TREATMENT for RICKETS 

  DIET and SUNLIGHT (vitamin D)

The connexion between abundance of sunlight and an absence of rickets was made by Theodor Palm, an English medical missionary, in the 19th century, whilst in the East - but his epidemiological findings were ignored(1). Use of cod liver oil had been known in Northern Europe since the 18th century and had been given prominence in the treatment of rickets in 1861 by Trousseau, a physician in Paris, in his textbook on clinical medicine. The link between diet and rickets was made by Jean Baptiste Dumas, a French chemist, who, in 1871, published details of his observations made of starving infants during the time that Paris was under seige from the Prussians. Dumas described the disasterous consequences of feeding these infants on artificial milk, prepared by emulsifying fat in a saturated solution(2).

In 1880, Nicholas Lunin, in his doctorate thesis cited his experiments with mice, maintained on artificial diets. Mice reciving sodium carbonate lived for 12 to 30 days, whilst those not given this, lived for 12 to 21 days. Lunin found that "artificial milk did not improve survival of the mice" - but with no mention of the results observed by Dumas in children fed on this diet.  Lunin found the mice thrived on powdered milk. Twenty five years later, Prof C A Pekelharing of the University of Utrecht in the Netherlands, published a paper in Dutch in 1905, describing his experiments which showed that mice could be kept healthy on an artificial diet to which a small amount of whey had been added - he had been preceded by Dumas over 30 years earlier, who had used emulsified fat in solution in his clinical application(2).

In 1906-07, Frederick Hopkins, in his animal experiments, found that mice could not survive on a mixture of basal foodstuffs alone(3). When he tried feeding the mice different supplies of casein, he found that one sample supported moderate growth, whilst another failed to maintain the animals. After these hit-and-miss experiments, Hopkins eventually turned to using butter - but even the choice of that was a "lucky chance"(4) as he, himself, later confessed "By sheer good fortune, as it afterwards turned out, I used butter as a fat supply in these early experiments"(5).

Hopkins worked with Edith Willcock and found that mice failed to grow when fed on diets in which zein, a protein from maize, was the sole source of protein. When, in 1914, J Goldberger, leader of the US Public Health Service, conducted epidemiological and clinical studies, he showed that human diets rich in maize were to blame for pellegma - the symptoms of which are scaly dermititis, diarrhoea, and depression(6) - not growth retardation (as seen by Hopkins in mice). 

In 1908, L Finlay induced rickets in puppies by feeding a diet deficient in raw milk(7). Four years later, in 1912, Hopkins suggested that rickets might be caused by deficiency of an "accessory food factor". Hopkins though that an inquiry should be made and recommended this to the newly-formed Medical Research Committee - which gave its agreement and, in 1914, Edward Mellanby, a former student of Hopkins, moved to Cambridge, where he started feeding experiments in dogs. Mellanby conducted hundred of experiments on puppies in an attempt to identify the type of diet which would induce rickets. Eventually, in 1918, Mellanby informed the Physiological Society that he had induced rickets in puppies by feeding a diet of either milk, rice, oatmeal and salts; or one of milk and bread; for three to four months. By adding a variety of foods to these diets, Mellanby noted that animal fats - such as butter, suet and cod liver oil had anti-rachitic activity(8) but nothing new came from these experiments: Dumas in 1871 had found from his clinical studies that diet containing emulsified fat in solution had induced rickets in starving infants; Goldberger had discovered, epidemiologically, that diets rich in maize were responsible for the cause of pellegma; dietary experiments on puppies had been conducted 10 years earlier by Finlay; and the anti-rachitic activity of cod liver oil had been promoted by Trousseau`s textbook of 1861.

Meanwhile, in 1916, Kurt Huldschinsky, a German pediatrician, showed, clinically, that ultra-violet light could cure or prevent rickets in children - establishing Palm`s clinical finding of  the 19th century, which had been ignored at the time(9).

Others also were conduct feeding experiments in animals but this merely added to the confusion - as Dr J Lawson Dick, a Fellow of the Royal College of Surgeons, explained in 1924: "Some experimentalists have claimed that by feeding dogs on a diet deficient in certain fats they have produced the disease called rickets, and the inference has been drawn that rickets is due to the absence of a vitamin associated in some way with the fats. Other experimentalists have repeated these experiments with dogs and have come to the directly opposite conclusion - namely, that with abundance of these fats in the food rickets is still certain to occur in the presence of defective hygienic conditions, notably absenceof sunlight, fresh air and the opportunities of exercise"(10).

 refs

1. Lloyd,WEB. A Hundred Years of Medicine. paperduck. 1971.

2. Sneader,W, Drug Discovery. John Wiley & Sons. 1985.

3. Hopkins,FG. Les Prix Nobel en 1929.

4. Stevenson,LG. Nobel Prize Winners in Medicine and Physiology 1901-50. Henry Schuman. 1953.

5. Hopkins,FG. Les Prix Nobel en 1929.

6. Martin,EA. Concise Medical Dictionary. Oxford Uni Press. 1994.

7. Lloyd,WEB. A Hundred Years of Medicine. Paperduck. 1971.

8. Sneader,W. Drug Discovery. John Wiley & Sons. 1985.

9. Lloyd,WEB. A Hundred Years of Medicine. Paperduck. 1971.

10. Dick,JL. Medical Press & Circular. 3 Dec 1924.