Vitamin D Deficiency: Why It’s So Common in the UK and How to Test for It

09 Oct 2025

Vitamin D is often called the “sunshine vitamin”, yet deficiency is surprisingly common in the UK. With our long winters and limited sun exposure, many people struggle to maintain healthy levels. Left unchecked, low vitamin D can affect bones, muscles, and even mood.

In this blog, we’ll explore why deficiency is so widespread, the symptoms to look out for, and how a simple test can give you answers.

Why Vitamin D Matters

Vitamin D helps regulate calcium and phosphate in the body — nutrients essential for healthy bones, teeth, and muscles. Without enough, bones can become weak, and muscles may ache or tire easily. Research also suggests vitamin D plays a role in immunity, mood regulation, and even cardiovascular health.

Why Deficiency is So Common in the UK

There are several reasons why so many people in Britain struggle with low vitamin D levels:

• Limited sunlight – From October to March, the sun isn’t strong enough for the skin to produce vitamin D naturally.
• Indoor lifestyles – Office work, commuting, and less outdoor activity reduce exposure further.
• Darker skin tones – People with higher melanin need more sun exposure to make vitamin D.
• Dietary factors – Few foods naturally contain vitamin D; oily fish, eggs, and fortified cereals are the main sources.
• Age – Older adults are less efficient at producing vitamin D through the skin.

These factors make deficiency almost inevitable for many people during winter.

Symptoms of Vitamin D Deficiency

Signs can be subtle and easy to mistake for other conditions. They may include:

• Persistent fatigue
• Low mood or “winter blues”
• Muscle weakness or cramps
• Bone or joint pain
• Frequent infections
• Hair loss

Because these symptoms overlap with other conditions, testing is the most reliable way to confirm deficiency.

You can book a Vitamin D Blood Test to check your levels quickly and accurately.

Who’s Most at Risk?

The NHS recommends that certain groups take extra care with vitamin D, including:

• Pregnant and breastfeeding women
• Infants and young children
• Older adults
• People with darker skin
• Those who cover their skin for cultural reasons
• Anyone spending little time outdoors

Role of Testing

While supplements are widely available, it’s best to check your levels before starting long-term supplementation. This helps you avoid taking too much or too little.

A blood test can measure:

• 25-hydroxy vitamin D (25-OH) – The main form used to assess deficiency.
• 1,25-dihydroxy vitamin D (calcitriol) – Sometimes tested in specific medical cases.

At South Kensington Medical & Dental, we offer Vitamin D Tests with next-day results.

Treatment and Prevention

If deficiency is confirmed, your doctor may recommend:

• Supplements – Usually in tablet or liquid form.
• Dietary adjustments – Eating more oily fish, eggs, and fortified foods.
• Lifestyle changes – Spending short periods in sunlight during spring and summer.

For most people, supplements are the simplest way to restore healthy levels, particularly in autumn and winter.

Why Early Action Matters

Vitamin D deficiency can be easily corrected, but if left untreated it may increase the risk of osteoporosis, rickets in children, and muscle weakness leading to falls in older adults. Early testing provides reassurance and allows you to take control of your long-term health.

Final Thoughts

In the UK, vitamin D deficiency is common and often overlooked. With subtle symptoms and widespread risk factors, testing is the only way to know for sure if you’re affected.