WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
Olfactory evolution — there's a term you're not likely familiar with, but it's the line of expertise one doctor has pursued to sniff out the reasons why some peoples' sense of smell has diminished, overall, in the last few decades or so.
Kara Hoover, Ph.D., a specialist in this field, says pollution and other environmental factors of this modern age are ruining mankind's ability to smell. It's worse for some, depending on where they live.1
One of the things this has led to, Hoover says, is that people with weak olfactory abilities can no longer detect the more subtle nuances of food fragrances.
For them, flavors are less distinct, which makes them crave foods with stronger, more pronounced flavors, such as salty and sweet tastes. "Taste is three-fourths smell," some used to say.
Hoover's hypothesis, which she presented in Boston at a meeting of the American Association for the Advancement of Science (AAAS), suggests that people with a reduced sense of smell are more likely to be obese because they prefer more rich-tasting food — food they can sink their teeth into, so to speak.
One thing she didn't mention, however, is that processed foods comprise a large percent of the average American's overall intake.
People are busier today than they've ever been, and once boiling a pan of water, throwing in some ready-made convenience food and calling it dinner becomes a habit, anything involving a cutting board and more than a few ingredients may seem like way too much to deal with.
How Food Manufacturers Go for Your Gut
There's no getting around the fact that many Americans crave junk food. Around $60 billion is spent every year on it, according to Steven A. Witherly, Ph.D., author of "Why Humans Like Junk Food."2 And yes, junk food junkies usually end up reaching for something sweet, salty or both.
Junk food manufacturers know how appealing convenience is. That and concocting an irresistible flavor profile are two ways they target their audience. Flavor science, Witherly says, employs the art of hedonics (related to the word hedonism) to tweak food ingredients in ways that will produce the greatest amount of food pleasure:
"Food pleasure is a combination of sensory factors (sensation) and caloric stimulation by the macronutrients (protein, carbohydrate and fat). Sensory factors that most contribute to pleasure are salty taste, sweet taste, umami taste and orosensation from the oral cavity (feeling).
The Food Pleasure Equation postulates that the brain has the ability to quantify the pleasure contained in an eating experience as performed by certain dopamine neurons in the brain and the sensing of calories by the gut.
When you have a food choice, the brain actually calculates how much pleasure will be generated during the eating and digestion of a particular food."3
In short, processed foods are carefully combined by food scientists to bring you the flavors you crave, even if you know they're not good for you, and make them as hard to resist as possible.
In contrast, natural, whole foods possess both the taste and texture to work with your body to satisfy your hunger — but your brain doesn't see it that way.
Sweetness is one of the most powerful taste sensations — and one of the most addictive. In fact, studies show it to be as addictive as cocaine.4 To reel you in, intense sweetness in artificial sweeteners such as aspartame, sucralose (Splenda) and saccharine are tailor-made to intensify your hunger.
Better Smell Sense Can Affect Not Just Your Weight but Your Life
While people who can't smell very well may have a tendency to eat saltier, fattier food, Hoover believes it stands to reason that those whose smell sense is working as it should may be more trim and generally weigh less.
Hoover suggests that part of the anxiety experienced by people with a lowered sense of smell — or none at all — may stem from the fear that, if they can't smell things very strongly, they may not be aware of their own body odor.
Further, they may not be able to smell potentially dangerous odors such as gas leaks or smoke, and that scares them. One study suggests that a low sense of smell, being strongly inked to numerous physiological processes, may be an indicator of older adults' future longevity.
Comparing those with anosmia (no sense of smell) with people having normosmia, or normal sense of smell, the former was found to be a predictor that such individuals may have only five years left to live.
"Olfaction, an ancestral chemical system, is a strong candidate biomarker because it is linked to diverse physiological processes … In a comprehensive model that included potential confounding factors, anosmic older adults had over three times the odds of death compared to normosmic individuals."5
Science shows that zinc, an essential mineral, is necessary to produce an enzyme called carbonic anhydrase, which is critical to having a normal sense of smell as well as taste.
Consequently, a loss of sense of smell is one of the classic signs of chronic zinc deficiency. If your smell sense is becoming weaker, you may want to eat more zinc-rich foods, because zinc is vital for many life-sustaining functions.
How Might Depression and Anxiety Result From a Low Sense of Smell?
What other problems might people experience due to a diminished sense of smell? Hoover says they may have a higher risk factor for mental health problems such as depression and anxiety.
"They suffer from poor quality of life and depression because they're no longer engaging with food or loved ones in terms of their sense of smell," Hoover explained, adding that chronic angst threatens to intensify into even more serious mental health issues.6
Many people feel anxiety should be controllable with a "mind over matter" mindset, but it's not always that simple. Chronic forms involve an internal process that can be so powerful, it can change your brain.
People who grew up with chaos may have brains now "wired" for anxiety. The fact that they can't manage it makes them feel even worse.
Internally, this level of anxiety can lead to depression that can even be manifested in physical symptoms; externally, it can trigger the "fight-or-flight" stress response or cause social isolation and feelings of hopelessness. There are methods to relieve anxiety, even if your sense of smell is altered.
One study7 suggests taking the bite out of anxiety by relegating it to excitement through self-talk. Because the intensity of anxiety and excitement are similar, putting a positive spin on it by speaking the words "I am excited" out loud has helped people turn a "threat" mind-set to one of opportunity, resulting in even better performance.
The Emotional Freedom Techniques (EFT) is another anxiety-relieving tool that can reduce food cravings and even pain. It involves psychological acupressure comparable to acupuncture, because it targets the same energy meridians, but without needles.
Exercise can also transform both your mind and energy level, because it triggers the neurotransmitter GABAalong with the brain chemicals serotonin, norepinephrine and dopamine.
These help ease stress and anxiety and even generate a sense of euphoria sometimes known as "runner's high," a welcome alternative to emotional distress.
Friendship Is a Strong Antidote for Anosmia-Related Depression
One of the most effective ways to combat depression and anxiety is to develop a strong network of friends and an active social life, which can come in many different forms. It can help you recover from depression and provide avenues that can help you flourish emotionally. One study reveals:
"Social support is exceptionally important for maintaining good physical and mental health. Overall, it appears that positive social support of high quality can enhance resilience to stress …
Strong social support has been shown to be an important factor in decreasing functional impairment in patients with depression and in increasing the likelihood of recovery."8
The study added that high levels of support can protect people against the ravages of both mental and physical illness.
Another study9 showed that friendships and social support help people emotionally, but further, those who exhibit a sunny disposition, positivity and humor can spread the same attitude to people around them. It's literally contagious.
Pollution and Smog May Damage Olfactory Abilities
London mayor Sadiq Khan suggested that older diesel vehicles, recently linked to a higher risk of both heart attack and stroke,10 be banned from highways on days when hourly levels of toxic nitrogen dioxide rise past the city's maximum pollution levels, set by law at no more than 200 micrograms per cubic meter (µg/m3).11 The Guardian explained:
"Sadiq Khan was responding to a series of toxic smog alerts in the capital, where pollution has been linked to around 9,000 early deaths a year. New research this month also suggested that diesel pollution could double the chances of developing dementia."12
The smog problem is worst in highly populated and industrialized cities such as London and Shanghai. Further, the Telegraph says people from poorer backgrounds are generally exposed to higher levels of pollution — for instance, bus passengers get eight times more exposure than people who drive cars — and that people in areas where garbage is not collected regularly are also more likely to suffer from a decreased sense of smell.
Eat Real Food to Maximize Mood
Pollution in the air is not the only way humans are being contaminated with toxicities. In fact, there's ample evidence that food addiction is a profit-driven strategy in the food business. Processed fructose, salt and unhealthy fats are the top three substances making processed foods so addictive. This can happen through "sensory-specific satiety," as well as through other factors, such as drugs and drug-injected foods, that you may not be aware of, including:
How you eat is directly related to how you feel. Whether you can smell well or not, you can eat foods that will enhance your health, not diminish it, and optimize your outlook on life, your mood and how you relate with others. Eating fresh, whole, organic foods will go a long way toward making you feel and function better. It will help minimize your risk for disease and obesity, and can even positively influence the environment, especially your own.
Tips to Improve Your Sense of Smell
If you notice your sense of smell slipping, and you know you're not zinc-deficient, there are steps you can take to improve it. First, I'd suggest reading through my nutrition plan for a comprehensive dietary plan that will support your health on multiple levels. Next, try these tips that are known to boost your sense of smell:13
- Exercise: Research shows that the more you exercise, the less likely you are to develop problems with your sense of smell as you age. Exercising even one time a week was found to reduce the risk of losing your sense of smell.14
- Become scent conscious: Make a point to smell your food before you eat it and notice the scent of flowers, cut grass or even rain. Doing this regularly will help increase your sense of smell.
- Try "sniff therapy:" Choose three or four different scents, such as floral, fruity and coffee. Sniff them four to six times a day, which will help the different receptors in your nose to work better.