Two new studies add to the evidence that diet and lifestyle affect a person’s risk of developing stomach or esophagus cancer. A Chinese study showed that high blood levels of alpha-tocopherol, a form of vitamin E, may reduce a person’s risk of getting stomach or esophagus cancer. A study in the United States measured the impact that lifestyle factors have on the development of the two cancers.
Stomach cancer is the second leading cause of cancer death in the world. Several studies over the past few years have drawn links between stomach and esophageal cancers and certain lifestyle factors: diet, being overweight, smoking, alcohol use and the presence of certain vitamins in the blood. A diet high in fruits and vegetables has been shown to reduce the risk of gastric and esophageal cancers, while high salt intake increases risk, at least of stomach cancer.
Both studies were reported Sept. 17 in the Journal of the National Cancer Institute.
In the Chinese study, some participants took vitamin E supplements and others did not; those who used the supplements were less likely to die of cancer. Another form of vitamin E, gamma-tocopherol, was found to be unrelated to cancer risk.
But alpha-tocopherol is not a miracle drug. High blood levels of the vitamin also appeared to raise the risk of one type of stomach cancer: gastric noncardia cancer (GNCC). The authors of the study said they had "no ready explanation" for that finding.
The second study examined risk factors associated with stomach and esophagus cancers—weight, smoking, diet, alcohol use and gastric reflux. These factors have all been identified before, but "no study has comprehensively examined their contributions to the cancer burden in the general population," according to the study’s authors.
The report identified the size of the role each risk factor plays in the development of four main types of stomach and esophagus cancer:
adenocarcinoma of the esophagus
squamous cell cancer of the esophagus
adenocarcinoma of the "cardia" region of the stomach
adenocarcinoma of other stomach areas. Being overweight accounted for 41 percent of esophagus adenocarcinomas, and smoking—even past smoking—accounted for 40 percent. Gastric reflux and low fruit and vegetable intake were also factors.
Adenocarcinoma of the esophagus has been increasing in prevalence in developed countries, especially among white men, according to the National Cancer Institute.
A significant connection was found between alcohol use and esophageal squamous cell cancers: 72 percent of cases could be linked to alcohol. Past or present smoking and low fruit and vegetable intake also contributed.
Smoking and being overweight accounted for 56 percent of stomach cardia adenocarcinomas, and high nitrite intake contributed to 41 percent of other stomach adenocarcinomas.
Vitamin C and beta-carotene may also help prevent gastric cancer. The Dec. 6, 2000 issue of the Journal of the National Cancer Institute published results of trial in which 600 people at high risk of developing the disease were given either:
vitamin C supplements
beta-carotene supplements
a standard treatment for the bacteria H. Pylori
some combination of the above three things
a placeboThe three potential treatments all reduced the risk of developing stomach cancer. The study added to the evidence that a diet rich in fruits and vegetables, which are sources of vitamin C and beta-carotene, decreases stomach cancer risk. (H. Pylori, the bacteria that causes most stomach ulcers, has also been shown to be a cause of cancer.)
Diet may have an even larger affect on stomach cancer risk in individuals with a family history of the disease, according to a 2000 Italian study.
