Chasing vitamin D

SIR – You recommend making time in the middle of the day to go outdoors during the winter, to keep vitamin D levels up (Health, November 27).

However, winter sunshine in Britain (from late October to March) does not contain enough UVB radiation for our skin to be able to make vitamin D. Even walking naked on a bright day would not increase production.

The NHS recommends that we all consider taking a 10mcg vitamin D supplement during autumn and winter months, as it is unlikely we will obtain enough from our diets. Joan Manning

Watford, Hertfordshire