It is probably fair to say that most people would consider Vitamin D to be nutrient that acts as a bone health vitamin. However, according to the medical literature including PubMed, "Vitamin D, a secosteroid (pro)-hormone, has been traditionally considered as a key regulator of bone metabolism, and calcium and phosphorous homeostasis through a negative feedback with the parathyroid hormone". However, they go onto say that during the last twenty years, the role played by vitamin D has been largely revised by recognising it a "pleiotropic" (i.e. affecting multiple body parts) action on a wide spectrum of systems, apparati, and tissues. Thus, vitamin D has growingly been involved as the key influencing factor of biological modifications and specific clinical conditions.
Your body makes vitamin D from cholesterol (in the presence of sunlight)
Dr Doug Corrigan explains it in a far more straightforward fashion, he says that vitamin D is, "a steroid hormone precursor that your body synthesises from cholesterol when your skin is exposed to UVB rays from sunlight".
Dr Corrigan Ph.D. ia s Biochemist & Molecular Biologist, Physicist, Award Winning Global Super Solver is also the author of;
The Author of Light: Did God Reveal His Identity in the Physics of Light
To become fully activated, the steroid hormone precursor must also be processed by your liver and activated becomes a substance known as 'calcitriol'. Once activated, Vitamin D binds to Vitamin D Receptors (VDRs) found in nearly every cell in your body. This binding causes modulation of the expression of over 200 genes involved in:
- Immune regulation
- Cell growth and repair
- Calcium and phosphate balance, and
- Inflammation modulation
This list underpins the importance of the 'steroid hormone precursor' and its role in immunity against viral infections, and normal, healthy body function. Vitamin D enhances innate immunity while preventing overactive inflammatory responses, which is critical for fighting infections without triggering chronic inflammation.
Vitamin D helps your gut absorb calcium efficiently, preventing osteoporosis. Low Vitamin D levels are associated with mood disorders and cognitive decline in observational studies, likely due to its role in neuroimmune pathways.
Deficiency is common, especially if you live in extreme latitudes, spend most of your time indoors, or have darker skin (which reduces Vitamin D synthesis).
Blood levels are best assessed as 25(OH)D (calcidiol). Levels above 30 ng/mL for optimal health, though ideal ranges can vary.
How do you optimise your Vitamin D levels?
Aim for moderate sun exposure.
Include fatty fish and egg yolks in your diet.
Take a Vitamin D3 supplement.
