Reasons for low response by vitamin D level in the blood

~ 50% of all people have a low response to vitamin D3

~ 10% of all people have a ZERO response to a LOW dose

OccurenceReason for low responseTypical %
extra Vit D
CommonExcess BMI/weight150% Obese need 2X to 3X more
CommonVitamin D supplement was not
taken with/after large meal
40%Take after large meal - provides more gut-time for vitamin D
evening meal or largest meal Note: avoid late in the evening
CommonMagnesium - low
(Gut needs Mg to absorb Vit. D)
30%Many reasons - which include low stomach acid and antacids
CommonSmoking30% Smoking reduces vitamin D -9 ng reduction
Commonmono-unsat fat ratio -low20%Need higher ratio of mono to poly fat ratio
CommonCola - soft drinks20%Cola removes Calcium, Vit D consumed in restoring Calcium
Common Oil-based Vitamin D 20%Oil-based Vitamin D helped the least
Some olive oils decrease absorption by 25 %
Bio-Tech uses a water-soluble form of Vitamin D
CommonVitamin K2 -low10% Overview Vitamin K and Vitamin D
perhaps 100 microgram/ 1000 IU of vitamin D
CommonBoron - low15%Boron increases vitamin D in the blood claims 6 mg ==> 24%
  -Boron is also known to build bone - perhaps by increasing vitamin D
CommonCholesterol - reduced in dietN.A.Cholesterol is needed to make Vitamin D from the sun
Low Cholesterol DOES NOT appear to affect vitamin D supplementation
- - - - -
SometimesExtremely Vit D deficient200%Low dose can result in ZERO increase if very deficient
When body is very deficient all vit. D is immediately consumed
Note: sometimes extreme deficiency is due to genes.
SometimesHealth - low200%Unhealthy body consumes a lot of vitamin D - see extremely deficient
(Examples: MS, HIV, some cancers, Diabetes, Depression. .
SometimesAnemia 40%Liver is needed to process vitamin D
Sometimes need to add Iron as well as vitamin D
SometimesFatty Liver40%Half of seniors have fatty liver, vitamin C reduces inflammation,
Calcidiol or Calcitrol might be taken instead of Vitamin
SometimesDrugs which consume
or block Vit D
50%Taking drugs such as Statins, Antiseizure, Prednisone, AIDS drugs,
Orlistat, Questran, Dilatin, Phenobarbital, Rifampin, Methamphetamine..
SometimesGenes10%?Genes need to be functioning properly to process vitamin D
Twin studies   Genetics    VDBP  also kidney
Note: sometimes cells do not get Vitamin D even though tests are OK
   see below on this page
SometimesTaking D2 vs D330% Sometimes D2 will actually DECREASE the level of D3
SometimesToo much UVA vs UVB20%UVA appears to actually DECREASE vitamin D levels
Avoid getting a lot of sun thru windows or very early/late in the day
SometimesWinter birth11%Winter birth, 11 % more likely to be vitamin D deficient as an adult
SometimesOral contraceptives
INCREASE response
-20% Oral Contraceptives INCREASES vitamin D levels
Perhaps due to less blood loss/anemia
SometimesTest results inaccurate+20% -20%Overview  Graph of tests from 1000 labs
Vitamin D differences of 5 ng are meaningless - Aug 2015
SometimesGut - poor100%Bio-Mulsion form of vitamin D was designed for poor guts, etc
SometimesProbiotic + - +20% -30% 1/3: 30% increased D bioavailability; 1/3: 20% decreases
SometimesDDT, pesticides20%Pesticides - 2016
SometimesPlastics (phthalates and BPA)10% 2016
SometimesVitamin A - excessive 30%Attenuates responses for > 10,000 IU vit D: from cod liver oil or Accutane
SometimesRoundup/glyphosate ? %Gut bacteria and liver
SometimesStress ? %Cortisol consumes Cholesterol needed to make Vitamin D
- - - - -
RareGallbladder removed
600,000/year in US
100%Gallbladder essential to absorb vitamins dissolved in fats
Consider other forms of Vitamin D: Biomulsion, water soluable, . .
RarePancreatic Insufficiency ??Fat soluble vitamins (A, D, E, K) are not absorbed as well
RareLiver problems50%Use Calcidiol or Calcitrol forms of vitamin D instead
Rare Burned skin 70% Burn - uncertain response to supplementation
- - - - -
Sun/UVSkin - Dark 250% vitamin D produced varies with darkness of skin: White = 0%, Black = 250%
Sun/UVSkin - Elderly 100% varies with age: teenager = 0%, 60 years = 100%
this due to thin skin or low cholesterol in skin
Sun/UVSkin - Sunburned 30% varies with % of skin which is burned
Burns and bone loss    75% less
- - - - - Reduction in Vitamin D getting to cells - downstream from Vitamin D Testing
Test invisibleGenes Genes, problems which often run in families
Vitamin D Receptor 18+ diseases
Vitamin D Binding Protein
Test invisibleCells Low Magnesium
Test invisibleCells Low Omega-3
Test invisibleKidney Poor Kidney


  • Any study will rarely consider even 4 of the above factors
  • Factors are sometimes additive: example, 50% + 50% = 100% = 2X as much Vitamin D is needed

Reasons for not getting benefits - even if blood tests are OK

Kidney   Low Magnesium, Low Omega,   Vitamin D Receptor    Vitamin D Binding Protein.

See also VitaminDWiki

Wide range in the responses after 1 year (black dots)
  Example: 2400 IU dose: 75-140 nmol response (30-56 ng)
  Example:  400 IU dose: 50-110 nmol response (20-44 ng)

Big differences between UVB response too 20-36 ng at 6 weeks


Alternate sources of vitamin D click on chart for details

Short URL = http://is.gd/lowresponse

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