Why Vitamin D Deficiency Is So Common in the UK, and How to Get the Right Dose
By Sally, Pharmacy Manager
Vitamin D deficiency is one of the most common nutritional issues in the UK, yet many people don’t realise their levels are low. Because symptoms are often subtle - or absent altogether - deficiency can go unnoticed for years.
In this post, we explain why vitamin D deficiency is so widespread, how much vitamin D most adults should take, who may need more, and how to supplement safely.
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Vitamin D plays an essential role in several key areas of health. It helps the body:
Absorb calcium and phosphate
Maintain healthy bones and teeth
Support normal muscle function
Contribute to immune system health
Unlike most vitamins, vitamin D is produced in the skin when exposed to sunlight. This makes deficiency particularly common in countries like the UK, where sunlight exposure is limited for much of the year.
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Vitamin D deficiency is common across all age groups in the UK, especially between October and March, when sunlight is too weak to trigger vitamin D production in the skin.
Other contributing factors include:
Spending more time indoors
Wearing sunscreen or covering skin
Having darker skin, which requires more sunlight to produce vitamin D
Living in northern latitudes
Limited dietary intake of vitamin D–rich foods
Because deficiency develops gradually, many people are unaware they are affected until levels are tested
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Symptoms can be mild or non-specific, which is why deficiency is often missed. Some people may experience:
Ongoing tiredness or fatigue
Muscle aches or weakness
Bone or joint discomfort
Frequent infections
Low mood during winter months
In more severe or long-term deficiency, bone health can be affected.
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General UK Guidance
For most adults, the recommended intake is:
10 micrograms (400 IU) per day
This recommendation comes from UK public health guidance, including NHS advice, and is intended to help maintain adequate vitamin D levels throughout the year.
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Some people may require a higher daily dose, particularly if they:
Have confirmed vitamin D deficiency
Have minimal sun exposure
Have darker skin tones
Are over 65
Have obesity or absorption issues
Have bone health conditions
In these cases, doses such as 1,000-4,000 IU daily may be recommended after assessment and, ideally, blood testing.
Higher doses should be taken with professional guidance, especially if used long term.
Can You Take Too Much Vitamin D?
Yes. Vitamin D is fat-soluble, which means excess amounts can build up in the body.
Long-term excessive intake may lead to:
High calcium levels
Kidney stones
Nausea or digestive upset
Confusion or abnormal heart rhythms
For most adults, 4,000 IU (100 micrograms) per day is considered the upper safe limit, unless a higher dose is prescribed and monitored.
Is Food Alone Enough?
Vitamin D is found in small amounts in foods such as:
Oily fish (salmon, mackerel, sardines)
Egg yolks
Red meat
Fortified cereals and plant milks
However, diet alone rarely provides enough vitamin D, which is why supplementation is commonly advised in the UK.
Should You Get Your Vitamin D Levels Checked?
A blood test may be useful if you:
Have persistent fatigue or muscle pain
Experience frequent infections
Are at higher risk of deficiency
Are considering higher-dose supplementation
Testing allows supplementation to be tailored safely, rather than relying on guesswork.
When to Seek Professional Advice
If you’re unsure how much vitamin D you should be taking, or you’d like to check your levels, speaking to a healthcare professional can help ensure safe and effective supplementation based on your individual needs.
This article was reviewed by Vicky - a UK-registered pharmacist. Information is correct at the time of publication.
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