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  • Joanna Injore

Vitamin D- Do I need supplements?

Vitamin D the sunshine vitamin

vitamin d sunshine vitamin

Vitamin D is a fat-soluble vitamin but is also a hormone because it can be made in the body.

The sunlight generates our main source of vitamin D; when your skin is exposed to sunlight (ultraviolet B -UVB) it is converted in the liver to Vitamin D3 the active form our body can use.

Food sources of vitamin D

Small amounts of vitamin D is found in food particular oily fish. There are smaller amounts in other foods as below:

  • Egg yolk, meat, offal -liver, milk (amounts of Vitamin D varies on the season)

  • Oliy fish: salmon, pilchards, trout, sardines, herring, kippers, eel

  • Fortified foods (foods which Vitamin D is added): margarine, breakfast cereal, baby formula milk, yoghurts

vitamin d facts, vitamin d food sources

Why do you need vitamin D?

Vitamin D regulates the calcium and phosphate in our bodies which helps keep bones, teeth and muscles healthy. Vitamin D plays an important role in maintaining our calcium balance in the body and it is needed to absorb calcium in your bones and body cells. Even if you are getting enough calcium you still need Vitamin D to help its absorption!

Why do you need supplements?

From October to March our exposure to sunlight is low and our intake of vitamin D cannot meet our needs- so supplements are needed.

The UK guidelines are that all adults and children over 1 years should take a 10 microgram (ug) (400 I.U) supplement of Vitamin D to prevent deficiency. Supplements containing vitamin D3 (cholecalciferol) are preferable to those containing vitamin D2 (ergocalciferol) 1

If you don’t have enough Vitamin D then your blood level of Vitamin D called 25-Hydroxycholecalciferol (25-OH D) will be reduced and may lead to Vitamin D deficiency. If this happens there will be less vitamin D circulating in your blood stream increasing you risk of osteomalacia (soft bones) and osteoporosis (loss of bone density).

What are the normal blood results for Vitamin D/ 25-Hydroxycholecalciferol?

Less than 30nmol/L- Vitamin D deficiency

30-50nmol/L- inadequate level

Over 50nmol/L- adequate level

(these may vary slightly depending on the reference values the lab uses)

Who needs supplements and how much?

There are a few exceptions to the above recommendation and the following groups of people may benefit from having a vitamin D supplement ALL YEAR ROUND:

  1. Those with little or no sun exposure (e.g. if you spend a lot of time indoors)

  2. People who cover up when going outside

  3. People from BAME groups (Black, Asian and minority ethnic groups) who may have darker skin tones

What about people effected by cancer?

Hormone sensitive cancers

Hormone therapy can be given to treat some prostate, breast, ovarian and uterine/endometrial cancer. If you are having hormone treatment for breast cancer is could be an aromatase inhibitor (e.g.anastrozole, exemestane or letrozole). You may be also be prescribed a calcium and Vitamin D supplement from you doctor because aromatase inhibitors reduce the your oestrogen levels which can weaken you bones - so calcium and Vitamin D is given to prevent this (you may have a bone scan to check this before). In this circumstance you should continue with your prescribed Vitamin D and calcium supplements.

Cancer prevention

Vitamin D and its role in preventing cancer has been investigated in many scientific studies over the years. Observational and some randomized trial have suggested that higher vitamin D levels in the blood are related to reduced risk of cancer (breast, bowel and prostate). However, there are mixed messages. It is difficult to obtain a clear conclusion as some of the research has not be well conducted so likely to be biased and as these studies are observational (i.e. where you ‘observe’ a group of people and measure a particular outcome, to see if there are any links). It is important to remember that observational studies only suggest a link or association which does not mean that it CAUSES something to happen.


You don’t need high dose Vitamin D supplement but do consider a 10 microgram (ug) (400 I.U) supplement from October to March to prevent deficiency or throughout the year if you are the exception group.

If you need some advice on supplements why not book a free call?


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