What is the absorption rate (or bioavailability) of supplements?
Bioavailability is defined as the degree and rate at which a compound is absorbed into a living system or is made available at the site of biological activity. Different vitamins and minerals have different absorption rates regardless of whether they come from a tablet, liquid, powder, or food. Calcium, for example, has a relatively standard absorption rate (between 25 and 35 percent).
The delivery form does not generally make a significant difference if an individual is healthy and intakes are adequate. However, there are many factors that can affect the absorption of vitamins and minerals in the human body. Some of these factors are a function of the person taking the nutrient and are dependent on an individual’s 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 deficient – may have significantly enhanced absorption rates for certain nutrients. Even absorption of minerals from food sources can vary significantly. Boron, molybdenum, and 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.
It should seem reasonable, then, that stating an overall absorption rate on a package or in advertising can be misleading.
A well-made tablet provides a very effective delivery system and is the chosen form of most quality multivitamins and pharmaceutical medications. Tableted products allow for a higher level of active ingredients – almost 3 times as much as a capsule and much more than a liquid or spray. In general, the stability of tablets is also superior to liquids.
USANA tablets are formulated to meet United States Pharmacopoeia (USP) standards, which require full disintegration within 30-45 min. They are also formulated to meet standards for dissolution. Because USANA tablets are formulated to these standards, the vitamins and minerals found in USANA supplements are properly absorbed into the body. Innovative formulations have been developed to optimize nutrient bioavailability.
Each lot of USANA tablets is tested against finished product specifications to ensure that it meets standards for identity, target weight, hardness, thickness, disintegration, potency, purity, and microbial counts. USANA provides its vitamins and minerals in amounts and forms so that, in conjunction with a healthy diet, customers will receive maximum bioavailability, full effectiveness, and uncompromised safety.
(Note: this article specifically targets 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.)