Practical application of flavonoid-poor menus was evaluated on the bioavailability of anthocyanins as model flavonoids. Detectable amounts of flavonoids were not found in plasma and urine collected from 13 participants, who took the menus. After ingesting bilberry anthocyanins (919 μmol), average plasma AUC0-6h, Cmax, Tmax values and urinary recovery were 386.0 nmol h/mL, 139.1 nM, 1.31 h and 0.21%, respectively.

植物性食品には，機能性成分であるフラボノイドが豊富に含まれている。本研究では，フラボノイドの機能性評価を目的としたヒト試験で有効な，日本人の食事摂取基準（2005年版）に基づいた食事におけるフラボノイド低減方法の提案を目指した。日本で食習慣がある植物性食品中のフラボノイド量を既報より調べ，1回の食事で0.1 μmol以上を摂取する可能性がある植物性食品は，フラボノイド低減食の作成時に使用しないこととし，使用可能な食材のみを使い，日本人の食事摂取基準に基づいた2日分の献立を作成した。さらに，作成した献立中には，ヒト試験で影響を及ぼす可能性がある量のフラボノイドが含まれていないことを確認した（＜0.2 μmol/食事）。以上の結果より，フラボノイドの機能性評価，特に生体内吸収性の評価を目的としたヒト試験で利用可能な，食事摂取基準に基づいたフラボノイド低減食の作成方法を提案することが可能となった。

Recommended Dietary Allowance for Japanese (RDA-J), the 6th revision (2000) newly introduced the concept of dietary reference intakes (DRIs). In this study, to review possible problems of RDA-J, the 6th revision, we conducted an questionnaire survey to the members of the Japanese society of nutrition and dietetics in 2002. Among randomly selected 1000 members, a total of 478 individuals responded to the questionnaire. The result indicated that RDA-J, the 6th revision could not be easily applied to individuals with diseases or elderly people in practical settings (51.3%, 43.4%, respectively). The RDAs of fatty acids (17.2%), vitamin A (13.8%) and beta-carotene (14.3%) might have some problems to use for preparing menu, diet surveys and so on, because appropriate values were not available for these nutrients on food composition table, the 5th revision. The needs for opportunities to attend training courses on the application of RDA and DRIs were large (85.4%). These data suggest that technical supports are important to solve some problems in practical uses of RDA and DRIs.

Recommended Dietary Allowance for Japanese (RDA-J), the 6th revision (2000) newly introduced the concept of dietary reference intakes (DRIs). In this study, to review possible problems of RDA-J, the 6th revision, we conducted an questionnaire survey to the members of the Japanese society of nutrition and dietetics in 2002. Among randomly selected 1000 members, a total of 478 individuals responded to the questionnaire. The result indicated that RDA-J, the 6th revision could not be easily applied to individuals with diseases or elderly people in practical settings (51.3%, 43.4%, respectively). The RDAs of fatty acids (17.2%), vitamin A (13.8%) and beta-carotene (14.3%) might have some problems to use for preparing menu, diet surveys and so on, because appropriate values were not available for these nutrients on food composition table, the 5th revision. The needs for opportunities to attend training courses on the application of RDA and DRIs were large (85.4%). These data suggest that technical supports are important to solve some problems in practical uses of RDA and DRIs.

The present study was conducted to provide basic data for the new method of dietary assessment proposed in the National Nutrition Survey. This newly proposed method incorporates several new codes for ‘school lunch’, ‘fast food’, ‘dishes’, ‘seasoning’, ‘water’, ‘cooking’ and a food code table based on the 5th revision of the food composition table to implement in the 2001 National Nutrition Survey. We tested the coding of food consumption data by using this method and conducted a questionnaire about the introduction of this newly proposed method with dietitians at local public health centers. The percentage of errors for ‘seasoning codes’ (50%) was higher than that for the other new codes, while ‘cooking code’ errors were also high (23%). However, the needs for introducing ‘seasoning codes’ and ‘cooking codes’ in the National Nutrition Survey were considered high (80% and 61%, respectively). The percentage of errors for ‘water codes’ was relatively low compared with the others (39%). These results suggest that the newly proposed method should be improved to adapt more to the National Nutrition Survey, although we expect that such coding errors will be decreased by dietitian training and adjustment to the new method.

The National Nutrition Survey is a unique survey that provides nationwide information on nutrient intake in Japan. Descriptive statistical data of nutrient intake, which has not been described in annual reports, are summarized in this report. A dataset from the National Nutrition Survey between 1995 and 1999 was used for analyses. The distribution of vitamin A intake had an extremely long right-hand tail and the difference between mean and median was very large. The results alert us to understand and use statistics properly when one summarizes the data. Means and medians of each nutrient intake except vitamin C were higher in men than in women, however, means and medians of nutrient density (per 1,000 kcal energy intake) for all nutrients were higher in women than in men. Fat intake was the highest in individuals in their 20 s and gradually declined in older age groups. Most of other forms of nutrient intake were the highest in individuals in their 50 s or 60 s and declined in older age groups. However, a declining trend with aging was not observed in the nutrient density of all nutrients except fat. These statistical data would support better interpretation of the survey data. Furthermore, some methodological limitations in the dietary assessment of the present survey, including the possibility of overestimating nutrient intake by not taking nutrient loss during the cooking process in households into account, were discussed. It is important to use and interpret the survey data under careful consideration on such methodological limitations.

The developmental patterns of expression of β-carotene cleavage enzyme activity were compared with those of retinal reductase and NAD-dependent retinol dehydrogenase activities in chick duodenum during the perinatal period. The β-carotene cleavage enzyme activity was not detected in the duodenum before hatching, but it increased rapidly during 24 h after hatching. On the other hand, a considerable level of β-carotene cleavage enzyme activity was observed in the liver of embryonic stages and its activity gradually rose during the perinatal period. Comparison of kinetic constants for the β-carotene cleavage enzyme activities in the duodenum and the liver indicated that the enzyme in the duodenum possessed a lower affinity for β-carotene than that in the liver. The retinal reductase activity was detected in the microsomes of the duodenum at the earliest time examined, i.e. day 16 of embryogenesis and its activity began to rise on the last day of embryogenesis, which was followed by a gradual increase until 1 day of age. The NAD-dependent retinol dehydrogenase activity was also seen in the microsomes of the duodenum in embryonic stages and its activity increased in parallel with the retinal reductase activity around the hatching period. These developmental inductions of β-carotene cleavage enzyme and retinal reductase activities in the duodenum coincided with those of cellular retinol-binding protein, type II (CRBPII) and lecithin: retinol acyltransferase (LRAT). These results suggest that a co-ordinated induction mechanism should be operative for β-carotene cleavage enzyme and retinal reductase, both of which are inevitable in the process of β-carotene absorption and metabolism.

The conversion of beta-carotene to retinal and the succeeding metabolic process of the retinal leading to production of retinol and retinyl esters are the prerequisite for the utilization of beta-carotene as a provitamin A. These processes are participated by beta-carotene cleavage enzyme, retinal reductase and retinol esterifying enzyme(s) in the small intestine. To examine whether these enzymes exhibit the coordinated distribution in the villus, we have used the cryostat sectioning technique to quantify the activities of beta-carotene cleavage enzyme, retinal reductase and retinol esterifying enzymes along the villus-crypt axis in 8-day-old chick duodenum. The beta-carotene cleavage enzyme activity was very low in the crypt and gradually increased, reaching a maximum in the mid-villus. The villus-crypt gradient of the beta-carotene cleavage enzyme activity corresponded with those of retinal reductase activity and lecithin: retinol acyltransferase (LRAT) activity, but distinct from that of acyl-CoA: retinol acyltransferase (ARAT) activity. Furthermore, the distribution of the content of retinyl esters was similar to that of LRAT activity. These results suggest that the beta-carotene cleavage enzyme is coordinately distributed along the villus-crypt axis with retinal reductase and LRAT, the two enzymes which require cellular retinol-binding protein, typeII (CRBPII) as the donor of the substrate.

Retinol absorbed and generated from dietary beta-carotene can be esterified by retinol esterifying enzyme(s) in intestinal absorptive cells. In this study, we observed the developmental changes and villus-crypt distribution of the activities of two retinol esterifying enzymes (lecithin-retinol acyltransferase (LRAT); and acyl-CoA-retinol acyltransferase (ARAT) in chick duodenum) to seek the possibility that these enzymes play distinct roles in retinol absorption and metabolism. Intestinal LRAT activity was barely expressed in embryonic stages until 2-3d before hatching, when its activity becomes detectable; thereafter it abruptly increased to the maximal level at the third day of the posthatch period. In contrast, ARAT activity was present in the duodenum at the earliest stage examined, the 15th day of embryogenesis, and was elevated to the maximal level 3-4d after hatching. An assay of LRAT and ARAT activities along the villus-crypt axis of the duodenum by a cryostat sectioning technique revealed that between the day of hatching and 1d posthatch, an abrupt induction of LRAT activity occurred only in the villus region of the duodenum, where a coordinated induction of cellular retinol-binding protein, type II (CRBPII), was observed. In contrast, the rise in ARAT activity observed around the hatching period occurred at the broader portions of the villi including the area of villus-crypt junction. These observations in the developmental changes and distribution of LRAT and ARAT activities suggest that LRAT activity but not ARAT activity is closely related to the induction of CRBPII in the duodenum of developing chicks.