When did organisms learn to synthesize vitamin D? How did its functions change throughout our evolution? How did the changes affect the entire Homo sapiens species? Professor Carsten Carlberg, a world-class vitamin D expert, writes about it in his article in the Nutrients journal.

What factors influenced the development of receptors that enable the absorption of vitamin D by humans? What are the reasons of vitamin D deficiencies? According to Prof. Carlberg vitamin D deficiencies have nothing to do with evolution, but rather human migrations to the north and lifestyle changes.

Long history of vitamin D

Prof. Carlberg explains how the role of vitamin D has changed over time. The "career" of this vitamin began 1.2 billion years ago, when eukaryotes (organisms with a cell nucleus) developed the ability to synthesize sterols (and thus vitamin D).

However, it wasn’t until 100 years ago that vitamin D was classified as a vitamin, because its administration could cure experimentally induced rickets in dogs and rats. Rickets is also a developmental disorder in children. Vitamin D regulates also physiological processes such as detoxification and energy metabolism, and modulates innate and adaptive immune responses. Scientists also point to a possible role for vitamin D in skin lightening in migrating peoples, especially in European populations.

How did vitamin D become a vitamin?

In his paper Prof. Carlberg points out that one of the evolutionary processes aimed at adapting to environmental changes was precisely the development of the vitamin D receptor (VDR), as well as the transport proteins and enzymes of vitamin D metabolism. This took place about 550 million years ago.

Initially, vitamin D regulated processes such as detoxification and energy metabolism. Thus, it could modulate energy-intensive processes of the innate immune system in its fight against microbes. The Professor mentions that about 400 million years ago, the species left the ocean, and were therefore exposed to gravity. Vitamin D took over the additional role of a major regulator of calcium homeostasis which is essential for the maintenance of a stable skeleton.

“In their evolutionary origin in East Africa, humans were every day around the year exposed to extensive UV-B radiation, which induced sufficient vitamin D₃ synthesis. Therefore, over a period of more than 200,000 years, they got used to a constantly high vitamin D status of 100 nM 25(OH)D₃ or more. However, within the last 50–75,000 years, the migration toward regions with a latitude above 37 °N let them experience seasonal changes in sun exposure and periods of the year when vitamin D₃ cannot be produced endogenously” we read in the publication.

As a result of the industrial revolution, people have adapted to an urban lifestyle with predominant work and indoor activity. Both conditions – vitamin D winters and indoor preferences – often led to vitamin D deficiency in industrialized countries. In the 19 century, rickets was common among children in England, and vitamin D deficiencies increased tuberculosis in many countries.

The article entitled "Vitamin D in the Context of Evolution" was published in the Nutrients journal.

Prof. Carsten Carlberg is a biochemist, a world-class specialist in vitamin D. He is also the ERA Chair in the WELCOME2 project at the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences. More information about ERA Chair WELCOME2 project is available here.

Source of information: PAS Institute of Reproduction and Food Research