Dulled sense of taste common

DEAR DOCTOR K: I’ve recently noticed a dulling of my sense of taste. What’s worse, my ability to taste sweetness (my favorite taste!) seems to be the most affected. Is it possible that I’ve damaged the part of my tongue that detects sweetness?

DEAR READER: We don’t give much thought to our sense of taste until it isn’t there. I’m sure your recent taste troubles have made you realize how much you rely on this sense.

You’ve actually touched on a medical myth about our sense of taste. It’s a common misconception that the taste buds for each type of taste are grouped together in a particular part of the tongue – sweet taste in one part, sour taste in another, and so on. That’s not true. To understand why, here’s how we taste things.

Our tongues can identify five tastes: sweet, sour, bitter, salty and savory (also called umami). Savory can be a tough taste to describe, but chicken broth is a good example. We have five different types of taste buds, one for each of the five tastes. The five different taste buds don’t look very different, but they are “wired” differently: They each send a different signal to the brain.

These five different types of taste buds are scattered around the tongue. So damage to one area of your tongue would not explain why you would lose an entire category of taste.

A reduced ability to taste is fairly common; I see it occasionally in my patients. It has many causes. Aging reduces the ability to taste in some people. Infections of the nose, throat and sinuses can, too, until they go away or are cured. That’s mainly because smell contributes to taste. Have you ever noticed how, when you get a bad cold, things don’t taste as good? Nothing’s wrong with your taste buds. It’s just your sense of smell that is temporarily reduced.

If none of the less serious explanations can be applied, it would be a red flag telling me to consider more serious diagnoses. Diabetes can injure the nerves from taste buds to the brain. So can liver disease, kidney disease, Alzheimer’s disease and Parkinson’s disease. A bad injury to the head, or surgery around the ear, can injure the nerves that go to the tongue. Cancer chemotherapy drugs can reduce the sense of taste. So can exposure to pesticides.

It sounds like this change in your sense of taste has lasted more than a day or so. If this is true, talk with your doctor about it. While there may be a simple explanation, it’s important to get it checked out.

As anyone with taste problems will tell you, it’s not something we should take for granted. Eating is one of life’s necessities. That’s why nature made it one of life’s great pleasures.