Why I started taking Vitamin D3
Professor Grant Schofield
All about vitamin D, and why you probably should take some D3 supplements (from a Professor mostly ambivalent about supplements).
I’ve often wondered just what it would take for me to move from a whole food template of eating, and believing that I would get all the nutrients I need from the healthy food I eat, to taking some supplements.
Mostly, it has seemed like an expensive, low evidence hobby to me.
But food isn’t what it used to be. Evidence from historical micronutrient studies shows that our food has less macronutrients in than it had 100, even 40 years ago. Modern industrial farming, poor soil quality, rapid growing speeds and large yield crops all are factors in this.
Have a look at the figure below and how some micronutrients in cabbages, spinach, tomatoes, and lettuce have dropped over the last hundred years. The average mineral content of calcium, magnesium, and iron in cabbage, lettuce, tomatoes, and spinach has dropped 80–90% between 1914 and 2018.
Wow.
Similarly, below look how things changed in broccoli over 22 years! It’s interesting that these data are now 20+ years old – I wonder how things have changed since 1997? If the above trend for cabbages, spinach, tomatoes, and lettuce is anything to go by, it’s probably looking similar for broccoli.
All “essential” nutrients are, of course, essential. But over the last 15 years, science has come in and shown that Vitamin D is really critical across many processes in the body.
Vitamin D might be the most important of all essential nutrients for us because it’s likely that large portions of the population, especially groups like pregnant women, children and the elderly are deficient or at least sub-optimal in Vitamin D. In some groups this may be ubiquitous.
It’s also unlikely that we can get all of our Vitamin D from food. We manufacture it from blue wavelength sunlight and cholesterol in the skin.
Therein lies the added problem.
A sedentary indoor lifestyle, high in screen time, and a poor quality ultra-processed, high sugar and seed oil diet are also contributors. These, of course, are the dominant waking behaviours for most of us in modern societies. The lack of exposure to sunlight goes hand in hand with this lifestyle, as does obesity, high blood glucose and insulin resistance, and low essential micronutrients such as K2 and Magnesium. These are all contributing factors to low Vitamin D serum levels.
Here is a list of known risk factors and the mechanisms. I’ll have a look at each in a bit more detail in the rest of this article:
- Seasonality and latitude – the less sun you are exposed to the less Vitamin D you can make.
- Dark skin – more melanin means more pigment which means less sensitivity to producing Vitamin D from the sun.
- Age – We lose the ability to produce Vitamin D from sunlight by up to 13% per decade of life.
- Obesity – Vitamin D is a fat soluble vitamin and can be sequestered away and inaccessible in large body fat stores.
- High glucose and insulin – High insulin depletes magnesium and is an essential cofactor in Vitamin D. Without adequate magnesium, we cannot properly use vitamin D.
- High glucose causes insulin resistance, low Vitamin D also causes insulin resistance. Both of these combined with an ultra-processed food diet cause obesity and you are trapped in a downward spiral.
- Excessive sun exposure, to the point of reddened skin, itself also causes inflammation and deletion of Vitamin D.
- Living at sea level – higher attitude means better Vitamin D production from the sun.
- Some medicines like cholesterol lowering drugs because Vitamin D is formed from cholesterol. Steroids, anti-seizure meds, and St John’s wort can deplete Vitamin D.
Straight to supplementation?
It’s obviously a great idea to get out and about in the sun whenever possible. Don’t get sunburnt as that’s bad for you including the fact that it lowers Vitamin D. Being active outdoors is independently good for you as well.
On the other hand, supplementing Vitamin D3 with K2 and possibly Magnesium can help some people. If you have more than a couple of these risk factors – you are older, dark skinned, living in sea level temperate climates, overweight, not very active outdoors, and your diet lacks in healthy fats and whole animal foods including liver and oily fish, then you might want to supplement.
Supplementation is likely to be effective in reducing viral and bacterial infections including COVID 19 severity. That alone is a big tick!
So, it’s a yes from me for Vitamin D through lifestyle, but probably supplements as well. Read on and make your own decisions.
The observable problem of supplements
Yes, I’ve seen the studies on various things from high dose multivitamins and mental health, to creatine and Coenzyme Q10 for mitochondrial function. It’s interesting, but my view has been that all things being equal, surely a healthy diet gets you all the things you need?
Clinical trials for actual deficiencies and diagnosed disorders are one thing, but what about optimal health and longevity? Well, some things probably do help. But how do you know if it worked or not? That’s always been my problem. I take something and I don’t feel better or worse. The evidence points to a likely small benefit but who really knows in my case? I’m already healthy, and I just want to further optimise things.
So realistically there is no observable change in anything. And even if there is, there is so much more going on. I have no experimental control. I exercise, I get stressed, work is hard, work is less hard, stresses come and go. Good and bad things happen. How is a science minded professor able to detect anything in the affect form supplementation on himself?
So here is where I have got to.
Creatine is cheap and very effective for metabolic, brain and muscle health. So that’s one that I consider useful for most people. I exercise, including lifting weights. I think there is an observable effect for me.
Besides creatine the only thing I take is Vitamin D3. Here’s why and where I think science is at.
The power of Vitamin D: Critical for so many aspects of health
The science is in, and keeps rolling in. Here’s where having enough Vitamin D can help you, or where not enough could harm you. The advice to make sure your Vitamin D levels are high and that it has the potential to improve so many aspects of your life are a little odds with the now 13 year old advice
The advice from NZ best practice guidelines is horribly out of date and frankly wrong in places.
Here’s a more up to date list of health benefits:
Bone Health
- Calcium Absorption: Vitamin D enhances calcium absorption, crucial for healthy bones.
- Prevents Disorders: It prevents osteoporosis and rickets by improving bone density.
- Fracture Reduction: Reduces fracture risks, especially in the elderly.
Immune System
- Immune Modulation: Helps regulate the immune system, reducing infection risks.
- Respiratory Health: Lowers the incidence of respiratory illnesses, including influenza.
- COVID-19 Protection: New evidence suggests potential protective effects against COVID-19.
Cardiovascular Health
- Blood Pressure Regulation: Vitamin D aids in regulating blood pressure.
- Heart Function: Improves heart health, reducing cardiovascular disease risks.
Metabolic Health
- Diabetes Risk Reduction: Linked to a lower risk of type 2 diabetes by improving insulin sensitivity.
- Improved glucose transport, reduced hyperinsulinemia even with normal blood glucose
Mental Health
- Mood Regulation: Associated with lower risks of depression and anxiety.
- Deficiency in Disorders: Common in individuals with mental health issues; supplementation can aid mood.
Cancer Prevention
- Anti-inflammatory Properties: Contributes to overall cellular health.
- Reduces Cancer Risk: May lower the risk of colon, breast, and prostate cancers.
Lots of deficiency
OK it’s critical to health and wellbeing, but so are a lot of things. The big question is how many of us are either critically low (deficient) in Vitamin D or are sub-optimal.
In NZ the last comprehensive survey was in 2012 with just under ⅓ with low Vitamin D, of which about 5% were severely deficient.
In Australia, one of the sunniest places in the world, according to the Australian Bureau of Statistics,
The last national survey was also completed nearly 15 years ago in 2012 where 23%, or 4 million adults, had a Vitamin D deficiency, which comprised 17% with a mild deficiency, 6% with a moderate deficiency and less than 1% with a severe deficiency. Overall, rates of Vitamin D deficiency were very similar for both men and women.
Here’s the cut points for serum levels:
- Mild deficiency: 30 – 49 nmol/L
- Moderate deficiency: 13 – 29 nmol/L
- Severe deficiency: <13* nmol/L
- Total deficiency: <50 nmol/L
- Adequate levels: ≥50 nmol/L
- Optimal levels: This is uncertain but here are claims that 120 nmol/L is optimal
Here are some data from other populations – in the Middle East where people are more covered up, especially Muslim women. Look at how high, insufficient and deficient they are!
Then the Korean teenagers in the next graph. 100% of the overweight teenagers in this Korean sample are deficient!
The last set of data is for at risk groups – maternal women. This analysis of studies up until about 2010 shows how prevalent low Vitamin D is an important group. Look at the NZ data here.
How do you get Vitamin D?
Well here’s the full biochemistry and physiology if you really want to get into it.
But basically you are going to need sunlight and or decent food.
Season and sunlight/sunscreen
As I said earlier, seasonality has a massive effect. Here’s New Zealand seasonal data.
Too much sun?
Yes, this is a factor as it depletes Vitamin D. And before that, there is a plateau anyway.
The synthesis plateau occurs because the vitamin D precursors in the skin can only absorb a certain amount of UVB before they become saturated and further exposure leads to the breakdown of the vitamin D3 molecule itself, not its production. This regulatory mechanism helps prevent vitamin D toxicity from excessive sun exposure, though it’s worth noting that vitamin D toxicity from sun exposure alone is very rare, with most cases resulting from excessive supplementation.
Actually high sun exposure impairs immune function by probably many mechanisms of increased oxidative stress, but I think one factor of deleted Vitamin D.
I was training an elite athlete in Maui (Hawaii) a few years back and I think excessive sun exposure caused shingles which affected his Hawaii Ironman preparation.
Sunscreen
Sunscreen gets a bad rap with Vitamin D, and health in general. I don’t go for it myself and try hard not to get sunburnt. But … this review found little evidence in the real world of sunscreen application 16 SPF affected Vitamin D3 levels. This may be because it prevents burning and depletion?
Age effects
This is the bit that really got me. There is a 13% decrease in D3 production per decade of life. D3 production at age 70 years is approximately half that produced at age 20.
Obesity effects
Vitamin D is fat-soluble. So the more fat (adipose tissue) you have the more Vitamin D gets sequestered away in the fat cells. That, as well as being a bigger specimen in the first place (volumetric dilution) means Vitamin D serum levels may be lower.
The figure below from this paper shows the possible cause and effect relationships. They say “The underlying pathogenetic mechanisms associating low vitamin D in obesity include volumetric dilution, sequestration into adipose tissue, limited sunlight exposure, and decreased vitamin D synthesis in the adipose tissue and liver“
Ethnicity effects
This is an amazingly big effect, and since I have dark skin (probably Type 4 below) then this affects me.
Wacker and Holick conducted a study that compared Fitzpatrick skin types in relation to vitamin D production using UV tanning beds. They found that when exposed to UV light from a tanning bed, those with Fitzpatrick type II skin increased their rate of vitamin D production by 30 times the rate of those with Fitzpatrick type V skin
Effects of insulin and glucose, and effects on glucose and insulin
Vitamin D helps transport glucose across cell walls. That’s a fundamentally important effect. Therefore we can predict that those low in Vitamin D will be insulin resistant. That’s exactly what we see.
This study “Effects of vitamin D supplementation on metabolic parameters in women with polycystic ovary syndrome: a randomised controlled trial” shows that vitamin D supplementation had beneficial effects on metabolic parameters in PCOS women, especially in women with obesity or insulin resistance.
Have a look at the figures below. I chose this study because PCOS is an example of serious insulin resistance. At least the PCOS phenotype associated with obesity probably is. And we see such a good effect here.
There’s also a reverse pattern here too. High glucose and insulin cause low Vit D, insulin depletes Magnesium, and Magnesium helps Vit D absorption. Hyperinsulinemia promotes magnesium depletion via increased renal excretion and other multiple mechanisms. If you are really interested see this paper: Hyperinsulinemia through multiple mechanisms reduces Vitamin D synthesis, uptake, and availability.
Immune system effects
Seasonal infections like the flu usually come around wintertime and early spring. This is also when serum vitamin D levels will be at their lowest for most people who do not live within 30 degrees of the equator.
Many studies have demonstrated this effect. For healthy adults living in New England, they halved their risk of acute viral respiratory tract infections if their serum 25(OH)D was above 38 ng/mL (close to 100 nmol/L). In Japan, children who ingested 1200 IU of vitamin D3 daily for four months during the winter reduced their risk of developing influenza by 42%. Infants whose 25(OH)D3 levels were >30 ng/mL were six times less likely to contract RSV than infants whose 25(OH)D3 levels were <20 ng/mL.
No one likes colds and flus. Vitamin D helps!
The Spanish COVID trial is a good one. Mainly because the effect is so huge.
In the trial 76 patients hospitalised with COVID-19 infection received as best available therapy the same standard care, (per hospital protocol), Eligible patients were allocated at a 2 calcifediol:1 no calcifediol.
Calcifediol is the active form of Vitamin D and can boost levels in just a few hours as opposed to weeks for Vitamin D3 which needs to be passed through the liver and kidneys.
Of 50 patients treated with calcifediol, one required admission to the ICU (2%), while of 26 untreated patients, 13 required admission (50 %). Of the patients treated with calcifediol, none died, and all were discharged, without complications. The 13 patients not treated with calcifediol, who were not admitted to the ICU, were discharged. Of the 13 patients admitted to the ICU, two died and the remaining 11 were discharged.
Wow, yes you read that right. See it again in the table below!
That’s a wrap on where I’m at with Vitamin D3 right now.
I’m older, dark(er) skinned, live in a temperate climate and hate getting colds and flus. So it’s 2000 international units of D3 a day for me. It’s probably the cheapest supplement and best evidence and bang for the buck out there, along with creatine which I’ll write about later.
What about you?
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