The What and Why: Vitamin D

Disclaimer: This information is based on my own research into this particular aspect of IBD as well as some personal experience and should not be used as medical advice or a diagnostic tool. The suggestions given within are taken from sources laid out in the references header.  If you seek advice regarding the things you experience within your own disease, please contact your IBD team for medical advice.

If you are looking for the entire ‘What and Why’ series, you can find them all here

What is Vitamin D?

Vitamin D is a nutrient needed to help control our absorption of calcium and phosphate entering our body from our diet. These particular minerals are important for healthy bones, teeth and muscles. Vitamin D is created from direct sunlight on our skin when we are outdoors. It is abundant in the months from April to October and found in some foods; such as oily fish, eggs, margarine, some red meat, mushrooms and fortified cereals.

How do you know if you’re deficient?

Most people in the UK are Vitamin D deficient due to the lack of sunlight, especially during the winter. Most people don’t realize that they are deficient, because the symptoms are generally subtle. They may not be noticed easily, even if they are having a significant negative effect on your quality of life. They can be:

  • Getting sick or infections often – Vitamin D plays a big role in keeping our immune system strong, so if you get sick easily, it lasts for a long period of time, or you get them persistently, you could be deficient.
  • Fatigue & tiredness – excessive fatigue or daytime tiredness could be contributed toward a Vitamin D deficiency.
  • Bone & back pain – Vitamin D is important in maintaining bone function and health; primarily with its role in absorbing calcium. This can lead to, over time, chronic pain in joints and the back due to deficiency.
  • Depression – low or a depressive mood has been linked to low levels of Vitamin D.
  • Impaired wound healing – low levels of Vitamin D could show as being more likely to have higher inflammatory markers which jeopardises healing. It’s been suggested that the vitamin has links to fighting infection and the production of new and health skin in wounds.
  • Bone loss – Vitamin D plays a crucial role in calcium absorption and bone metabolism. Having both Vitamin D & calcium in the body reduces the risk of fractures and bone loss in older age.
  • Hair loss – In severe hair loss, Vitamin D can sometimes be a contributing factor; along with other nutritional deficiencies.

Who is at risk?

  • Vegans – they can have low levels of Vitamin D, because most natural sources are animal based. Pay extra attention to your diet, and eat fortified foods (cereals, soya milk, almond milk, and orange juice) and take a quality Vitamin D supplement.
  • Limited sunlight exposure –  If you are housebound for any reason, if you live in a grey climate, or if you cover your skin for work, lifestyle or religious reasons, your skin might not get enough sunlight.
  • People with darker skin – The pigments in the skin will reduce your ability to make Vitamin D, even if you get plenty of sunlight. Older adults with dark skin are particularly at risk.
  • Your digestive tract cannot adequately absorb vitamin D – Certain medical problems, including Crohn’s disease, cystic fibrosis, and celiac disease, can affect your intestine’s ability to absorb vitamin D from the food you eat.
  • Being overweight or obese  Vitamin D is extracted from the blood by fat cells, altering its release into the circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D.

How is it tested & treated?

Vitamin D is usually diagnosed through a blood test. The marker is the status of 25-hydroxyvitamin-D [25(OH)D], a metabolite of vitamin D3. A 25(OH)D level determines whether a person is deficient, sufficient, or toxic in vitamin D. At this time, there is not a consensus in medicine in what blood levels define these categories.

But the NHS recommends maintaining serum levels of 50 ng/ml (equivalent to 125 nmol/L), with the following reference ranges

  • Deficient: 0-40 ng/ml (0-100 nmol/l)
  • Sufficient: 40-80 ng/ml (100-200 nmol/l)
  • High Normal: 80-100 ng/ml (200-250 nmol/l)
  • Undesirable: > 100 ng/ml (> 250 nmol/l)
  • Toxic: > 150 ng/ml (> 375 nmol/l)

Your result from this test will determine the dosage of the supplement you need and the length of time you need to take it for.

Why is this important if you have IBD?

There is lots of research and studies looking at the link between IBD and Vitamin D. As many suspect that the cause of IBD is partly down to your immune system; they looked into what people with IBD lacked in their immune system and Vitamin D was high on the list. Add in the fact that Vitamin D is fat soluble so you need a health digestive trace to fully absorb the vitamin, we are already at a loss. In addition; being on steroids doesn’t help – this is why having calcium alongside your steroids is fundamentally important! – and being unwell and staying inside, away from the natural sunlight magnifies the problem. A study explored by CCUK suggests that IBD patients who are deficient in Vitamin D – estimated at about 30% – need more steroids and have almost double the chance of surgery than IBD patients who aren’t deficient. What’s not very clear is if a deficiency in Vitamin D is a cause of IBD or a result of it. Probably both but what we do know is that treating Vitamin D deficiency does help your immune system in the long run.

My experience

I’ve been deficient for a long time now. I’ve been tested on several new hospital appointments with new departments in the last eighteen months to two years, but sadly it’s been a back burner issue for me; as more serious problems were at the forefront. It’s only when I was put on anti depressants for my anxiety that it was flagged once again and I was prescribed medication. I am currently on a loading dose of 3200IU for 12 weeks before they test my level again and see where we are, prescribing a dose as necessary. My latest test on January 24th was 19ng/ml – defiantly in the ‘deficient’ range.

So far – five weeks in – I do feel some benefit. But it could be my anti depressants; having both prescribed at the same time might have a positive effect on each other, but we’ll not know if one is working better than the other until my levels are checked in late April.

Are you Vitamin D deficient? How do you find this? Are you currently on medication or recently finished?

Do you have any questions or queries? Or just want to share your own experiences? Leave me a reply or tweet me @sapphire20 or find my blog page on Facebook!


NHS Choices: Vitamin D &  The new guidelines on Vitamin D (July 2016)

IBDRelief – Vitamin D Deficiency and IBD

A Balanced Belly: Nutrition Explored – Vitamin D & IBD

Crohns & Colitis UK: Research Study – Vitamin D & IBD


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