How do I know if I’m deficient in Vitamin D?


If you are deficient in Vitamin D the symptoms are often subtle and non-specific, so it’s difficult to know if they are caused by inadequate Vitamin D or something else.   However it is estimated more than half the UK adult population is deficient in Vitamin D which is why Public Health England recommend all adults supplement with it.

A severe Vitamin D deficiency can weaken bones.  In children this can result in Rickets, a condition that affects bone development and can lead to bone deformities.  Adults can experience a similar condition, known as Osteomalacia or ‘soft bones’.  These conditions cause muscular weakness, bone pain and fragile bones that are more prone to fractures.

Potential signs of Vitamin D deficiency

Getting frequent colds or infections: Vitamin D helps support the immune system, and one of the most common symptoms of deficiency is an increased frequency of catching colds or flu.

Bone and joint pain: Vitamin D helps maintain bone strength by supporting the absorption of Calcium.  Bone and joint pain may indicate inadequate levels of Vitamin D in your blood.

Muscle pain:  Low levels of Vitamin D can cause impaired muscle function and studies indicate that a Vitamin D deficiency may be a cause of muscle pain. (1, 2)

Feeling fatigued:  There is evidence showing a connection between low Vitamin D levels and self-reported fatigue, and that a lack of Vitamin D can have a negative impact on your energy levels.(3)

Depression: A low mood may indicate a deficiency of Vitamin D. Evidence shows that people with depression tend to have lower blood levels of Vitamin D than those without depression.(4)

Slow healing of wounds: A deficiency in Vitamin D may lead to wounds taking longer than normal to heal, for example after injury, infection or surgery.

Who is more at-risk of Vitamin D deficiency?

Everyone during Autumn and Winter months when there is less sunlight, people who spend a lot of time indoors, who wear sunscreen when outdoors, and those who wear clothes that cover up most of their skin.  Anyone with lower exposure to the sun is unlikely to get adequate Vitamin D from sunlight.

People with dark skin: Darker skin reduces the body’s ability to make Vitamin D from sunlight, so people with dark skin need more sunlight than people with lighter skin to produce the same amount of Vitamin D.

Older adults: As we age, our skin is less efficient at making Vitamin D from sunlight, so adults aged over 60 years are more at risk of Vitamin D deficiency.

Being overweight or obese: Vitamin D is fat-soluble and can be absorbed into the fatty tissue beneath the skin, making it less available to the rest of the body.(4) 

A restricted diet:  It is very difficult to get the recommended amount of Vitamin D from food alone as there are few dietary sources.  Diets that don’t include food sources such as fish, eggs, or foods fortified with Vitamin D increase the risk of inadequate levels.

Is my diet providing Vitamin D?

It can be difficult to know what nutrients your diet provides and what it doesn’t, and how they support your body, so we’ve created a free online Diet Profile that shows you.  You can try it here, it only takes a few minutes.

Today it is more important than ever to ensure you have adequate levels of Vitamin D.  The good news is Vitamin D deficiency can be fixed by any combination of eating more Vitamin D rich foods, spending more time in sunlight, and taking a Vitamin D3 supplement.

Want to find out more?  Discover the best food sources of Vitamin D here.

by Dr Laura Wyness, Phd, RNutr