We have developed “Nutrition Delivery System (NDS)” using emulsion technology to deliver minerals, vitamins and other nutrients in a certain place under a certain condition. Using NDS, it has become possible to fortify foods with nutrients having merits of stability, taste, safety and bioavailability.

For example, many iron sources that exhibit the best bioavailability adversely affect food quality by accelerating lipid oxidation or by producing an unfavorable color or flavor. Compatible and nonreactive iron compounds are needed for fortification of foods because it has less of an “iron taste” compared to soluble iron. However, due to its insolubility precipitation of the iron prevents fortification in large amounts.

We prepared a superdispersed Fe (SDFe:SunActive Fe™) ferric pyrophosphate, which disperses insoluble iron in liquid formulations and produces no precipitation. SDFe masks disagreeable flavor of iron without affecting the flavor of the final product.

SDFe is stable under the condition of heating and high salt concentration. The particle size of SDFe measured was found to show a sharp distribution size (average 0.5 μm), which is several folds smaller than ferric pyrophosphate.

SD male rats were orally administrated with various iron sources at 2 mg/kg as iron per body weight. Total amount of the concentration of the serum iron after 8 -12 h was 909 μg/dI in the control (water) group, 1573 μg/dl in ferric pyrophosphate group, 2001 μg/dl in ferrous sulfate group, 2108 μg/dl in sodium ferrous citrate group, 2294 μg/dl in heme iron group and 2839 μg/dl in SDFe group. Hemoglobin Regeneration Efficiency and Relative Biological Values were the highest with diets containing SDFe as compared to other iron sources. SDFe did not show any toxic effect on the gastrointestinal system as compared to other iron sources.

Many iron fortified products like milk, yogurt, and beverages including sports drinks have been launched in Japanese market and abroad. Similar formulations have been prepared of calcium and magnesium salts, vitamins and polyunsaturated fatty acids.

Vanadium with insulinomimetic action exists as vanadyl and vanadate species in nature. Recently, vanadyl sulfate (VOSO₄) and sodium vanadate (NaVO₃) have been examined clinically to find whether they improve human diabetes mellitus (DM). In 2001, it was reported that DM has been improved by the treatment of VOSO₄, in which plasma vanadium level during VS treatment was found to correlate with insulinomimetic activity. Therefore, we studied the absorption processes of VOSO₄ and Na VO₃ with respect to total vanadium as well as vanadyl levels in the blood by using electron spin resonance (ESR). Four blood concentration curves for the two compounds exhibited two absorption maxima, indicating that more than two absorption sites of ionic vanadium compounds exist in the gastrointestine. Bioavailability of NaVO₃ was higher than that of VOSO₄, indicating vanadyl is less toxic than vanadate.

Three NifS-like proteins, IscS, CSD, and CsdB, from Escherichia coli catalyze the removal of sulfur and selenium from L-cysteine and L-selenocysteine, respectively, to form L-alanine. These enzymes are proposed to deliver a sulfur atom for iron-sulfur cluster, thiamin, 4-thiouridine, biotin, and molybdopterin. It was reported that selenium mobilized from free selenocysteine is incorporated specifically into a selenoprotein and tRNA in vivo, supporting the involvement of the NifS-like proteins in selenium metabolism. We here report evidence that a strain lacking IscS is incapable of synthesizing mnm⁵se²U and its precursor mnm⁵s²U in tRNA, suggesting that the sulfur atom released from L-cysteine by the action of IscS is incorporated into mnm⁵s²U. The lack of IscS also caused a significant loss of the selenium-containing formate dehydrogenase H. Together, these results suggest a dual function of IscS in sulfur and selenium metabolism.

Iron (Fe), an important essential trace element, causes oxidative stress in excess. Aluminum (Al), one of the most abundant elements in nature, also impairs plant growth. Al is recently suspected to cause degenerative nerve diseases in mammals. Al has been reported to enhance Fe-induced oxidative injuries in mammals. The present study was undertaken to assess whether similar adverse effect would be observed in the unicellular algae and protist, Euglena gracilis Z. The effect of single or combined exposure of Fe and Al from 0 to 5.0 mM on cell growth was examined. In comparison to the growth of E. gracilis in the Koren-Hutner medium [KH] containing 0.16 mM Fe²⁺ as the control, that in the KH without Fe was ca 25% less than the control. Addition of Fe²⁺ from 0.31 to 5.0 mM inhibited the cell growth dose dependently. Meanwhile, single addition of Al³⁺ from 0 to 5.0 mM also suppressed the growth above 0.16 mM, however, it was not dose dependent. Moreover, complex addition of Al³⁺ and Fe²⁺ from 0.16 to 5.0 mM for each element increased suppression of the cell growth than Fe and alone. Possible reasons for growth suppression by Fe and Al are discussed.

Animals and plants differently respond to inorganic arsenite. In the present study, the authors examined the toxicity of sodium arsenite on the growth of an algae Euglena gracilis Z and its achlorophyllous mutant SMZ strains. The metabolism of sodium arsenite in Z and SMZ strains was also investigated by HPLC/ICP-MS. Comparing cell growth, Z strain was retarded under 0.25 to 0.5 mM, while the growth of SMZ retarded above lmM indicating difference of cellular response between photosynthetic strain and non-photosynthetic strain. HPLC/ICP-MS analysis identified methyl arsenic acid, dimethyl arsenic acid, and trimethylarsine oxide in both the strains suggesting similar metabolic pathway in Euglena gracilis as reported in higher organisms.

We intended to investigate effects of Hijiki intake on biochemical modification of the arsenic ingested by the human body. The 24 hour-urine was collected either before or after starting the Hijiki diet, and urinary arsenic components were analyzed with an HPLC/ICP-MS instrument. Some differences in the urinary arsenic components were observed between before and after starting the Hijiki diet, but the differences were not the same in each individual, probably owing to different physiological or biochemical conditions.

Organotin compounds have been widely used as antifouling paints for ships. However, once these compounds are released into the aquatic environment, they act as environmental hazards. One of the well-known effects of organotin compounds is the endocrine-disrupting activity on marine snails. Tributyltin chloride (TBTC) has been shown to induce imposex in female gastropods, producing male genitals to female ones. However, the effects of organotin compounds on the reproduction of mammal are largely unknown. Here we demonstrate the toxicity of TBTC on mammalian reproduction. Histopatholotical examination of testes of rats treated with TBTC showed the loss of interstitial tissue. Histochemical staining showed the accumulation of organotin in the interstitial tissue. As there are leydig cells responsible for the production of androgens in the interstitial tissue, we examined the concentration of testosterone in the blood. The concentration of testosterone was decreased significantly by the TBTC administration. These results indicate that TBTC can act as toxicant to the mammalian reproduction system by damaging the leydig cells in the interstitial tissue and by which disturbing the production of testosterone.

Tributyltin chloride (TBTCl) has been widely used as marine anti-fouling and caused serious toxicity to organisms. In this study, effects of low concentration TBTCl exposure to Euglena gracilis Z and SMZ, particularly, on cell growth and DNA strand were examined. The inhibition of cell growth for 3 days exposure to TBTCl was observed dose dependently from 1 to 4 μM in both the strains. Comet assay showed DNA strand breaks at lμM TBTCl exposure in both the strains. These results suggest that micro-molar TBTCl exposure inhibited cell growth and induced DNA breaks to E. gracilis Z and SMZ.

We have already obtained zinc-rich fraction (ZRF) from boiled oyster by extraction with 0.1 N HCl followed by neutralization and heating (patent No. 3267962 ). In the present study, to evaluate a nutritional availability of the ZRF, several characteristics of the ZRF were investigated. An insolubilization of zinc in the 0.1 N HCl-extract of boiled oyster was promoted with an elevation of pH. In particular, a rapid insolubilization was observed at pH 6.5 to 7.5 independently to the insolubilization of ninhydrin positive substances. This indicates that zinc recovered into the ZRF by the neutralization is mostly present as zinc hydroxide. Zinc in the ZRF was more soluble in solutions containing citrate or casamino acids than zinc as a form of zinc carbonate. Zinc in the ZRF could be solubilized by digest of protein or organic acids in a digestive tract; intestinal absorption of zinc in the ZRF may be higher than that of zinc carbonate.

Recent increase of ultraviolet (UV) lights owing to the increase of ozone hole may induce enhancement of the skin damage in all living systems on the earth. The harmful effects of UV exposure on the skin are supposed to associate with the generation of reactive oxygen species (ROS), however, no direct proof of ROS production in the skin under UV exposure was established. Recently, we reported first the in vivo detection and imaging of ROS generation in the skin of live hairless animals following UV A exposure, using both the sensitive chemiluminescent probe (CLA) and the ultralow-light imaging apparatus with a CCD camera. It was proposed that ・O₂^- is formed spontaneously and ¹O₂ is generated by UV A exposure in the skin of live mice. The method was applied to find suppressive agents against skin damage by UV A exposure. The topical application of zinc(II) chloride suppressed the ROS generation induced by UV A exposure even after the removal of Zn(II) from the skin. The mechanism for suppression of skin damage by Zn(II) is now under investigation.

The high incidence of iron deficiency in developing countries is attributed to the bioavailability of iron derived from staple food. Iron fortification has been implemented to improve iron deficiency in many countries. Sodium iron ethylenediaminetetraacetic acid (NaFeEDTA), a metal chelator, is one of the food additives for iron fortification. On the other hand, it is possible that EDTA may bind to metals and influence their absorption because of its chelating property. Thus, to investigate the effects of NaFeEDTA and ferrous sulfate on the absorption of trace elements, we determined the uptake of trace elements in rats everted intestinal segments. The result suggests that NaFeEDTA is increased the intestinal absorption of iron, zinc and cobalt, and less affected by tannic acid on the absorption of these elements.

Antiserum against gly-L-his-L-lys (GHK)-Cu²⁺ complex has been generated using BSA-GHK-Cu²⁺ conjugate as an immunogen, and an EIA for the determination of GHK -Cu²⁺ has been developed. The standard curve allows the determination of 8×10^-7M to 1×10^-5 M of GHK-Cu²⁺. The EIA method was applied to the determination of GHK-Cu²⁺ spiked in rat plasma. Recoveries from o-phenanthroline treated rat plasma were satisfactory whereas they from untreated rat plasma were low. The antiserum can bind to not only GHK-Cu²⁺ but also GHK, though the affinity is higher for the former than for the latter.

Folate deficiency has recently drawn attention as a risk factor that causes fetal malformation. We conducted a dietary survey using a measuring method on female students to investigate the state of nutrient intake, and folate intake in particular. The female students had a low energy intake of 1,550 ± 450 kcal, which accounted for 86% of the dietary energy allowance for women in their twenties. The female students' intakes of many vitamins and minerals were also much lower than the respective dietary allowances. Their intakes of protein and lipid accounted for 97% and 114% of the dietary allowances, respectively. The rates of meeting the intake targets classified by food group for men and women in their twenties were low for many food groups. However, the mean folate intake was 223 土 105 μg, accounting for 112 % of the dietary folate allowance in women in their twenties. This finding indicated that a dietary folate allowance of 200 μg for women in their twenties could be consumed from the ordinary diet practically taken by the female students. The former Ministry of Health and Welfare recommended that pregnant women took 400 μg folate from meals and 400 μg from nutrition supplementary food during before one month and the third month of pregnancy to reduce the risk of developing fetal neural tube defects. It has been reported, however, that few women in the fertile age take nutrition supplementary food. Therefore, we analyzed the food dietary constitution that allowed folate intake of 400 μg or 800 μg from diet. It was demonstrated that consumption of 200 g of green vegetables and 200 g of other vegetables allowed folate intake of 400 μg, and that consumption of 450 g of green vegetables and 200 g of other vegetables with green tea as something to drink allowed a folate intake of 800 μg just from the diet.

The change of free-amino acid and mineral contents during the maturation of Murasakizukin, immature black soybean (Glvcine Max Merrill.Forma Kuromame Makino) were examined.

The contents of free-amino acids, especially asparagine, γ-Aminobutyric acid (GABA), glutamic acid and alanine, were high in the early stage of maturation, but they decreased according with to maturation. The GABA content of the early stage of Murasakizukin. was 15 times high, comparing with that of yellow soybean. Mineral contents were increased according with to maturation. Especially magnesium content (mean content of all stages of maturation) was 4 times high in Murasakizukin compared with that of yellow soybean.

In the view points as functional foods, the best seasοn of Murasakizukin were thought to be the early stage of maturation.

Vitamin B6 deficiency increases the lipid peroxidation and the synthesis of xanthurenic acid from tryptophan. Antioxidant properties of xanthurenic acid were examined in relation to the coordination of transition metals. Xanthurenic acid inhibited the formation of thiobarbituric acid-reactive substances as a marker of iron-mediated lipid peroxidation, and copper-dependent oxidation of low density lipoprotein. NADP-isocitrate dehydrogenase and malic enzyme, principal NADPH-generating enzymes for antioxidant defense system, was inactivated by reduced iron, and xanthurenic acid protected the enzyme from this inactivation. Xanthurenic acid may participate in the enhanced regeneration of reduced glutathione by stimulating NADPH supply. Xanthurenic acid further enhanced the autooxidation of Fe²⁺ ion. Other tryptophan metabolites such as kynurenic acid and quinaldic acid did not inhibit the lipid peroxidation and the inactivation of NADP-isocitrate dehydrogenase, and showed little or no effect on the Fe²⁺ autooxidation. Antioxidant properties of xanthurenic acid are related to the metal-chelating activity and probably to the enhanced oxidation of reduced transition metals as prooxidant.

The overexpression systems of Cytophag a alcohol dehydrogenase and aldehyde dehydrogenase in Escherichia coli were constructed, and both enzymes were purified to homogeneity. The alcohol dehydrogenase contained 2 g-atoms of zinc per subunit, but the aldehyde dehydrogenase was independent of any metals. Both enzymes showed low substrate specificities. They showed thermostability, although were produced by a psychrophilic bacterium: the half-life times of Cytophag a alcohol dehydrogenase and aldehyde dehydrogenase were over 200 and 65 min at 50°C, respectively. The Km value of Cytophag a alcohol dehydrogenase is 40-50 times lower than that of the Saccharomyces enzyme, and the kcat/Km value of the Cytophag a enzyme is much higher than that of the Saccharomyces enzyme. Ethanol was determined with about 175 times less Cytophag a alcohol dehydrogenase than the Saccharomyces enzyme. The addition of Cytophag a aldehyde dehydrogenase led to an increase in sensibility.