen are vegan-friendly options.

For more information read our pages on healthy vegetarian and vegan diets.

What about vitamin D and COVID-19?

In response to emerging studies suggesting a link between vitamin D and risk of COVID-19, the government asked for the National Institute for Health and Care Excellence (NICE), in collaboration with SACN and Public Health England, to review the scientific evidence for a specific link between vitamin D status and COVID-19 infection and/or worse health outcomes. After reviewing the best available scientific evidence, NICE concluded that it was not possible to determine a direct relationship between vitamin D and COVID-19. They advised that there is not enough evidence to support taking vitamin D supplements to specifically prevent or treat COVID-19. However, NICE recommended that people should continue to follow UK government advice to consider taking a daily 10µg (microgram) vitamin D supplement to maintain bone and muscle health if they have limited opportunities to get outside and/or for sun exposure to make vitamin D in the skin.                    

You may have seen claims during the early stages of the coronavirus pandemic that large doses (as much as 250µg [microgram] per day – 25 times the recommended daily intake) can help to prevent or treat coronavirus, but there is no evidence to support this, and this could be harmful for some people, such as those with reduced kidney function.  

There are some studies to suggest that getting enough vitamin D may protect against respiratory tract infections, such as the common cold and flu. However, it is unclear whether there is a direct link between the two. A review of the science suggested that following existing advice to take vitamin D supplements might have the added benefit of reducing the risk of respiratory tract infections. 

For more information about the science on COVID-19 and vitamin D see our pages on COVID-19, nutrition and immunity.

Can taking vitamin C or zinc stop me from getting a cold?

Vitamin C has been suggested to treat the common cold ever since it was first discovered in the 1930s. A review of the scientific evidence found that 200mg/day or more of vitamin C (an amount that can easily be consumed as part of a balanced diet) has no effect on the likelihood of getting the common cold, but that it may have a small benefit in reducing the duration and severity of symptoms of colds that develop while supplements are being taken.

Trials in which high doses of vitamin C were given after the onset of symptoms do not show any consistent positive effect on the duration or severity of symptoms. Therefore, while getting enough vitamin C from a healthy and balanced diet is important (adults need 40mg/day), taking large doses to treat or prevent the common cold is unlikely to have a significant benefit. Note that effervescent or ‘fizzy’ vitamin C tablets can contain high levels of sodium and so if you do take vitamin C it is better to choose a non-effervescent tablet.

There is some evidence to indicate that zinc supplements, in particular zinc lozenges, can reduce the duration of the common cold, but zinc preparations can have side effects such as nausea and an unpleasant taste and more research is needed to determine the dosage and formulations of zinc that may have a clinical benefit. Again, as with vitamins C and D, we do not have evidence that zinc supplements would have any benefit against coronavirus.

It is worth remembering that there are several different nutrients that support our immune system to work normally (others include vitamins A, B6 and B12, iron and selenium), and so aiming for a healthy, varied diet is the best way to get all the nutrients that we need to support our bodies to fight infections and stay healthy.

You can find out more information on which nutrients are important for immunity, and which founds they are found in, from our guides to nutrition and immunity at all ages.

Do IV vitamin drips or injections work?

Receiving vitamins intravenously (IV, through the veins) has become an increasingly popular trend in recent years, especially among celebrities, and some clinics that offer these often expensive treatments claim a wide range of health benefits. However, it is important to emphasise that there have been no clinical studies to show that vitamin injections of this type offer any health benefit or are necessary for good health, Also, compared to the dietary route, far less is known about the appropriate doses or the potential toxic effects of IV vitamins, and the short- and longer term health outcomes of such treatments are unclear.  

Injecting anything into the blood stream also comes with risks such as ‘air bubbles’ in the syringe that can transfer to the blood stream, allergic reactions and infection, which are more likely to occur if the person administering the injection is not properly qualified. At present, there are no regulatory processes governing safety among those offering vitamin injections.

Most people can get the right quantities of vitamins and minerals needed for good health from a healthy diet that includes a diverse range of foods from all the food groups. If you are worried that you may not be getting enough vitamins and minerals in your diet it is a good idea speak to your GP to discuss your individual needs and whether supplementation is necessary.

Last reviewed June 2021. Next review due June 2024.