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Vitamin D deficiency

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The NHS advises people during the autumn and winter months in the UK due to the changes in daylight to consider taking 10mcg of vitamin D each day. Sunlight is our primary “source” of vitamin D, particularly during the spring and summer. When the UVB rays in sunlight make contact with the skin, the body is stimulated to produce vitamin D. If you’ve found yourself being inside most of the day due to lifestyle or seasonal changes it can make it hard to achieve the recommended amount, and can lead to a vitamin D deficiency.

Why is vitamin D important?

Vitamin D is a vital nutrient that our body needs to maintain good health. Though our bodies are capable of producing it via sun exposure, we can also consume it in certain foods such as oily fish and egg yolks.

Bone health

Having the correct levels of vitamin D in the body is associated with good bone health and your immune system. This is because vitamin D helps the body absorb and reclaim calcium that would otherwise be excreted.

Regulates calcium and phosphate in the body

Vitamin D also regulates levels of phosphate, another mineral that contributes to good bone health. Both calcium and phosphate contribute more widely to the health of the teeth and muscles.

Causes of vitamin D deficiency

The NHS state that you’re more likely to experience low vitamin D if you don’t get enough sun exposure. This may be because you’re housebound due to illness or frailty, live in a care home, work night shifts, or simply live in a place that doesn’t get much sun. Additionally, you’re more at risk if you have dark skin e.g. you’re of African or South Asian descent. People with darker skin need to spend more time in the sun to stimulate adequate production of vitamin D.

Sun exposure aside, you may be more prone to a deficiency if you follow a vegan diet. This is because most food sources that are rich in vitamin D (e.g. oily fish, egg yolks) are not suitable for vegans.

Symptoms of low vitamin D

In the short term, low vitamin D symptoms include the following:

Regularly getting sick

Having good levels of vitamin D in the body can help to maintain the immune system, meaning you can fight off common infections such as colds or the flu. If you notice that you’re regularly becoming unwell, this could be a sign that you’re not getting enough vitamin D.

Fatigue and tiredness

Feeling very tired, to the point of exhaustion, is a common symptom of vitamin D deficiency.

Bone and and lower back pain

Because vitamin D helps the body maintain bone health, a deficiency can lead to pain in the bones. This is commonly felt as pain in the lower back.

Muscle aches and pain

In addition to bone and back pain, low vitamin D can also lead to aches and pains in the muscles.

Long term effects of low vitamin D

In the long term, a severe vitamin D deficiency may lead to chronic health problems. In children and adults, low vitamin D can cause bone deformities – in children, it can cause rickets, while in adults it can cause a similar condition known as osteomalacia (soft bones).

Sources of vitamin D

The best sources of vitamin D are:


Aim to spend some time outdoors each day, with your hands, forearms and/or lower legs exposed and no sunscreen on your skin (but be careful not to let yourself burn).

Oily fish

Salmon, mackerel, tuna, herring and sardines are all excellent sources of vitamin D (particularly the wild, fresh varieties).

Egg yolks

Eggs from hens reared outdoors and/or fed a vitamin D-enriched diet will contain the most vitamin D.

Vitamin D supplements

An easy way to get more vitamin D is to take supplements such as Nutri Within liquid. There’s also vitamin D gummies for children, effervescent tablets as well as easy to take oral sprays.

You should not take supplements as a substitute for a varied, balanced diet or a healthy lifestyle. 

You can find out more about increasing your vitamin D intake by eating foods that contain vitamin D