Gut check

Nutrition Action Healthletter, April, 2003 by Bonnie Liebman

Most people don't think much about their lymph glands kidneys, blood cells, or lungs. But, when it comes to the digestive, system everyone's an expert,

Or are they?

Do you know, for example which of these statements are true and which are false?

* Heartburn can increase your risk of esophageal cancer.

* Ulcers are usually caused by stress and spicy foods.

* If left untreated, diverticulosis causes serious complications in most patients.

For the answers, see our top-to bottom speed course on the most common threats to your gastrointestinal tract.

Gut Check

You may be surprised to learn that:

* heartburn can increase your risk of esophageal cancer,

* stress or spicy foods do not cause ulcers, and

* diverticulosis usually has no complications.

It's not just the myth and misinformation surrounding the gut that may have led you astray. What we know about the GI tract is rapidly changing. Researchers now have a much better idea of what can and cannot protect your digestive tract. Whether you're trying to avoid an uncomfortable bout of indigestion or a life-threatening case of cancer, our guide can tell you what to eat, what drugs or tests to take, and what warning signals to watch out for. This month we cover the most common and potentially serious problems of the GI tract. In a future issue we'll tackle gas and some other short-term stomachaches.

Heartburn or Acid Reflux

Most people call it heartburn. Commercials call it acid reflux. If you have it often enough, doctors call it gastroesophageal reflux disease, or GERD. But it always feels the same: a burning sensation in your chest or throat.

"What people experience as acid indigestion or heartburn is stomach acid making its way up the lower esophagus," says Susan Taylor Mayne, a cancer researcher at Yale University.

In some people, for unknown reasons, the sphincter muscle that's supposed to keep acid in the stomach isn't tight enough, so the acid flows up into the esophagus. But the lining of the esophagus, unlike the stomach, can't withstand strong acids.

"The esophagus does fine with reflux over the short term," says Mayne. "But if it's a chronic problem for decades, you begin to see changes in the lining of the esophagus" (see "Esophageal Cancer").

The good news is that most people can avoid heartburn by changing what and when they eat or by taking drugs that curb stomach acid. "Inhibiting acid production may reduce the risk of cancer, but it's too early to know," says Mayne.

Symptoms: A burning sensation in the chest or throat and acid regurgitation. Some people have pain in the chest, hoarseness in the morning, difficulty swallowing, a dry cough, bad breath, or a feeling that food is stuck in their throat or that their throat is tight.

What to do: If you have symptoms at least once a week, see your doctor, who may recommend drugs that keep acid out of your esophagus (see "Dropping Acid," p. 4). But often, lifestyle changes can help:

* If you smoke, stop.

* Don't drink alcohol.

* Lose excess weight.

* Eat smaller meals.

* Wear loose-fitting clothes.

* Avoid lying down until at least three hours after a meal.

Some people claim that they're more likely to get heartburn after eating citrus fruits, chocolate, drinks with caffeine, fatty or fried foods, garlic, onions, mint flavorings, spicy foods, or tomato-based foods like spaghetti sauce, chili, and pizza.

But the evidence is sketchy, so don't swear off the entire list unless you're sure that it makes a difference in your symptoms.

Esophageal Cancer

Adenoma of the esophagus is not a good diagnosis. Only one out of eight people is alive five years after getting the news. (Four out of five victims are white men.) And the rate of new cases jumped four-fold between 1976 and 1994.

What causes adenoma of the esophagus? The best clue so far: chronic heartburn, or GERD.

"In people who have chronic reflux for decades, the cells lining the esophagus may undergo metaplasia--they start to look more and more abnormal," explains Yale's Susan Mayne. That condition, called Barrett's esophagus, occurs in 10 to 15 percent of people who have heartburn at least once a week.

People with Barrett's esophagus are 30 to 40 times more likely to get esophageal cancer than people without it. But only one out of 100 people with Barrett's gets esophageal adenocarcinoma each year. (The other major esophageal cancer, called squamous cell carcinoma, typically occurs in poorly nourished, heavy-drinking, low-income smokers, and it's on the decline.)

What's behind the jump in adenocarcinomas? The obesity epidemic may bear some of the blame, but researchers don't know how too much weight harms the esophagus.

"People assumed that obesity caused reflux because of overeating or because a high body mass could increase pressure on the stomach," says Mayne. "But recent studies don't support a clear link between obesity and reflux."

"Obesity may raise the risk by promoting growth factors or some other mechanism, as it does with other cancers," she adds.

Researchers have only a few other clues to go on. "We find a strong protective effect of fiber, as well as folate, vitamin C, and beta-carotene," Mayne notes. Those results are still preliminary, but they send a clear message. "The protective nutrients all show up in the same foods--fruits and vegetables." The fiber also shows up in whole grains.