Gut Feelings

A bacterium called Helicobacter pylori is the chief culprit in gastritis, ulcers and stomach cancer. Antioxidant nutrients can protect you.

For decades, physicians believed ulcers were caused by too much stomach acid. It was a simple idea, based on the belief that excess acid would eat away at the stomach's lining. Bland diets and drugs to reduce stomach acid were the treatments of choice, though their long-term benefits were questionable.

By the mid-1990s, it became clear that ulcers were usually the result of a gastrointestinal infection with Helicobacter pylori bacteria. Again, the cure seemed obvious enough. Patients were treated with antibiotics, and the infection and ulcer went away. Yet doctors failed to answer a key question: why do 80 percent of people infected with H. pylori never develop ulcers?

The answer may be antioxidants. H. pylori infections significantly reduce stomach and blood levels of key dietary antioxidants such as vitamins C and E and beta-carotene. Low levels of these antioxidants leave the stomach highly vulnerable to hazardous molecules known as free radicals, which can damage stomach cells and set the stage for cancer. Conversely, antioxidant supplements (even without antibiotics) can often eradicate H. pylori infections.

But there's more at stake than just ulcers. Untreated chronic H. pylori infections boost the risk of stomach cancer by up to 80 percent. Although stomach cancer doesn't garner a lot of headlines, it is the second most common fatal cancer in the world, and in most countries the five-year survival rates are less than 20 percent. However, recent studies have found that antioxidant supplements can also reverse precancerous changes in the stomach.

Infection Depletes Antioxidant Levels

Discovered in the stomach in 1983, H. pylori is a bacterium involved in a continuum of three diseases: gastritis, gastric or duodenal ulcers, and stomach cancer. Gastritis, an inflammation of the stomach wall, increases the risk of ulcers; ulcers subsequently increase the risk of stomach cancer.

When H. pylori infects the stomach or duodenum (the top few inches of the small intestine, located right below the stomach), the immune system responds by flooding the area with a variety of white blood cells. Normally, these cells use free radicals to destroy the infecting bacteria. However, according to Peter Ernst, DVM, PhD, a researcher at the University of Texas Medical Branch, Galveston, this powerful immune response cannot always eradicate H. pylori infections. Nonetheless, white blood cells continue their attack, with free radicals damaging the stomach wall and potentially causing inflammation, chronic gastritis and mutations that may lead to cancer.

Research shows H. pylori depletion of antioxidant levels is made worse when people consume few antioxidant-rich fruits and vegetables. In a study of 1,106 men and women, researchers at the University of Glasgow, Scotland, reported that H. pylori infection interfered with the body's utilization of vitamin C. When people infected with H. pylori also ate few fruits and vegetables, their vitamin C levels dropped to one-third less than normal. Another study at the University of Auckland, New Zealand, found people with H. pylori had only one-fifteenth the vitamin C in their gastric acid compared with healthy subjects.

Similar patterns have been noted with vitamin E and beta-carotene. Satheesh Nair, MD, of Johns Hopkins University School of Medicine,

Baltimore, and his colleagues, recently found that patients with gastritis had low blood and stomach levels of vitamin E. People with gastric ulcers, a more serious condition, had significantly lower levels of vitamin E, vitamin C, beta-carotene and other carotenoids.

Antioxidants Protect Against Stomach Cancer

Researchers estimate that 50 to 73 percent of stomach cancers are the result of H. pylori infection (Journal of the National Cancer Institute, 2000; 92:1881-1888). One study found H. pylori increased the risk of precancerous changes to stomach cells and outright cancer by 80 percent. However, high levels of vitamin C definitely appear to be protective. A study of 2,646 people, conducted at the National Cancer

Institute, Bethesda, MD, found that high blood levels of vitamin C were associated with an 80 percent reduction in stomach cancer risk.

Several studies more clearly confirm the benefits of antioxidant supplements in actually reversing precancerous cell changes in people infected with H. pylori. In a small trial sponsored by the World Health Organization, researchers gave five grams of vitamin C daily for four weeks to 32 people with chronic gastritis and H. pylori infections. The high-dose vitamin C supplements eradicated H. pylori infections in 30 percent of the patients.

Another study, led by Angelo Zullo, MD, of La Sapienza University, Rome, Italy, followed 58 patients with precancerous gastric cells after antibiotic treatment for H. pylori. Half were given either 500 mg of vitamin C daily for six months or no further treatment. At the end of the study, Zullo and his colleagues found that precancerous gastric cells were reversed in about one-third of the patients taking the vitamin C. In contrast, only one of the patients from the other group improved.

Perhaps the most dramatic study, which compared antioxidant supplements with antibiotic therapy, was conducted by Pelayo Correa, MD, of Louisiana State University, New Orleans. Correa asked 631 people with precancerous changes to stomach cells to take 30 mg of beta-carotene (50,000 IU), two grams of vitamin C daily, a combination of both antioxidants or a placebo for six years. Some subjects also underwent a standard 14-day antibiotic treatment for H. pylori;others received both antioxidants and antibiotics. Changes to the gut were examined through endoscopy orbiopsy after three and six years.

All three treatments beta-carotene, vitamin C and antibiotics resulted in significant reversals of the precancerous stomach cells. In the treatment of nonmetaplastic atrophy, one type of precancerous condition, people receiving beta-carotene supplements were 5.1 times more likely to improve than those taking placebos. People taking vitamin C or antibiotics were five times and 4.8 times more likely to improve, respectively. Similarly, people with intestinal metaplasia, another type of precancerous condition, were 3.4 times more likely to improve with beta-carotene, 3.3 times with vitamin C and 3.1 times with antibiotics. In addition, 15 percent of those taking antioxidants alone (no antibiotics) were cured of their H. pylori infection.

Other antioxidants may also offer protection against H. pylori infections and their consequential damage to the stomach. Chinese researchers recently reported that extracts of the herbginkgo biloba could protect the gastric mucosa (membrane) from free radical damage. At a 1998 scientific meeting, Gowsala P. Sivam, PhD, of Bastyr University, Bothell, Wash., described experiments showing that garlic inhibited the growth of H. pylori. Population-based studies also show that diets high in lycopene, the antioxidant carotenoid that makes tomatoes red, are associated with a relatively low incidence of stomach cancer.

Antioxidant nutrients are well established for their roles in preventing mutations to cells and reducing the risk of cancer. Indeed, diets high infruits and vegetables are associated with a low risk of stomach cancer, whereas diets high in refined sugars and grains (which are low in antioxidants) appear to increase the likelihood of developing stomach cancer.

Two features of recent research on antioxidants and H. pylori are especially remarkable. One, antioxidant supplementation can sometimes eradicate H. pylori infection (although antibiotics will ensure successful treatment). Two, antioxidants can interrupt the progression of precancerous cell changes to actual stomach cancer. Such dramatic findings make for especially compelling reasons to supplement with antioxidants.

A study of 2,646 people at the National Cancer Institute, Bethesda, Md., found that high blood levels of vitamin C were associated with an 80 per cent reduction in stomach cancer.

The esophagus moves food into the stomach. In the body of the stomach, food is stored and mixed with gastric secretions. The duodenum receives secretions from the liver and pancreas, then moves food into the small intestine.

PDF Diagram of Stomach