Vitamin D: Your Questions Answered



With Autumn now in full swing, it's time to talk about vitamin D. The UK government recommends that EVERYONE take vitamin D supplements between September and April. This is because we usually generate a lot of our vitamin D from having sunlight on our skin and during the winter months, we don’t get enough sunlight in the UK to prevent deficiency.


If you take prescribed medications, always talk to your GP, pharmacist or a registered dietitian before taking a supplement.


Here we answer your most asked questions about Vitamin D.


What do I need vitamin D for?


Vitamin D is a fat soluble vitamin which we can also generate from the UV rays of sunlight when it hits our skin.


Vitamin D promotes calcium absorption in the gut, allowing our bones to be mineralised properly. Because calcium is also essential to muscle contraction, vitamin D is also essential for the normal functioning of muscles and other tissues.


Vitamin D also helps to reduce inflammation in the body and modulates cell growth, neuromuscular and immune function. ‘Modulates’ refers to its ability to ensure there is enough activity without it being too much, so that’s how it is linked to cancers and autoimmune conditions.


Many tissues in the body have vitamin D receptors indicating that it has a vital role in many parts of the body.


Can I get vitamin D From food?


We can get vitamin D from food such as oily fish, red meat, liver, egg yolks and some fortified foods. The problem is, the vast majority of people aren’t eating adequate amounts of those foods regularly.


Our changes in patterns of eating, moving more towards plant based eating, coupled with the lack of sunlight, means that the vast majority of people don’t meet their vitamin D requirements.


How much vitamin D should I take?


The UK government recommends that we all take 10 micrograms (μg), which is 400 international units (IU).


The reason the government recommends 10μg is because this is from the Recommended Dietary Allowance (RDA), which is defined as the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals.


There is a lot of talk about whether the RDAs need to be updated because we have learnt SO much about nutrition and vitamin D in particular since they were published in 1941.


The safe upper limit of vitamin D is set at 100μg (4000IU) for men and women over the age of 18. That means that it is considered medically safe to take up to 100μg of vitamin D per day.


High dose supplements shouldn’t exceed this amount and if you are taking high dose vitamin D supplements, it is very important to only take one supplement that contains vitamin D and try to avoid vitamin D fortified foods. It is generally a good idea to take less than 100μg per day in supplement form so you have room for more from other sources.