Incidence of Stomach Cancer and Its Relation to Dietary Habits and Nutrition in Japan Between 1900 and 1975'

[CANCER RESEARCH 35, 3254-3258,November1975]

Incidence of Stomach Cancer and Its Relation to Dietary Habits and Nutrition in Japan between 1900 and 1975'

Toshio Oiso2

National Institute of Nutrition, Tokyo, Japan

Summary any stimulation in the body, so that a specific cause or a certain pathogenic microorganism is looked for in a given The diet of the Japanese people may be an important disease. However, it seems that some diseases occur as a factor contributing to the high morbidity and mortality reaction to various conditions repeated over a long period of rates of stomach cancer in Japan. Heavy rice consumption time. Thus, a simple repetition of food habits could become plus many salty foods in the diet are characteristic of the the cause of a disease. traditional eating habits in Japan. Fat intake and use of al Rice is the main traditional food of Japan, and Japanese cohol and tobacco are also considered possible factors. As climatic conditions are most suitable for the cultivation of the diet of the Japanese people changes to a more Western rice. When rice is prepared for consumption, the hard outer diet, there may be a concomitant change in the incidence layer of a rice grain, called the husk, is removed and then of stomach cancer. the bran layer is taken off. The remaining oval white particle, which is 5 mm long, 2.5 mm wide and 2.0 mm thick, is called white rice. This unground rice is cooked Introduction in about 1.5 volumes of water that has been brought to a boil. Upon cooking, the water is absorbed by the rice, This article is written from the viewpoint of a nutrition which swells to 2.5-fold its previous volume, but the struc researcher, as I am a layman in the field ofcancer research. ture does not change. However, the cause of cancer is known to be complex and Charts I to 5 show the trends in Japanese dietary habits. not due to a single factor, as had been thought in the past. The Japanese people consume more than 1 kg of food per Since it has become clear that cancer is related to the capita per day, of which rice constitutes approximately 40% biological aspects of the body itself, its etiology is now (350 to 400 g) (Chart 1). Because the Japanese have a great considered from many viewpoints. Therefore, the relation preference for rice, it is not unusual for rice to comprise as between cancer and dietary habits and nutrients cannot be neglected. 40C @e Since cancer occurs in various organs of the human body, a relation to daily food intake might not be expected. On the 300 other hand, cancers of the mouth, esophagus, stomach, 200 small and large intestines, and related secretory organs more readily appear to have some relation to food. 90 Vital statistics show that morbidity and mortality rates of stomach cancer in Japan are the highest in the world. It 80 seems that, besides the physical characteristics of the 70 Japanese people, daily food intake or dietary habits can also be considered a factor in this disease. In view of this, the 60 traditional food habits and the contents of the Japanese diet will be discussed in relation to stomach cancer. It would be 50 gratifying if any relationship betweenstomach cancer and food habits is considered concrete enough to be useful to 40

specialists in this field. 30

20 Generally speaking, it is thought that pathological changes occur as a result of certain biological reactions to l0@

I Presented in Dr. Oiso's absence by Dr. James A. Peters at the ?94950.55 @iaâ€”-â€˜65â€˜7l'73'75 Conference on Nutrition in the Causation ofCancer, May 19 to 22, 1975, Key Biscayne,Fla. Chart I. Yearly changesof food intake per capita perday. Data (in g)

2 Now a consultant to the International Medical Foundation of Japan, are from the report of the National Nutrition Survey, 1973, Ministry of Tokyo, Japan. Health and Welfare.

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@@ 2300 . V V V â€¢ These habits of rice consumption are likely to lead to gastric 2200 V dilation, gastric ptosis, and gastric insufficiency, and the 2I00 â€” CalorIes â€” diet becomes high in calories and low in protein. In contrast, 2000 wheat, which undergoes milling, is eaten in the form of bread, noodles, or dumplings resulting in consumption of a l00 90 fairly small amount or harmless small particles of wheat 80 flour. Rice, which is consumed as particles, not only @ 70 Total Protein stretches the stomach wall but also influences digestion. 60 In some districts of Japan, for example the Nara Vegeta@g@P @ 50 prefecture, hot rice gruel is customarily eaten every morn 40 ing; this gruel is made by adding a large amount of water to 30 20 the cooked rice left over from the previous day. Soybean 0 sauce, with a salt content of 18%, is added as a condiment. Eating this very hot gruel (chagayu) appears to be related to UI949,50 @55 @60 â€˜65 â€˜70'71'72'73 stomach cancer, because the morbidity rate is extremely Chart 2. Yearly changes of nutrient intake per capita per day. Data (in high in this district. g) are from the report of the National Nutrition Survey, 1973,Ministry of Salty foods, such as soybean paste (miso), soybean sauce Health and Welfare. (shoyu), salted pickles (shiozuke), and small fish, shellfish, % I00 Others % I00 Fats & Oils Others [email protected] Fish & Shellfish Meat & Poultry Legumes 7- / Milk & Eggs 7, Vegetables / Fruits Potatoes 50 / / Starch / / / Cereals / / / / Cereals 50 / / / / / â€˜/ / Fish & Shellfish U 1960 965 1970I972 Chart 3. Calorie supply by food items (yearly changes). Data are from the Food Balance Sheet, 1972, Ministry of Agriculture and Forestry. Milk & much as 50 to 60% of the food consumed. Milk Products The main component of white rice is rice starch. When Eggs boiled rice is chewed, the starch is converted into a sugar, so that a sweet taste combines with the salty taste. By taking a large amount of rice at one time one may be satisfied with Meats only a somewhat salty taste. About 10 years ago in rural areas ofiapan, working farmers commonly consumed more 0 than I kg of rice per capita per day, which caused their 960 1965 1970 1972 stomachs to expand and become very heavy and full and Chart 4. Protein supply by food items (yearly changes). Data are from prevented the entrance of other foods into the stomach. the Food Balance Sheet, 1972, Ministry of Agriculture and Forestry.

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Downloaded from cancerres.aacrjournals.org on September 25, 2021. © 1975 American Association for Cancer Research. T. Oiso % people's taste for a salty burned flavor to their fish. Now, even beef steak is preferred broiled over a charcoal fire and I00 then sprinkled with soybean sauce. Some other ways in which rice is used by the Japanese are Others as follows. Cold rice can be formed into balls and baked. The surface of the rice ball is burned slightly black, and it becomes as hard as glass. Japanese people enjoy the burned Cereals salty taste of the hard rice grains and appreciate the chewy sensation of this food. / Milk & Glutinous rice can be boiled with water and pounded into

, Milk Products a rice cake that is baked on a charcoal fire and dipped in / soybean sauce with some pepper. People also enjoy rice Eggs crackers (sembei), which sometimes contain very hard glasslike rice particles. However, the crunching sound of I biting these crackers is avoided, so people tend to swallow Meats these particles whole. Hard rice crackers are eaten as a side

I dish when drinking sake (a Japanese alcoholic drink), beer, , or whiskey. 50 - 7- Japanese sake is made from boiled white rice to which a / 7 Animal Fats fungus (koji) is added; the mixture is fermented into alcohol and then filtered. Sake contains 15 to 16% alcohol and some 7 2 organic acids and sugars. It is usually drunk warm, at about 400, but some prefer it at temperatures above 600. Hot sake causes a burning feeling in the esophagus and stomach. / Although the alcoholic content of sake is lower than that of whiskey or brandy, the amount of sake consumed at one time is higher than for most alcoholic drinks. It is not Vegetable Oils uncommon, at certain receptions, for 2 liters per capita to / be consumed with salty snacks. The sweet taste of sake may be a reason for this. Hot sake may be preferred because it / stimulates the stomach. Those who dislike sake prefer sweetmeats. There are 2 yokan (very sweet thick jelly) and zenzai (thick bean soup with plenty of sugar and rice cake), which are made from / / red beans boiled with a large amount of sugar. Sugar U 1960 1965 970 1972

Chart 5. Supply of fats and oils by food items (yearly changes). Data Table I are from the Food Balance Sheet, 1972, Ministry of Agriculture and Salt consumptionper capita per year (1908to 1973) Forestry.

YearSalt or seaweed boiled with soybean sauce (tsukudani), are eaten (kg)190811.5193011.2195210.2190911.8193111.5195310.4191011.2193211.1195410.9191112.7193310.9195511.7191213.0193411.0195611.0191312.8193510.9195711.4191412.1193611.2195810.8191512.4193712.0195911.2191612.5193813.1196011.6191713.4193913.7196111.6191813.4194014.1196211.5191915.8194113.4196312.6192012.8194213.5196411.9192113.0194314.1196512.6192212.2194411.8196612.9192312.219456.4196713.4192411.919466.2196813.8192511.919478.2196914.1192611.8194812.7197014.9192711.819498.8197115.4192811.419509.1197215.5192911.919519.7197316.3(kg)YearSalt (kg)YearSalt as side dishes to complement boiled white rice. The salt content of these foods is about 10% for soybean paste, 18% for soybean sauce, 10 to 13% for salted pickles, and about 3 to 20% (as a common preservative) for raw or dried salted fish. For centuries, fish and shellfish have been popular in Japan. For the past 50 years, small fish have been caught on the coast and boiled or broiled with salt. Fish is also salted and dried. Fish is generally broiled until it is burned black; the same is true for dried fish. Teriyaki and sashimi are examples of favorite fish dishes, and both are made with soy sauce. Teriyaki is fish fillet that is dipped into soybean sauce and baked until it is burned black. Sashimi is raw fish served with soybean sauce plus grated radish, horseradish, or ginger. With the development of deep-sea fishing, advances have been made in techniques of freezing foods, leading to a decrease in the consumption of salted fish in the cities. However, teriyaki and sashimi remain popular, reflecting

3256 CANCER RESEARCH VOL. 35

Downloaded from cancerres.aacrjournals.org on September 25, 2021. © 1975 American Association for Cancer Research. Stomach Cancer in Japan consumption in Japan has doubled in the last 10 years. incidences of cerebral hemorrhage and stomach cancer. The consumption of salt per capita per day has not Rice is the most commonly consumed food per capita per decreased (Table I), but there are large differences among day, with consumption of other kinds of food being rather districts. For example, the northeast district has a high low. Among these other foods are fibrous foods, for consumption of salt as well as of rice. It is common in a example, flowering ferns and bamboo shoots. These foods, certain district for the consumption of salt to be greater than high in fiber content and oxalic acid, which are eaten 25 to 30 g per capita per day. In such districts, there are high seasonally and are not very popular, seem to be the cause of acute stomach inflammation. The National Nutrition Sur Table 2 vey, which is carried out every year in Japan, has reported 7 Polyunsaturated fatty acid intake in Japanese diet per capita per day (A) g of fiber intake per capita per day. (calculated figures from National Nutrition Survey, 1967)2 Differences between Japanese and Western diets may be PolyunsaturatedFood seen in fat and oil intake. Chart 5 and Tables 2, 3, 4, 5, and 6 acid show that intake of these substances has increased 3-fold in Japan from 1960 to 1970 but is still lower than that in itemAmount of intakeFatsfatty gCereals318.74.60.44 % Western countries. In terms of the ratio of animal fat to 2.02Nuts1.90.90.25 vegetable fat, consumption of animal fat seems to have 0.23Potatoes41.1Sugar19.2Cakes32.42.00.30 increased. Intake of polyunsaturated fatty acids, however, may exceed that of the Western diet, which is said to mean 0.60Fats 1.65.55Legumes74.04.0Fruits82.30.40.83andoils12.91 Table 4 Estimated polyunsaturatedfatty acids in 1-day diet (average through 0.13Green I year)2 0.03blesOtherand yellowvegeta 44.00.10.83 PolyunsatTocopherolEstimateduratedpolyunsat 0.03Pickles39.80.10.33vegetablesI 54.60.30.33 0.01Seaweeds6.90.1Seasoning107.70.70.40 uratedFat fatty acidsNon acidSpring38.114.910.338.70.69Summer30.512.63.620.30.29Autumn41.214.24.824.90.34Winter28.38.24.923.50.60Average34.512.55.926.90.48(g)(g)aafatty 0.28Fish 1.92Meatandpoultry34.87.20.13and shellfish84.03.20.60 0.94Eggs 0.75 Milk and milk products 75.34.4 2.9 0.06 0.17 Total38.9 42.10.17 14.73

a Fukuba, H., Nutrition of Linolic Acid. Sci. of Cooking, 6: 2 15-222, 1973. a Fukuba, H. Nutrition of Linolic Acid. Sci. of Cooking, 6: 2 15-222, 1973. Table 3 Polyunsaturated fatty acid intake in Japanese diet per capita per day (B) Table 5 (calculated figures from National Nutrition Survey, 1967)2 Estimated fatty acids components in Japanese diet' (average per capita per day) PolyunsaturatedFood acid I 2 3 (%)14:0664516:0172016183018:0677718:12528212518:217II121318:3222220:1641422:168171020:444Il67020:5632424:12312?113122:5111122:61222Polyunsaturatedfatty32243330acidFatty acidMenu (%)Menu (%)Menu (%)Av. gFatsandoils12.911.65.55Butter1.51.20.06itemAmount ofintakeFatsfatty %

0.07Margarine0.40.30.25 0.08Vegetableoils7.87.80.54 4.21Animalfats0.10.10.11 0.01Mayonnaise3.12.10.56 1.18Fish 1.92Meatandshellfish84.03.20.60 0.94Beef5.10.7Pork13.44.7Chicken6.00.3Others10.31.5Eggs38.94.40.17andpoultry34.87.20. 13

0.75Milkandmilkproducts75.32.90.06 0.17Milk64.72.2Cheese0.80.2Others9.90.5Total29.39.33 (%)Fat (g/day)43.44343.543.6Polyunsaturatedfatty13.31013.712.4acid/day

a Fukuba, H. Nutrition of Linolic Acid. Sci. of Cooking, 6: 215-222, a Ikehata, H., Tanaka, H., and Kamishima, C. Vitamin E Content and 1973. Fatty Acid Compositionofiapanese AverageDiet. 38(4):253-258, 1968.

NOVEMBER 1975 3257

Table 6 bral hemorrhage appear to be analogous to those changes Estimated fatty acids components in Japanese diet' occurring in the stomach wall. In this connection, it is supposed that the high morbidity of cerebral hemorrhage (%)Fatty SpringSummerAutumnWinterAv. and gastric ulcer is related to the above pathological acids(%) changes of the capillaries. C10 Recently, the intake of animal protein and fat has C12 0.5 0.7 1.1 0.7 0.8 increased in Japan (Charts 2, 4, and 5). Figures for both 2.2 2.2 2.5 2.1 C14 1.6 these substances have been reported by the Ministry of C1. 13.8 17.0 19.9 18.6 17.3 C1@:0 7.8 5.1 5.7 9.6 7.1 Agriculture and Forestry, and the National Nutrition C21:2 36.7 33.3 36.3 39.3 30.4 Survey of the Ministry of Health and Welfare shows that Caâ€¢:2 17.5 29.7 25.5 15.4 22.0 .,Fat the increase in animal protein is noticeable. C1@,3 9.8 5.6 3.6 6.2 6.3 Another factor to be considered is cigarette smoking. Other Polyunsatu 12.0 5.9 4.3 7.2 7.4 rated fatty acids Japan ranks second in the world in terms of smoking, while Total Polyunsatu 39.10.5 41.20.5 34.40.5 28.80.5 35.8728 the United States is first. People should refrain from rated fatty acids smoking, especially during meals, because of the â€œswallow (%)0.5 ingâ€•of cigarette smoke. This is of concern not only in lung intake/day38.130.541.228.3 cancer but also in stomach cancer. Generally, in recent years, the causes of death in Japan a Fukuba, H., Nutrition of Linolic Acid. Sci. of Cooking, 6: 2 15-222, seem to resemble the Western pattern. Stomach cancer is 1973. the only exception that reflects the Japanese diet and dietary habits. In conclusion, it seems that no decrease in the death safety from heart and circulatory problems. However, the rate for stomach cancer can be expected until dietary habits pathological changes of the capillaries which lead to cere change.

3258 CANCER RESEARCH VOL. 35

Downloaded from cancerres.aacrjournals.org on September 25, 2021. © 1975 American Association for Cancer Research. Incidence of Stomach Cancer and Its Relation to Dietary Habits and Nutrition in Japan between 1900 and 1975

Toshio Oiso

Cancer Res 1975;35:3254-3258.

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