Vitamin D: The sunshine vitamin.
If you live in the UK, especially somewhere like me (Manchester) where the sun is more of a stranger than a friend, it’s possible, and I’d go as far as to say probable that you’re vitamin D levels are low. This is because we get most of our vitamin D from the sun. Your levels are likely to be even lower if you keep your skin covered, spend long periods indoors and have darker skin.
So what is Vitamin D?
It’s a vitamin that helps you absorb calcium and both are important in keeping your bones, muscles and teeth healthy. We get it from the sun - so it’s often referred to as the sunshine vitamin - but we can also get some Vit D from food such as oily fish (mackerel, salmon, sardines), egg yolks, red meat, liver and fortified cereals and spreads.
In the UK it’s recommended from October to March that EVERYONE takes a vitamin D supplement as we won’t be getting enough from the sun. It’s recommended you take 10µg (micrograms) or 400IU (international units) but you can take up to 4000IU a day. I’ve increased my intake, but I’ll tell you about that later.
You may have heard in the news recently about Covid-19 and the role that vitamin D may play in helping fight an infection, so much so that the NHS were giving free vitamin D supplements to patients who were at high risk of Covid-19. However there are conflicting studies out there, watch this space as there are current trials looking further into this. See here for summary of evidence thus far.
When I went to see my oncologist (cancer doctor) they tested my vit D levels, amongst numerous other things, which I thought was a bit odd at the time. I was also taking a multivitamin which has the recommended amount of vit D in it (10µg/400IU) and had been doing for some time (somewhere between 6-12 months before they took my bloods). So you can imagine my surprise when the only blood test that came back abnormal was my vit D level which came back undetectable, in fact it was so low my calcium levels were low too! I was given a 7 week course of treatment of high dose vitamin D, 1 tablet daily for 7 days and then one tablet once a week for 6 weeks to top up my levels.
I never really thought anything of it and it wasn’t until I was doing some reading around alcohol and cancer that I read some interesting articles and studies, which BLEW MY FREAKING MIND. Firstly because I had no idea, secondly that with my results it made sense as to why they’d tested it and thirdly because vitamin D is such an easy thing for people to take.
Vitamin D deficiency is associated with diabetes, rheumatoid arthritis, Parkinson’s disease, Alzheimer’s disease, osteoporosis and fractures. There have been reports that higher levels of vit D mean a reduced incidence of several cancers including breast, colorectal, kidney, lung and pancreatic.
Vitamin D receptors are found in breast cells and it’s thought that vit D helps keep breast cells in check, making sure that the new cells look and behave like they should, killing any that start to go a bit funky or precancerous and stop cancer cells from growing.
Some studies have shown a 45-50% reduction in cancer risk for people who have higher levels of vit D compared to those who have the lowest. Low vit D levels in some studies associated with poorer outcomes (metastatic disease, and death due to the cancer). However, not all studies have shown a reduction, there have been some that associate high vit D concentrations with increased risk of breast cancer. There is a fantastic summary to read here.
Another study suggests that vit D supplementation can reduce your risk of metastatic cancer (in patients who haven’t got cancer) especially if you are a healthy weight. Click here to read more.
So what does this all mean?
More studies need to be done to look at the role vit D plays with regards to cancers but it would seem having too low or too high levels can increase your risk.
Personally, I am taking a 3000IU supplement daily as I live in England so the sun is unreliable and my levels were undetectable on 400IU a day. I wouldn’t recommend any brand or type specifically, some people use a spray, some take tablets, some chew gummies - whatever you prefer! I take these, but you can definitely get cheaper ones elsewhere.
Do NOT take more than 4000IU a day as this is the maximum recommended and taking too much can cause toxicity which can lead to calcium build up in your blood and problems with your heart, kidneys, and bones. See here for vit D info including toxicity.
Here are some really useful websites…
Vitamin D and Covid-19.
Fact sheet on vit D and cancer.
Study looking at metastatic cancer risk and vit D.
Info on vit D.
Study looking at data - showing the higher your vitamin D level predominantly the lower the cancer risk.
Breast cancer and vit D.
Interesting study looking at vitamin D receptors and it appears the higher vit D receptor expression is associated with better outcomes for breast cancer patients.
Interesting study looking at vit D and chemo - in summary it doesn’t matter if you’ve got low or normal levels.