April 10, 2002

Liquid vs. Solid Delivery of Supplements
Fact Sheet

Bioavailability – A Definition

Bioavailability is the rate at which a drug, trace element, nutritional supplement, etc., enters the bloodstream and is circulated to specific organs or tissues (Webster’s New World Dictionary, Third College Edition).

Bioavailability – Solid Supplements

According to the United States Pharmacopeial Convention, Inc., calcium supplements should dissolve within 30 minutes in stomach acid. Other supplements should dissolve within 45 to 60 minutes. Anything remaining in solid form after that time will not reach organs and tissues within the body. As a result, many pills and tablets that offer a variety of nutritional supplements are unable to provide full benefits for their users. And as supplements become more complex, it can be increasingly difficult for manufacturers to provide all of the required elements in a form that will be soluble in stomach fluid.*

In addition, solid supplements are often buffered to reduce gastric discomfort, which may also reduce bioavailability.* And individuals who do not have the level of stomach acid necessary to dissolve the coating easily will not receive the full benefits of the nutritional supplements.*

Supplements in tablet or pill form may also contain high, local concentrations that can overwhelm the absorption capacity of the intestine. *

Bioavailability – Liquid Supplements

“In liquid supplements, the vitamins and minerals are already dissolved and therefore are immediately bioavailable,” according to Gerhard N. Schrauzer in a 1998 article published in the Journal of Medicinal Food.

Dr. Schrauzer adds that liquid supplements are usually formulated to contain citric acid, ascorbic acid and other substances that increase the bioavailability of minerals.*

 

* Schrauzer, Gerhard N. (1998). “An Evaluation of Liquid-Mineral Supplement Technology. Journal of Medicinal Food Volume 1, Number 3. 207-216.