Vitamins & Supplements

The Ultimate Guide to Vitamin D: Benefits, Sources, Levels & More

Vitabiotics | Published: 06/03/2024

The Ultimate Guide to Vitamin D: Benefits, Sources, Levels & More

Vitamin D is an essential nutrient needed by adults and children. There are several benefits of vitamin D, so knowing how much vitamin D you need each day as well as the sources of vitamin D is vital.

As vitamin D is such an important nutrient for our bodies to work properly, it’s important tht you have sufficient vitamin D in your diet.. A vitamin D supplement can help to safeguard your intake, especially during the darker autumn and winter months.

For all you need to know on vitamin D, from what vitamin D does, to vitamin D levels, look no further…

What is vitamin D?

Vitamin D is a fat soluble vitamin, which means it can be stored in the body for a long time. It’s often known as the ‘sunshine vitamin’ because we get the majority of our vitamin D we need from sunlight. This means that in the UK’s cooler months - typically October through to March - it can be harder to obtain the recommended amount of vitamin D.

The benefits of vitamin D, which we’ll detail shortly, do vary, from helping support our immune system, to maintaining normal muscle function.

What’s the difference between vitamin D and D3?

There are two types of vitamin D: vitamin D3 and vitamin D2.

The main difference between vitamin D and D3 is that vitamin D3 is a type of vitamin D. Vitamin D3 comes from animal sources and is the type that is made in our body when skin is exposed to sunlight.

Vitamin D2 comes from plants and fungi. The preferred type of vitamin D is vitamin D3 as our bodies can absorb and use vitamin D3 more effectively than vitamin D2.

When choosing the best vitamin D supplement, be sure that it contains vitamin D3.

What are the benefits of vitamin D?

Vitamin D provides some key benefits for the body.

Primarily, vitamin D helps to regulate the amount of calcium and phosphate in the body. These are two nutrients which help to keep bones, teeth and muscles healthy. Vitamin D contributes to normal blood calcium levels too.

Vitamin D has also been shown to play a role in contributing to the normal function of the immune system in both children and adults.

Can you have too much vitamin D?

Although you cannot get too much vitamin D from sunlight exposure, you can obtain too much vitamin D from supplements. Over a long period of time, too much vitamin D from supplements can cause too much calcium to build up in the body. which can weaken bones and cause damage to the kidneys and the heart.

If you choose to take vitamin D supplements, 10µg a day is enough for most people although many people look for higher levels of support. It’s recommended to not take more than 100µg of vitamin D a day as this could be harmful. The UK’s Department of Health and Social Care also states that Children aged 1 to 10 years should not have more than 50µg per day whilst infants under 12 months should not have more than 25µg a day.

Speak to your GP or a healthcare professional if you need further advice.

Sources of vitamin D

Unlike several other nutrients, there aren’t that many sources of vitamin D as the primary source is sunlight. When skin is exposed to sunlight, vitamin D3 is produced, which is the body’s preferred type of vitamin D.

In the UK, from about late March to the end of September, most people should be able to make all the vitamin D they need from sunlight as it is during this time that the sun is stronger and the UK has more daylight hours. However, between October and early March we do not make enough vitamin D from sunlight, so vitamin D supplements can be useful.

Vitamin D is also found in some foods, however there aren’t many vitamin D rich foods, which means sunlight is our main source of this nutrient. Some vitamin D food sources include oily fish such as sardines, mackerel and salmon, liver, egg yolks, red meat such as beef, mushrooms and fortified foods such as cereals and juice.

In saying this, an average UK diet provides 3 to 4 µg of vitamin D per day and only a little more if oily fish is consumed, so it’s important to get enough sunlight when possible, or safeguard your intake with a supplement.

Supporting vitamin D levels with supplements

A useful way to safeguard your levels of vitamin D, is by taking a supplement. Ideally, to reap the benefits of vitamin D, you’ll want a supplement that contains vitamin D3 as this is more easily absorbed by the body.

The UK’s Department of Health and Social Care advises adults and children over four, consider to take a daily vitamin D supplement containing 10µg of vitamin D during the UK winter months, when sun is scarce.

People at high risk of not getting enough vitamin D such as those who spend most of their time indoors, all children aged one to four, and all babies (unless they're having more than 500ml of infant formula a day) should take a daily supplement throughout the year.

For a supplement containing the exact level of vitamin D as recommended by the UK Department of Health and Social Care try Vitabiotics Ultra Vitamin D 400IU which provides 10μg of vitamin D3.

Vitabiotics Ultra Vitamin D 4000 IU provides the maximum adult dose of 100μg in each tablet in vitamin D3 form, however it is recommended for use under the guidance or supervision of your pharmacist or health professional.

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Recommended vitamin D intake

To avoid low vitamin D levels and to ensure you’re reaping the health benefits of vitamin D, it’s wise to know the recommended vitamin D intake. Although you can obtain vitamin D from sunlight as well as a small number of foods, it can help to take a vitamin D supplement, to help achieve the recommended vitamin D intake.

A daily vitamin D supplement containing 10µg of vitamin D is a recommended consideration for adults and children over four. Although this is recommended from around October to March, there are certain groups of people who are advised to take a 10µg supplement of vitamin D throughout the entire year.

Anyone who spends the majority of time indoors, for example in a care home or if they are frail or housebound, will benefit from taking a vitamin D supplement all year round as they will see little sunlight throughout the year. Plus, anyone who usually wears clothes that cover up most of their skin when outdoors will also benefit from taking a vitamin D supplement, as sunlight is absorbed through the skin.

If you have dark skin – for example you have an African, African-Caribbean or south Asian background – you may also not make enough vitamin D from sunlight so a vitamin D supplement, taken throughout the year, can help ensure you are getting enough of this important vitamin.

How much vitamin D per day for a woman?

Women should be able to get all of the vitamin D they need from sunlight during the spring and summer months, if they are spending time outside. Around 10 to 15 minutes per day of sun should be sufficient for lighter skin types, with 25 to 40 minutes recommended for darker skin types. Adults require 10µg of vitamin D a day, including pregnant and breastfeeding women.

Vitamin D in pregnancy

It’s advised that pregnant and lactating women need 10μg of vitamin D each day, and the advice is that a supplement is taken between September and March, the darker months. . The Vitabiotics’ Pregnacare range has been specially formulated for pregnancy and helps to safeguard the daily intake of important nutrients. Each product in the During and After Pregnancy ranges provide 10μg of vitamin D to safeguard the amount needed every day.

How much vitamin D per day for a man?

Men should be able to meet their daily vitamin D requirements from sun exposure between March to early October. However, for the remainder of the year, it is recommended that men should consider taking a vitamin D supplement containing 10µg of vitamin D a day. It’s best to choose a supplement that contains vitamin D3.

How much vitamin D for children

Vitamin D is important for children as it is needed for normal growth and development of bones and the normal function of their immune system.

The UK’s Department of Health and Social Care recommends that breastfed babies from birth up to one year old, should be given a daily vitamin D supplement containing 8.5 to 10µg.Vitabiotics Wellbaby Vitamin D Drops, suitable for from birth to four years, include a useful measuring dropper.

For babies who are given formula, a supplement should only be taken when they are consuming less than 500ml of formula a day as infant formula is already fortified with vitamin D. Children up to four years old should be given a daily supplement containing 10µg of vitamin D. Vitabiotics Wellkid Peppa Pig Vitamin D soft jellies have been made for children aged three to seven years and come in an easy chewable, strawberry flavour, soft jelly. For children that prefer a liquid format Vitabiotics Wellkid Vitamin D Liquid provides a comprehensive formula with 15 nutrients, including 10µg of vitamin D , and is suitable from 4 to 12 years old. Vitabiotics Wellkid Marvel Vitamin D gummies have been produced with children's needs in mind to provide a source of Vitamin D for children, aged seven to 14 years.

How much vitamin D is too much?

You can’t overdose on vitamin D from sunlight, however the UK’s Department of Health and Social Care recommends that adults avoid taking a supplement with more than 100μg of vitamin D each day.

If you do choose to take a high-strength vitamin D supplement, it’s recommended to take this under the guidance or supervision of your pharmacist or health professional.

How to take vitamin D correctly

To maximise absorption, vitamin D supplements should be taken with food. Vitamin D is a fat soluble vitamin, so should ideally be taken alongside a meal that contains some fat.

When to take vitamin D?

There is no set time of day to take vitamin D. Some people find that it is easier to fit their supplements into their morning routine, with breakfast for example. The most important thing is that you remember to take it.

Vitamin D is essential for good health, however with sunlight being the primary source, it can be hard to achieve the recommended daily intake all year round. For babies, children and adults, healthy levels of vitamin D, or more specifically vitamin D3, is important. That’s why one of the best vitamin D supplements can help hugely.

Discover the Vitabiotics range of Vitamin D supplements and ensure you’re safeguarding your intake.

Meet the Author

lucy gornall

lucy gornall


lucy gornall


Lucy is an award winning freelance health, fitness and wellbeing journalist and copywriter. She is also a personal trainer, teaching at London based studios. With 10 years of journalistic experience under her belt, Lucy was formerly a health editor across various women’s magazines and also editor for a national women’s glossy title. She now writes for various publications whilst also working on various branded content

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