Vitamin D Quick Reference

Page edition: 2021-03-13
Note: although this basenote is publicly-visible, some links and responses may be UIC members-only.

Contents

• Overall context for this topic
• General information
• Program target
• Cautions
• Supplement considerations
• Supplement suggestions
• Testing considerations

Context

Vitamin D is a core program supplement. Unless you are under 40, live near the equator, spend most of your daytime outdoors, year-round, with extensive skin exposure (i.e. live an ancestral lifestyle), your vitamin D levels are very likely suboptimal.

General Information

The need for vitamin D has been part of the program, going back at least a decade, and is extensively discussed in all the books and program materials:
Book: Wheat Belly Revised and Expanded: starting page 243 of print edition.
Book: Undoctored: starting page 272 of print edition
Video: DIY Healthcare: Vitamin D (public)
Video: Do I Really Need Vitamin D (members)
Blog Video: Common misconceptions surrounding vitamin D (public)

Program Vitamin D Target

Program target is based on a periodic blood test; a 25-hydroxy vitamin D level of:
  60 to 70 ng/mL (150-180 nmol/L)
See Testing considerations below for more information.
Note that consensus nutrition is only slowly catching up. The program’s lower limit usually requires Vitamin D intake well above common official guidelines. Although the guidelines recently doubled, from 10µg (400 IU) to 20µg (800 IU), they are still usually sub-optimal.
Note also that FDA labelling standards shifted from IU to µg (mcg) in 2020.

The program target usually requires a vitamin D supplement, often in the range 150 µg±100µg (6000 IU±4000 IU). This is about 7.5× common RDAs.

Individual requirements vary with age, situation and season, so getting tested is strongly encouraged. Return to ToC

Cautions

Response to vitamin D is an inverted U-curve, with benefits dropping off above and below target titer. This is why testing is needed to determine what you need.

At extremely high values, there is some risk of Hypervitaminosis D. Supplementation above 250 µg (10,000 IU) is not something to guess at. That said, people starting the program with a high BMI are apt to need more D₃ to hit program 25OH-D3 target, and then less over time as weight is lost.

Tanning salons may be completely ineffective at stimulating vitamin D. Return to ToC

Supplement considerations

Supplement form

The molecular form of vitamin D to supplement is D₃ (cholecalciferol), and not D₂ (ergocalciferol).

The supplement formulation to use is oil-based (and not dry, such as tablet). Gel caps are fine, as are liquid drops. Thousands of IUs are still just low hundreds of micrograms (µg) of actual D3, so the overall product formulation must be carefully considered. Don’t worry about any incidental D3 in any tablets you might be taking, but also don’t expect it to be well absorbed.

Store your D3 supplement out of sunlight. Refrigeration is fine.

Dose timing

Take D3 supplements early in the morning, to mimic the circadian effect of sunlight. Avoid taking D3 in the evening or at night, as it may disrupt sleep.

Depending on your situation, seasonal dose adjustment could be appropriate:
Video: Should I Take Vitamin D Year Round? (members)

Dose adjustment

The general rule of thumb for D3 supplementation adjustment is:
  2.5 µg/ng/ml (1 µg/nmol/L)
  100 IU/ng/ml (40 IU/nmol/L)
So if your 25OH test came back at 40 ng/ml at the start of your program, and using the middle of the target range ((60+70)÷2)=65 as a goal, you might increase your vitamin D supplementation by:
  2.5×(65-40) = +62.5 µg
  100×(65-40) = +2500 IU

See Testing for more information on dose adjustment. Return to ToC

Supplement suggestions

For the cautious buyer, subscription site ConsumerLab.com periodically tests Vitamin D supplements.

Check ingredients. In a stand-alone D3 gelcap, coconut, EVOO or MCT oil are fine. Junk oils like soybean, corn, safflower (or other grain or legume) are distressingly common in D3-only products, and indicate formulators who are either clueless, or not terribly concerned about your health. Entirely avoid relying on tablets and dry capsules (absorption issue). Most vitamin D liquid (drop) product are fine, if they use otherwise acceptable ingredients.

Because fish oil is also a core supplement in the program, using a fish oil product that contains D3 is an interesting option. This normally means having two forms of that fish oil on hand, one with D3, and the other without, due both to dose ratios, and wanting to spread the fish oil across the day. These two Sam’s Club Members Mark products may work for you (and are available on Amazon):
Double Strength Fish Oil with D3 (540 mg DHA+EPA, 2000 IU D3 per capsule)
Triple Strength Fish Oil 1400mg (900 mg DHA+EPA per capsule)
Similar products may be available from Nordic Naturals. Return to ToC

Testing considerations

Test details

If this test isn’t routinely covered by your carrier, it’s often cheaper to obtain it on your own, nanny state permitting, from a walk-in lab, perhaps via a Life Extension order, or via a home ZRT Test Kit.
Self-directed price range: US$30.00-83.00

Test day considerations

Fasting status: It is not necessary to test D3 fasting.
Day’s D supplement: may be taken before or after draw
Time of day for test: anytime

Re-Test timing

After a supplement dose adjustment, wait at least 21 days before re-test. Re-testing every 2-3 years is reasonable. Return to ToC