What is Vitamin D and What Does it Do?

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Commonly known as the 'sunshine vitamin', vitamin D is essential for the normal functioning of bones, teeth and muscles. Learn what vitamin D does, here.

We all need vitamins in our lives to support the normal functioning of our bodies, but it’s very easy to get bogged down with what each is supposed to do and how much we even need to begin with. Vitamin D is one in particular that’s known to confuse people as some say you get enough from sunlight alone, whereas others suggest you should take supplements and eat foods fortified with vitamin D to keep your body in tip top condition.Vitamin D

Find out from our trusted experts all about what vitamin D does, how you get it and the recommended daily dosages in this guide.

What does vitamin D do?

Widely known as the sunshine vitamin, vitamin D is essential in regulating the amount of calcium and phosphate in your body, which in turn helps to keep bones, teeth and muscles healthy. You may have heard of this vitamin being important for ensuring normal growth and development of children, but it’s necessary for adults too as it aids in normal immune function, provides improved resistance against some diseases and prevents certain health issues relating to weakened bones.

How do you get vitamin D?Woman in sun

Your body makes Vitamin D from direct sunlight on the skin from ultraviolet (UV-B) radiation that the sun emits. You should be able to get enough from sunlight exposure alone between the months of March and September in the UK, however from October to March, your body won’t be able to get enough. The NHS recommends taking vitamin D supplements of 10 micrograms (400 IU) a day between October and early March to keep your bones and muscles healthy. It’s also important to eat foods which are rich in vitamin D.

Benefits of vitamin D

Alongside keeping your bones and teeth healthy, what vitamin D does is protect you against certain health conditions. Research is currently being done in this area, but so far there’s been promising results on vitamin D helping with the following conditions:

  • Heart disease
  • High blood pressure
  • Diabetes
  • Infections
  • Immune system disorders
  • Multiple sclerosis
  • Certain cancers including: colon, prostate and breast

How much vitamin D do you need?

Children over one and adults (including pregnant and breastfeeding women) need 10 micrograms of vitamin D per day. Babies under the age of one need between 8.5 to 10 micrograms per day.

Children that don’t get enough vitamin D run the risk of developing rickets, a condition which results in bones which are weak and soft – in adults this is known as osteomalacia. There are also other complications that can come from having weakened bones such as osteoporosis which is a loss of bone density. Find out more about vitamin D deficiency in our guide.

Can you take too much vitamin D?

Yes, you can take too much vitamin D. If you take too much over a long period of time you can develop a calcium build up in your body (known as hypercalcaemia) and over time this can weaken your bones and damage your kidneys and heart.
Symptoms of hypercalcaemia include:

  • Nauseaman with lack of apetite
  • Lack of appetite
  • Increased thirst and urination
  • Constipation
  • Confusion
  • Weakness
  • Ataxia (a neurological condition)

If you notice any of the above symptoms it’s important that you go to your healthcare professional right away.

How much is too much vitamin D?

Adults should never take more than 100 micrograms of vitamin D per day, whereas children aged between one and ten shouldn’t have more than 50 micrograms and babies under one shouldn’t have more than 25 micrograms as this could be harmful. You can’t overdose on vitamin D from sunlight exposure alone, but it’s still important to cover up your skin if you’re going to be spending long periods outside in order to reduce skin damage and the risks of skin cancer.

If you’re unsure about how much vitamin D you should be taking or have a health concern, consult your doctor. They’ll be able to recommend an appropriate dosage by checking your blood levels and analysing your medical history. If your doctor happens to prescribe you more than the average daily recommended dose, it’s important you follow their advice and ensure you take the prescribed amount.

Now you know what vitamin D does, learn about other essential vitamins with our guide to vitamin D3, next.




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