Chemical Formula: C28H44O
Amount included in 1 pouch of Soylent: 10 ug
Food and Drug Administration Recommended Daily Value: 10 ug
Vitamin D helps to form compounds which regulate calcium and phosphorus absorption in the body. Insufficient amounts of vitamin D can lead to rickets, a disorder characterized by weak or brittle bones.
There are two common forms of vitamin D (also known as calciferol).
Cholecalciferol (D3) enters the body either by being produced when cholesterols in the skin are exposed to UVB light or through ingestion. Ergocalciferol (D2) cannot be produced by the body and must be ingested.
In their raw forms, neither vitamin D3 or vitamin D2 can be used by the body (are bioavailable) until they undergo two rounds of hydroxylation (The first hydroxylation occurs in the liver, the second takes place in the kidneys). Eventually, both forms are metabolized into calcitriol.
Calcitriol functions as a chemical signal and initiates the creation of proteins which assist in regulating calcium and phosphorus absorption in the small intestine. Furthermore, calcitriol triggers the formation of osteoclasts, which play a primary role in bone remodeling and calcium reabsorption into the bloodstream.
Reason this form chosen
Some studies have suggested that vitamin D3 is slightly more bioavailable than vitamin D2. Vitamin D2 was selected because it can be produced without the use of animal products and still provides more than enough inputs to yield calcitriol.
Ergocalciferol is part of the custom vitamin blend produced by DSM Fortitech. Ergocalciferol is produced industrially by exposing fungus to specific wavelengths of UVB radiation (light).
 Nelson, David L., and Michael M. Cox. "Lipids." In Lehninger Principles of Biochemistry. 6th ed, 373 New York: W.H. Freeman, 2013.
 Hydroxylation is when a hydroxyl group (an oxygen atom which is covalently bonded to a hydrogen atom) joins onto a larger molecular compound.
 Stipanuk, Martha H., and Marie A. Caudill. "Vitamin D." In Biochemical, Physiological, and Molecular Aspects of Human Nutrition, 704. Third Edition ed. St. Louis: Elsevier, 2013.