Answer: They can cause toxic effects or they can cause failure of therapy, depending on the drug-nutrient combination.
Explanation: Consider this example: Green leafy vegetables, broccoli, Brussels sprouts, and cabbage contain vitamin K, which inactivates Coumadin. A patient who is to take Coumadin should be instructed to maintain the same dietary intake of these vegetables and not to vary their intake greatly. The dosage of Coumadin for each patient is based on that patient’s bloodwork. If the patient’s diet is stable with the amount of these types of vegetables, then the Coumadin will be dosed correctly. If the patient decides to eat several big green leafy salads filled with vitamin K rich vegetables for a few days, then the result will be a decrease in the Coumadin’s effectiveness... PF