When was Vitamin D Discovered? The History of the 'Sunshine Vitamin'

December 27, 2025 •

3 min read

In 1922, American biochemist Elmer McCollum officially named and identified the fat-soluble substance we now know as Vitamin D, a pivotal finding in the fight against rickets, a debilitating bone disease. The journey to this discovery, however, began centuries earlier with observations linking sunlight and certain foods to preventing this condition.

Quick Summary

The discovery of Vitamin D was a multi-stage process culminating in the 1920s. Initial observations linked rickets to lack of sunlight, while later research isolated a specific antirachitic factor. The nutrient was named Vitamin D after being isolated from cod liver oil, leading to food fortification efforts.

Key Points

1922 Naming by McCollum: American biochemist Elmer McCollum isolated and named Vitamin D after proving it was the distinct, anti-rickets factor in cod liver oil.
UV Light as a Cure: In 1919, Kurt Huldschinsky demonstrated that ultraviolet light could heal rickets, establishing the link between sun exposure and bone mineralization.
Food Fortification Begins: Following Harry Steenbock's 1924 discovery that food could be irradiated to become rich in Vitamin D, widespread fortification programs in the 1930s effectively eliminated rickets in industrialized countries.
Rickets was the Driving Force: The long-running search for a cure for the bone-deforming disease rickets was the primary motivation behind the early 20th-century discoveries of Vitamin D.
Windaus Confirmed Structure: The chemical structures of Vitamin D2 and D3 were later clarified by chemist Adolf Windaus in the 1930s, work for which he was awarded the Nobel Prize in 1928.
Eradication of Rickets: The combination of identifying the nutrient and finding methods for food fortification virtually eradicated rickets as a major public health issue in developed nations.

From Ancient Observations to Modern Science: The Quest to Find Vitamin D

The story of how Vitamin D was discovered is a fascinating blend of ancient folklore, early clinical observations, and rigorous scientific experimentation. For centuries, the crippling bone disease rickets plagued children, particularly in crowded, sun-deprived cities. It wasn't until the early 20th century that a series of groundbreaking discoveries finally put a name to the vital nutrient and revolutionized public health.

Early Links: Sunlight and Cod Liver Oil

Before the formal discovery, key connections were made linking environment and certain dietary factors to the prevention of rickets:

The 17th Century: Medical texts by physicians like Daniel Whistler (1645) and Francis Glisson (1650) provided the first scientific descriptions of rickets, often dubbed the "English Disease".
The 1820s: Polish physician Jędrzej Śniadecki made a critical observation, noting that children in rural, sunnier areas of Warsaw were less likely to suffer from rickets than those in the sun-starved city.
The 1800s: Based on long-standing folk wisdom, cod liver oil began to emerge as a recognized remedy for rickets.
1918: Sir Edward Mellanby: In a landmark experiment, Mellanby fed oatmeal-based diets to indoor dogs, causing them to develop rickets. He then successfully cured the condition by adding cod liver oil, mistakenly believing the anti-rickets factor was Vitamin A.

The Breakthrough of the 1920s

The decade of the 1920s was a period of intense discovery that coalesced these earlier findings into a unified understanding:

1919: Kurt Huldschinsky: This German researcher demonstrated that ultraviolet (UV) light from mercury arc lamps could cure children with rickets. His work proved that exposure to UV radiation initiated a systemic, rather than a localized, effect that healed bone deformities.
1922: Elmer McCollum names Vitamin D: At Johns Hopkins University, Elmer McCollum famously destroyed the Vitamin A in cod liver oil by bubbling air through it. He found the oil still cured rickets, proving that a distinct, new fat-soluble factor was responsible. He named it Vitamin D, following the alphabetical naming convention.
1924: Harry Steenbock and Alfred Hess: Independently, these two researchers showed that irradiating foods with UV light could make them anti-rachitic. Steenbock patented the process of irradiating food to fortify it with Vitamin D, a major step toward public health campaigns.
1928: Adolf Windaus' Nobel Prize: German chemist Adolf Windaus received the Nobel Prize for his work on sterols, clarifying the structure of Vitamin D and its precursor compounds, which are converted to Vitamin D by UV light.

Comparing Early Findings on Rickets


Discovery	Year	Researcher(s)	Key Contribution	Outcome
Sunlight and Rickets	1822	Jędrzej Śniadecki	Noticed lower rickets rates in rural, sunny areas.	Established early link between sun exposure and bone health.
Cod Liver Oil Treatment	1824	D. Scheutte (early)	Began prescribing cod liver oil to treat rickets.	Became a common folk remedy, later scientifically validated.
UV Light Cure	1919	Kurt Huldschinsky	Cured children's rickets using UV lamps.	Proved sunlight's active role, leading to phototherapy.
Isolated and Named	1922	Elmer McCollum	Separated the anti-rickets factor from Vitamin A and named it Vitamin D.	Formally identified the nutrient, paving the way for fortification.
Food Irradiation	1924	Harry Steenbock	Patented a process to irradiate foods, fortifying them with Vitamin D.	Made Vitamin D accessible through fortified milk and cereals, virtually eradicating rickets in developed nations.

Fortification and Broader Understanding

The discoveries of the 1920s quickly led to widespread public health changes. The fortification of milk and cereals with Vitamin D began in earnest, particularly in the United States, and proved highly effective in combating rickets. However, the story didn't end there. Further research revealed Vitamin D was not a traditional vitamin but a prohormone, activated by the body in the liver and kidneys to its active form, calcitriol. This understanding has continually expanded, revealing the nutrient's role far beyond bone health, influencing areas from immune function to cellular growth.

Conclusion

The timeline of Vitamin D's discovery demonstrates how centuries of observation and focused scientific inquiry can converge to create a public health revolution. What started as an unknown factor in cod liver oil, and a mysterious benefit from sunlight, was meticulously unraveled by researchers in the early 20th century. Their work led to interventions that saved countless children from a debilitating disease, and it laid the groundwork for our ongoing exploration of this vital nutrient's complex role in human health.

Frequently Asked Questions

Elmer McCollum is most commonly credited with discovering and naming Vitamin D in 1922. However, Kurt Huldschinsky also made a crucial discovery in 1919 by showing that UV light could cure rickets.

The discovery was driven by the quest to find a cure for rickets, a disease of bone malformation. Centuries of observations linking sun exposure and cod liver oil to better bone health provided the foundation for controlled scientific experiments in the early 20th century.

No, initially researchers believed rickets was caused solely by a dietary deficiency, with Sir Edward Mellanby thinking it was Vitamin A. The link between sunlight and the nutrient was confirmed later by researchers like Kurt Huldschinsky and Harry Steenbock.

The nickname comes from the fact that our bodies produce Vitamin D naturally when our skin is exposed to ultraviolet (UV) B radiation from sunlight. This critical connection was uncovered during the vitamin's discovery.

The discovery led directly to the fortification of staple foods like milk and cereal. This public health measure, implemented in the 1930s, caused the dramatic and near-total eradication of rickets in industrialized countries.

Harry Steenbock was a key figure who patented the process of irradiating foods with UV light to increase their Vitamin D content. His work was instrumental in making food fortification possible and widespread.

No, Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol) have slight structural differences. Vitamin D2 is derived from plants and irradiated yeast, while Vitamin D3 is produced in the skin of humans and animals.