Contrary to the researchers' predictions, detection of salty, sweet, sour and bitter tastes appeared to be enhanced rather than reduced following heart bypass surgery. The unexpected findings, they note, might be at least partially explained by hunger after fasting around the time of surgery.
Nearly half a million coronary artery bypass surgeries are performed in the U.S. every year, according to the American Heart Association. To better understand how heart surgery might influence tastes, patients who had undergone heart bypass operations were studied. Participants' tastes were tested four times: before admission, at discharge from the hospital, again at five weeks and then four months after the surgery. Each time, patients underwent several rounds of sipping liquids from small cups until they could detect each taste.
Compared to pre-surgery, patients had significant improvement in their ability to pick out the four tastes during later tests, the researchers note in a report in the Journal of the American Dietetic Association. According to earlier research, hunger naturally heightens the sense of taste, so the light diet consumed by patients before and after surgery could have influenced this result, they point out.
They also point to some limitations to their study, including a small size and the large proportion of patients who chose not to continue their participation following surgery. It may have been that these dropouts were in more discomfort and would have tested differently. Still, the results point to a potentially important area for further research – it is possible that if taste sensitivity is improved or heightened after surgery, then perhaps food becomes unpalatable for other reasons and therefore is perceived to taste different.
Such changes could potentially limit food intake and put patients at risk of poor nutrition during the critical recovery period. For example, most nutritional supplements are sweet and may prove to be too sweet for altered tastes. Doctors working with heart surgery patients need to be aware that changes in taste do occur in the post-surgery period and that patients may find foods unappealing or unappetizing.