The rate that electromagnetic energy is absorbed into the body. The specific absorption rate (SAR) is measured in watts per kilogram (W/kg) of human tissue. In the U.S., the maximum allowed SAR ...

The absorption rate, or bioavailability, refers to the extent to which the nutrient enters your bloodstream to interact with the needed part of the body. Some supplements form seamlessly into the ...

Having Crohn's or kidney disease and taking certain medications may inhibit vitamin D absorption. If you have trouble absorbing vitamin D, try a supplement with fatty and/or magnesium-rich foods.