It's often known as the sunshine vitamin, because the main source of vitamin D is from sunlight – unlike other vitamins which we get from food. Vitamin D is produced in our bodies from exposure to sunlight on our skin, but if we are spending a lot of time indoors, we are at risk of not getting enough.
During the autumn and winter months, because the sun is not as strong, we can't make all the vitamin D we need. It was thought that our bodies could make enough in the summer months to store for the winter – but recent evidence suggests this may not be the case for most of us. Because of this, we are advised to take a vitamin D supplement from October to March.
Although we're now in May, the current situation in the UK means we're probably spending less time than usual outside, so it makes sense to keep supplementing our diets with vitamin D. And if you are someone who isn't able to go outside at all, it's definitely important to continue taking a vitamin D supplement. For advice on Vitamin D supplementation check out this NHS web page.
While some foods contain vitamin D, it's not many, so food is not a great source of this vitamin. Sunlight or supplementation are most effective.
In recent years, research has found a link between vitamin D and immunity, with some studies indicating that vitamin D deficiency could increase susceptibility to certain infections. There is currently a lack of long term studies in humans to back up the laboratory research, so more work is needed before we understand the full effect of vitamin D on immunity. That said, we do know the important role vitamin D plays in bone health, so ensuring you're getting enough is definitely important – and it may also help to protect you from certain infections.
People often choose to take a multivitamin to ensure they're getting all the nutrients they need to stay healthy. But in truth, if your diet is varied and nutrient-rich, most of us aren't advised to take vitamin supplements. As long as you're eating plenty of fruits, vegetables, wholegrains, proteins and calcium rich dairy foods or calcium fortified dairy alternatives, you should be getting all the nutrients you need and a supplement will not be beneficial.
In fact, taking a supplement with water soluble vitamins C and B vits, can just mean we end up having a rather expensive wee, as our body will simply get rid of what we don't need! Fat soluble vitamins A, E, K can be stored by our body, so taking larger amounts than we need can potentially be harmful. So it's important to read the labels of your supplements to check the amounts and ensure you're not doubling up and taking very high doses of certain vitamins.
Nutritionist Emma Brown (ANutr), MSc Human Nutrition is passionate about how food science applies to the human body, and how the nutrients in what we eat affect us and ultimately have an impact on our health.