Various supplements containing potassium citrate (KCit) and potassium chloride (KCl) are currently available and the overdose of these supplements is expected to cause health problems. Because KCit but not KCl is known as an alkalinizing salt, the effects of high intake may be different between KCit and KCl. Some studies have suggested that dietary citrate affects zinc metabolism, in which the action of citrate is not consistent. In this study, growing rats were given a feed supplemented with KCit or KCl, as dietary potassium (K) content was five-fold more than its requirement, for four weeks. The growth and the femoral zinc concentration were examined. Both K salts did not affect plasma K concentration and feed intake, but reduced feed efficiency and weight gain. Further, feed efficiency and weight gain were not different between the KCit and the KCl groups. Neither K salt affected the relative weight to body weight in the liver, the kidney, the spleen, and the femur. These results suggested that the high intake of both K salts at the level of this study did not disturb K homeostasis but suppressed growth through lowering feed efficiency. Additionally, bone zinc concentration decreased in the KCit group as well as the KCl group, suggesting that K overdose disturbed zinc metabolism, irrespective of its form. Further research is necessary for clarifying the effect of high intake of citric acid and K on zinc metabolism in detail.

Although Zinc (Zn) is an essential element, an excess amount of Zn is known to cause neurotoxic effects. The increased consumption of saturated fats in a westernized high-fat diet contributes to neurodegenerative disease and senile dementia. In our previous study, aged female mice were administered 0, 200, or 500 ppm Zn in drinking water for 30 weeks and subjected to Y-maze, novel object recognition, and step-through passive avoidance tests. Thirty-week exposure to Zn did not inhibit learning and memory in the Y-maze test, but was found to inhibit learning and memory in the novel object recognition and step-through passive avoidance tests in a dose-dependent manner. These results suggested that administration of excess Zn impaired long-term memory and object recognition memory in aged mice. As such, we studied whether a high-fat diet influences learning and memory deficits caused by chronic exposure to Zn in aged mice. The results of novel object recognition, step-through passive avoidance, and fear conditioning tests showed that high-fat diet feeding inhibited learning and memory in the step-through passive avoidance and fear conditioning tests but improved learning and memory in the novel object recognition test.

The use of health foods and supplements has been on the rise in recent years as people become more health conscious in their daily lives. According to previously research, excessive intake of polyphenols in late pregnancy may cause heart failure or persistent pulmonary hypertension in the newborn due to premature closure of the ductus arteriosus of the fetus. This study surveyed 109 pregnant women regarding the intake of polyphenols. On being asked if they knew about polyphenol foods, 71% of the respondents provided an affirmative answer. Atotal of 38% of the respondents said that they had learned about polyphenol foods through commercials and advertisements, while 20% learned about such products by seeing them at stores. Regarding the effects of polyphenols, 39%said that they were good for the body, while 18% said that they were useful inmaintaining health. Many of those who consumed polyphenols did so by consuming rooibos tea or black tea.

Registered dietitians may have the opportunity to provide pregnant females with important information about folic acid. Registered dietitian course students are expected to learn important information about folic acid. We provided lectures and administered questionnaire surveys to investigate the knowledge of folic acid, which reduces the risk of neural tube defects, and the intake of folic acid in the diet by registered dietitian course students. Among female registered dietitian course students, 564 provided effective responses. The folic acid intake of students with knowledge of folic acid (N = 448, 233.9 ± 73.5 µg/day) was significantly higher (p < 0.05) than that of students without (N = 116, 210.0 ± 58.2 µg/day). Similarly, the intake of green and yellow vegetables significantly differed (p < 0.05) between students with knowledge of folic acid (N = 448, 66.6 ± 43.4 g/day) and those without (N = 116, 55.4 ± 33.9 g/day). It was clarified that conscious promotion of the intake of green and yellow vegetables promotes the intake of folic acid. However, at the time of the survey, most of the students who responded were not considered to have responded in consideration of pregnancy, suggesting that they may not consciously ingest folic acid even if they have knowledge of it.

Sprouts of common beans, mung beans, and azuki beans were cultivated in an environment exposed to selenite at a level of 1, 5, 10 or 20 µg Se/mL, and the molecular species of selenium produced were analyzed by high performance liquid chromatography with inductively coupled plasma mass spectrometry. Selenohomolanthionine (SeHL), Se-methylselenocysteine (MSeC), and selenomethionine (SeM) were identified in the sprout of all beans at 20 µg Se/mL exposure. The amount ratio of the three selenoamino acids was about 1/1/0.5 for SeHL/MSeC/SeM in common beans, but SeHL accounted for most of the selenium molecular species in mung beans and azuki beans. When the exposure concentration was 10 µg Se/mL or less, the amount ratio was the same as in the case of 20 µg Se/mL in common beans and azuki beans, but in mung bean, an amount of MSeC was close to that of SeHL. These results indicate that SeHL is the major selenium metabolite in sprouts of common beans, mung beans, and adzuki beans exposed to selenite, and that these bean sprouts have a low ability to methylate selenol.

Prooxidant properties of uric acid and xanthurenic acid as quinoline compound were analyzed. Production of reactive oxygen species was evidenced by the inactivation of aconitase, the most sensitive enzyme to oxidative stress in permeabilized yeast cells. Uric acid and xanthurenic acid produced reactive oxygen species in the presence of iron (ferrous) ion. The inactivation required sodium azide the inhibitor of catalase and KCN the inhibitor of Cu, Zn-SOD and cytochrome c oxidase, suggesting that the superoxide radical produced from these compounds/transition metal complex is responsible for the inactivation of aconitase. Uric acid showed a potent reducing activity of copper (cupric) ion, and further scavenging activity of DPPH radical, and xanthurenic acid showed reducing activity lower than uric acid. Uric acid and xanthurenic acid may produce periferryl ion and causing continuous generation superoxide anion by redox cycling. Toxicity of these compounds may be related to their prooxidant activities.

Hijiki seaweed (Sargassum fusiforme) is regarded as iron source in Japan, although that hijiki seaweed contains excessive amounts of inorganic arsenic. The PTWI of inorganic arsenic once established by the WHO had been withdrawn, because the JECFA concluded that the current PTWI for inorganic arsenic was no longer health protective. We have reported how many baby food products containing hijiki seaweed are on the market in Japan in the previously report. The 24 baby food items were found to contain hijiki seaweed in the 560 baby food products (4.3 %). In this study we aimed to measure amounts of hijiki seaweed in 10 baby food products. The highest hijiki content was 3.8 g/ individual package, and the smallest was 0.4 g/ individual package. The average hijiki content in 10 items was 1.5 g/ individual package, and the median was 0.9 g/ individual package. It is necessary to pay attention to use of hijiki seaweed for babies and toddlers.

Biotin in foods is generally measured by a microbiological method using Lactobacillus plantarum (ATCC 8014). This bacterium responds not only to biotin but also to biotin d- and l-sulfoxides, which have no effect as biotin in rats. Since these analogs influence measured values, biotin and its analogs in foods were fractionated by column chromatography. Then, the proportion of growth activity of L. plantarum responding to these biotin compounds was examined. The results show that in mushrooms, the proportion of a compound presumed to be biotin d-, l-sulfoxides, or both was relatively high compared with egg yolk, chicken liver, and broccoli. This indicates that the biotin content in mushrooms may be overestimated when determined by L. plantarum.

To confirm the effect of black tea on manganese intake, the extraction of manganese from black tea leaves to the tea infusion was examined. Thirty-one tea leaf samples (black tea, 22; flavored black tea, 5; Chinese Puar tea, 1; Louis Bosti, 2; herbal tea, 1) were collected. An infusion was prepared by adding 160 mL of boiling water to each 3 g of leaf sample and allowing it to stand for 3 minutes. The manganese concentration of tea leaves was measured by fluorescent X-ray analysis, and that in tea infusion was measured using an atomic absorption spectrophotometer. The manganese concentration of 28 samples using leaves of Camellia sinensis was 684 (257 to 2259) µg/g, which was significantly higher than that of 84 (58 to 131) µg/g for Louis Bosti or herbal tea without leaves of Camellia sinensis. The manganese concentration in the infusion of 28 samples was 1.64 (0.34 to 6.74) µg/mL, and a significant correlation (R² = 0.75) was observed with the concentration in tea leaves. The manganese extraction rate of 28 samples into the infusion was 12.4 ± 4.8 %. Comparing the extraction rates for each shape of black tea leaves, the values of the tea leaves that were cut and crushed by a machine and then shaped into a round shape were significantly higher than those of needle-shaped elongated large leaves or finely cut leaves. Since it is calculated that nearly 1 mg of manganese can be ingested by drinking 3 teacups of black tea infusion, habitual drinking of black tea is a factor that significantly increases manganese intake.

To clarify the role of biotin in palatal development, we investigated the effects of biotin supplementation to pregnant dams on the development of palatal processes in biotin-deficient fetal mice. Pregnant mice were administered either a biotin-deficient diet or biotin-supplemented (control) diet from day 0 of gestation (dg 0). Several mice in the biotin-deficient group were administered biotin intraperitoneally at 0900 on dg 10. After biotin administration, they were fed the biotin-supplemented diet during day 10-12, 10-13 or 10-14 of gestation, and then switched to a biotin-deficient diet until dg 15. The incidence of cleft palate was 63.6 % in the biotin-deficient group, whereas no cleft palate was noted in the other groups. This suggested that biotin is necessary for palatal development in the initial stage of palatogenesis.

Nutritional zinc deficiency leads to immune dysfunction. In our previous study, we found that the number of T-helper 2 (Th2) cells in the spleen of zinc-deficient rats was reduced, and this change was improved by interleukin (IL)-4 administration and zinc supplementation. In this study, the effects of zinc deficiency on other effector T cells (Th1, Th17, and regulatory T cells) in the spleen of rats were investigated. In addition, the effects of IL-4 administration and zinc supplementation of zinc-deficient rats were determined. Five-week-old male Sprague-Dawley rats were fed a standard or zinc-deficient diet (n = 7 each) with saline or IL-4 treatment, or a zinc-deficient diet for 6 weeks, followed by a standard diet for 4 weeks. The numbers of interferon-gamma⁺ CD4⁺, CD161⁺ CD3^－, IL-17⁺ CD4⁺, and IL-17⁺ cells in the spleen of zinc-deficient rats were significantly increased compared to those in the other groups. However, the numbers of viable, IL-10⁺, and FoxP3⁺ CD4⁺ cells, determined using the Viobility 405/452 Fixable Dye, in the spleen were comparable in all groups. In conclusion, spleen cells in zinc-deficient rats were induced to differentiate into Th1 and Th17 cells associated with the inflammatory response. IL-4 administration or zinc supplementation of zinc-deficient rats reduced the numbers of Th1 and Th17 cells, which are inflammation-related factors.

Although several complexes of thiamine and inorganic compounds had been reported in several literatures, the thiamine-sodium compounds have not been identified as yet. While conducting studies for the purpose of synthesizing thiamine-calcium-phosphorus compounds, we found a method for synthesizing thiamine-sodium precipitate in the trial processes. Based on the findings of elemental analysis, FT-IR analysis, and HPLC and TLC analysis, the formation of the thiamine-sodium complex was firmly confirmed.

Insufficient intake of vitamins and minerals during pregnancy and lactation has been reported. However, it has also been reported that there are deficiencies in these nutrients before pregnancy, and it is not easy to increase their intake when the pregnancy is confirmed. Therefore, the intake of these nutrients by pre-pregnant women and the motives that affect their dietary behavior of thinking about health were determined, and the approach for future guidance was examined.
An exploratory factor analysis was conducted by surveying folic acid, calcium, and iron intakes through a dietary record survey of 53 pre-pregnant women and by the Motivation for Healthy Eating Scale, and their relevance was examined.
The results of the survey on motivation for a healthy diet identified four factors, happiness, comfort, pressure/stress, and pessimism, in descending order of autonomy.
The contribution rates of folic acid and calcium to the top foods are 32.6 % for vegetables and 29.8 % for milk and dairy products, respectively, both of which were typical foods containing folic acid and calcium, and the items of comfort and happiness were high.
In the case of iron, the highest contribution rate is grains at 25.6%. However, grains are inconsistent with foods containing a large amount of iron, and the pressure/stress was high for intake. Therefore, to increase iron intake, it was considered necessary to provide support, such as the introduction of multiple practical menus and then that increase satisfaction, rather than introducing foods with a high iron content.

Akamoku (Sargassum horneri) is a popular seaweed product in Japan but has a high arsenic content. We investigated arsenic accumulations in various organs of rats fed Akamoku. Sprague-Dawley male rats, 5 weeks old, were fed three kinds of diets for 2 weeks : pre-treated Akamoku diet, non-treated Akamoku diet, and control diet. Arsenic distributions in several organs were determined by atomic absorption spectrophotometry. The pre-treated Akamoku samples were prepared by washing in water, soaking in a boiling saline solution for 1 minute, and then washing with cold water. The samples were then lyophilized and pulverized. After this pre-treatment process, the ratio of the arsenic content retained in the pre-treated Akamoku samples to that in the non-treated Akamoku samples was 0.35. The non-treated samples were washed with water, lyophilized and pulverized. The pre-treated Akamoku diet group showed less accumulation of arsenic in the all organs examined in comparison with those of the non-treated Akamoku diet group. The degree of arsenic accumulation could be classified into three groups : in the spleen, heart and femur, the ratio was approximately 0.35, but in the liver, kidney and testis, the ratios were higher while in the lung and muscle, they were lower. This may be related to the different states of arsenic present in the Akamoku plant.

Magnesium deficiency (MgD) and psychological stress are suggested to be common risk factors for some diseases such as hypertension, type 2 diabetes, and depression. However, effects of the combination have remained unclear. In the present study, we investigated effects of the combination of MgD and repeated-restraint stress, as a psychological stressor, on excretion of urinary metabolites by gas chromatography-triple quadrupole mass spectrometry-based metabolomic analysis. Sixty-six excreted urinary metabolites were affected by MgD and/or repeated-restraint stress. The combination of MgD and repeated-restraint stress affects the excretion of pantothenic acid, kynurenic acid, 3-Hydroxy-3-methylglutaric acid and so on. These metabolites could reflect on nutritional and/or physiological conditions and thus may be useful to understand effects of the combination on the body. These results suggest that more detailed studies focusing on the metabolites observed in the present study will be required to clarify the relationship among Mg deficiency, psychological stress, and related diseases.

Application of gamma distribution to arithmetic of iron losses of women and population data analysis for requirements are discussed. In factorial analysis for iron requirements in women, the sum of basal iron losses and menstrual iron losses is crucial. Because menstrual iron losses are skewed to the right, the sum of these losses is not a simple matter. The shifted lognormal distribution, convolution, and Monte Carlo simulation were applied for this problem. The use of gamma distribution makes this problem simpler. Gamma approximation by Stewart enables simple calculation of the sum of gamma random variables including basal iron losses and menstrual iron losses. The use of gamma distribution enables simple calculation of population data analysis for requirements also. In addition, the basic characteristics of gamma distribution are summarized to help understanding of this new knowledge in nutritional sciences.

Zinc is an essential trace element. It has physiological functions in proteins and is a structural, catalytic, and signaling component within them. As it has a wide range of functions, zinc deficiency causes various symptoms, such as taste disorders, dermatitis, hair loss, decreased appetite, growth disorders, gonad dysfunction, and more. About 25 % of the world’s population is estimated to be at risk of zinc deficiency, which is common in Japan. Thus, its prevention is very important for human health. Here, we briefly review zinc in food items and the mechanism of dietary zinc absorption, focusing on the zinc transporters involved. Moreover, we discuss the possibility that dietary components may increase the efficiency of zinc absorption through zinc transporters.