Lisinopril Apple Cider Vinagar, Potassium Supplements, High Blood Pressure, Precaution, Banana

My husband was prescribed lisinopril 10 mg today and is suppose to start on it tonight, and now, I find this site. I read the precautions and noticed that it said do not take potassium supplements.
He has borderline high blood pressure. I have read in the past that eating a banana a day or taking a teaspoon of apple cider vinegar helps high blood pressure because of the potassium contained in them. So, when I read the precaution, I thought thats why they advise against it for fear your blood pressure would become too low. I am not a doctor, but I think my husband should try the banana or the apple cider vinegar first. We shall see. I just thought I should mention this on this site.