Is vitamin D effective in supplement form, or is the sulfating effect of sunlight required?

Jacked Check – An occasional series fact checking the world of bro science

Claim: Vitamin D in a pill form provides the body with the full benefits of vitamin D. The sulfating effect of the sunlight is not necessary for the body to make effective use of ingested vitamin D.

Rating: True, unless you have gut issues.

Conclusion: A vitamin D supplement is a good alternative to sunlight if this natural source is unavailable.

The Details

One intriguing aspect of the vitamin D3 pill vs. sun debate is the success of The Hammer protocol. The Hammer is a recommendation to beat flu-like symptoms by taking massive amounts of vitamin D supplements for one or two days after the onset of symptoms. If the sun was necessary, presumably The Hammer wouldn’t work.

In a short, remarkable medical journal article, one of pioneers of The Hammer protocol wrote:

A colleague of mine and I have introduced vitamin D at doses that achieved greater than 100 nmol/L in most of our patients for the past number of years, and we now see few patients in our clinics with the flu or influenza-like illness. In those patients who do have influenza, we have treated them with the vitamin D hammer … We urgently need a study of this intervention. The cost of vitamin D is about a penny for 1,000 IU, so this treatment costs less than a dollar.

Which of course is why there will never be a study of this intervention. But wait, there’s more:

The Institute of Medicine recommendation for adults younger than 70 is 600 IU of vitamin D daily. We are told that this would achieve a level of 50 nmol/L in greater than 97.5% of individuals. Regrettably, a statistical error has resulted in erroneous recommendations by the Institute of Medicine leading to this conclusion. It might actually take 8,800 IU of vitamin D to achieve this level in 97.5% of the population. This is a serious public health blunder.

A serious public health blunder? By a factor of 10x? Well I never. It’s preposterous to suggest that, due to malice or stupidity, our public health experts would recommend widescale interventions that have no effect on a virus.

In any event, let’s look at what it means to sulfate vitamin D3.

Sulfating vitamin D means the body metabolizes vitamin D into a form the body can use. According to my reading of this article from 2019, vitamin D produced by the body (skin+sunlight, in the liver, in the small intestine), and vitamin D consumed via food or supplements, end up in the same place. Enzymes in the liver, kidneys, and elsewhere convert the vitamin D into active metabolites.

While the focus of this article was the relationship between vitamin D and cardiovascular disease, the authors have swerved into the answer about vitamin D supplements: Your body ultimately creates the same metabolites regardless of where the vitamin D comes from. I’ve pasted the key paragraph in full science-speak below¹.

It’s worth noting that D3 produced by skin+sun is carried in the blood on a different molecule than ingested D3. As a result, an individual with gut and digestive problems should strive to get his or her vitamin D from the sun instead of a supplement. Taking a vitamin D supplement with an impaired gut will just make everything worse.

I’d add that I’m very much in favor of sunlight. It’s hugely important for a stable circadian rhythm, hormetic effects, mitochondria stimulation, and more. It seems, however, that you can indeed get your vitamin D from a bottle.

¹ For both endogenous and exogenous sources, the D₃ carried in the bloodstream on either DBP or lipoproteins undergoes a two-step sequential hydroxylation to active metabolites. First, it is converted by 25-hydroxylase to the monohydroxy- derivative, 25(OH)D₃, the metabolite that is measured for “vitamin D levels.” This occurs primarily in the liver, but may take place in other tissues as well. Next, 25(OH)D₃ is further hydroxylated by 1-alpha hydroxylase to the active, dihydroxy- form, 1,25(OH)₂D₃. This occurs primarily in the capillaries surrounding the proximal convoluted tubules of kidney, but, importantly, the enzyme producing the active form is also found in vascular cells and monocytes among other tissues and cells.