Junko Hirose

Relationship Between Urinary Concentrations of Nine Water-soluble Vitamins and their Vitamin Intakes in Japanese Adult Males

Excess water-soluble vitamins are thought to be eliminated in the urine. We have reported a strong relationship between water-soluble vitamin intake and urinary excretion in females. The relationship, however, is not well understood in males. In the present experiment, 10 Japanese male subjects were given a standard Japanese diet for the first week. The subjects remained on the same diet, and a synthesized water-soluble vitamin mixture containing one time the Dietary Reference Intakes (DRIs) for Japanese was given for the second week, three times the DRIs for the third week, and six times the DRIs for the fourth week. Twenty-four-hour urine samples were collected each week. Urinary excretion levels for seven of the nine water-soluble vitamin levels, excluding vitamin B12 and folate, increased linearly and sharply in a dose-dependent manner. These results suggest that measuring urinary water-soluble vitamins can be good nutritional markers for assessing vitamin intakes in humans.

Method for Evaluation of the Requirements of B-group Vitamins Using Tryptophan Metabolites in Human Urine

Tryptophan metabolism is directly involved with B-group vitamins such as vitamin B2, niacin, and vitamin B6, and indirectly with vitamin B1 and pantothenic acid. We evaluated the validity of requirements of B-group vitamins set by the Dietary Reference Intakes for the Japanese (DRI-J). We investigated the fate of dietary tryptophan in 10 Japanese adult men who ate the same diet based on DRI-J during a 4-week study. Vitamin mixtures were administered based on the amounts in the basal diet during weeks 2, 3, and 4. Daily urine samples were collected eight times (days 1 and 5 in each week). Administration of vitamin mixtures had no effect on tryptophan metabolites such as anthranilic acid, kynurenic acid, xanthurenic acid, 3-hydroxyanthranilic acid, and quinolinic acid within individuals. Surplus administration of B-group vitamins against DRI-J requirements did not elicit beneficial effects on tryptophan metabolism. Our findings supported the requirements of B-group vitamins set by the DRI-J.

Molecular Features of Food Allergens in Human Breast Milk.

ヒト母乳のゲル濾過解析の結果, 本来分子量28kDaの主要食物アレルゲン, 卵白オボムコイドが分子量約450kDaの位置に溶出された。また, オボムコイドの溶出パターンとその分泌型IgA免疫複合体の溶出パターンが一致し, オボムコイドが母乳中で免疫複合体として存在していることが明らかとなった。他の食物アレルゲンでも同様の結果が得られてきている。母乳中のアレルゲンを考える場合, その濃度だけでなく分子形態も考慮する必要がある。