cholecalciferol
standing-straight in the sun
seeking the warmth
finding the light
you made your own strength
sitting-low in the office
huddled over the desk
flourescents flickering
your weakness company profits
We are surprisingly fragile creatures, we humans. As any engineer knows, the more complex the design the more likely something will fail — something important. For humans, changing the availability of a single hormone or, in this case, prohormone, can wreak havoc among the many interrelated systems. Vitamin D is not a true vitamin because the body can make it when the skin is exposed to direct sunlight. It helps control many systems in the body, most well known perhaps is the ability to help the body absorb and use calcium as in making bones. It also appears to regulate how the liver and kidneys function, how well the heart beats, some neurological functions and immune system responses (inflammatory diseases in particular).
Cholecalciferol is made then transformed in the body in three steps: first skin converts UVB into a preliminary form, then the liver creates an intermediate form and finally the kidneys excrete the usable hormone. Without the final form, the body cannot use the cholecalciferol to regulate and support the many functions, and people get ill (and even die). It used to be that rickets was a sign that the body needed more Vitamin D (as well as C and Calcium), but with supplementation of cereals and milk children generally get enough to appear physically healthy. However, a host of other ailments can appear in both children and adults, partially or fully hidden until a major health crisis occurs.
Vitamin D can be made by most people with a few minutes’ exposure to sunlight. It can be stored in fatty tissues once made and gradually used by the body during times that the sun is not available. At one time, when most people worked out of doors throughout the year they probably got enough just from their normal activities. It can be obtained in the diet, through careful food choices as well as with supplements (pills). Again, in times past when people in colder climates relied on particularly fatty fish and animal foods they likely were getting most of what they required. Most people probably think they are getting enough Vitamin D in their diet, but additional factors can interfere with the body’s ability to make and use this essential hormone. A simple blood test for Vitamin D deficiency can help identify if a person needs more Vitamin D in their diet — or sunlight (within reason, skin cancer is still a real issue!).
Here are a few of the websites that talk about the purpose of this hormone and its structures.
From Colorado State, a page on the Endocrine System
Medline’s entry on Vitamin D, sponsored by National Institutes of Health
The nonprofit organization, The Vitamin D Council has a wealth of knowledge and summaries of peer-reviewed research available. The page About Vitamin D is a good place to start.
And here is Medscape’s entry on Rickets. This was eye-opening to me.