Diet and Atherosclerosis Prevention: Rethinking the Significance of "The Japan Diet".

Although the mortality rate from cardiovascular disease (CVD) in Japan remains lower than that in Western countries, the need for the prevention of atherosclerotic diseases still merits emphasis. Cardiovascular disease develops due to the accumulation of risk factors such as visceral obesity, impaired glucose tolerance and diabetes, dyslipidemia, metabolic dysfunction associated with steatotic liver disease, hypertension, and chronic kidney disease. Dietary therapy must comprehensively improve these factors through the intake of nutrients and food components. This narrative review aims to confirm the effects of well-known nutrients that influence atherosclerotic risk factors and foods providing each nutrient in the Japanese diet. Furthermore, the actual dietary intake of the Japanese population is described. Target foods and dietary habits to modify patients' diets should be determined through nutrition assessment. Reducing carbohydrate intake requires limiting confectioneries, sweet beverages, and sweet fruits while avoiding the consumption of a lot of refined grains at once. The consumption of foods rich in saturated fatty acids, such as lard, beef tallow, butter, fatty red meat, fresh cream, and trans fatty acids contained in shortening, margarine, oily processed and fried foods, should be reduced. To meet the dietary fiber intake requirement, more unpolished grains, vegetables, citrus or whole fruits, seaweed, mushrooms, and konjac should be consumed. Fish intake is higher in Japan than in Western countries but it has been decreasing in younger generations, indicating the need for education and environments that encourage fish consumption for EPA and DHA intake and limit excess oil intake. Japanese people have higher candidate gene polymorphisms responsible for salt-sensitive hypertension than Caucasians; therefore, strict salt reduction is desirable. Sodium is included in salt, seasonings, and sodium salt additives in take-away, prepared, and ultra-processed foods, the cumulative impact of which cannot be ignored. The Japan Atherosclerosis Society (JAS) recommends a dietary pattern called "The Japan Diet," featuring higher consumption of fish, soybeans and soy products, vegetables, citrus fruits, low-fat milk and dairy products, seaweed/mushrooms/konjak, and unrefined cereals with reduced consumption of animal fat, fatty meat and poultry, sweets including desserts and snacks, and alcoholic drinks, along with reduced salt intake. "The Japan Diet", a reasonable and useful strategy for nutrition therapy, improves multiple atherosclerotic risk factors comprehensively by providing prescribed nutrients. Nutrition education for "The Japan Diet" intake improved serum lipid and metabolic parameters in patients with dyslipidemia. However, clinical intervention studies on patients with atherosclerotic risk factors remain limited. Further studies on the effect of "The Japan Diet" on CVD prevention are needed.