Vitamin D - Its history and vital importance
June 29, 2011
How Vitamin D was discovered
Vitamin D existed on earth for at least 500 million years, but it was not discovered until 1920. What led to its discovery was the disease of rickets, a disease caused by a lack of vitamin D. Rickets is recorded in human history as early as the second century A.D., but it was not significant in human history until the industrial revolution in northern Europe. Then it became epidemic: in the latter part of the nineteenth century, autopsies done in the Netherlands showed that 90 percent of the children had rickets. The disease was characterized by bowing of the legs, bending of the spine, and weak and toneless muscles. It was especially devastating to women of childbearing age, who often had a deformed pelvis, resulting in a high incidence of infant and maternal mortality.
The industrial revolution caused this epidemic of rickets because peasants from the countryside poured into the cities and lived in crowded, polluted, and sunless tenements. Since the main source of vitamin D is sunlight, rickets was the result. It was not until 1822 that anyone made the connection between lack of sunlight and rickets. Unfortunately, little attention was paid to this observation. In 1919 Huldschinsky showed that exposure to light could cure rickets.
During the eighteenth and nineteenth centuries, cod liver oil was used as a common folklore medicine for the prevention and cure of rickets. It worked. Children with rickets were cured with amazing speed by cod liver oil. In 1920 a team of scientists led by E. F. McCollum investigated the anti-rickets factor in cod liver oil. It was known that cod liver oil contained vitamin A. The scientists wanted to know if the anti-rickets factor in cod liver oil was vitamin A or something else. They heated and oxidized the cod liver oil so that all vitamin A activity was destroyed. The resulting cod liver oil was still able to cure rickets in rats. Thus the anti-rickets factor in cod liver oil was clearly not vitamin A but a new fat-soluble vitamin. They named it vitamin D.
What Vitamin D does
Vitamin D increases the efficiency of calcium and phosphorus absorption from food in the intestines. If you are deficient in vitamin D, you only absorb about 10 to 15 percent of the calcium you consume. Vitamin D is necessary for the normal growth and development of bones and teeth in children. It protects against muscle weakness. It increases the activity of bone cells that make and lay down matrix. Matrix is like the frame of a building. Young children who are deficient in calcium and vitamin D are unable to properly mineralize the rubbery matrix. Gravity pushes on the skeleton and causes the typical bowing of the legs that you see in a child with rickets. In adults, vitamin D deficiency results in osteomalacia, a softening and bending of the bones that involves bone pain and muscle weakness. Many patients are diagnosed with some kind of arthritis or fibromyalgia when it is really a vitamin D deficiency that they are suffering from. Deafness, too, can result from vitamin D deficiency because sounds are transmitted to the brain along tiny ear bones, and these bones can degenerate when vitamin D is lacking. In next week's article, we will discuss the sources of vitamin D.
Mary Lou Williams, M. Ed., is a writer and lecturer in the field of nutrition. She welcomes inquiries. She can be reached at 267-6480.