Bowed legs and vitamin D deficiency: what to know

Vitamin D helps the body absorb calcium, which supports bone mineralisation. When a child has too little vitamin D, bones may become softer and bend under normal weight-bearing. The legs may appear curved, and there may also be delayed growth, bone discomfort, muscle weakness or difficulty walking. Bowing can be a normal variation in young children, especially during early development, so its appearance alone cannot identify the cause. A clinician considers age, growth pattern, diet, sunlight exposure, family history and examination findings. Blood tests and sometimes an X-ray can help distinguish nutritional deficiency from inherited bone conditions or another orthopaedic problem.

Arrange an appointment with a GP or paediatric clinician if bowing is marked, worsening, unequal between the legs, painful, or continuing beyond the expected stage of growth. Do not give high-dose vitamin D without medical advice; the appropriate supplement depends on age, diet and test results. Keep a note of when the bowing was first noticed, any falls or walking changes, and medicines or supplements already used. A balanced diet containing calcium-rich foods can support bone health, but it does not replace assessment when deficiency is suspected.

Seek prompt medical advice for severe bone pain, a new inability to stand or walk, a suspected fracture, marked weakness, or a child who is unusually unwell. Urgent assessment is also appropriate if one leg changes suddenly or the limb becomes swollen, red or very tender. These features may point to an injury or another condition rather than simple nutritional bowing.

Ask whether the leg shape is expected for the child’s age, whether vitamin D and calcium tests are suitable, and whether imaging or referral is needed. Ask how any supplement should be taken and when growth or alignment should be reviewed.