Is it really OK to take this with food? Old interactions with a new twist

In response to consumers' increased interest in preventive health care, the food industry is producing a variety of foods fortified with calcium, iron, and other minerals and vitamins. This well-meaning idea of food fortification is troubling in the context of clinical pharmacology. The recommended Food and Drug Administration (FDA) meal used in food-drug interaction studies is a high fat, high-calorie meal with little nutritive value. While some drugs may appear to be safe when taken with food, this may not be true when fortified foods are considered. The mechanisms causing drug fortified food interactions are the same well-known mechanisms that cause other drug-mineral interactions. Certain drugs may exhibit decreased absorption due to chelation and adsorption. Other drugs may have decreased absorption or increased excretion due to changes in gastric and/or urinary pH. The results of such interactions may be clinically insignificant or severe, including treatment failure, frequent dose changes, antibiotic resistance, and increased morbidity and mortality. Revisions of current regulatory guidelines are necessary to take into account this potentially major source of "new" drug interactions.