A matter of taste

Try this simple test. Ideally you’ll need a fruit-flavored jelly bean, but you can also use hard candy, a cough drop, or a piece of Mentos “freshly picked” gum. It should be chewable and relatively odorless. You won’t need to swallow it, so you can do this even if you’re counting calories.

Hold your nose and put the jelly bean or equivalent in your mouth. Keep your nose closed and chew (with your mouth closed). Notice what you taste. If it’s fruit flavored, you probably notice a sweet and maybe a little sour taste. Now pay close attention as you let go of your nose. There’s a rush of flavor. If you were eating a strawberry jelly bean, you’d notice the complex fruit flavor that we identify as strawberry.

How we taste food: Flavor is more than taste

Technically, taste is what happens on your tongue. Flavor, on the other hand, is a combination of taste, smell, and touch. Our sense of smell allows us to distinguish thousands of different odors, whereas the tongue detects only five basic tastes: sweet, sour, salty, bitter, and savory (umami).

When you eat a jelly bean, odors are released by chewing. These gaseous molecules get pumped up into your nasal cavity, where they interact with a postage-stamp sized area on the roof of the nasal cavity called the olfactory (smell) epithelium. There are millions of olfactory receptor cells here with microscopic hairs (cilia) waving in the passing air currents. Information from the receptor cells is sent to the olfactory bulb, which is part of the brain. From there, signals get relayed to other parts of the brain, including those involved in memory, speech, emotion, and decision making. There’s a very complex process going on whenever you identify a distinct odor or flavor.

This combination of taste and smell has been going on all our lives. We don’t usually stop to notice that taste happens on the tongue and that flavor needs the nose. But it explains something you may have noticed: Food doesn’t taste as good when you have a stuffed-up-nose cold.

Do flavor and taste have anything to do with health and with how much we eat? Yes, but it’s more complicated than simply having a sweet tooth. Studies show that taste is the most important factor in choosing food, followed by cost. Whether food is actually nutritious and good for us is much less relevant to the decision process.

This may or may not seem obvious. You would need to conduct a scientific study to be absolutely certain. Sure enough, someone has: “Why Americans eat what they do.” The study recommends that “nutrition education programs should attempt to design and promote nutritious diets as being tasty and inexpensive.” All I can say is, good luck with that one. The snack food industry is light years ahead of nutritionists and dieticians in scientifically designing food that’s tasty and inexpensive.

Why do we taste food?

Humans are omnivores – they’ll eat anything. This creates the problem of deciding what to eat, as Michael Pollan documents so well in The Omnivore’s Dilemma.

From a survival point of view, it would make sense for nutritious foods to taste good. Yet all we have are those five basic tastes: sweet, sour, salty, bitter, and savory.

The sweet taste of honey tells us that this food contains calories, which we need for energy. Being able to taste salt helps us control the necessary balance of salt and other minerals in the body. The body also needs to be balanced between acids and bases (pH level). Acids taste sour. The sour taste also lets us know when fruit is ripe.

The savory taste tells us that food contains protein, which the body uses to build and repair cells, and for a host of other essential things, like producing enzymes, hormones, and antibodies. Glutamic acid, an amino acid, has a savory taste. Proteins are a combination of amino acids, and glutamic acid is found in meat, fish, and aged cheese. The savory, or umami, “taste bud” was only discovered 1908 by a Japanese scientist investigating the strong flavor of seaweed broth. It remained relatively unknown in the West, except among taste researchers, until Asian food became more popular.

When you convert glutamic acid to a sodium salt, such as monosodium glutamate (MSG), it can “enhance” the flavor of food. “Savory” is a translation of the Japanese word umami, and the Chinese equivalent is “fresh flavor.” Originally MSG was associated with Chinese food, or more precisely, with the headache of Chinese Restaurant Syndrome, allegedly brought on by MSG. Interestingly, only Westerners seem to have this problem.

The sweet, salty, umami, and even sour tastes are pleasant, and as we evolved over the millennia, they’ve helped us choose foods that were good for us. The bitter taste, on the other hand, helped us avoid foods that might be poisonous, rancid, or contaminated by bacteria or fungi.

More on the bitter taste and people especially sensitive to it – supertasters – coming up in the next few posts.

Related posts:
How do you taste?
Orange juice and toothpaste
What is a supertaster?
The genetics of supertasting
Are you a supertaster: Do you really want to know?
Are you a supertaster: Look at your tongue
Are you a supertaster: How does PROP Taste to you?
Are you a supertaster: DNA
testing
Why do we love high-fat foods?
Do we taste fat?
The taste advantage
“Killer” grapefruit?
Grapefruit and the Pill
This is your brain on sugar — and sugar substitutes
The Pepsi challenge: How beliefs affect what you taste