title: Estimated daily intake and seasonal food sources of quercetin in Japan.
abstract: Quercetin is a promising food component, which can prevent lifestyle related diseases. To understand the dietary intake of quercetin in the subjects of a population-based cohort study and in the Japanese population, we first determined the quercetin content in foods available in the market during June and July in or near a town in Hokkaido, Japan. Red leaf lettuce, asparagus, and onions contained high amounts of quercetin derivatives. We then estimated the daily quercetin intake by 570 residents aged 20-92 years old in the town using a food frequency questionnaire (FFQ). The average and median quercetin intakes were 16.2 and 15.5 mg day(-1), respectively. The quercetin intakes by men were lower than those by women; the quercetin intakes showed a low correlation with age in both men and women. The estimated quercetin intake was similar during summer and winter. Quercetin was mainly ingested from onions and green tea, both in summer and in winter. Vegetables, such as asparagus, green pepper, tomatoes, and red leaf lettuce, were good sources of quercetin in summer. Our results will help to elucidate the association between quercetin intake and risks of lifestyle-related diseases by further prospective cohort study and establish healthy dietary requirements with the consumption of more physiologically useful components from foods.
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. nagata@seitoku.ac.jp.|Department of Human Nutrition, Seitoku University, Matsudo, Chiba 271-8555, Japan. nagata@seitoku.ac.jp.
authors: Haruno
authors: H
authors: Nishimuro
authors: School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan. hohnishi@sapmed.ac.jp.
authors: Hirofumi
authors: H
authors: Ohnishi
authors: Sobetsu-cho, Usugun, Hokkaido 052-0101 Japan. sato.midori@town.sobetsu.lg.jp.
authors: Midori
authors: M
authors: Sato
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors: Mayumi
authors: M
authors: Ohnishi-Kameyama
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. izm@affrc.go.jp.
authors: Izumi
authors: I
authors: Matsunaga
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. naito@affrc.go.jp.
authors: Shigehiro
authors: S
authors: Naito
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. Ippoushi@affrc.go.jp.
authors: Katsunari
authors: K
authors: Ippoushi
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. oike@affrc.go.jp.
authors: Hideaki
authors: H
authors: Oike
authors: Department of Human Nutrition, Seitoku University, Matsudo, Chiba 271-8555, Japan. nagata@seitoku.ac.jp.
authors: Tadahiro
authors: T
authors: Nagata
authors: School of Medicine, Sapporo Medical University, Sapporo 060-8556, Japan. akasaka@sapmed.ac.jp.
authors: Hiroshi
authors: H
authors: Akasaka
authors: Sapporo Medical University School of Health Sciences, Sapporo, Hokkaido 060-8556, Japan. ssaitoh@sapmed.ac.jp.
authors: Shigeyuki
authors: S
authors: Saitoh
authors: Sapporo Medical University, Sapporo, Hokkaido 060-8556, Japan. simamoto@sapmed.ac.jp.
authors: Kazuaki
authors: K
authors: Shimamoto
authors: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan. kobori@affrc.go.jp.
authors: Masuko
authors: M
authors: Kobori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D027761:Asparagus Plant; D002212:Capsicum; D004032:Diet; D015930:Diet Records; D004034:Diet Surveys; D002149:Energy Intake; D005260:Female; D006801:Humans; D007564:Japan; D018545:Lactuca; D008019:Life Style; D008137:Longitudinal Studies; D018551:Solanum lycopersicum; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D019697:Onions; D011794:Quercetin / Q000008:administration & dosage* / Q000032:analysis*; D012621:Seasons; D011795:Surveys and Questionnaires; D013662:Tea; D014675:Vegetables; D055815:Young Adult
chemical_list: D013662:Tea; D011794:Quercetin