Gut Reactions

IN LATE 1990 MICHAEL VONELLI'S life was at a standstill. The 27-year-old shipping supervisor had been incapacitated by chronic diarrhea, abdominal pain, constant fever and severe weight loss. He had been diagnosed with Crohn's disease, a chronic inflammation of the small intestine and bowels, and though he was taking multiple medications--including steroids and antibiotics--his condition hadn't improved. He was on a leave of absence from his job and had postponed starting a family. As a last resort, Vonelli left his home in Bethlehem, Pa., to see a doctor--his eighth--in New York City who had a reputation for treating the patient rather than the disease. ""I was at my wits' end,'' he recalls. ""I had battled this for three years and put everything on hold.''

Vonelli's eighth doctor was Leo Galland, author of ""The Four Pillars of Healing'' (330 pages. Random House. $24), who diagnosed a wide variety of food sensitivities. He put Vonelli on a strict diet and weaned him from his drugs. Seven years later Vonelli's life is moving again. Symptom-free, he is back at work and taking night classes.

Galland told Vonelli his problem was leaky-gut syndrome, the unhappily named condition that some researchers say is implicated in dozens of diseases. Leaky-gut syndrome, or increased intestinal permeability, occurs when the wall of the small intestine is damaged. A healthy intestine allows only nutrients to pass into the bloodstream; when it is damaged, larger molecules--such as incompletely digested fats, proteins and starches--slip through, as well. (So do bacteria.) These substances, recognized by the body as foreign, can trigger an immune response in other organs. Galland and others who have written on the syndrome claim that healing a ""leaky gut'' with strict diets and nutritional supplements can help control insomnia, obesity and bad breath, as well as diseases from asthma to arthritis to eczema. Many researchers agree that the intestinal tract plays a key role in the immune system--but whether the gut is the root of so many problems is still hotly debated.

When the gut works right, as with most organs, we don't notice it. The small intestine is a convoluted, 25-foot tube between the stomach and the large intestine. Its lining is made up of millions of leaflike structures called villi, which in turn are covered with millions of microvilli. This intestinal forest harbors bacteria and yeast, which normally maintain a healthy balance and help carry out the intestine's main functions--breaking down food into nutrients the body can use and moving along waste and harmful substances to the bowel. Since most of the potentially dangerous material a human being encounters is in food, the gut's immune function is especially crucial, and researchers now estimate that more than two thirds of all immune activity occurs in the gut.

But in some people the wall of the gut seems to have been breached--either because the network of intestinal cells develops gaps, or bacteria and yeast overwhelm it and migrate into the bloodstream to cause an infection. Researchers still don't know exactly why or how these microscopic breaches occur. Among the possible causes: food allergies, too much aspirin or ibuprofen, certain antibiotics, excessive drinking, a compromised immune system or a parasitic infection. An overview of the subject published in 1995 in the journal Gastroenterology found evidence of leaky gut in diabetics, alcoholics, smokers, burn patients, iron-deficient children, schizophrenics and long-distance runners.

Leaky-gut syndrome isn't a disease itself but is thought to play a part in other diseases. Allowing undigested food or bacteria into the bloodstream sets in motion a chain of events: the immune system reacts, the body thinks it's sick and expresses it in a number of ways, such as a rash, diarrhea, joint pain, migraines, even psychological symptoms such as depression. Those problems can add up to a disorder that has no obvious relation to the original cause. A three-year survey of chronic-fatigue-syndrome patients in Ne- vada and California showed that the only thing one group had in common was a history of infection with the waterborne parasite giardia, which is suspected of causing tears in the intestinal wall. To confuse matters more, treatments for other ailments can cause or worsen a leaky gut. Untangling what is gut-induced and why that happens can be tricky.