Vitamin and Mineral Supplement Basics

This is a brief summary discussion about vitamins. This will review fat soluble vitamin, and provide clarity on why post-op Duodenal Switch patients need to take “dry formulary” instead of “regular” fat soluble vitamins. Vitamin and mineral supplement basics will also provide details of what to look for in vitamin and mineral labels, because often the information can be very misleading.


A, D, E and K Fat Soluble Vitamins

The A, D, E and K vitamins are fat-soluble. This means that these vitamins are mostly absorbed by dissolving in dietary fat, and since DS patients do not absorb as much of the fat there is an associated malabsorption of the fat-soluble vitamins.


Wet vs. Dry Vitamins.

Wet vitamins are oil filled soft-gel forms of the vitamin.

Dry vitamins refers to a powdered form of the vitamin and can be called dry, allergy, miscible or water-miscible.

Since wet vitamins are delivered in an oil based solution they will not be absorbed adequately in DS patients.. This is why “dry” forms of A, D, E and K vitamins are needed. These dry formulated fat-soluble vitamins have been prepared to allow the absorption without relying on a fat carrier molecule.


Understanding Vitamin and Mineral Supplement Labels

Vitamin and mineral supplement basics continues with a lesson on how to read vitamin labels. A patient has to read the fine print; the labels on these bottles can be very deceiving. Pay particular attention to the dosages. What it says in big print on the label may not be per tablet and may need anywhere from 2-6 tablets to obtain that amount.

It is very important to understand the mineral potency of the supplements. We will use calcium as an example. Elemental calcium is the amount of calcium that is actually in the supplement from the source. (The same is true for all other minerals.)


Example A: Elemental Calcium: 315mg

This means there is 315mg of calcium per tablet.


Example B: Calcium (Citrate): 500mg

When the source of calcium appears in parentheses it means the amount of calcium listed is elemental calcium, so in this example a recipient is receiving 500mg of calcium.


Example C: Calcium Citrate: 500mg

When the source does not appear in parentheses it means it, the 500mg, is not a elemental calcium. Since calcium citrate is 21% calcium the recipient would actually only be receiving 105mg of calcium in this example.


Scientific Units of Measure

There are different scientific units for measuring the amounts of vitamins and minerals in each soft gel or tablet. An international unit (IU) is the global standard for measuring fat-soluble vitamins (vitamins A, D, E and K). Water-soluble vitamins and minerals measured in milligrams (mg) and micrograms (mcg); one milligram (1/1000 of a gram) is equal to 1000 micrograms.


How to Organize Daily Supplements

Some vitamin and mineral supplements have the potential to interact with prescriptions and over the counter medications. Be sure with check with the doctor. Check with the surgeon for their recommended post-op vitamin and mineral supplementation.

According to Michelle at these are the simple DOs and DON’Ts everyone agrees with:

  • Do take iron with vitamin C
  • Do take calcium with vitamin D


  • Don’t take iron at the same time as calcium or zinc
  • Don’t take zinc at the same time as iron or calcium
  • Don’t take calcium at the same time as iron or zinc


The rest of supplements can be grouped together as long as the patient keeps in mind the above rules.


Vitamins and Minerals

Detailed vitamin and mineral information on the benefits, best absorbed sources, synergistic nutrients (works with), negative interactions and deficiency symptoms.

Vitamin A
Vitamin D

For Vitamin and Mineral Supplements:




This document is an invaluable resource for any bariatric patient or PCP providing follow-up care to bariatric patients.

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