Is Vitamin D Supplementation Even Optional?

I love it when my favorite health and wellness experts agree.  The topic of vitamin D supplementation is one of these areas. In short, there is much more consensus than not on at least some fundamentals, namely:1) vitamin D is supremely important; 2) big problems occur when we are deficient in it; and 3) it’s pretty easy to solve a deficiency through supplementation.


In my opinion, vitamin D is the single most important missing ingredient necessary to restore your gut health and therefore your overall health.  It is essential to stimulate the growth of enterocyte stem cells, which repair the gut wall that has been damaged by lectins on a daily basis.  –Dr Stephen Gundry, MD, author of The Plant Paradox, [1]

Having optimal levels of vitamin D is practically a super power that, in addition to protecting against osteoporosis and rickets:

  • Reduces risk of some cancers [2]
  • Reduces the chance of obesity and diabetes.

Cray-cray as it may seem, not enough vitamin D may be what’s coming between us and the skinny jeans we want to wear.  — Dr Sara Gottfried, MD [3]

  • Fights infections – including prevention and treatment of the common cold, flu, pneumonia and tuberculosis[4].  I plan to delve into this further as I am always on the lookout for ways to hack my health, especially while traveling.
  • Controls epilepsy[5]
  • Activates the genes that release dopamine and serotonin, the lack of which are commonly linked to depression [6]
  • Fights auto-immune diseases[7]
  • More, because vitamin D impacts more than 3,000 of our 30,000 genes[8]


So where do you begin your vitamin D journey? With testing, of course.  There is an easy way to know your vitamin D levels:

Test Name:  serum 25-hydroxy vitamin D test

Type of test:  blood test

What it does:  measures the active form of vitamin D in your body.  Regular testing (from 2-4 x per year) is advisable as your levels can fluctuate due to factors such as hormones, age and where you live – more vitamin D will be produced naturally the closer you live to the equator, assuming you are allowing some sun to touch your body each day (which incidentally rules out most Thai women I know).


So here there is some variability:

Dr Gundry is not afraid to go big and advocates a vitamin D blood level range of 70-100 ng/ml per day, which may require a supplement of up to 40,000 IUs a day of vitamin D3 to achieve.  If you are just beginning supplementation he suggests to start with 5,000 IUs of D3 per day or 10,000 IUs if you have an autoimmune disease.  But he admits he is comfortable keeping his patients’, as he does his own blood levels, at over 100 ml, and that he doubts that vitamin D toxicity even exists.[8]

Dave Asprey, founder of the Bulletproof Coffee company and international bio-hacking expert, seems to agree.  He advocates vitamin D in the blood level range of 70-100, or higher.  He also points out that if you supplement with vitamin D you should add vitamin K2 supplementation to your protocol as well.[9]

For Dr William Davis, MD, who wrote an entire book on empowering regular people to become their own best health and wellness experts, called, Undoctored, the ideal range is 60-70 ng/mL.  Dr Davis believes as well that the benefits of eliminating grains from one’s diet, in addition to the restoration of vitamin D to appropriate levels is profound.  A deficiency in vitamin D, has a “permissive” effect on many organ systems in the body and that the damaging effects of grains in the diet and vitamin D deficiency overlap.  Thus, elevating vitamin D levels alongside a grain-free diet can totally reverse many modern illnesses, where pharmaceuticals have fallen short.[10]

Dr Mercola, MD, and woman’s hormone expert, Dr Sara Gottfried, MD, are more conservative in this regard, advocating ranges between 50-70 ng/mL and 50-60 ng/mL, respectively, for optimal benefits.[11][12]

The National Institutes of Health?  They say 20 ng/mL is sufficient(and that 200 ng/mL is potentially toxic.[13]


My favorite experts seem to agree that the best way to get your Vitamin D is through sensible sun exposure, which creates the conditions for your body to produce it.  What exactly is sensible sun exposure?  20 minutes per day without sunglasses and sunscreen.

Food is not the greatest source of vitamin D.  While in the US, at least, a number of processed foods – such as milk, bread, orange juice and breakfast cereal – have been fortified with vitamin D, these are not things I tend to consume.  Vitamin D does naturally occur in fatty fish, like salmon, mackerel and sardines, as well as cod liver oil, but not in amounts offering significant benefits, even if you’re eating fish every day.

If you think you are maximising your healthy sun exposure, but testing reveals your vitamin D levels to be lower than you want, vitamin D3 supplements could be your answer.  And don’t let anyone talk you into supplementing with vitamin D2.  It’s more expensive and less effective.

It is also wise to consider the interaction between vitamin D, vitamin K2, calcium and magnesium.  If you are heavily supplementing with vitamin D3, you will likely need vitamin K2 as well. And you may already be supplementing with magnesium.

Also be aware that if you begin supplementing with vitamin D it will take up to 3 months for any effects of supplementation to show up.  So wait that long before you test yourself again.


Vitamin D is important enough to make it worthwhile to measure regularly.  You can decide for yourself what your target levels are from a range of recommendations.  A number of health and wellness experts agree those levels should be higher than US government guidelines.  Supplements might help.

What’s stopping you from getting your own vitamin D game on and welcome the benefits that comes with it?


  1. Gundry, MD, Dr Stephen.  The Plant Paradox.
  7. Gundry, MD, Dr Stephen.  The Plant Paradox.
  8. There are many many studies on this but you can read a referenced article on some of them here.
  10. Davis, MD, Dr William.  Undoctored.
  13. https:\\

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