Vitamin D, Essential to the Immune System

Although many people are aware that vitamin D is important, they may not know HOW important and why. The term “vitamin” is actually a misnomer as Vitamin D is really a non-essential prohormone. It is non-essential because it can be synthesized in the body from sunlight and a prohormone because it is converted to the hormone calcitriol in the kidneys. A vitamin is usually used to help potentiate a reaction in the body while a hormone actually sends a message to increase or decrease levels of certain substances in the body. In the case of vitamin D and calcitriol, adequate levels of calcium and phosphorus are maintained through Parathyroid hormone signaling for an increase in the active form of Vitamin D, calcitriol, to be made. Calcitriol then stimulates calbindin to increase calcium absorption in the intestines. There is even more complexity where that came from. There are vitamin D receptors in the intestines, bone, kidney, brain, heart, skin, gonads, prostate, and breasts. It’s no wonder that vitamin D is therapeutic in so many conditions and is so vital to maintaining health. It is considered the prohormone of the immune system.

How Much Vitamin D Do I Need?

Although many labs consider a level above 30 to be adequate, I like to see Vitamin D levels around 60. Anything below 50 is a Vitamin D insufficiency and below 40 is a deficiency in my opinion. Many doctors will load their patients up with 50,000 iu of Vitamin D2 once a week. There are 2 problems with this. The first is that it is hard to measure the true levels of a patient because while blood levels may be adequate according to lab tests, this does not reflect body storage. They may have little to no reserve outside of the circulating levels in the blood. The second problem is that Vitamin D2 is the plant form, ergocalciferol, which has to undergo more steps to be converted to the biologically active form, calcidiol. While levels may reflect an adequate amount, the body may not be processing it at the same level. In the case of the docs that use 50,000 iu of D3 1-2 times per week, it may be hard for the body to regulate once coming off of that dose. Levels are often more reflective of body stores when supplementing with lower levels more frequently.

Below is a list of conditions that often benefit from Vitamin D supplementation or are typically associated with lower vitamin D levels.

Vitamin D is an invaluable marker for immune system health and when monitored by your doctor alongside other immune and inflammatory markers, can often provide insight into the health of the patient.