What Is A Vitamin D Deficiency?

Vitamin D is vital for bone health, immunity and wellbeing. However, many of us in the UK aren’t getting enough, leading to vitamin D deficiency. Learn who’s at risk, when to supplement, and how to test your vitamin D levels from home with Check My Wellbeing.

Vitamin D plays a crucial role in maintaining the proper functioning of our bones, muscles, and immune system. But here in the UK, many of us don’t get enough, especially during the autumn and winter months. Left untreated, vitamin D deficiency can lead to serious health issues. Here’s what you need to know.

Why Is Vitamin D Important?

Vitamin D helps regulate calcium and phosphate in the body, two minerals that are essential for healthy bones, teeth and muscles. Without enough vitamin D, your body struggles to absorb calcium, which can lead to conditions like:

• Rickets in children (soft, weak bones)
• Osteomalacia in adults (bone pain and muscle weakness)

How Do We Get Vitamin D?

Most of our vitamin D comes from sunlight. From late March to the end of September, spending time outdoors allows your body to get enough. However, between October and early March, the sun isn’t intense enough in the UK, which means deficiency becomes much more likely.

Other sources of vitamin D include:

• Oily fish (salmon, sardines, mackerel)
• Egg yolks
• Red meat
• Fortified foods (certain cereals and spreads)
• Vitamin D supplements

Unlike in other countries, cows’ milk in the UK is not usually fortified with vitamin D.

Who’s Most at Risk of Deficiency?

You may be more at risk of vitamin D deficiency if you:

• Spend little time outdoors
• Cover most of your skin when outside
• Are housebound or living in care
• Have darker skin (African, African-Caribbean or South Asian backgrounds)
• Are pregnant or breastfeeding

Babies and young children, particularly those who are breastfed or have less than 500ml of formula per day, are also at higher risk and should take a supplement all year round.

Government Guidelines on Supplementation

The UK government recommends:

• Everyone over 4 years old should consider taking 10 micrograms (400 IU) of vitamin D daily in autumn and winter.
• High-risk individuals (including those with limited sun exposure) should take 10 micrograms daily throughout the year.
• Babies under 1 year need 8.5–10 micrograms daily (unless having more than 500ml of formula).
• Children aged 1–4 should take 10 micrograms of vitamin D daily, all year round.

Supplements are widely available in supermarkets and pharmacies. If you qualify for the Healthy Start scheme, you may be eligible for free vitamin D drops.

Can You Take Too Much?

Yes. Taking too much vitamin D over time can lead to hypercalcaemia (a dangerous buildup of calcium in the body), which can affect your bones, kidneys and heart.

• Adults and children over 11 should not exceed 100 micrograms (4,000 IU) per day.
• Children aged 1–10 should not exceed 50 micrograms (2,000 IU).
• Infants under 12 months should not exceed 25 micrograms (1,000 IU).

You can’t overdose on vitamin D through sunlight, but do be cautious when taking high-strength supplements, and always speak to your doctor if you’re unsure.

What About COVID-19?

Some reports have suggested that vitamin D may reduce the risk of coronavirus. However, there’s not enough evidence to recommend taking it for this purpose. That said, maintaining healthy levels year-round remains vital for overall immunity and wellbeing.

Test Your Vitamin D Levels at Home

If you’re unsure about your levels, or you’re feeling symptoms like fatigue, bone pain or low mood, a vitamin D test can provide clarity. At Check My Wellbeing, we offer easy-to-use home testing kits with fast results and expert guidance on the next steps.