John Christofides is a Principal Clinical Scientist with the Epsom and St Helier University Hospitals NHS Trust based at the Specialist Biochemistry lab at West Park Hospital, Epsom in Surrey. Apart from Vitamin D the author’s other interests include metabolic disorders associated with the porphyrias, neuroendocrine tumours and fatty acids, as well as providing an analytical service to the mental health services in the detection of drugs of abuse. These varied interests have provided opportunities for lecturing and supervising undergrad and postgraduate student projects whilst also maintaining a modest flow of papers, posters and two book chapters.
The author developed an interest in vitamin D after setting up an in-house assay in the mid 1980s predating the introduction of commercial kits by several years. This service has grown from a dozen requests a week to over 10,000 requests from his laboratory a year.
As a student the author worked in the private sector as an analytical chemist but has worked in the NHS since 1976 preferring to use his skills to develop tests and interpreting test results to help clinicians arrive at a diagnosis when dealing with a sick patient. Advising the press, John provides a public service and explains how three quarters of the UK population has vitamin D deficiency during winter and spring and that elderly and immobile people are dangerously deficient all year round.
Diagnosing nutritional vitamin D deficiency is done by measuring the combined 25-hydroxycholecalciferol plus 25-hydroxyergo-calciferol in blood. Interpretation of an adequate blood level has changed in opinion over the last 10 years but a consensus has now been reached allowing clinicians to diagnose and treat various degrees of insufficiency and dangerous deficiency.
My interest in food supplements and vitamins has suggested that people on normal diets may be wasting their money on food supplements or so-called 'superfoods' other than vitamin D itself. It is probably one of the very few vitamins where scientific evidence conclusively shows the benefit of boosting our vitamin D blood levels with supplements, especially during the winter months when natural sun stimulation is inadequate.
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