Understand Bioavailability of Supplements Now

What doesn't get absorbed is not used and is wasted. This is particularly true for the nutritional supplements or multivitamins that we take. Most people are unaware of the absorption rate or bioavailability of supplements. We are not sure that we are really getting the amount of each nutrient (vitamins and minerals) stated in the label of the supplement that we buy. Knowing the bioavailability of nutrients determine whether we are getting our money's worth.

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Different vitamins and minerals have different absorption rates regardless of whether they come from a tablet, liquid, powder, or food. Bioavailability is defined as the degree and rate at which a compound is absorbed into our body, or is made available at the site of biological activity. In the case of nutritional supplements and prescription drugs, it is made available to the site of biological activity if it gets into our blood.

The delivery form does not generally make a significant difference if an individual is healthy and intakes are adequate, though there are many factors that can affect the absorption of vitamins and minerals in the human body. These may be a function of the person taking the supplement or nutrient, and are dependent on an age, digestive system integrity, overall state of health, gender, whether the supplements are taken on a full or empty stomach, and even the time of day.

People whose nutrient needs are greater,  such as growing children, pregnant or lactating women, and those who are currently nutrient deficient, may have significantly enhanced absorption rates for certain nutrients. Absorption of minerals from food sources can even vary. Iodine can be absorbed at over 90 percent, while the average absorption rates of zinc, copper, and selenium can range from 30 to 80 percent. Calcium, for example, has a relatively standard absorption rate, between 25 and 35%.

If you have already observed, most quality multivitamins and pharmaceutical medications are in tablet form. It is because a properly made tablet provides an effective delivery system, and tableted formulations allow for a higher level of active ingredients to be incorporated in a product – almost 3 times as much as a capsule and much more than a liquid. And generally, tablets are more stable than liquids. People are often mislead that liquid form is more effective, it may be for some cases like if you formulating for a children's medicine or if the formulation is for a specific nutrient. But in general, a tableted formulation is more preferred.

Aside from bioavailability, a good nutritional supplement shall be manufactured according to the standards of United States Pharmacopoeia (USP), which require full disintegration within 30-45 min. USP standards is not typical for nutritional supplements because USP is really a standard for drugs or medications. Nutritional supplements formulated and manufactured under USP standards are also required to meet standards for dissolution and are properly absorbed into the body. Innovative formulations have been developed to optimize nutrient bioavailability.

(Note: this article is specific to multimineral and multivitamin formulations. There may be certain products, such as children’s medicine or single nutrients, that are appropriate in a liquid form. However, these are the exceptions and not the rule.)