Vitamin D discovery
Vitamin D was discovered in the early 20th century as a crucial nutrient for bone health, particularly in the prevention and treatment of rickets, a disease that caused severe bone deformities in children. During the mid-17th century, a surge in rickets cases prompted observations linking the condition to insufficient sunlight exposure. By the 1800s, cod liver oil emerged as a treatment, setting the stage for further scientific exploration. In 1919, German researcher Kurt Huldschinsky demonstrated that ultraviolet light could cure rickets, leading to the identification of a previously unknown substance in the skin responsible for this effect.
By 1922, American scientist Elmer McCollum named this nutrient vitamin D after isolating it from cod liver oil, recognizing that it was distinct from vitamin A. Harry Steenbock's work in the mid-1920s on food irradiation further advanced the application of vitamin D, culminating in a public health campaign advocating for increased sun exposure and the fortification of foods. The introduction of vitamin D supplements and irradiated foods significantly reduced rickets cases, establishing a legacy that has broadened our understanding of vitamin D's multiple roles in health, now recognized as a hormone that undergoes activation in the body.
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Vitamin D discovery
The 1920s was a decade of numerous scientific advances related to food and medicine, including the discovery of antibacterial medicines, vaccines to help wipe out disease, and vitamins to improve health. The identification of vitamin D and its role in bone formation and bone health led the way to the prevention and cure of certain bone diseases.
The mid-seventeenth century witnessed an epidemic rise among children of the potentially fatal bone disease known as rickets. Observers of the epidemic noticed an association between a lack of sunlight and an increased prevalence of rickets. By the early 1800s, cod liver oil was recommended as a treatment, and by the early part of the twentieth century, scientists discovered the curative powers of a then-unknown substance and its role in the prevention and cure of rickets.
In 1919, German researcher Kurt Huldschinsky found that infants exposed to ultraviolet light rays were cured of rickets and that a substance in the skin was the means of the cure. In 1922, American scientist Elmer McCollum proved that when cod liver oil was heated, the beneficial effects of vitamin A in the oil were diminished; however, the oil remained effective in curing rickets. McCollum soon deduced that a nutrient different from vitamin A must be present in the oil, and he named it vitamin D, the fourth vitamin to be discovered and named.
Harry Steenbock of the University of Wisconsin demonstrated in 1924 that foods exposed to ultraviolet radiation promoted growth in rats, and in 1925 he was granted a patent for his food irradiation process. The Wisconsin Alumni Research Foundation was founded in 1925 to administer the patents, with the first license being granted in 1927 to Quaker Oats for vitamin D–fortified cereal. Soon a nationwide public health campaign was launched promoting increased sun exposure and food fortified with vitamin D.
Impact
The irradiation of food and the synthesis of vitamin D supplements led to a dramatic decline in the incidence of rickets in the 1920s and prevented epidemic recurrences of the disease for future generations. Subsequent research in the 1930s established that vitamin D is not a true vitamin: Activation by light converts it, through a process involving the liver and kidneys, into a hormone. In the following decades, scientists discovered a multifaceted role for vitamin D in the body, and new applications of this hormone continue to be developed.
Bibliography
Carlson, Laurie Winn. The Sunlight Solution: Why More Sun Exposure and Vitamin D Are Essential to Your Health. Amherst, N.Y.: Prometheus Books, 2009.
Frankenburg, Frances Rachel. Vitamin Discoveries and Disasters: History, Science, and Controversies. Santa Barbara, Calif.: ABC-CLIO, 2009.
Holick, Michael, F., ed. Vitamin D: Physiology, Molecular Biology, and Clinical Applications. 2d ed. Totowa, N.J.: Humana, 2010.