Japan has long prided itself as the "land of longevity," but the latest survey on life expectancy released by the Ministry of Health, Labour and Welfare has caused considerable anxiety among many people. The survey data shows that the average life expectancy of the Japanese people has declined for the first time in six years. Consequently, the highly vigilant Japanese public has exclaimed that unhealthy eating habits must be eliminated and corresponding measures must be implemented to curb the downward trend in life expectancy.
In response to the survey results, the Ministry of Health, Labour and Welfare analyzed that cancer, heart disease, and cerebrovascular diseases are currently the "three major killers" contributing to the increase in mortality among the Japanese population. The ministry stated that if these three major diseases could be overcome, the average life expectancy of the Japanese people could potentially be extended by about 8 years. Of course, in addition to these primary causes, there are other factors that affect life expectancy, such as an increase in suicides, obesity, diabetes, and excessive alcohol consumption.
In investigating the causes, researchers found that in modern life, people eat their breakfast too late and dislike eating vegetables. Moreover, almost all Japanese people love to drink, and excessive alcohol consumption is harmful to health. Some diseases are related to nutrition.
Regarding cancer, the WHO's Cancer Advisory Committee pointed out that 45% of cancers are caused by dietary factors, including long-term excessive calorie intake, increased fat intake, obesity, reduced intake of plant fiber, and insufficient Vitamin A.
It has been reported that in recent years, some knowledgeable people in Japan have called for vigilance against the nation's dietary structure aligning with Western patterns, with the intake of high-calorie, high-fat foods continuously increasing.
The relationship between high-fat diets and colorectal and breast cancers is the most significant. Animal experiments have found that increasing the fat content in feed raises the incidence of tumors in animals. When the fat content increases from 2% to 5% of total calories to 20% to 27%, the incidence of animal tumors increases, and the tumors appear earlier. When fat accounts for 35% of total calories, it can increase the incidence of intestinal tumors in animals caused by chemical carcinogens. This is because fat interacts with bacteria in the intestines and salts in bile to produce carcinogenic substances. Furthermore, if fiber intake is low, intestinal motility slows down, bowel movements decrease, and the time carcinogens spend in the intestines is prolonged. Epidemiological data shows a very close relationship between fiber and colorectal cancer; a low-fiber diet is associated with a high incidence of colorectal cancer.
Nutritional factors related to heart disease include obesity caused by excessive intake of energy and saturated fats, as well as insufficient intake of vitamins and dietary fiber. Therefore, dietary nutrition plays an important role in both the onset and prevention of heart disease.
Abnormal blood lipids, smoking, and alcohol consumption are the most closely related dietary factors for cerebrovascular diseases. Meanwhile, diseases such as heart disease, high blood pressure, and diabetes are also risk factors for cerebrovascular diseases, and all of them are related to dietary nutrition.
Whether they are preventive medicine experts or cancer research experts, there is a consensus that changing the dietary structure can prevent cancer. Food and nutrition experts and cancer pathologists from 15 countries in Asia, Europe, and America, after four years of research, have proposed 12 dietary recommendations for cancer prevention.