A doctor explains why gut health is as important as heart health

We’ve long been obsessed with our heart health. Now it’s time to pay more attention to our digestive system.

Darin Sabine with his wife, Jennifer, at Dana-Farber Cancer Institute.Suzanne Kreiter/Globe staff

Almond cakes and lemon squares sit under glass bowls at Violette Bakers, a gluten-free bakery in Cambridge’s Porter Square, and I can’t decide what to eat.

“Are those gluten-free oats?” a patron asks the server, who repeats what must be a mantra here: “Everything is gluten free.”

A minute later, I meet baker and owner Leesteffy Jenkins, who estimates that about 60 percent of her typical customers have eliminated gluten from their diets. Some, like herself, have been diagnosed with celiac disease, while others may simply be more sensitive to gluten-containing foods.

Nursing moms with colicky babies may want something without gluten, Jenkins says. “And I’ve got people who can’t eat egg, soy, or dairy that want alternative options.”

Among other questions in my head (how do you hold a cookie together without gluten or egg?), I wonder why our city, like many across the United States, has become so gut conscious. Jenkins thinks food sensitivities among children are driving adults to adapt their diets as well. Yet the changing food culture reflects a greater trend: People are increasingly interested in healthy food — and in how what we eat impacts the gut. As a gastroenterology fellow at Brigham and Women’s Hospital, I’m intrigued by this rising popular fascination rife with both myth and fact. For instance — while gluten-free diets are necessary for those with true celiac disease, such restrictive intake can prove nutritionally taxing for others, without any clear clinical benefit demonstrated in trials. Much of the gluten-free movement rests on a niche market supporting a surging $4.7 billion for-profit industry that shows no signs of slowing.

The vital functioning of the intestines has long been a point of neglect — and, perhaps, disgust — among the public. In the long swath of medical history, the gut was considered a system of “lower functions” compared to those of the brain and the heart. From the brain, Hippocrates said, come “joys, delights, laughter . . . sorrows, griefs, despondency, and lamentations.” The heart, Aristotle reasoned, is where all sensation lives. What comes from the gut other than our waste?

Nowadays, the gut is no longer taboo, but rather the topic of cocktail party conversations, national bestsellers, and a star-studded documentary. And for good reason: Medical researchers increasingly say that intestinal health is more important than we have previously believed. The dense and delicate nerve networks that ensheathe the bowels and the long arm of the immune system that patrols the gut wall suggest that the intestines not only digest food, but may regulate mood, emotion, and play a central role in immunologic response to disease.

Consequently, patients want to know whether stool tests are useful, what probiotics they should take, whether specific diets might help in illnesses ranging from multiple sclerosis to depression. Now that the gut is in the spotlight, we should model its care after how we’ve historically treated the heart: Prevent future illness by doing the right things now. We must not take the dangers of failing to care for the gut lightly.

Colon cancer rates are spiking among younger people, a population that doesn’t usually get screened with colonoscopies. The American Cancer Society estimates that there has been about a 50 percent increase of cases of colon cancer among people under age 50 in the past two decades, with the largest increases among those in their 20s and 30s. In Massachusetts, colon cancer is the third-leading cause of cancer deaths overall, among all age groups. What’s behind this disturbing change?

“The trend for rising colorectal cancer rates is in parallel with the increase of obesity,” says Rebecca Siegel, a strategic director and researcher at the American Cancer Society, who has pioneered much of the work in this arena. Based on research, this past spring the American Cancer Society lowered its colon cancer screening recommendation to start at age 45, rather than at 50, for people at average risk.

In November, I met Darin Sabine, 34,  at the Dana-Farber Cancer Institute. Sabine, who recently became fire chief in Newington, New Hampshire, was there receiving a chemotherapy infusion targeting his metastatic colon cancer.

Sabine has spent much of his career fighting blazes, but the conflagration that now threatens his life began with a spot of blood in his stool when he was just 27.

“I went to the doctor multiple times, who figured I probably had an ulcer or hemorrhoids,” he recalls. “I even brought up colon cancer to my doctor, who said something like, ‘You’re way too young for that!’” But in the summer of 2017, Sabine developed flu-like symptoms, and a CAT scan revealed he had metastatic colon cancer. Now, he’s considering new clinical trials in case the chemotherapy fails to stop the cancer from spreading.

Among older adults, the gut starts to break down in various ways. The much-hyped gut microbiome — a teeming ecosystem of trillions of organisms — becomes more sparse in later years, potentially due to less healthy eating habits, lifestyle changes conferred from living in nursing homes or long-term care facilities, and overuse of antibiotics. The lower diversity of bugs leaves the elderly gut open to invasion by dangerous bacteria like Clostridium difficile, which kills thousands of elderly patients in the United States each year. In Massachusetts, 90 percent of deaths from C. diff in 2014 occurred in people age 65 and older.

Older adults face other intestinal difficulties, too. The elderly gut doesn’t move food and stool along as well, a problem compounded by the lack of fiber in our diets. Many seniors I treat suffer from a constipation epidemic afflicting older Americans, with nearly half of older adults suffering from its symptoms and associated complications, like diverticulosis. These patients rely on daily laxative regimens to keep their bowels functioning properly.

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So what can we do — both the young and the old alike — to avoid these unpleasant medical problems?

Get screened for colon cancer.

Almost 1 in 3 adults over age 50 still isn’t being screened with a colonoscopy. Many of the reluctant people I meet in my clinic fear the test, though the procedure itself is very safe and bothers few, and the prep has gotten a lot easier. Several companies, such as ColonaryConcepts, are developing “tastier” bars and beverages to replace the infamous drink. As an alternative, people can also opt for a stool fecal immunochemical test (FIT) that looks for hidden blood in the stool — the downside is you have to get the test once a year. I’m frustrated by the numerous men and women who are diagnosed with a preventable colon cancer because they never got screened close to their 50th birthday — and later develop incurable colon cancer. While Massachusetts leads in colon cancer screening compared with the rest of the country, we still have more work to do to prevent unnecessary deaths, especially among the Hispanic and African-American communities where screening practices lag. If you’re younger than 50 and have a family history of GI cancers, ask your doctor if you should be screened, too.

Pay attention to bodily changes.

Given alarming spikes in cancer rates, younger people should be alert to changes in their own gut symptoms — and even look at their bowel movements now and then. Blood can color the stool as black as tar or a bright red. “Most men don’t look,” Sabine points out. “Call me weird, but that’s when I noticed the blood.” Younger people should also look out for unexplained weight loss or persistent changes in bowel habits, which can be a sign of cancer or, more commonly, other debilitating conditions of the GI tract, like inflammatory bowel disease and celiac disease, which tend to strike when people are in their 20s and 30s. If you decide to shell out money for a pricey “functional stool test” at a wellness center, know that they are almost impossible to interpret or act on without professional medical help. It’s best to discuss your symptoms and validate any third-party analyses with your doctor.

Improve your diet — but be wary of fads.

Diet reform is good for both young and old guts. Avoid processed deli meats and red meat while feeding the dense jungle of bacteria in the colon with fibers, fruits, and vegetables. Siegel says unhealthy and sedentary lifestyles rife with fast foods and processed meats are contributing to the rise in colon cancer among young people. A lot of people go to the deli and buy very expensive turkey breast and think they are eating healthy, Siegel says. Shifting away from the standard Western diet to the Mediterranean diet — composed primarily of plant-based foods, olive oil, fish, and mixed nuts — supports both gut health and a healthy heart. Sprinkling food with curcumin — the activated ingredient in turmeric — may dampen inflammation. Routine exercise staves off obesity, which does wonders for the gastrointestinal tract and reduces cancer risk. While particular diets are effective in treating specific gut conditions, consult with a gastroenterologist or nutritionist before pursuing anything radical.

Limit use of antibiotics.

Probiotics are often considered a panacea in mainstream wellness movements, but they have proven useful only in a small percentage of conditions so far, including in some people with inflammatory bowel disease, irritable bowel syndrome, and in some who develop diarrhea from antibiotics. The popularity of probiotics belies their effectiveness — which remains otherwise limited — and there is no evidence supporting their use in healthy people. Antibiotics, however, continue to be rampantly overprescribed and not only raise the risk of C. diff infection in the gut, but can further breed resistant “superbugs” that also take up residence in the intestine. When prescribed antibiotics — especially among the elderly — it’s best to ask your doctor whether these are truly necessary.