Among all the vitamins we need, there is just one that we can produce in our own bodies: vitamin D. Vitamin D is made in our skin, from a form cholesterol (7-dehydrocholesterol). Sunlight is needed to turn this cholesterol into vitamin D.

In recent years, there has been a lot of research around vitamin D, revealing an astounding list of functions of this vitamin, which some say would be classed as a hormone, were it discovered today. Every single body cell has vitamin D receptors, which means that every single body cell has some sort of use for it, and the function is not always the same. So, what does vitamin D do? 

  • It supports the immune system, helping us to fight infection.
  • It has anti-inflammatory properties.
  • It is required to transport calcium from the blood into the bones.
  • It is needed for muscle function and physical performance.
  • It activates serotonin – a neurotransmitter needed for a stable mood and happiness and which is the precursor for melatonin, the “sleep hormone”.
  • It activates oxytocin – the “love hormone”.
  • It accelerates wound healing.
  • It stimulates hair growth.

Unfortunately, vitamin D deficiency is common among those who live in the Northern hemisphere as we do not get as much sunlight as would be needed for adequate vitamin D levels, especially in the winter. Moreover, we are quick to cover our skin with sunscreen as soon as the sun does come out. By protecting our skin from UV rays, we are also blocking vitamin D synthesis. While the pigment melanin protects people with dark skin from the impact of UV rays, it also hampers the production of vitamin D. Vitamin D deficiency is often observed in shift workers such as healthcare professionals and police who work nights and in people whose religious dress code may not allow them to expose their skin to sunlight.

As we age, our ability to synthesise vitamin D declines. There is less cholesterol in our skin and what there is does not respond as well to sunlight as it used to. To make matters worse, older people may not have much access to direct sunlight, if they are less mobile or disabled. Certain health conditions can also contribute to a deficiency. Body fat acts like a vitamin D sponge, pulling the vitamin out of the bloodstream, which puts overweight and obese people at a higher risk.

If you live in the UK, vitamin D deficiency is likely, especially in the spring. However, I highly recommend getting your vitamin D level tested before rushing out to purchase some vitamin D. Like all of the fat-soluble vitamins, excess vitamin D gets stored in the body rather than excreted as a water-soluble vitamin would. That means that toxicity is possible and that your level could get too high. Once you know your result, a health practitioner can pick the right vitamin D supplement for you and calculate the appropriate dosage. Testing also gives you a baseline and you can retest later to see whether – if applicable – your efforts are having an effect. An inexpensive home test is available at

Good natural food sources are oily fish – such as salmon, mackerel, herring, sardines, pilchards and anchovies – liver, eggs and mushrooms. Plant foods contain vitamin D2. The form that our body needs is the ‘animal form’, vitamin D3. The body can convert D2 to D3, and mushrooms are a rich source of it. Some varieties pack up to 2,300 IU per 100 grams, which is nearly three times the daily requirement. Other food sources of vitamin D are fortified cereals, orange juice, soya milk, butter and margarine.

As you can see there are not many food sources of vitamin D. The best way to increase your vitamin D levels is to spend time outdoors. It takes less time than you might think: Just 10 to 30 minutes of exposure – depending on the time of year – of your face and forearms without sunscreen is sufficient. This even makes a difference in the winter, but luckily it is now getting warmer and there is more sunlight to enjoy most days.

Changes in diet, lifestyle and supplementation can have a significant impact on vitamin D levels, but it can be difficult to work out a strategy and make the adjustments without support. If you are concerned about your vitamin D levels or already know that you are deficient, why not book in for a session with me. Together, we can create a plan that works for you. Give me a call or drop me a line. You will find my contact details here.

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