Study links salted foods to stomach cancer
risk of stomach cancer, according to a report published this week
in the British Journal of Cancer.
Based on around 40,000 middle-aged Japanese people, the study examined their dietary, drinking and smoking habits over an 11-year period.
The study shows that the risk of stomach cancer for Japanese men with the lowest salt intake was one in 1000 per year. This doubled to one in 500 among those with the highest salt intake.
For women with a low salt intake the risk was one in 2000, rising to one in 1300 for those whose diet was high in salt.
Gastric or stomach cancer is the second most frequent cause of cancer deaths worldwide with an estimated 776,000 deaths in 1996. It is the fourth most common cancer in the world and in the UK stomach cancer is the sixth most common cancer with 10,000 new cases each year.
Scientists from the National Cancer Centre Research Institute in Kashiwa studied questionnaires detailing the diets of men and women in four districts of Japan (Iwate, Akita, Nagano and Okinawa).
Out of 18,684 men studied a total of 358 cases of stomach cancer were reported while 128 cases of the cancer were found in 20,381 women.
"Although there is a steady decline in its incidence, gastric cancer is still the most common form of cancer in Japan," said Dr Shoichiro Tsugane, who led the study.
In addition to salt intake the study also shows that smoking and low consumption of fruit and vegetables increases the risk of stomach cancer particularly in men, he added.
Scientists know that high salt intake can induce atrophic gastritis which is a precursor to stomach cancer. Salting, pickling and smoking are traditionally popular ways of preparing food in Japan. Pickled vegetable and noodles are rich in sodium and low in vitamin C.
As the Japanese diet has become increasingly westernised, note the scientists, there has been a noticeable drop in the rates of stomach cancer.
Dr Tim Key, an epidemiologist for Cancer Research UK, commented :"This study shows strong associations of stomach cancer with the intake of highly salted Japanese foods including salted fish and pickled vegetables. What we don't know is whether it is specifically the salt in these foods that can cause cancer or a combination of salt and other chemicals."
"In Britain, stomach cancer rates are much lower than in Japan and these types of highly salted foods are not widely consumed. But limiting salt intake is also important for reducing the risk for high blood pressure and cardiovascular disease,' he concluded.
Full findings of the Japanese study 'Salt and salted food intake and subsequent risk of gastric cancer among middle-aged Japanese men and women' by S Tsugane, S Sasazuki, M Kobayashi, S Sasaki are published in the British Journal of Cancer 90, 128 - 134 (12 Jan 2004).
