Vitamin D and You
Vitamin D is an important signaling molecule for our immune system and our neurotransmitters. Your CGM doc may order your Vitamin D levels, here’s what you should know.
What is Vitamin D?
Vitamin D is a fat-soluble secosteroid; a steroid with a broken ring shape.
Classically, Vitamin D is thought of in the context of its ability to increase intestinal absorption of calcium, magnesium and phosphate.
More recently, however, attention has shifted towards Vitamin D’s regulatory impact on processes outside of bone density and mineral utilization.
How is it made?
Vitamin D is mainly sourced by the synthesis of cholecalciferol in the lower layers of the skin. This happens whenever we are exposed to UVB radiation (sunlight).
Cholecalciferol travels from the skin to the kidneys, where it is eventually transformed into the active 1,25 hydroxycholecalciferol, or Calcitriol. This is the molecule that makes magic happen.
Who is low in Vitamin D?
Vitamin D status differs by latitude and race, with residents of the northeastern US and individuals with more melanin being at an increased risk of deficiency.
Additionally, adipose (fat) tissue is known to store fat-soluble vitamins, and an increase in body fat percentage is associated with lower levels of circulating Vitamin D due to this sequestering effect.
There are many single-nucleotide polymorphisms associated with Vitamin D receptors, most widely studied being rs731236, or Taq1. This mutation results in reduced stability of the VDR, and leads to lower Vitamin D.
Tell me more about this connection between Vitamin D and my genes…
Vitamin D has numerous genomic effects, meaning that it affects the expression of genes in various tissues throughout the body. These effects are mediated by the vitamin D receptor (VDR), which is a protein found in many different types of cells. Some of its effects include:
Regulation of cell proliferation and differentiation: Vitamin D has been shown to regulate the expression of genes involved in cell proliferation and differentiation, which can affect the growth and development of various tissues in the body.
Metabolic regulation: Vitamin D can affect the expression of genes involved in insulin secretion and glucose metabolism, which may play a role in the development of type 2 diabetes.
Regulation of blood pressure: Vitamin D can affect the expression of genes involved in blood pressure regulation, which may help to explain the link between vitamin D deficiency and this common condition.
What does Vitamin D have to do with my mood and gut health?
Vitamin D up-regulates an enzyme called Tyrosine Hydroxylase. This enzyme is the rate-limiting step in the synthesis of dopamine, a neuro-modulatory molecule associated with “reward orientation;” or the ability for one to self-motivate towards productive behaviors.
In addition, Vitamin D also modulates an enzyme called Tryptophan Hydroxylase 2 - an important driver in the production of serotonin from dietary tryptophan. Serotonin is an important mood stabilizer, and low levels of this neurotransmitter have been associated with depression and anxiety.
Interestingly, a study investigated the Vitamin D levels of of 86 patients with chronic functional constipation associated with intestinal motility disorders and 86 matched healthy subjects. Patients with intestinal motility disorders had lower 25-hydroxyvitamin D levels (P < 0.001), and they showed a significant impairment of all health-related quality of life and psychological tests. This may be due to serotonin’s effect on gut motility.
What does Vitamin D have to do with my immune system?
Cells of our immune system have receptors for Vitamin D, which acts to regulate the function of immune cells responsible for identifying and attacking pathogens in the body. It also helps to promote the production of certain antimicrobial peptides that can directly destroy pathogens.
In addition, Vitamin D has been shown to have anti-inflammatory effects, which can help reduce the severity of certain immune-related conditions, such as asthma and rheumatoid arthritis.
Studies have also suggested that Vitamin D deficiency may increase the risk of developing certain infections and autoimmune diseases, such as multiple sclerosis and type 1 diabetes.
Why do I need to get Vitamin D measured, can’t I just take it?
Getting a baseline Vitamin D is an important measure for ensuring your safety. When Vitamin D levels get too high, they put individuals at an increased risk of kidney stones.
Ultimately, we know getting your Vitamin D can be an expense, but having documentation of your levels is imperative to providing you with the best care as we walk with you in your treatment journey.
Written by Dr. Emily D’Adamo