Cholestiramine binds with fats in your foods and transports them out with the waste. The label says that it can interfere with medications and absorbtion of fat-soluble vitamins. I would assume that any vitamin/mineral/nutrient that binds with fat would also be absorbed and eliminated. Try to take your supplements at least an hour before or 2 hours after taking cholestiramine. I, too, have ibs d and have a terrible time getting enough potassium & magnesium. Try soaking in epsom salts or applying magnesium oil. Lack of proper minerals can cause the symptoms that you have, but good luck getting a dr to address it. They are clueless.