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Sunshine important for Vitamin D

Vitamin D: Micronutrient, Mega Important

The existence of vitamin D has been known about since the early part of the 20th Century but interest and research into vitamin D has exploded in the last twenty years. 

What is Vitamin D

It is a fat-soluble vitamin necessary for maintaining bone health, regulating calcium and phosphorus levels in the body, and supporting immune function.


Vitamin D was known to be important for bone metabolism, specifically preventing the disease of rickets in children, and osteomalacia in adults, but we now know that vitamin D has a plethora of effects away from the skeleton. Vitamin D seems to have a number of important roles such as supporting the immune system, reducing the risk of some cancers, reducing the risk of osteoporosis and maintaining muscle strength, and it even seems to be beneficial for improving mood and energy levels.

How Vitamin D differs from other Vitamins

Vitamins in general are defined as essential micronutrients that the body can’t make on its own and therefore must be included in our diet. 


But vitamin D is unusual. 


Whilst it is contained in some foods such as oily fish, egg yolks and red meat, most of our vitamin D is made by our skin in response to exposure to sunlight. And herein lies the problem for those of us whole live on this damp, little island. Although fair skinned people can maintain vitamin D levels with just half an hour of midday sunshine to the face and forearms, two to three times a week, even this is difficult to achieve in the UK.

Reasons why the UK population is Vitamin D deficient

Unfortunately, between October and March most parts of the UK simply don’t get enough sunshine to produce adequate amounts of vitamin D. 


Therefore, many of us end up being deficient in vitamin D over the winter months - up to 40% of us according to some studies. And, given the increasingly indoor nature of our lifestyles, the situation in the summer is not always much better. 


Those with darker skin, or who keep their skin covered, are at even higher risk from this problem, as are elderly people living in residential homes, and young children.



Symptoms of Vitamin D deficiency

Vitamin D deficiency is therefore something of an epidemic in the UK. Sadly, we are now even seeing cases of rickets in the UK amongst children despite the disease having all but disappeared by the 1950s. Rickets can lead to bone deformities, impaired growth and sadly, if it isn’t picked up, it can actually be fatal in children. In adults, the condition of osteomalacia can cause aches and pains, muscle weakness leading to a so called ‘waddling gait’, and possibly broken bones.


Despite the widespread prevalence of vitamin D deficiency, it is easily overlooked. The symptoms of vitamin D deficiency, particularly if the deficiency is mild, are often vague and difficult to define.


Frequently the feeling of malaise or lethargy that may be caused by low vitamin D levels are attributed to something else, or just blamed on the general stresses of life. This is a real shame because replacing vitamin D is very straightforward.

Lethargic man

Vitamin D supplements are readily and cheaply available over the counter. The recommended daily dose of vitamin D for adults is 400 International Units (IU) which is the same as 10 micrograms.


As vitamin D levels can be easily checked with a blood test and easily corrected with treatment, if you have symptoms suggestive of a vitamin D deficiency, it is worth taking the test.


Vitamin D supplements are readily and cheaply available over the counter. The recommended daily dose of vitamin D for adults is 400 International Units (IU) which is the same as 10 micrograms.

Diagnosing Vitamin D deficiency

As vitamin D levels can be easily checked with a blood test and easily corrected with treatment, if you have symptoms suggestive of a vitamin D deficiency, it is worth taking the test.


At One Day Tests we offer a Vitamin D blood test.


This test is available as a finger prick home test or a venous test taken at one of our UK blood testing clinics.

Simply click on the test below, select the blood collection method you wish to use and place your order. In a couple of days you can find out your Vitamin D levels.

About One Day Tests

One Day Tests offer you the power to manage your health like never before by monitoring and understanding your current and future health status. Whether it’s for routine health checks, managing a chronic condition, or just staying informed about your body, our range of blood tests provides the ease, speed and accuracy in your results and providing the peace of mind you deserve.


Whether you choose to visit a clinic for your blood test or opt for the convenience and comfort of using our at-home blood test kits , we ensure a service that is not only dependable but also tailored to suit your preferences.


For additional assistance, guidance or queries regarding our custom panels, do not hesitate to get in touch. Our team is here to help you with any questions and provide you with the information you need. You can contact us at 0845 527 07 67 , send an email to hello@onedaytests.com , or reach out to us via WhatsApp.

Other blood tests you may be interested in

A simple blood test can unlock the answers to your health. There are 3 key benefits to getting a blood test:


  1. Early Detection - Identify potential health issues in their early stages
  2. Health Status - Gain knowledge of how your body is currently functioning
  3. Peace of Mind - Get reassurance about your health and knowledge that will help you make informed decisions.

For a full body MOT we recommend taking our Ultimate Performance Blood Test.


This is the largest panel we offer testing for 57 different biomarkers in the blood, available in the clinic or as a home kit. The Ultimate Performance Blood test gives you incredibly detailed information about your health, including:

  • A comprehensive hormone profile
  • Micronutrient levels
  • Cardiovascular risk factors
  • The health of your immune system
  • The health of vital organs geared towards lifestyle and nutrition, dieting and tracking sports activities for ultimate health monitoring and performance

Every system is covered, putting you on a transformative path towards optimising performance and well-being.


We also offer other comprehensive tests for both Me and Woman, called our Healthy Man and Healthy Woman blood tests.


Click the tests below to find out more.



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