Though I have a fairly healthy, balanced diet, I do take some vitamins. I take a daily multivitamin as insurance, to make sure I get a little bit of everything every day. However, I also take a vitamin D3 supplement on the advice of my doctor. About a year after moving to the UK, my blood levels of vitamin D were below normal. This is when I learned just how important adequate vitamin D levels can be.
Vitamin D is produced when sunlight hits our skin, plus we get small quantities from our diet. It’s essential for proper bone growth and maintenance. The most common disease of vitamin D deficiency is rickets, found in children whose bones fail to develop properly. Even today, there are children with rickets in the UK. As northern countries (like Great Britain) have much less sunlight in winter, and people spend a lot of time indoors, it’s hard to get enough vitamin D. Children with darker skin tones are particularly at risk. Simply put, the darker your skin pigment, the more natural sunscreen it contains. So less vitamin D is produced for the same light exposure. This has little effect on those living in African or Asian countries with plenty of strong sunlight year round, but is a real problem for darker skinned people living in cloudy northern countries.
What’s interesting about vitamin D is its biological actions are still being discovered. Low levels have been associated with reduced immune function (more colds and flu), depression, high blood pressure, some cancers and diabetes. There is also evidence that athletes need more vitamin D than the general population, depending on their sport. Many impact sports, including running, cause micro tears in the bone that then need to be repaired. This is a normal part of adapting to exercise, but if there is insufficient calcium and vitamin D to make new bone, symptoms like stress fractures and reduced immunity can result.
The UK government recommends everyone get at least 10 micrograms of vitamin D per day in winter. Unfortunately, as the Covid-19 crisis continues, many of us are now spending most of our time indoors. This is why the government has issued new guidelines, suggesting everyone consider taking vitamin D3 supplements until lockdown is lifted. You can also increase your intake with foods like oily fish (salmon, mackerel, sardines, etc.), red meat, liver, egg yolks, mushrooms and some fortified foods (for example, milk in North America has added vitamin D, but not in the UK.).
As I’m now at home 23 hours of the day and training for my second marathon (with lots of high impact running), I’ll certainly be taking my vitamin D!
You can find information about the new Vitamin D guidelines and answers to common questions on the BBC news website, at https://www.bbc.co.uk/news/health-52371688.