As the age-old proverb rightly states, “You are what you eat.” Our diet largely influences our health and well-being. A balanced diet lays the foundation for healthy living and disease prevention. However, a ‘one-size-fits-all’ approach may not work, given the biological, cultural, socioeconomic, and lifestyle differences. Moreover, gender and age can dramatically influence dietary preferences. Many studies have explored dietary diversity and how often certain foods are consumed. However, little is known about how dietary patterns, food choices, and combinations vary with age and gender.
To bridge this gap, Professor Katsumi Iizuka from the Department of Clinical Nutrition, Faculty of Medicine, Fujita Health University, Japan, and his team sought to analyze dietary patterns among young and middle-aged Japanese individuals. Explaining why this is important, Prof. Iizuka says, “Being aware of the gender- and age-specific differences in dietary patterns and diversity can lead to individualized nutritional improvement for each age and gender group.” Their findings were published in Volume 17, Issue 13 of the Nutrients journal on July 2, 2025.
The researchers analyzed the anonymized responses from a dietary survey obtained during health checkups of 2,743 Fujita Health University employees. The respondents were stratified into four age groups: 20–29, 30–39, 40–49, and 50–59 years.
The Food Intake Frequency Questionnaire was used to assess their weekly consumption frequency of 10 different foods, including meat, fish, eggs, dairy products, soy, green vegetables, seaweed, fruits, potatoes, and oil; the frequency of drinking sugar-sweetened coffee and tea; and the frequency of consuming soft sweets, colas, other soft drinks, and alcohol.
Previous studies utilized diversity indices to evaluate food intake. However, these scores do not adequately reflect dietary patterns or combinations. In this study, the researchers applied previously unexplored statistical techniques that are commonly used in ecology to examine microbial diversity. They assessed ‘alpha diversity,’ or the diversity in a single group, and ‘beta diversity,’ or the diversity across different groups. Further, they performed multivariate analysis to incorporate age and gender variations.
The analysis revealed that the intake frequency of the individual food items did not vary greatly between male and female respondents, except that women consumed fruits more frequently than men. On grouping the participants by age and sex, the researchers noted significantly different dietary patterns influenced by the intake of meat, fish, eggs, fruits, seaweed, dairy products, vegetables, and potatoes. Women had more diverse dietary patterns compared to men. Further, younger men were least likely and older women were most likely to follow a meat- or egg-centered dietary pattern with fruits and dairy products. On the flip side, older men preferred a fish- and fat-centered traditional Japanese diet, while younger women leaned toward plant-based foods, including fruits, vegetables, and potatoes. Notably, the differences between male and female dietary patterns became smaller with age, suggesting a shift in dietary preferences.
Interestingly, dietary diversity and the intake of beneficial foods, including fruits, seaweed, and dairy products, increased with age for both men and women. The researchers suggest that this increase may be because of generational gaps between adults in their 20s and those in their 40s. While middle-aged individuals often live with their families, younger adults tend to live alone, which may affect their food intake and choices. Healthy food choices at a young age can significantly impact future health. Therefore, including micronutrient-rich foods like fruits, seaweed, and dairy products at staff cafeterias and workplaces can help improve their intake by younger adults.
Overall, these findings provide novel insights into how dietary patterns differ by age and gender. These results can further be extended to understand how dietary variations impact gut health and microbiota and the occurrence of diseases like obesity, diabetes, heart disease, and cancer. Additionally, understanding dietary variations can help nutritionists provide tailored guidance to address individual deficiencies.
“By eating fiber-rich foods and fermented products from a young age, it is possible to reduce the risk of developing heart diseases and cancer. Visualizing differences in dietary patterns across generations can improve the general public’s understanding of dietary balance and diversity,” Prof. Iizuka concludes.
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Reference
DOI: https://doi.org/10.3390/nu17132205
About Fujita Health University
Fujita Health University (FHU) is a private medical university located in Aichi, Japan. Established in 1964, it houses one of the largest university hospitals in Japan. It's 900 member faculty provides diverse learning and research opportunities to medical students worldwide. Guided by its founding philosophy of "Our creativity for the people" Fujita Health University believes that it's students can shape the future through creativity and innovation. FHU has earned global recognition, ranking eighth among all universities and second among private universities in Japan in the 2020 Times Higher Education (THE) World University Rankings. The university ranked fourth worldwide in the 2024 THE University Impact Rankings for contributions to the "Good Health and Well-being" SDG (Sustainable Development Goals) of the United Nations (UN). In June 2021, the university made history as the first Japanese institution to host the THE Asia Universities Summit. In 2024, Fujita Health University was awarded the Forming Japan’s Peak Research Universities (J-PEAKS) Program by the Japanese government to establish an innovative academic drug discovery ecosystem and hub of a multi-university consortium for research and education.
Website: https://www.fujita-hu.ac.jp/en/index.html
About Professor Katsumi Iizuka from Fujita Health University
Professor Katsumi Iizuka is a leading expert in clinical nutrition at Fujita Health University in Japan. He earned his medical degree from Osaka University in 1993 and completed his Ph.D. in 2000. His research focuses on metabolic diseases, including obesity, diabetes, and insulin resistance, with a particular interest in the role of carbohydrate-responsive element-binding protein (ChREBP) in nutrition-related disorders. With over 95 publications and more than 3,000 citations, Prof. Iizuka's work significantly contributes to understanding the nutritional factors influencing metabolic health and disease prevention.
Funding information
This research received funding from the Dairy Products Health Science Council, Japan Milk Academic Alliance, Japan Dairy Association (J-milk) (women’s health).
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