Why You Become More Sensitive to Certain Foods as You Age

There are plenty of things that tend to sneak up on you during the aging process (like the grunting noises you can't not make as you get off the couch), but none are quite as sneaky as your body no longer digesting your favorite foods in a peaceful manner.

"There can be both age-related physical changes that happen to the digestive tract, as well as chronic lifestyle factors, like stress or alcohol use, that cause inflammatory damage to the gut," says Anna Binder-McAsey, RD, registered dietitian and owner of Rethink Nutrition in Manhattan, Kansas. "All of these factors can cause strain on the GI tract and lead to some weakening or damage that ultimately impacts digestion."

Because there are both mechanical and chemical processes at play during the digestion process—and a disturbance to any one of them can trigger your gastrointestinal tract to retaliate at mealtime—nailing down exactly where your digestion's going off the rails can be complicated. Here are the likeliest culprits and how best to tackle them.

Why You Can Become Sensitive to Certain Foods as You Get Older

Your chewing skills need work.

The mechanical process of digestion starts in the mouth through the act of chewing food. If you rush your way through your meals and snacks or the condition of your teeth makes chewing a grind (pun totally intended), the larger chunks of food, once swallowed, can lead to increasing levels of digestive discomfort as you age.

"Once the large food particles are transferred to the stomach, they can slow digestion and decrease gastric emptying," says Amy Stratton, D.O., a gastroenterologist specializing in motility at Gastroenterology Consultants in Reno, Nevada.

Besides taking the time to thoroughly chew your food, good dental hygiene is key to preventing difficulty with chewing—and the upset stomach that follows.

Related: The 9 Best Foods for Digestion

Your mouth isn't producing as much saliva.

The chemical process of digestion also starts in the mouth, where it secretes enzymes via our saliva to help break down food. "As we age, the salivary glands produce smaller quantities of saliva, which inhibits food breakdown and can also lead to dry mouth," says Stratton.

This can be exacerbated by medications, such as antihistamines, diuretics, antihypertensives, decongestants and alcohol. "Other than avoiding medications that can cause dry mouth, there are no ways to prevent development of decreased saliva production," she says, "But you can stimulate saliva production by sucking on sugar-free candies."

You're on medication.

The digestive tract doesn't slow down much on its own as we age, but medications taken for pain management (such as narcotics) or conditions (such as diabetes) can slow down the rate that food moves through the digestive tract.

"Medications can have a variety of side effects that impact digestion, including reducing saliva production, constipation and nutrient deficiencies," says Binder-McAsey, who recommends letting your doctor know you'd like to minimize medication use and score intel on alternative treatments—or diet and lifestyle changes—for issues like pain, high cholesterol, high blood pressure or diabetes. (And don't stop medications that are messing with your digestion without discussing it with your doctor first, says Stratton.)

Certain meds can also increase the risk for Clostridium difficile (C. diff) colitis. "It's a bacteria that naturally inhabits the gastrointestinal tract, and exposure to certain antibiotics and acid-blocking medications can increase the risk of overgrowth of this bacteria," says Kathleen Holland, M.D., a pediatric gastroenterologist at Gastroenterology Consultants in Reno, Nevada.

Symptoms of a C. diff infection include large-volume, foul-smelling number-two sessions, watery diarrhea and possibly blood in your poop. If you think you might have C. diff, get in touch with your doctor to get tested and make sure to practice good hand hygiene, as C. diff can spread from person to person via everything an infected person touches.

Related: 6 Ways Stress Can Mess with Your Digestion

Your body's not producing as much lactase.

There are multiple enzymes along the lining of the small intestine that are responsible for digestion of sugars. "These enzymes consist of lactase (breaks down lactose), maltase (maltose), sucrase (sucrose) and trehalase (trehalose)," says Stratton. "There can be a significant decline in lactase with aging."

This is known as lactose non-persistence and results in difficulty digesting lactose-containing foods, such as milk and cheese. Common symptoms of a lactase deficiency include bloating, abdominal discomfort and diarrhea after lactose ingestion.

"Many people are able to prevent symptoms by eating small quantities of lactose-based products on a less frequent basis and don't always need to eliminate lactose from their diet entirely," says Stratton. For cheese fiends, using over-the-counter lactase supplements can also help to minimize symptoms.

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Related: Easy-to-Digest Foods You Should Try

Your blood sugar's perpetually high.

The digestive tract moves in a rhythmic manner that helps propel food through the gut. "Persistently elevated blood sugar levels can damage nerves responsible for digestive tract movement, resulting in slower stomach emptying (called gastroparesis) and symptoms of bloating, reflux, feeling full after small amounts of food, nausea and vomiting," says Holland.

In addition to working with your doctor to balance your blood sugar, you can help alleviate these symptoms by eating smaller meals, avoiding high-fat foods, avoiding larger meals within 30 minutes of bedtime, and avoiding foods that typically irritate the upper GI tract (think: caffeine, chocolate, spicy foods and acidic foods).

"But if you're experiencing persistent nausea or vomiting, bloating, heartburn or abdominal pain, you should check in with your doctor for a consult," says Holland.

You're running low on stomach acid.

Chronic inflammation of the stomach lining (also called atrophic gastritis) is more common in older adults and causes a decrease in stomach acid.

"Stomach acid is important for helping digest food, but also maintains a very specific pH in the stomach," says Binder-McAsey. "When the pH of the stomach becomes less acidic, harmful bacteria that we may be exposed to in our food or the air we breathe can pass safely through the stomach and take hold in the small intestine."

This can lead to SIBO (small intestinal bacterial overgrowth). Common foods, like starches and sugars, then provide fuel to these pesky bacteria and cause ongoing digestive drama. Atrophic gastritis can be caused, in part, by an H. pylori infection, so treating the infection can improve symptoms. Your doctor or dietitian can then work with you on a gut-friendly diet and lifestyle plan.

Your microbiome's out of whack.

The last component in digestion is checked off by the bacteria in the small bowel. "As we age, there's a decrease in the biodiversity and composition of the bacteria in the small bowel, with an increase in pro-inflammatory bacteria and no change in the number of health-promoting bacteria," says Stratton.

Overgrowth of bacteria in the small bowel can lead to SIBO or IMO (intestinal methanogen overgrowth), along with weight loss, diarrhea and malabsorption.

Both SIBO and IMO can be diagnosed via breath testing and can be treated with a short course of antibiotics, says Stratton, while eating a diverse, high-fiber diet and avoiding processed foods can help stimulate microbiome diversity. (Try our 7-Day Meal Plan for a Healthy Gut: 1,200 Calories.)

How to Improve Your Digestive Health

"It's never too early or too late to start adopting a gut-friendly lifestyle, starting with bringing more good bacteria to the gut," says Binder-McAsey. "This can be done by choosing probiotic-rich foods like yogurt, kefir, tempeh, sauerkraut, kimchi and kombucha." (These are the best and worst foods for your gut health.)

If you're not a fan of these foods or struggle to eat them on the regular, Binder-McAsey recommends popping a probiotic supplement that has at least five different strains of good bacteria and 5 to 10 billion CFUs.

Prebiotic foods are also important, since they contain fibers that help feed and fuel the good probiotic bacteria. Enter beans, onions and garlic, bananas, artichokes and whole grains.

"For someone already experiencing digestion issues, these foods may cause unwanted gas or bloating," says Binder-McAsey. "But focusing on these foods before digestion issues start showing up can be an important part of building a strong microbiome and aiding digestion." (Working with a dietitian who specializes in digestion can help you work toward safely adding them into your diet without causing symptoms.)

Meanwhile, bone broths can provide the tissue of the gut with the nutrients it needs to repair and strengthen—most notably, collagen, which is an important protein needed for tissue repair. "Alternatively, collagen powders are a widely available supplement and can be found in flavorless varieties that mix discreetly into your favorite foods and drinks," says Binder-McAsey.

Also think about adding more colorful fruits and veggies to your plate, like berries, spinach and citrus. These foods are high in fiber and keep the number-two train running smoothly.

But most importantly, try not to let your digestive problems go unaddressed, and seek out professional help sooner rather than later.

"If digestive issues persist for more than a few weeks or months, this would be an ideal time to reach out to your doctor," says Binder-McAsey, and possibly ask for a gastroenterologist or dietitian referral. They can recommend plenty of simple diet and lifestyle strategies to get your gut back on track before symptoms become chronic—or nail down the root cause if they already have.