Vitamin D – the ‘vitamin’ with an identity crisis

Written by Louise

Let’s get one thing clear right from the start. Vitamin D is not actually a vitamin. When it was first discovered, scientists thought it was a vitamin, so it was wrongly labelled. It’s actually a hormone, and it’s produced by the skin in response to the UVB rays in sunlight (as well as being available in very small amounts in food). The right amount of ‘vitamin’ D, it turns out, is crucial to our health and wellbeing.

Back in July, one of my British friends posted on FaceBook: “I don’t know what it is, but everyone seems to be tired at the moment.” Most people agreed with him, but I bucked the trend – and probably irritated a lot of people – by saying I was completely the opposite. In fact, I was only sleeping about 6 hours a night and I had more energy than I’d had for a long time.

It wasn’t until a couple of weeks ago that I started to connect the dots.

It’s no secret that most of us tend to feel better about life in summer, and I’m certainly no exception to that rule. In fact, the difference between my mood and energy levels in winter and summer is literally like night and day. In summer, I feel happier, more awake, and generally more able to cope with whatever challenges life happens to throw at me. Most people I know are the same, which is why I was surprised that so many of my friends were struggling when I was feeling so great.

SAD (which stands for Seasonal Affective Disorder) is a recognised disorder that leads sufferers to feel generally depressed in winter. According to NHS Choices, symptoms include:

  • a persistent low mood
  • a loss of pleasure or interest in normal everyday activities
  • irritability
  • feelings of despair, guilt and worthlessness
  • feeling lethargic (lacking in energy) and sleepy during the day
  • sleeping for longer than normal and finding it hard to get up in the morning
  • craving carbohydrates and gaining weight

When I lived in the UK, I experienced most of these in winter, and everyone told me I would feel so much better when I moved to Spain. UK winters are typically rainy, dark and dreary, but Spanish winters are bright and dry. The sun is out most of the time, and it doesn’t rain much. Going back to NHS Choices, the medical profession seems to support my friends’ unofficial diagnosis. Their website states:

The exact cause of SAD isn’t fully understood, but it’s often linked to reduced exposure to sunlight during the shorter autumn and winter days. The main theory is that a lack of sunlight might stop a part of the brain called the hypothalamus working properly…

It goes on to list some possible effects:

  • production of melatonin – melatonin is a hormone that makes you feel sleepy; in people with SAD, the body may produce it in higher than normal levels
  • production of serotonin – serotonin is a hormone that affects your mood, appetite and sleep; a lack of sunlight may lead to lower serotonin levels, which is linked to feelings of depression
  • body’s internal clock (circadian rhythm) –your body uses sunlight to time various important functions, such as when you wake up, so lower light levels during the winter may disrupt your body clock and lead to symptoms of SAD

I was surprised to find that moving to Spain only reduced my SAD symptoms, but didn’t eliminate them – I still feel very low in winter (although I haven’t done anything quite as dramatic as buying a new car I don’t need on finance, in an effort to cheer myself up, which I did one January while living in the UK). In fact, I’ve often joked that I must be the only person who can suffer from SAD while living on the Costa del Sol.

A few weeks ago, while I was trying to learn more about vitamin B12 deficiency, I posted a list of blood tests in a FaceBook group, and asked if there were any other tests I should have at the same time. Someone suggested vitamin D because “it seems to go along with B12 deficiency” and, although I pointed out where I lived and that I was unlikely to be deficient, I added it to my tentative list.

The more I researched B12 deficiency, the more often I noticed references to vitamin D deficiency going alongside it, and eventually, I started to research vitamin D as well.

What I found surprised me.

(I read many articles on vitamin D during my initial research, and it would be impossible to find them all again, so I’ll just summarise a few of the key points.)

  1. Vitamin D is made by our bodies when the UVB rays in sunlight fall directly on unprotected skin.
  2. As well as protecting us against burning, sunscreen also blocks UVB rays from reaching the skin, and prevents the production of vitamin D.
  3. A person living in a very sunny place, and wearing minimal clothing, can produce 20,000 – 30,000 IU of vitamin D a day in summer. (That’s a lot of vitamin D!)
  4. UVB rays only reach the ground (and our skin) when the sun is at a height of 50 degrees or more. To put this into perspective, where I live, on the Costa del Sol, the sun only reaches this height between the middle of March and the end of September. For the rest of the year, due to the tilt of the Earth’s axis, it’s below 50 degrees.
  5. Vitamin D helps to control levels of calcium and phosphate in the body, maintaining healthy bones and teeth, and too little of it can lead to rickets in children and osteomalacia (weak bones) in adults. That’s according to NHS Choices again. A little more research turns up a lot of other things vitamin D is good for.
  6. Vitamin D levels drop quickly, so regular “top ups” are needed to prevent deficiency.

I’ve believed for a long time that sunlight is good for us. Bruises fade quickly, and cuts and grazes heal faster, when you spend time in the sun. From personal experience, being in the sun helps us to heal.

I’ve also argued (and bear in mind I don’t have any references for scientific studies to back up this point, so agree with me at your own risk!) that the sun doesn’t cause skin cancer. If the sun promotes healing, which happens through the replacement of damaged cells, perhaps it also helps cancer cells to spread and grow faster. Perhaps the relationship between the sun and cancer is that the sun speeds up the growth of already existing skin cancer cells, so they spread too fast for the immune system to destroy. Perhaps the reason for the increase in skin cancer since the 1980s (when sunscreen started to become widely used) is that we put nasty, cancer-causing chemicals on our skin and then go and sit in the sun for hours and help the cancer grow.

I have always believed that the sun is good for us and, as long as we avoid burning and don’t put nasty chemicals on our skin, spending time in it is healthy.

Back in early July this year, I realised I didn’t have much of a tan yet. I’d been working indoors a lot, and my skin was still pale and unhealthy looking. I needed to do something about it, before people started thinking I was on holiday here from somewhere in northern Europe, so I started sunbathing for 40 minutes every day. (I started with 40 minutes because that was how much sun my skin could handle without burning – 20 minutes each side – but by the end of summer, I was spending up to 1.5 hours each day relaxing in the sun with my book.) I didn’t wear sunscreen.

By the time my friend, who lives in Britain, posted his comment on FaceBook, I had been sunbathing every day for a couple of weeks, but it took a few more months and a lot of research into vitamin D before I realised the connection.

According to the Vitamin D Council, “…symptoms of vitamin D deficiency are sometimes vague and can include tiredness and general aches and pains…” But isn’t that how many of us feel in the winter? Tired, lethargic and generally out of sorts. More severe deficiency can lead to “…pain in your bones and weakness…” and “…you may also have frequent infections…” Well, frequent infections are pretty much a given if you spend a winter in Britain.

The medical profession is well aware of this. When one of my British friends asked her doctor for a blood test to determine her level of vitamin D, he refused her on the grounds that “everyone’s deficient.” He wouldn’t even send her for tests, never mind prescribe supplements. (Not that the supplements doctors prescribe are any use for treating a deficiency, but more about that in another post.)

The image below shows some different levels for vitamin D (note the different measurements – the UK generally uses the scale on the right).

Most people are deficient in vitamin D.

Most people are deficient in vitamin D.

If you’ve ever had your vitamin D level tested, you were probably well below the recommended 80ng/ml or 200nMol/L shown in the image. And unless your vitamin D was extremely low (right down in the blue zone), you were probably told you were fine. I’m certain I’m well within the ‘normal’ range for vitamin D, and yet I still feel much more sleepy and much less ‘well’ in general than I do in summer.

So, I’ve ordered some vitamin D supplements and I’m going to conduct an experiment on myself. My plan is to start by supplementing 5000 IU a day (along with vitamin K2, which I’ll explain in another post), and see how I feel, maybe increasing to 10000 IU a day if there’s an improvement but I still don’t feel as well as I do in summer. I’ll get a blood test done in January or February some time, to check that I’m not raising my level too high because 5000 or 10000 IU is a pretty big dose of supplement.

Hopefully, the vitamin D added to the vitamin B12 will give me a lot more energy and zest for life.

About the author


Animal lover, asexual, blogger, cyclist, daughter, dreamer, entrepreneur, expat, optimist, procrastinator, reader, realist, rescuer, runner, sister, writer ... Hate labels? Me too. Just read my blog.

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