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Should I be taking Vitamin D in the Winter?

Written by Benjamin Evans

Before we answer this question, let us take a look at what Vitamin D really is. Vitamin D, as the name suggests is a vitamin that we mainly get from the sun. As stated by the World Health Organisation, Micronutrients are vitamins and minerals needed by the body in very small amounts. However, their impact on a body’s health are critical, and deficiency in any of them can cause severe and even life-threatening conditions. They perform a range of functions, including enabling the body to produce enzymes, hormones and other substances needed for normal growth and development [1].

How does it work?

Vitamin D is produced by UVB (ultraviolet B) as soon it touches the skin. the skin then acts as a transducer and changes the sunlight energy into a different type of energy, a chemical energy. This can only take place if the sunlight has a UV index of 3 or above and reach skin with no sun lotion. Sun lotion onto the skin will act as a barrier and make it impossible to produce adequate amount of Vitamin D. This Vitamin d then travels to the liver and is hydroxylated before going into the kidneys at which point it is converted again into the type, we see on blood tests.

This is a vital stage as adequate Vitamin D means we hold onto calcium, which is essential for muscle and bone health.

Can I get enough Vitamin D from the sun in winter?

The short answer to this is no. As stated previously, there must be a UV3 or above hitting skin with no lotion on. This being said, between the months of September to the following April, it is impossible to get sufficient amounts of Vitamin D onto the skin as the sun is not ‘high enough’. A good rule of thumb for this is to pay attention to your shadow. If your shadow is longer than you (meaning the sun is low) UV is not strong enough to create adequate Vitamin D regardless of sunlight touching the skin. On the other hand, if your shadow is shorter than you (sun is high), UV radiation will be strong enough to activate the transducers in your skin and kick off Vitamin D production [2].

How much Vitamin D can my body make from the sun?

Vitamin D is generally measure in IU (International Units). If the sunlight is strong enough to make someone with fair skin (not advised) turn pink, you can create 20,000IU in just 30 minutes. As a general rule, the best advise here is to spend a third to half of the time in the sun than it would normally take skin to go pink.

How many of us are deficient/insufficient?

In the winter months, 87% of people in the UK are classified as deficient or insufficient. Even towards the summer time, deficiency/insufficiency rates are still as high as 60%.

What symptoms might I experience if I am low in Vitamin D?

Because Vitamin D plays such an important role in many functions of the body, symptoms can vary dramatically. This also depends on the severity of the deficiency. If someone is severely deficient, symptoms may be more aggressive than another person who may only be partially insufficient. Symptoms can include muscle pain and stiffness, fatigue, weakness, depression, and behavioural issues. People low in this essential Vitamin may also have a diagnosis of Fibromyalgia and Chronic fatigue syndrome and have a non-response to previous therapeutic interventions [3].

So to answer the question ‘should I be taking Vitamin D in the winter’, YES.

Vitamin D plays a pivotal role in many body processes. When there is a lack of Vitamin D, the processes that rely heavily on this micronutrient are performed poorly, resulting in symptoms discussed earlier. Many supplements these days might contain a approximately 400IU. This is however nowhere near sufficient to have a positive impact on the body. 4000IU would be the ideal quantity to aim for when choosing supplements [4].






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