Banana - What has it got to do with her heart?

Two months ago  this 51 year old hypertensive patient of mine, SS, came for her usual follow-up. She has been  my patient for the last two years and has attended clinic regularly. It has been my practice to always feel the pulse of all my hypertensive patients before I take their blood pressure. And so when I felt for SS's pulse that instant, I could feel her pulse bounding and her heart rate was increased compared to the last visit. And she was not on any drug that could have caused an increase in heart rate.

I then asked her whether she could feel her heart beating stronger and faster than usual. She then related, yes, for the last six week or so she did sense her heart  was beating abnormally. I then asked her whether he had taken any another drugs or herbs without my knowledge, for which she denied vehemently.

Now what was it? I persisted by asking her what had she been eating which was different in terms of amount or frequency for example caffeine-containing drinks such as coffee. She thought hard about it then reminded me that I once  told her to reduce fatty foods as her cholesterol level was abnormal and that she was on a cholesterol-lowering drug so for the previous two months before coming to see me she had decided to take bananas as it does not have any fat according to her. Yes, she took six bananas each day and since then she had experienced her heart beating faster but did not attribute it to anything,... Ahah..

I immediately advised her to stop taking bananas especially in that amount because banana is known to convert amines in the body into 5-hydroxytryptamine (5HTT) or serotonin which can cause an increase in heart rate and strength of the heart beat especially in some predisposed patients. Had I not examined her pulse, she would not have voluntarily given me that information and an undesirable heart outcome could occur in the long term.

Taken daily in large amount can make some peoples' hearts go "bananas"

Today she returned to report that she had not been feeling her heart racing since she stopped the large daily intake of bananas. I felt for her pulse and noted that the rate had returned to normal though the bounding was still there.

It is indeed my work-satisfaction to be able to detect a  risk before it becomes another medical mishap. This can only be done with careful physical examination and history taking and engaging  patients on their health habit.