Vitamin D deficiency

The skin makes vitamin D under ultraviolet sunlight. From October to March the sun in Ukraine and the UK is too weak for that, so almost everyone’s level falls in winter. Ukrainian studies found low levels in a quarter to a half of adults, depending on the season, the region and the threshold used.

Symptoms

Mild deficiency usually causes no symptoms. Marked deficiency can cause:

• deep bone pain in the ribs, hips or shins;
• weak leg muscles: trouble climbing stairs or getting up from a chair;
• tiredness.

These signs are non-specific, and most people with low vitamin D have none of them.

Who is at risk

Here circumstances outweigh symptoms almost entirely:

• little time in daylight with skin uncovered, or skin always covered;
• dark skin;
• age 65 or older;
• no dairy or fortified foods;
• conditions that impair fat absorption (coeliac disease, Crohn’s disease), bowel surgery;
• kidney or liver disease;
• anti-epileptic medicines or long-term steroids;
• pregnancy and breastfeeding.

Which test to ask for

25-hydroxyvitamin D, 25(OH)D. But guidelines disagree. The Endocrine Society advises against testing everyone. Central and Eastern European experts suggest testing risk groups. In the UK everyone is advised to consider prevention in autumn and winter without a test.

So a test makes sense if you are in a risk group or have the symptoms above. The result depends on the season, and laboratories use different thresholds.

What not to do

Do not choose a dose yourself or take large “loading” doses. Too much vitamin D raises blood calcium, which harms the kidneys and the heart. Discuss winter prevention with a doctor.