Vitamin D is an essential nutrient that is a part of the fat-soluble vitamin family.
Vitamin D receptors can be found in every single cell in the body, hence it's wide-ranging effects. It plays a role in over 200 processes in the body. Including bone health, immune function, mood stabilising, pain reduction, and more.
But first some science
When our skin is exposed to UV light from sunshine, we can create a form of pre-vitamin D3. There are many factors that can limit this including wearing sunscreen, the amount of melanin in your skin, the time of the day, etc.
Sunshine is the preferred source of pre-Vitamin D, but with our busy indoor lifestyles, religious beliefs, geographic location, and certain medications causing photosensitivity’s it not always possible. This is where food and supplementation can help. Vitamin D2 can be found in certain mushrooms. D2 is generally inferior to D3 but it's a good dietary vegan source to increase this vitamin. D3 can be found in fatty fish, especially cod liver oil, and also in egg yolk. These food options are great not just because of the form of Vitamin D that they contain, they also provide us with important co-factors such as the retinol form of Vitamin A.
Vitamin D extracted from your food or supplementation has to be absorbed via the digestive system. Various digestive conditions reduce our ability to do this. This is where skin-produced vitamin D has an advantage and where transdermal Vitamin D therapy may be indicated. The area with the most research on topical application is the vagina. In the European Menopause and Andropause Society, 2022 Vitamin D position statement, they discuss the use of vaginal suppositories of Vitamin D for vulvovaginal atrophy.
Once Vitamin D has made it to the bloodstream it needs to undergo a 2-step process in order to be useable. The first step is via the liver and the second is primarily in the kidneys. So you can see that if your liver function or kidney function isn’t optimal this can slow your ability to process Vitamin D into the active form.
I want to briefly mention Calcifediol, an active form of Vitamin D. In Australia this is a practitioner-only compound. This product is reserved for patients with known liver issues as it bypasses the need to be processed as it already is the active form of Vitamin D.
What we also need to discuss is the many nutrient co-factors needed along the way.
Let’s start with the rest of the fat-soluble nutrient family, which includes vitamins A, E, and K. (Previous article on Vitamin A.) It really scares me the number of women I consult with who have been taking high-dose Vitamin D on their own for the long term without retesting and without considering the rest of the family. We seem to know that Vitamin A in high doses is dangerous but many haven’t received the memo about Vitamin D. Vitamin D can also be toxic in high doses. When taken with the rest of the family it minimises toxicity. Signs of toxicity include too much calcium in the blood promoting the development of calcium stones eg kidney stones, and bone pain due to the pulling of calcium from the bones and moving it to the bloodstream. This is why it's also an idea to test for serum calcium and parathyroid hormone when checking vitamin D levels.
Other required cofactors include
A fat source, being a fat-soluble nutrient, it needs a fat source in order to be properly absorbed and utilised. Magnesium - the master menopause mineral, is needed for 8 various steps of Vitamin D metabolism. Zinc may be required for optimal Vitamin D receptor function and to facilitate entry into your cell. Other nutrients of interest include Potassium, Boron, Resveratrol, Vitamin C, Iodine, and Vitamin B12.
Benefits of optimal Vitamin D status.
Possibly its most well-known role is to do with bone density. It does this by enhancing calcium absorption from the digestive system. It also helps to maintain serum levels of both calcium and phosphate, these 2 minerals are crucial for bone health. But did you know Vitamin D also plays a key role in muscle as well as nerve health?
After the last few years, I bet most of you have heard about the immune strengthening benefits of Vitamin D. I think of Vitamin D as an immune regulator, great for low immunity, great for autoimmunity (especially when combined with Vitamin A), and for allergies.
Vitamin D and depression. Have you ever experienced seasonal affective disorder or winter depression? I have when I lived in Germany, with its long and cold winters. But some Vitamin D deficient individuals can experience depression all year round. Vitamin D receptors have been discovered in parts of the brain that regulate mood as well as parts of the brain that assist with memory and cognition.
Glucose metabolism can also be improved with adequate Vitamin D, due to its role in enhancing glucose metabolism and insulin signaling.
Vitamin D may benefit the cardiovascular system. It is thought to play a role in cholesterol and triglyceride management as well as blood pressure regulation.
Vitamin D can act as an anti-inflammatory agent. Several studies have linked decreased pain tolerance with lowered vitamin D levels.
And the list of Vitamin D benefits goes on.
But I wanted to give a balanced outlook on Vitamin D, it's not about how high you can get your levels, it's about finding the magical medium, not too high or too low.
I also wanted to bring to your attention that all supplements come with cautions, contra-indication and medical interactions and Vitamin D is no different. If you are taking any medication you should check with your health care team for interactions. Some medications such as certain diuretics may increase your risk of vitamin D toxicity whereas other medications like statins, and steroids may reduce your levels of vitamin D and create a deficiency.