The Dynamic duo of Calcium and Vitamin D Can Sustain Your Life
Virtually everyone can recite the milk industry’s campaign slogan: It does a body good. Much of this goodness no doubt hinges on the calcium content of milk. Calcium is the most abundant mineral in the human body, with over 99 percent of the amount present being found in the bones and teeth. For the growth and maintenance of healthy bones it is essential that we have sufficient calcium intake; we are at risk of developing bone disease such as osteoporosis when calcium leaching is not balanced by dietary ingestion. But calcium is not only important for the skeleton; it also has a role to play in nerve function, blood clotting, muscle health, and other areas.
And, like an orphan child without a parent to guide it properly, calcium cannot work properly in the body without the help of vitamin D. Calcium and vitamin D share special relationship that plays into everything about you, from your ability to build and maintain bone strength to your neuromuscular faculties and brain power. It is also well recognized that vitamin D aids in the absorption of calcium as well as phosphate.
The Missing Link Between Vitamin D and Bone Health
To discover that sunlight held a secret ingredient to preventing and treating bone diseases like rickets was one thing, but understanding why and how this all worked, from a single ray of UVB to health in the human body, was clearly another. It took scientists several decades to uncover the mechanism by which vitamin D produced in the skin could effect so many positive health benefits.
One of the reasons it took so long to tease out vitamin D’s complex biological pathway and influence on other physiological processes is that we simply didn’t have the tools to track vitamin D down. It wasn’t until the mid 1960s that new laboratory techniques emerged to afford researchers the opportunity to follow vitamin D’s intricate actions using radioactively labeled substances. By 1971, it was clear that vitamin D went through sequential transformations in the body that entailed inactive metabolites along the way until the kidneys converted the major circulating form to activated vitamin D.
Isolating and determining the molecular structure of all these vitamin D metabolites helped put to rest the biggest mystery that had troubled vitamin D scientists for decades: just how did vitamin D influence calcium deposition to build strong bones? In the early 1950s, the researcher discovered that vitamin D can actually remove calcium from bones when it is needed by the body. At about the same time, the Norwegian biochemist, who had been testing different diets on animals for years, concluded that the uptake of calcium from food is guided by some unknown “endogenous factor”. He believed this endogenous factor sent a message to the intestines that the body needed calcium. That message turned out to be activated vitamin D. With vitamin D’s identity solved, answers began to emerge in the experiments tracing the activation of vitamin D.
Once we had our finger on activated vitamin D, and how it came to be in a complex series of conversions through organs and bloodstream, it was apparent that we weren’t dealing with just another vitamin. We were deciphering a previously vague and convoluted picture of how “vitamin D” worked on the body. And because of its profound effects, medical scientists quickly that it belonged in the hormone category. No sooner had they singled out the active form of vitamin D, than they reclassified it as a hormone that controlled calcium metabolism, which refers to how the body maintains adequate levels of calcium. This marked the genesis of understanding not only the relationship of vitamin D to the body’s endocrine system and calcium regulation but also how vitamin D could effect positive change of myriad biological processes, from modulating the immune system to inhibiting the skin cell growth that leads to skin disorders like psoriasis.
Hormones are unique substances produced in the body. The word itself from Greek verb horman, meaning “to stir things up”. Acting as internal signals, hormones control not only different aspects of metabolism but also many other functions – from cell and tissue growth to blood sugar, heart rate, blood pressure, and even the activity of the reproductive system. By definition, hormones are produced by one organ and then transported in the bloodstream to a target organ, where they can cause a specific biological action. Evidence for reclassifying the active form of vitamin D came with the realization that this form of vitamin D is produced by the kidneys and that its secretion by the kidneys into the bloodstream, where it can then travel to the small intestine, leads to its buildup in cell nuclei of the intestine, where it regulates the efficiency of the absorption of dietary calcium.