The vital role of Vitamin D in Evolution - Dr. Grimes Dec 2025
His blog post
His conclusion
The Cambrian explosion of advanced life-forms 550mya followed the end of Snowball Earth, allowing a clement climate that included liquid water. Pre-existing plankton would have provided the basis of the food-chain for the new aquatic life.The appearance of photosynthesising green plants on the newly exposed land would have increased the oxygen content of the atmosphere and provided food for terrestrial animals.
The survival of complex aquatic life-forms identified in the Cambrian explosion depended on defensive immunity against pre-existing bacteria. The major player in immunity was the intracellular molecule VDR and its encoding gene. The VDR molecule was synthesised within cells incomplete, lacking the building block molecule cholecalciferol / vitamin D, which could not be synthesised by animal life-forms as it required the input of high energy from solar UV.
Plankton had evolved 1,000my earlier, and as part of their defence against solar UV they synthesised the oil 7-DHC that absorbed UV energy, converting 7-DHC into the waste product cholecalciferol / vitamin D. This had no function until evolution had brought about defensive immunity with the incomplete VDR.
VDR became the controlling molecule in the evolution of immunity, and 100my later in the control of bone production. In both these processes vitamin D was essential for the completion and activation of the VDR molecule.
Aquatic animals were able to obtain vitamin D from plankton, the basis of the aquatic food chain. In addition to eating fish, land animals became able to obtain vitamin D by the action of solar UV on 7-DHC synthesised in the skin.
The evolution of VDR has been critical, but also vitamin D to complete and thereby activate VDR. Without vitamin D, evolution beyond plankton in the form that we know it would not have taken place.
It is important that we understand how human behaviour can disrupt evolutionary effects leading to serious vitamin D deficiency with impaired immunity and bone production (rickets and osteomalacia). Evolution provided humankind with large brains, so that in 1920 vitamin D was identified and its importance appreciated. VDR was identified in 1969, but its importance in the escalation of defensive immunity remains under-appreciated by most medical scientists, so that millions of people with vitamin D deficiency stilll exist, with suboptimal immunity and at risk of serious health disadvantages.
Related in VitaminDWiki
- Vitamin D has been needed by land vertebrates for over 400 million years
- Vitamin D has been used for 750 million years by virually all forms of life
- Evolution and Vitamin D, Omega-3, obesity, mitochondria, DNA, etc.
Vitamin D in the Context of Evolution (400,000,000 years) – July 2022
Vitamin D: calcium and bone homeostasis during evolution – Jan 2014
History of Vitamin D from 500 million years ago to orthopaedic practice today – 2019