Beans decrease gastric cancer risk

Those who eat beans and soy products often are less likely to have stomach cancer, according to a study. / Korea Times file

By Yoon Ja-young

Eating beans and soy products such as tofu decreases the risk of gastric cancer, research has shown. Salty soy products such as soybean paste, however, have no such positive effect.

A research team led by Prof. Ko Kwang-pil at Gachon University and Prof. Yoo Keun-young at Seoul National University showed that there may be ways to prevent gastric cancer, which is the most common form of cancer in the country — the more often you eat foods containing beans, the less likelihood there is of developing stomach cancer.

The research team conducted a massive cohort study, following a group of people to analyze the correlation between risk factors and the disease. They surveyed 9,724 healthy people regarding the frequency of certain food intakes and other risk factors in 1993. The food items in the survey included vegetables, fruits, soy/tofu, soybean paste, seaweed, mushrooms, meat, dairy products, fresh fish, salted fish, eggs, instant food, fried food and coffee, and the participants were asked to report the average frequency of consumption for each food item. Following this group for 15 years until 2008, the research team found 166 gastric cancer cases in the group. Then they analyzed whether the diet had a correlation with the gastric cancer.

It showed that those who eat soy/tofu everyday or between once and four times a week had between 32 and 43 percent less risk of developing gastric cancer than those who answered “almost never.”

“Frequent intake of soybean/tofu was significantly associated with reduced risk of gastric cancer,” the research team said in the paper. “Because soy foods contain isoflavones that have anti-inflammatory and anti-oxidant effects, they could prevent development of gastric cancer,” they added.

Soybean paste, a fermented soy food with a high salt content, however, didn’t decrease the risk of gastric cancer. “Although soybean paste is a type of soy food, it contains high levels of salt and N-nitroso compounds, which form during fermentation. Thus, soybean paste intake could be a risk factor for gastric cancer,” they noted in the paper. N-nitroso compounds are known to be carcinogenic.

“Fermented soybean pastes contain considerable salt and activate Helicobacter pylori colonization and development of atrophic gastritis,” the authors added. Helicobacter pylori infection is an important factor in gastric cancer among Koreans.

The research was published on the latest edition of “Journal of Epidemiology.”