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Win at Winter – Supplementing with Vitamin D

What is vitamin D?

Vitamin D is a fat-soluble vitamin found in small amounts in oily fish, red meat, liver, egg yolks, mushroom and some fortified foods. Vitamin D is often referred to as the sunshine vitamin as your body produces it when exposed to sunlight. Although there are dietary sources of vitamin D, we get a minimal amount this way; most of it is manufactured when UV light triggers our body to convert a type of cholesterol in our skin to vitamin D.

There are two types: D3 and D2. D3 is found in animal products and is what we produce from sunlight, D2 is found in plant products and it is believed not to be utilised by our bodies as well as D3.


Relying on sun to obtain vitamin D makes many people prone to deficiency, which is why it is now recommended to all people in the UK to take a supplement during autumn and winter. Based on a national survey, it is estimated that 1 in 5 people have low vitamin D levels.

Certain groups of people are more likely to suffer from deficiency, these include:

  • people who are rarely outside in day light hours (those who are housebound, those that work inside etc.)

  • people who wear clothes that cover most of the skin

  • people with darker skin

Vitamin D is best known for its role in promoting and maintaining healthy bones, as it aids with calcium absorption. However, vitamin D is being identified as playing a role in more and more body functions, with deficiencies being linked to many different diseases. One of the key areas that vitamin D is showing as important for is our bodies immunity, so especially critical during the winter when we are more prone to illnesses and have less sun exposure.


It is generally recommended that you spend 10-15 minutes in the sun (with exposed skin and no sun cream), if you are fair to medium toned, each day to manufacture enough vitamin D. It is best to do this when the sun is at it’s highest (around 10am to 3pm). Having darker skin and living further from the equator will require you to be outside for longer (up to an hour).

With this in mind, you can see why supplementing in autumn and winter is recommended.

The NHS recommends the following guidelines for supplementation:

  • Breastfed babies up to 1 year should be given 8.5-10 micrograms a day (340-400IU). For formula fed babies, check if it is fortified with vitamin D.

  • Children from 1 year old, up to adults need 10 micrograms a day (400IU).

  • Children aged 1-4 should be given 10 micrograms a day (400IU).

  • Children over 5 and adults should supplement with 10 micrograms a day (400IU) in autumn and winter.

It is recommended not to take more than 25 micrograms (1000IU) for babies up to 1 year old, no more than 50 micrograms (2000IU) for children aged 1-10 and no more than 100 micrograms (4000IU) a day for children over 11 and adults.

The UK guidelines are more conservative than other countries and some people may require higher doses, particularly those with conditions that may be linked with deficiency such as autoimmune disease, arthritis and depression. In these cases, it can be helpful to have your levels checked and work with a professional to establish an appropriate dose.

There are certain conditions in which vitamin D supplementation should only be used under the guidance of a professional such as sarcoidosis, kidney disease and over active parathyroid gland.

Selecting a supplement

Vitamin D is so widely used and manufactured now, most brands are reasonable quality. Make sure it is in the form of D3 (Cholecalciferol) and check the dose so you know how much to take. I usually use Nutriadvanced as they are one of my go to companies (and currently have 25% off vitamin D), along with BioCare & Lamberts.

This information is provided as general guidance and should not be considered a substitution for personalised advice. If you have any specific medical conditions, are taking prescription medication or pregnant, it is always advisable to discuss with a trained medical herbalist before taking any supplements or herbal treatments.

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