There is good news for the estimated 4 million people who are losing - or have lost - their sense of smell. New research shows there are things we can do to protect, sharpen, or even regain our sense of smell - even after we've lost it! That's according to Dr. Alan Hirsch, who directs the Smell And Taste Treatment Foundation. He says there are many environmental factors that cause people to lose their ability to smell - things like air pollution and chemical fumes, which can damage nerve endings in our nose. Also, health issues, like respiratory infections, can have an impact on our sense of smell. Then there's our age. Because by age 60, statistics show that half of us show a "measureable loss" in our sense of smell. In fact, companies are now working on producing foods and products that have stronger smells, to appeal to baby boomers! But losing your sense is a big deal - it's one of the body's first warning systems for danger. If you can't smell food that's gone bad, then you might eat something that makes you sick. And if you can't smell a gas leak in your home, it could be deadly. So, how do you know if you're losing your sense of smell? Dr. Hirsch says try closing your eyes and tasting a little vanilla and chocolate ice cream. If you can't taste the difference, then you may have a problem. Or, hold a cotton ball soaked with rubbing alcohol just below your chin. If you can't smell it, that's a red flag. Also, one of the last scents people can detect - even long after they stop being able to recognize other smells - is the fragrance of a rose. So, try smelling one that grows in a garden. Ones from the florist don't smell as strongly, because when roses are bred for long life, they lose their scent. If you failed these tests, there are some simple "smell therapy" tricks we can practice at home - which can protect, sharpen, or even help us regain our sense of smell - even after it's gone! Here's what you need to know, according to neurobiologist Dr. Alan Hirsch: Practice being "scent-conscious" in your day-to-day life. For example, professional smellers tell aspiring perfumers to always take a whiff of their coffee or food before putting it in their mouth. That way, you'll increase your awareness of different smells. Break out the spices in your kitchen. Get out things like cinnamon, nutmeg, vanilla, and celery. Then, sniff them all for about half an hour a day - taking two or three short sniffs of each one. Experts say if you do that over and over again, you'll sharpen your sense of smell, to the point where you'll be able to identify ingredients without looking. In between each different scent, sniff some coffee beans, or even your arm. That's how the pros say they cleanse the palate of the nose. Try smelling stuff right after you shower. Research shows that is when our sense of smell is sharpest because warmer, humid environments open nasal passages, and stimulate smell receptors in the nose. Also know this, Dr. Hirsch says when we sniff scents that we find pleasant - like coffee, berries, or the cedar in pencil shavings - it sparks different receptors in the nose to work. And in some cases, that can cause nerve connections to "turn on" again, even after they've been damaged!