Solid vitamin supplements:
most important ingredients
are not vitamins
Let's have a look at the most common form of vitamin supplements: a solid form.
Most of vitamin supplements are produced as pills, tablets, caplets or capsules.
During the manufacturing process of solid supplements, the active ingredients are mixed with a variety of excipients (other ingredients).
What's inside that tablet?
Excipients are needed for several reasons: to take up space (fillers), to hold the ingredients together (binders), to assist in disintegration (disintegrants), and for other functions. Sometimes it might be necessary to coat the tablet because of bad taste or odor of its ingredients (coatings).
Fillers are necessary for the manufacturing process, but are only needed to take up volume of the pill. The pill must be large enough for human fingers to readily handle. Even small vitamin supplement tablet might be much larger in volume than vitamins and minerals it contains. Some common fillers are lactose (milk sugar), cellulose, corn starch, sugars (including sucrose, mannitol, sorbitol, fructose, dextrose), whey and yeast.
Binders are used to make the components stick together when the ingredients are compressed to make the pill. Some common binders are povidone, xanthan gum and Carbopol (an acrylic resin). Some fillers may also act as binding agents, and may be referred as filler/binders.
Disintegrants stimulate the break-up of the tablet in the stomach.
Coatings help to prevent the tablet from dissolving too soon, thus breaking up in your mouth.
There are also other kinds of excipients: lubricants, colorants, flavors and plasticizers.
The acceptable excipients are generally either food products (such as lactose, sugar or starch), or chemically inert ingredients that pass through the body without any effect (such as cellulose).
Tablet materials impact dissolution process
Overall, the function of excipients is to make sure that vitamins and minerals contained in the tablet will make their way into the stomach. Once the tablet is in the stomach, it is extremely important that excipients will not prevent disintegration of the pill and absorption of the active ingredients.
Excipients used in low-quality vitamin supplements can prevent the tablet from being disintegrated (dissolved) in the stomach. If this happens, and the tablet leaves stomach undissolved, its ingredients will not be absorbed in small intestine, and will have no effect.
In addition to the excipients of poor quality, factors as high pressure and high temperature during the manufacturing process can also negatively impact dissolution characteristics of the tablet.
This picture is from the medical book "Essentials of Skeletal Radiology", by Terry R. Yochum and Lindsay J. Rowe (ISBN 0781739462).
These non-transparent objects in the lower-right corner are undissolved pills in one's intestine, passing through the body intact!
The importance of dissolution of tablets in human stomach was understood more than a century ago.
Here is a quote from a book published in 1895 ("A Treatise on Pharmacy," Gaspari C, Lea Bros., Philadelphia):
"..it would seem that prompt action of certain remedies must be considerably impaired by firm compression. ...the composition of all compressed tablets should be such that they will readily undergo disintegration and solution in the stomach."
However, criteria for tablet's efficiency did not exist for a long time, and up to 1950 tableting technology was rather empirical (per "Historical Perspectives on Dissolution Technology" by L. T. Grady).
Tablet disintegration testing
By 1950, disintegration tests for tablets were officially adopted by US Pharmacopeia. Home page has a video about vitamin tests conducted by US Pharmacopeia.
Currently accepted standard is that the tablets must dissolve within 15 to 30 minutes once in your stomach. To test your vitamin supplements at home, put some warm water with white vinegar (to simulate the stomach acid) in a glass and drop in your pill. It should dissolve within 15 to 30 minutes to meet standards. If it doesn't, your pill does not work, and you need to change your vitamin supplement! You can keep this test up to 60 minutes. If the pill is not dissolved by then, it is highly unlikely to be of any benefit to your body.
My wife was taking multivitamins for several months, but then noticed that the condition of her nails is not improving, as she expected. I did this test on multivitamin pills that she was taking. The tablet did no dissolve after 2 hours! We understood then why this brand was so cheap...
Things to consider
So, what you can do to assure that your body benefits from the dietary supplements that you are taking?
First, if you use solid supplements, make sure their quality is high. From my experience, higher price usually indicates higher quality, but not always.
Apart from using solid supplements of high quality, you may consider other forms of supplements, which do not have problems with dissolution.
Liquid vitamins, spray vitamins and gel supplements are not solid, and their ingredients are readily available for absorption.
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