Some tea and wine may cause cancer - tannin, found in tea and red wine, linked to esophageal cancer

Nutrition Health Review, Fall, 1990

Some Tea And Wine May Cause Cancer

Evidence from around the world shows a correlation between tannin, an ingredient found in tea, and cancer of the esophagus. For those who have given up coffee to seek comfort in the harmlessness of tea, the news can be upsetting.

A researcher has devoted more than 24 years collecting evidence that tannins, compounds of plant origin found in tea and red wine, can cause cancer of the esophagus (the muscle-membrane gullet that extends from the pharynx to the stomach).

Tannins have strong chemical power. In larger quantities they are used to tan leather.

Julia Morton, a botanist on the staff of University of Miami, has identified a suspected link to cancer of the throat among native inhabitants of Africa (the Bantus), and the populations of Curacao and other Caribbean islands who were known to use plants in the making of tea.

She collected these plants, had them tested by the National Cancer Institute and concluded that at least three plants implicated contained tannin.

Tannin, like caffeine and nicotine, provides plants with defenses against insects and other predators. She also identified tannin in sorghum, a tropical grass that both the people of Bantu Africa and those of Curacao used as part of their food supply. Coincidentally, Morton discovered high rates of cancer of the esophagus among both populations.

Dr. Morton has also found a correlation between tea drinking and esophageal cancer in Japan (they eat a gruel made of tea), and in parts of Iran where tea is used as a remedy for diarrhea.

A historical note: According to Gerhard Haneveld, a Dutch scientist, esophageal cancer was widespread among the Dutch when they were insatiable tea drinkers. By the early 1800s, however, coffee had displaced tea as the national drink and throat cancer practically vanished in the Netherlands.

Dr. Morton has also found relationships between the consumption of dry red wine, high in tannin, and cancer of the esophagus.

The Chinese, although they are heavy tea drinkers, drink tea that is low in tannin and have little throat cancer. The British, also profuse drinkers of tea that contains tannin, add milk to their drink which binds tannin, rendering it harmless.

Dr. Morton has her critics making her theory controversial. John Higginson, of Georgetown University Medical Center, disputes Morton's assumptions about her example of esophagus cancer among tannin-wine drinkers in Normandy, France. He attributes the malignancy to the inhabitants' high usage of alcohol. Others merely question the validity of her theory, calling for further studies. The project does not seem to be high on the list of the National Cancer Institute.