Ever wonder why some prescription medications, mostly tetracycline-derived antibiotics, have a label stating that they should not be taken with milk? Tetracyclines are a category of broad spectrum antibiotics that are normally used to treat a variety of bacterial infections such as urinary tract, respiratory tract, and sexually transmitted infections. The Food and Drug Administration finds that although both are separately beneficial to human health, milk actively reduces the effectiveness of tetracyclines when they are combined.
Milk contains lots of calcium.
Image Source: Michael Wildsmith
According to an article in the journal Drugs, milk works to decrease the effectiveness of tetracycline through its calcium component. Calcium ions bind to the antibiotic and decrease its molecular ability to pass through the membrane of the gut into the blood stream. When a lower dosage is absorbed, less antibiotic is able to reach the area of infection. This lower level of antibiotic in blood serum makes it possible for genetically resistant bacteria, which have a higher tolerance for the antibiotic, to survive and replicate in the host. This can be harmful, as the host is then infected with a strain of antibiotic resistant bacteria. As the Center for Disease Control states, antibiotic resistance to medication is of high concern in the medical field and pharmaceutical industry, as more resistant strains are more likely to cause mortality in a host.
Hopefully, this article has given you good insight into why its best to avoid taking tetracycline with milk. It is easy to forget to read medicine bottles, but the information should always be read and considered carefully. Follow directions given with medications, and understand why those directions are important. For antibiotics, these steps are vital to maximizing drug effectiveness and minimizing the number of resistant strains available to harm humans.
