From Henry Johnston
Colin Brown asks your Last Word column whether he can get the full benefit of vitamin D from sunshine through glass (13 June). When I was a small boy in Edinburgh in the early 1920s my mother had Vitaglass fitted to our huge west-facing nursery windows – she understood this was the only way we would get our vitamin D from the sun while indoors. Does anyone remember this window glass? Was she right?
Perhaps this is why I am such a healthy 94-year-old.
London, UK
