Interventional Studies with Vitamin D


Vitamin D, often referred to as the "sunshine vitamin," plays an integral role in our health, impacting everything from our bones to our immune system. Many of you might have seen the YouTube video where we dive deep into various aspects of sun exposure, Vitamin D, and health outcomes. In this comprehensive blog post, we will focus on one crucial part of that discussion: interventional studies on Vitamin D. The goal is to give you an exhaustive understanding of what science says about the potential benefits of Vitamin D supplementation and natural sun exposure.

What is Vitamin D and How is it Made?

Vitamin D is not just another nutrient; it's a precursor to important hormones. The skin synthesizes the precursor form of Vitamin D when exposed to sunlight, specifically ultraviolet B (UVB) rays. The precursor molecule here is 7-dehydrocholesterol, which turns into cholecalciferol or Vitamin D3.

Did you know?

  • The precursor form of Vitamin D is 7-dehydrocholesterol.
  • Cholecalciferol, commonly known as Vitamin D3, is the form found in supplements.

And let's talk about cholesterol for a second. 7-dehydrocholesterol comes from cholesterol—yes, the same cholesterol that has been villainized for years by mainstream medicine. This underlines yet another benefit of cholesterol, challenging its demonized reputation.

How Does the Body Process Vitamin D?

Once Vitamin D3 is synthesized by the skin or ingested, it undergoes two key transformations. First, the liver converts it into 25-hydroxy Vitamin D. After that, the kidney transforms it into its active form, calcitriol (1,25-dihydroxy Vitamin D).

Stage Conversion Organ Involved
1 Cholecalciferol to 25-hydroxy Vitamin D Liver
2 25-hydroxy Vitamin D to calcitriol (1,25-dihydroxy Vitamin D) Kidney

One essential point here is that the body does not usually supplement with 1,25-hydroxy Vitamin D because it can lead to pathological calcification, particularly in patients with compromised kidney function.

Vitamin D Levels and Body Regulation

The relationship between the consumption of Vitamin D3 and the level of 25-hydroxy Vitamin D in the serum is fairly linear. Your liver converts as much as it needs, but interestingly, your body usually doesn't convert excess 25-hydroxy Vitamin D into the active form unless there's a pathological process going on.

Evolutionary data offers fascinating insights into this. Communities like the Hadza and the Maasai, who have lived near the equator for hundreds of thousands of years, have average Vitamin D levels around 46-48 nanograms per ml.

Evolutionary Perspective

  • Hadza and Maasai average Vitamin D levels: 46-48 nanograms per ml
  • Suggested optimal level for most humans: Around 50 nanograms per ml

Vitamin D in Pandemics and Other Health Events

Recent observational epidemiological research, particularly during viral pandemics, suggests that maintaining Vitamin D levels above 30 nanograms per ml can be protective.

Importance of Individual Differences

It's essential to note that individual responses to Vitamin D can vary. Some people may not see a linear relationship between Vitamin D3 supplementation and their 25-hydroxy Vitamin D levels. Always consult a healthcare provider for personalized advice.

Optimal Levels of Vitamin D

Additional evidence for optimal Vitamin D levels comes from observations around parathyroid hormone (PTH) suppression. For nursing mothers to transfer adequate Vitamin D to their offspring via breast milk, they need to maintain around 48 nanograms per ml of Vitamin D in their plasma.

Interventional Studies on Vitamin D

Study 1: Vitamin D and Calcium Supplementation Reduces Cancer Risk

Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial

This study, a four-year population-based double-blind randomized placebo-controlled trial, involved 1179 post-menopausal women. It found that improving calcium and Vitamin D nutritional status substantially reduced all cancer risk. The Kaplan-Meier regression curves also indicated that the women with adequate calcium and Vitamin D levels did much better over the four years.

Conclusions: Improving calcium vitamin D nutritional status substantially reduces all-cancer risk in postmenopausal wonen

Key Findings Implications
Reduced all-cancer risk Suggests potential cancer-protective role
Kaplan-Meier regression curves Indicates better disease-free survival

Kaplan-Meier survival curves

Kaplan-Meier survival curves at 1 y of intervention

Study 2: Vitamin D Supplementation and Low-Risk Prostate Cancer

Another study indicated that Vitamin D3 supplementation at 4000 IU per day for a year resulted in a decrease of positive cores in low-risk prostate cancer patients.

Vitamin D3 may protect against low-risk prostate cancer

Key Findings Implications
Decreased positive cores in prostate cancer Suggests potential protective role

Additional Notes

Importance of Calcium

Calcium is vital for bone health and neuronal signaling. It can be sourced from dairy or supplements like microcrystalline hydroxyapatite.


Vitamin D is more than a vitamin; it's a crucial precursor to many bodily functions and processes. While supplements are beneficial, especially for those who don't get enough sunlight, natural sun exposure offers additional benefits like endorphin release and nitric oxide production. It's time we embrace this often misunderstood yet essential nutrient and heed what science and evolution have taught us about its importance.