Imagine that you have lost your ability to smell. Everything. Those flowers you received on Valentine’s Day? Nothing. Your favorite meal may become bland and flavorless, as most of the taste from food is derived from its smell.

More important than that, researchers that investigate the sense of smell say that many people’s emotions and memories are directly tied to the olfactory sense. While many may consider this one of the least important of the five senses — less important than sight for instance — it can lead to many problems that people may not realize.

According to the National Institute of Health, more than two million people in the United States have a problem with smell and taste. About 1.2 percent have no sense of smell at all, a condition called anosmia.

Dr. Alan Hirsch, founder and neurologic director of the Smell and Taste Treatment and Research Foundation, said one of the major problems of those with a decreased ability to smell is that they “can’t detect if there is a gas leak” and may receive food poisoning from rotten food that goes undetected. Also, people with anosmia sometimes develop major psychiatric problems including depression, problems interacting socially, feelings of isolation and agoraphobia.

“They are in a bubble and lose a sense of oneness with others,” Hirsch said.

Half of people over age 65 have problems with their sense of smell and three quarters of people over age 80, Hirsch said. The most common cause of this condition is head trauma. In order to prevent these problems, Hirsch suggests not smoking cigarettes or using drugs.

While there are some real dangers associated with smell loss, such as not being able to smell smoke or bad food, it is mostly a quality of life issue, said Dr. Karl Wuensch, a professor in East Carolina University’s Department of Psychology. Wuensch himself suffers from anosmia. “Foods lose almost all their flavor, social odors are not detected and so on,” Wuensch said.

“Most psychologists pay little or no attention to it,” Wuensch said. “Most people do not recognize what a big role it plays in our everyday lives, until they lose it. Even then they don’t really appreciate it until they get it back. You should see how people act when they get back a lost sense of smell. They are deliriously happy, running about sticking their noses into everything.”

According to the National Institute of Health, many types of smell disorders are curable, and for those that are not, counseling is available to help people live with the condition.