By Dr Frank Dunn
I get my medical information from a number of sources. My wife asked me recently if I knew that eggs contained Vitamin D.
I had to ashamedly admit no, blaming this gap in my knowledge, on either my biochemistry lecturer in 1965 or a dodgy memory.
It got me thinking about this vitamin which has a key role in bone development and formation. I did know that the sun was an important source of this vitamin, and that deficiency caused rickets in Glasgow in the early part of the 20th century.
Tenement flats did a good job at blocking whatever sunlight Glasgow had, and there was not enough Vitamin D in the diet. Hence the development of rickets, which curtailed growth and caused the legs to become curved.
The solution was to make sure that there was sufficient Vitamin D in the diet, and this was achieved through cod liver oil.
This contains both Vitamin A and Vitamin D. The addition of orange juice ensured that Vitamin C was also covered.
The combination of “cod liver oil and the old orange juice” was immortalised in the Scottish folk song by Hamish Imlach.
I also remember being persuaded to swallow a spoonful of malt as a child. This had Vitamin A and riboflavin (a member of the vitamin B family), but also considerable amounts of sugar, since it was felt that children were deficient in carbohydrate. I don’t think that is still the case!
Rickets was also seen in the post war years among children who came from the Asian sub continent. They had relied on the sun for their Vitamin D and on arrival in Scotland they found that the sun could not be relied on.
A former Stobhill colleague of mine, Dr Matthew Dunnigan, demonstrated this and more importantly was instrumental in incorporating Vitamin D into their favourite foods.
At the other end of the spectrum, my late father, who was a Consultant for Care of the Elderly, noted with others that osteomalacia (the result of Vitamin D deficiency in adults), was an unrecognised and a fairly common occurrence in old people. This was due to a combination of being indoors with lack of sunlight, reduced conversion to the active ingredients of Vitamin D and dietary deficiency.
Osteomalacia can cause small but painful bone fractures, weakness of the muscles, and a variety of other illnesses. Incorporation of calcium into the bone becomes affected. Treatment rests in improving dietary intake of Vitamin D and calcium. The main foods that naturally contain Vitamin D are tuna, mackerel, eggs, beef, liver, cheese, and of course cod liver oil.
Some foods such as milk and cereal are fortified by vitamin D. Pure supplements are also available, but it is worth noting that too much vitamin D from supplements can cause ill health. Therefore the best ways to receive Vitamin D is from sunlight or in the diet.
A well-balanced diet for those adults who are healthy, will provide sufficient vitamin supplements, provided we do not over cook our vegetables. The situation is different in infants, and your doctor will advise you in this area.
A variety of illnesses can result in deficiency of vitamins, including, in particular, diseases of the digestive system and the kidney. In such situations, vitamin supplements may be required, as directed by your doctor.
I am currently in Oman with the Royal College and can report that you do not need to worry about Vitamin D deficiency here. The sun shines all day and for a Glasgow person in February, this is quite confusing. I will accept it however. My Vitamin D levels will be well topped up, despite using factor 50 to protect my pale freckly skin. February is a beautiful month weather wise, with warm days and balmy nights. It is a hard life!