Foods Don't Taste Quite the Same?
What we know about the biology of smell and taste senses and tips to reawaken the palate
My brother treated my mom on her birthday to a meal at her favorite Thai restaurant. I had heard about the plan from both of them for weeks ahead. It's a little family-run no-frills place in a New Jersey strip mall where the food is reliable. They both were looking forward to the shrimp pad Thai, a comforting plate of rice noodles and egg made sweet and salty by tamarind paste and peanuts.
The food came and my brother and his wife dug into their plates, but my mom set down her fork, shaking her head. Her food was bland and off, she said, with great disappointment.
My brother and his wife were perplexed as their plates appeared identical. My mother insisted a different cook in the kitchen must have served up her order. But the more likely explanation was in her own palate.
A decline in taste and smell is part of the normal aging process. What once tasted sweet and savory can seem one-note and flavorless. Taste sensory decline can begin as early as one's 60s, impacting 13% of the population and up to 40% of those over 80. Since COVID, when many experienced loss of taste and smell, blunting their palates, renewed interest has shifted more focus to the sensory biology that affects flavor perception.
Sensory receptors detect food's unique qualities of salty, sweet, bitter, sour as well as umami, the "meatiness" associated with mushrooms, soy and tomatoes. With aging, the threshold for a food's taste, the intensity at which, for example, sweet or salty may be detected, has been found to shift upward.
"The underlying causes of age-associated decline in taste are not well understood."
"Any taste changes can affect one's appetite and enjoyment of food whether it be related to age, COVID infection, or other causes," says Chee Chia, M.D., from the National Institute on Aging. "The underlying causes of age-associated decline in taste are not well understood."
Genetics is one determinant — as well as factors like smoking, sinus inflammation and recent respiratory illness. Underlying physical and cognitive health conditions and many medications, including common drugs like those that lower lipids and treat hypertension, can promote altered taste and "metallic taste" syndromes. Not all will experience or be aware of gradual shifts in their palates, and, as a result, taste changes are rarely reported to physicians.
However, for those who perceive changes, a meal once enjoyed as flavorful may now seem lackluster, resulting in poor appetite and eating habits that don't support the nutrition needed for vibrant aging. For some, loss of interest in food may become a social obstacle leading to friends' invitations declined and increasing rates of isolation and depression.
Those who notice a change should discuss the situation with their doctor and review medications to help identify reversible causes.
Common Disorders
"Smell and taste disorders are just as prevalent as hearing and balance disorders and deserve more attention, research funding and public health intervention," says Valerie Duffy, a nutrition scientist at the University of Connecticut who researches how chemosensory perception impacts health. Duffy says that though many senses play a role, smell is most essential to the full experience of flavor. Affecting more than half of the population over age 65, olfactory loss occurs more frequently than taste loss.
Smell, both through the nose and through the mouth, through a process termed "retronasal" smell, triggers olfactory receptors that lie behind the bridge of the nose.
To demonstrate their role, Duffy recommends comparing the taste of a jelly bean with one's nose plugged then free. "Most will taste sweetness, but can't distinguish the difference between say a coconut or cherry-flavored bean," she says. The nose must be free to sniff food's aroma as well as to inhale volatile molecules through the mouth liberated with chewing.
"Smell and taste disorders are just as prevalent as hearing and balance disorders."
Mechanical and other receptors contribute the third component of flavor perception — signaling food's texture and pungency, as well as mouthfeel or creaminess, such as distinguishing the difference between whole versus skim milk. The crunch of tortilla chips or the cooling sensation of peppermint are translated to the brain through these tactile receptors.
The myriad taste, smell and tactile receptors on the tongue and in the nose and mouth carry information to the brain that then "packages" these signals into what is perceived as food's distinct flavor. The desire for foods is more complex than simply appealing to the taste buds. "Smell, taste, texture, colors and even the sounds we make when eating influence what we like to eat and purchase," Duffy says.
Evidence is also mounting that the gastrointestinal tract and the trillions of bacteria that inhabit it, known as the gut microbiome, may influence taste preferences. A craving for sweet or fat can stem from the gut communicating nutrient needs directly to the brain through its web of neural circuits.
Understanding how the body's network of sensory receptors supports eating habits is important to healthy aging. When a national survey asked about smell and taste over the past year, 23% of adults over 40 reported problems with smell and 17% with taste.
"What we are learning is that alterations in sensory function may lead to less healthy diets," Duffy says. Those aware of loss of smell who don't get the same "flavor sensation" from food as previously, she notes, may compensate by developing preferences for higher calorie and sweeter and saltier foods. Eating foods with more saturated fat, sodium and sugar habitually can promote weight gain and chronic diseases like diabetes.
Adding More Flavor
But don't assume that eating should inevitably become chore-like with age, particularly for the many people living alone who may not feel motivated to cook. For those who suspect food lacks flavor due to sensory decline, making some changes in the foods they buy and how they prepare them can help make meals more appealing.
Variety is the spice of life, so the old proverb goes. Be sure to include different food groups at each meal — lean proteins like poultry, fish, beans or tofu; fruits and vegetables, quick-cooking grains like wild rice and quinoa, and calcium-rich dairy and yogurts — for meals that are both nutritious and satisfying.
Make eating a Kodachrome experience. A variety of bold colors and food textures can stimulate the senses. Fill the shopping cart with brightly colored blueberries and strawberries, green leafy vegetables, orange-fleshed sweet potatoes and winter squashes, and vivid citrus. The vibrant shades of peak season produce can help boost food interest and will add fiber and inflammation-fighting nutrients to the diet.
"What we are learning is that alterations in sensory function may lead to less healthy diets."
Consider the way foods feel in the mouth. The contrasting crunch of cucumber and carrot sticks with silky yogurt dips or creamy hummus, or the "butterfly" shapes of popcorn and walnuts send signals to the brain that engage tactile sensors.
Avoid high salt and high fat foods. "When shopping, it's a good common practice to regularly review sodium content on labels," Duffy recommends. "Most people are likely to be satisfied with low-sodium cheeses and soups whose regular counterparts can be notoriously high in salt."
Instead, use spices and fresh herbs to ramp up food's flavor. Sauté roast chicken, onions and red peppers with a blend of aromatic spices, ground ginger, turmeric and cumin for an easy meal. Try adding fresh tarragon or thyme when roasting carrots or cod and make simple green salsas by chopping flat-leaf parsley, cilantro or mint with olive oil and lemon. While cooking, a tablespoon or two of rice or apple cider vinegar over string beans or sauteed red cabbage or balsamic on brussel sprouts can add yet another dimension.
Duffy recommends people take their time when eating as well, slowly chewing and inhaling. "Savoring the smell, taste, touch, temperature, and even the burn from a chili pepper," Duffy says, "can help us to be more mindful of what we eat by experiencing all of foods' flavor components."
Perception of flavor has strong associations to emotion, memories and experiences people have had with food in the past. If an exotic dish piqued an interest while traveling, track down a recipe to re-create in the kitchen. Hungry for a childhood favorite? Prepare it at home and invite a friend for lunch. The best meals are shared over laughter and good conversation. Even a Zoom call or videochat can bring old school chums and grandkids together to tables from miles away.