Background: Achieving a low dietary ratio of n-6 to n-3 polyunsaturated fatty acids (PUFA) is clinically relevant for the nutritional management of many patients.
Objective: We examined the possibility of creating substantial differences in the n-6 to n-3 PUFA ratio within a typical Japanese diet by developing Model Diet Menus.
Methods: We prepared a standard menu called the Model Diet Menu for female subjects aged 18-29. We then developed modified menus using different foods or oils and compared their n-6/n-3 ratios with that of the Model Diet Menu. In Development 1, we replaced all dishes using fish and fish products with meat, creating a "Meat Menu." Next, we replaced all dishes using meat and meat products with fish, creating a "Fish Menu." In Development 2, we replaced vegetable oil with rapeseed oil to produce the "Rapeseed Oil Menu." In another modification, we replaced vegetable oil with perilla oil, creating a "Perilla Oil Menu." In addition, we investigated the differences in n-6/n-3 PUFA ratio produced by changing cooking methods (boiling, grilling, and deep frying) within Japanese, Western, and Chinese cuisine styles.
Results: The mean (±SEM) n-6/n-3 PUFA ratio in the Model Diet Menu was 4.55±0.67. In Development 1, the ratios for the Meat Menu and the Fish Menu were 6.18±0.97 and 3.72±1.01, respectively. In Development 2, the ratios for the Rapeseed Oil Menu and the Perilla Oil Menu were 3.71±0.66 and 1.40±0.76, respectively. The n-6/n-3 PUFA ratios of Japanese-style meals were lower than those of Western-style or Chinese-style meals because the amount of oil in the Japanese-style meals was less than that of the Western-style or Chinese-style meals. No differences of n-6/n-3 PUFA ratio between foods prepared by boiling and those prepared by grilling were detected, probably because of the small amount of oil used in cooking.
Conclusion: The n-6/n-3 PUFA ratio can be lowered from 4.55±0.69 to 1.29±0.64 by decreasing the amount of oil used for cooking, using an oil rich in n-3 PUFA such as rapeseed oil and perilla seed oil, and substituting fish for meat in the diet.
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