What is Rickets, History of Rickets

Rickets
Much of the pioneering work on the aetiology of
rickets should be accredited to the eminent French
physician Armand Trousseau during the 1830s.
Trousseau called attention to the experiments of Jules
Guérin, published in 1838. Weaned puppies were
placed in a dark basement and fed raw meat while
their litter mates were given a varied diet in a normal
environment. After a few weeks the meat-fed animals
exhibited all the classic signs of advanced rickets, in
contrast to the littermates which showed no signs of
rickets. A similar experiment conducted on young
pigs given no access to animal fats or to sunlight gave
analogous results. This led Trousseau to postulate that
rickets was due in part to defi cient diets. Trousseau
also postulated that cod-liver oil, which had been
demonstrated to cure rickets in children, was acting
as a fat containing unknown benefi cial dietary factors,
rather than acting as a specifi c drug. He recognized
that ‘good general alimentation’ is of prime importance
in the aetiology of rickets as well as the benefi cial
effects of sunshine. Unfortunately, these experiments
were ignored and forgotten by 1900. Most medical
authorities at the time advocated the development of
a vaccine in the belief that rickets was a chronic infectious
disease. They dismissed cod-liver oil as a useless
‘quack’ remedy.

In 1918, Sir Edward Mellanby in Great Britain undertook
the study of rickets, starting again at the same
point as Guérin 80 years before. Mellanby produced
rickets in puppies by raising them without the benefi t
of sunlight or UV radiation, and feeding them a highcereal,
low-fat diet in which white bread was replaced
by unrefi ned oatmeal. Mellanby further showed that
the addition of cod-liver oil or butterfat to the feed
prevented rickets. This clearly showed that rickets was
6 Vitamins: their role in the human body
a nutritional disease, and cod-liver oil or butterfat
contained a factor that prevented it.

In 1922 McCollum and associates published the results
of experiments designed to determine whether
the antirachitic factor in cod-liver oil was identical to
or distinct from the previously discovered vitamin A.
They found that cod-liver oil retained its antirachitic
properties after destruction of the vitamin A by heating
and aeration. Thus, in addition to vitamin A, codliver
oil contained a new fat-soluble vitamin, which
McCollum later (1925) called ‘vitamin D’. Zucker and
co-workers in 1922 found that vitamin D was present
in the unsaponifi able fraction of cod-liver oil, and
suggested that it was closely related to cholesterol.