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Featured researches published by Akiko Tamura.


Bioscience, Biotechnology, and Biochemistry | 2007

Ingestion of Difructose Anhydride III Enhances Absorption and Retention of Calcium in Healthy Men

Kyoko Tomita; Takuya Shiomi; Yasuhide Okuhara; Akiko Tamura; Norihiro Shigematsu; Hiroshi Hara

We examined the effects of a nondigestible disaccharide difructose anhydride III (DFAIII) on calcium absorption and retention by means of a human balance study of single-blind crossover design. Twelve healthy male subjects ingested 250 mg of shell powder as calcium carbonate (corresponding to 100 mg of calcium) with or without 1.0 g DFAIII three times a day for 13 d. In the last 4 d as a balance period, all urine and feces were collected and evaluated for calcium excretion. The apparent calcium absorption (mg/d) and rate of absorption (%) were higher, and those of retention were much higher, in the DFAIII group than in the control group. Furthermore, serum osteocalcin increased after the experimental period in the DFAIII group but not in the control group. These results indicate that DFAIII ingestion enhances intestinal calcium absorption, which might be beneficial for bone metabolism.


Bioscience, Biotechnology, and Biochemistry | 2004

Comparative effect of repeated ingestion of difructose anhydride III and palatinose on the induction of gastrointestinal symptoms in humans.

Akiko Tamura; Takuya Shiomi; Noriko Tamaki; Norihiro Shigematsu; Fusao Tomita; Hiroshi Hara

We evaluated the safety and change in fermentability from repeated ingestion of difructose anhydride III (DFAIII) in humans. A randomized controlled single-blind crossover study with thirteen subjects was conducted. Each subject ingested 5 g of DFAIII or palatinose daily for 12 days, before and after which the subject was loaded with 10 g of DFAIII and had breath hydrogen measured from 0 to 9 h (DL test) to evaluate the fermentability of DFAIII. The defecation frequency and abdominal symptom score were the same between each ingestion period. Moreover, DFAIII ingestion had no influence on blood test results. Only the breath hydrogen excretion in post-DFAIII ingestion was slightly higher at h 8 than the pre-ingestion. Consequently, repeated ingestion of DFAIII for 12 days was as safe as palatinose ingestion, especially with respect to abdominal symptoms and blood test results, and its high resistance to enterobacterial fermentation in humans was not impaired.


Clinical Nutrition | 2008

Low activities of intestinal lactase suppress the early phase absorption of soy isoflavones in Japanese adults.

Akiko Tamura; Takuya Shiomi; Sachiko Hachiya; Norihiro Shigematsu; Hiroshi Hara

BACKGROUND & AIMS The contribution of lactase to isoflavone bioavailability has not been clarified. We evaluated the association between lactase activity and the bioavailability of isoflavone glucosides in Japanese adults. METHODS Twenty-six Japanese adult participants completed a study that included tests of breath hydrogen after a lactose load, orocecal transit time, and isoflavone glucoside absorption. Lactose malabsorbers were defined as those with an increase in breath hydrogen level (DeltaH(2)) of more than 20 ppm after a load of lactose (20 g). Participants ingested 200 ml soymilk, and serum isoflavones were analyzed until 480 min. RESULTS Serum daidzein and genistein levels increased rapidly until 60 min, then slowly increased. The increases of serum isoflavones in the early phase, but not the later phase, were suppressed in lactose malabsorbers. DeltaH(2 max) after a load of lactose inversely correlated with serum daidzein levels at 30 min. The percentage of equol producers tended to be greater among lactose malabsorbers (P=0.067). CONCLUSIONS Lactase may be involved in absorption of isoflavone glucosides in the small intestine, but the bacterial deglycosylation in the large intestine compensates the reduction of isoflavone absorption. The beneficial effect of isoflavones may not be impaired by low lactase activity.


British Journal of Nutrition | 2006

Supplementation of difructose anhydride III enhanced elevation of plasma equol concentrations and lowered plasma total cholesterol in isoflavone-fed rats

Akiko Tamura; Megumi Nishimukai; Norihiro Shigematsu; Hiroshi Hara

Equol, a derivative of daidzein produced by enterobacteria, has greater activity as a phyto-oestrogen compared with daidzein. Difructose anhydride III (DFAIII) is a newly manufactured non-digestible disaccharide with unique fermentation properties. The present study evaluated the prebiotic effects of DFAIII on equol production and on plasma cholesterol concentrations related to the changes in equol production. We compared plasma equol concentrations at 10.00 and 18.00 hours and faecal isoflavone excretion in three groups of seven rats (male Wistar-ST strain, 6 weeks old) fed a basal diet or a DFAIII or fructooligosaccharide (15 g/kg diet) diet containing 1 g soya isoflavones/kg diet for 20 d. Equol concentrations in the DFAIII group were higher than in the control and fructooligosaccharides groups, especially in the later phase of the light period (18.00 hours) throughout the experiment. Daizein and genistein concentrations did not change between the diet groups. The faecal ratios of equol:daidzein were very high in all groups, but the ratios were higher in the DFAIII group than the control and fructooligosaccharide groups on day 3, and this tendency continued throughout the experiment. On day 20, the plasma total cholesterol concentration was lowest in the DFAIII group. Additionally, the cholesterol concentrations were inversely correlated to plasma equol concentration in all the rats. In conclusion, DFAIII efficiently enhanced plasma equol concentrations, which may be associated with an increase in equol production and a decrease in equol degradation by enterobacteria. Higher plasma equol concentrations may contribute to the hypocholesterolaemic effect of DFAIII feeding.


Bioscience, Biotechnology, and Biochemistry | 2006

Difructose anhydride III does not contribute to body energy accumulation in rats

Akiko Tamura; Hadzuki Nino; Tomoko Minobe; Violeta Raneva; Norihiro Shigematsu; Hiroshi Hara; Taro Kishida; Kiyoshi Ebihara

We evaluated the body energy accumulation as fat and protein from ingestion of difructose anhydride III (DFAIII). Male Wistar rats were fed 0, 0.25, 0.5, 1.0, or 1.5 g per d of sucrose or DFAIII added to a 7 g of basal diet for 20 d. Supplements of DFAIII did not increase whole body or peripheral fat or total body energy, whereas sucrose increased them in a dose-dependent manner. Dose-dependent increases in body water were observed in both groups. The body protein was influenced by the dose of sugars. The estimated available energy value of DFAIII was 0.263 kcal per gram; this value is one-fifteenth that of sucrose. Ingestion of DFAIII dose-dependently increased the cecal SCFA pool. DFAIII was not detected in feces, showing complete degradation of DFAIII in the intestine. These results indicate that DFAIII is a fermentable saccharide with quite low available energy for fat accumulation.


Archives of Animal Nutrition | 2006

Different effects of difructose anhydride III and inulin-type fructans on caecal microbiota in rats

Akiko Tamura; Yuki Mita; Norihiro Shigematsu; Hiroshi Hara; Naomichi Nishimura

Abstract The effects of different kinds of inulin-type fructans on caecal microbiota were evaluated in rats. Four groups of male Wistar rats were fed either a control diet, or diets containing 5% inulin, 5% fructooligosaccharides (FOS), or 5% difructose anhydride III (DFAIII) for two weeks. In the DFAIII group, caecal propionate, butyrate, counts of bifidobacteria, and total anaerobes were lower than in the inulin group, while caecal propionate, succinate, counts of bifidobacteria, and total anaerobes were lower than in the FOS group. Compared to controls, in the DFAIII group the counts of clostridia in caecum were increased by 3 log units. However, this change was statistically not significant. There were no differences between inulin and FOS groups for the pool of short chain fatty acids in caecum and bacterial counts. Results indicate that DFAIII has different effects on caecal microbiota compared to inulin and FOS and that these differences are most likely due to the α(3→2) bonds in DFAIII.


Journal of Bioscience and Bioengineering | 2004

The effects of di-D-fructofuranose-1,2':2,3'-dianhydride (DFA III) administration on human intestinal microbiota.

Kimiko Minamida; I Nengah Sujaya; Akiko Tamura; Norihiro Shigematsu; Teruo Sone; Atsushi Yokota; Kozo Asano; Yoshimi Benno; Fusao Tomita


Archive | 1993

Mineral absorption promoting composition

Yasuhide Okuhara; Norihiro Shigematsu; Takuya Shiomi; Akiko Tamura; Fusao Tomita; Kiyouko Tomita; 房男 冨田; 卓也 塩見; 響子 富田; 亜紀子 田村; 典宏 重松


Archive | 2003

Difructose anhydride-containing composition and use thereof

Takuya Shiomi; Yasuhide Okuhara; Akiko Tamura; Kyoko Tomita; Norihiro Shigematsu; Hiroto Kikuchi; Tsutomu Aritsuka; Fusao Tomita


Journal of Nutritional Science and Vitaminology | 2003

Evidence Suggesting That Difructose Anhydride III Is an Indigestible and Low Fermentable Sugar during the Early Stages after Ingestion in Humans

Akiko Tamura; Takuya Shiomi; Norihiro Shigematsu; Fusao Tomita; Hiroshi Hara

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