While it may sound complex, bioavailability is actually a simple concept. Bioavailability refers to how much of a specific ingested compound your body is able to recognize, absorb, and utilize in its active form. As impressive as that nutrition label or supplement facts panel may be, if a substance isn’t absorbed and delivered in its proper form to the target site in the body (if it isn’t “bioavailable”), then it is essentially useless. Food and dietary supplements with low bioavailability do not support health and well-being, and in some cases, they may even be harmful. The source of the food or vitamin, how it is processed or prepared, and even what it is consumed with can all influence bioavailability. Although it is generally recommended that your efforts to meet your nutritional needs start with whole food3, there are other considerations to take into account. For instance, a significant percentage of the population is unable to properly digest and absorb natural vitamin B12 and folic acid when provided by whole food sources, so supplementation or eating fortified foods may be necessary.