Can you Smell It? (If not, there could be trouble.)

++ I'm sure you've noticed that food doesn't taste as good if your nose is stuffed up from a cold or allergies.  This is because your sense of taste and your sense of smell are linked.  Here is are highlights of some recent research about tasting our food.

When I was a child first learning about the human body, I learned that there are 4 basic tastes: sweet, sour, salty, and bitter.  Later, I learned that substances like mono-sodium glutamate enhance the taste of meats.  Now, those who study taste disorders say that MSG actually stimulates the 5th basic taste - umami (savory). The difference between the bitter taste in coffee and the bitter taste of some over-cooked vegetables (for example) is more correctly referred to as flavor.

Some flavor preferences are in-born in all of us - babies like the sweet taste of mother's milk; or in some of us - there are people who are "super tasters."  Some are learned in the first few months - babies with severe digestive problems will readily drink special formulas if introduced young enough, even though adults find the flavor to be nasty.  Some preferences can be learned later - by repeated exposure, by the fact that your taste buds dull as you get older, etc.

Your ability to taste food and identify the flavor can change.  When you chew a food, some of the scent molecules travel from your mouth to your nose.  This can be blocked when you have a cold, which is why food doesn't taste as good then.  If you are in a place with smoke or a strong smell, this can overwhelm the system, also making it harder to enjoy your food.  If you are stressed out, the connection from your nose and mouth to your brain can be disrupted.  You can get an unpleasant metallic taste in your mouth from a variety of things, including some medications (or chemotherapy), or a tooth or gum infection.  Fortunately, these are reversible.  After all, lack of ability to smell doesn't just affect pleasure in eating - it can also be a safety issue (what if you couldn't smell smoke if your home was on fire, or notice a gas leak!).

Other causes of taste-distortion are uncommon, but can sometimes indicate a serious problem.   Malnutrition might do this if you lack certain nutrients.  Some people who have diseases marked by nervous system damage might have it - Alzheimer's and Parkinsons's diseases, for example, and some cases of diabetes. 

Scientists who study taste and smell are trying to help people eat more healthfully and safely.  However, in the process, they have come up with some interesting "factoids:"

• dogs and horses really can smell fear in humans 
• babies can recognize their mothers by smell; they do this well enough that if a nursing mother uses a pad in her bra (to catch leaks), the baby can tell which pad is mom's and which had just been used by another woman 
• distinctive smells can trigger strong memories 
• people smell different when they are ill; in fact, some illness have their own distinct smell - such as diabetic acidosis, some fungal infections, gangrene 

Now you know why an apple and a potato taste the same when you have a cold.