Journal of nutritional science and vitaminology最新文献

With the western influence in our diets, food consumption has changed, and our magnesium (Mg) intake is no longer optimal. Serum Mg (S-Mg) level is currently used as an indicator of Mg deficiency and is strictly regulated via compensatory mechanisms. It is believed that a 24-h urine collection can be used to evaluate potential Mg deficiency. This study aimed to assess whether Mg deficiency state as found in urine Mg (U-Mg) excretion and improving such deficiency with a diet that meets the Recommended Dietary Allowances (RDAs) of Mg for 15 d. Healthy Japanese women were recruited for Study 1 (n=22) and Study 2 (n=10). Study 1 was 1-d balance test, where fasting blood and 24-h urine samples were collected. Study 2 was 15-d diet load test, where fasting blood (days 1, 7, and 15) and 24-h urine (odd days) were collected. All test meals were made certain to have met the RDA for Mg for women in their 20s. In Studies 1 and 2, S-Mg was within the normal range. In Study 1, U-Mg excretion was 67.7±17.0 mg/d, with a large dispersion. In Study 2, U-Mg excretion on days 7 and 15 was significantly higher than on day 1, but have no significant differences in U-Mg excretion between days 7-15. U-Mg excretion can be a valuable indicator to evaluate Mg state. In young women, improvements in Mg deficient state were observed after 7-15 d of taking meals that met the RDAs of Mg.

Senile cataract has become the leading cause of visual impairment and even blindness in the world, but there are few reports on its relationship with methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms. This study is aimed to investigate the correlation between MTHFR gene polymorphisms or its enzyme metabolites and senile cataract. From January 2019 to June 2020, 663 patients with senile cataract at the Mianyang Central Hospital were enrolled as the observation group, and 646 healthy subjects were randomly selected as the control group. MTHFR gene polymorphisms (i.e., CC, CT, or TT genotypes) and serum homocysteine (HCY), folic acid (FOL), vitamin B₁₂ (VitB₁₂), and vitamin B₆ (VitB₆) levels were detected. The mutation rate of MTHFR C677T and HCY levels in the observation group were significantly higher than those in the control group, whereas FOL, VitB₁₂, and VitB₆ were significantly lower. With an increase in the MTHFR C677T mutation, HCY showed an upward trend, whereas FOL and VitB₁₂ showed a decreasing trend in both the observation and control groups. Multiple logistic regression analysis showed that HCY and FOL were associated with senile cataract and MTHFR mutations; VitB₁₂ was only associated with senile cataract. Compared to that with the CC genotype, CT and TT genotypes were associated with an increased senile cataract risk. Monitoring MTHFR gene polymorphisms and changes in serum HCY, FOL, and VitB₁₂ levels could provide references in predicting senile cataract.

Luteolin (LU), a natural compound, has diverse bioactivities; it alleviates lipid accumulation by enhancing the oxidation of fatty acids in nonalcoholic fatty liver disease (NAFLD). Mitochondrial dysfunction promotes the development of steatosis in NAFLD. However, few studies have focused on the mechanism by which LU affects mitochondrial function in NAFLD. In the present study, we investigated whether LU could ameliorate hepatic steatosis and affect mitochondrial function in Western diet-fed mice. After LU treatment, the indicators of hepatic function and markers of mitochondrial biogenesis were evaluated. The results showed that LU intervention 1) decreased the levels of serum triglyceride, total cholesterol, alanine aminotransferase, and low-density lipoprotein cholesterol; 2) increased the succinate dehydrogenase activity of mitochondrial enzyme; and 3) increased mitochondrial biogenesis by upregulating the AMPK/PGC-1α pathway. Therefore, LU might have the potential to prevent NAFLD.

Ferulic acid (FA) is the most abundant phenolic acid in wheat grains. Recent studies have reported that FA intake significantly suppresses body weight gain and accumulation of fat deposits in mice. However, the mechanism by which FA intake affects body fat accumulation remains unclear. We hypothesized that dietary FA induces the formation of beige adipocytes and contributes to the suppression of body fat accumulation. In this study, we investigated whether dietary FA significantly induces beige adipocyte formation and thermogenesis in mice. We found that intake of dietary FA (control diet supplemented with 10 g of FA/kg diet) for 4 wk significantly decreased white adipose tissue (WAT) deposits and body weight gain and significantly induced beige adipocyte formation in inguinal WAT (iWAT) in mice. Furthermore, dietary FA specifically induced thermogenesis in iWAT, dependent upon the significant induction of uncoupling protein 1 expression. These findings suggest that the dietary FA-mediated reduction of WAT accumulation and body weight gain is associated with the induction of beige adipocyte formation and thermogenesis in iWAT, which increases energy expenditure. Our study presents a novel example of dietary FA intake-mediated bioactivity as a functional food-derived factor.

Human serum albumin is categorized into human mercaptalbumin (HMA) and human non-mercaptalbumin (HNA), according to the redox state of the cysteine residue at position 34. The ratio of HMA to total albumin (%HMA) is a novel biomarker of oxidative stress as well as protein nutritional status, but measuring %HMA normally requires an expensive analyzer such as HPLC and LC-MS, and can hardly be conducted in many clinical sites. To address this issue, we aimed to develop a methodological basis for estimating %HMA without these analyzers. An analytical method was investigated consisting of three steps, i.e., 1) removal of HMA from serum or plasma by using a thiol-binding resin (i.e., thereby obtaining a HNA fraction), 2) determination of both total albumin and HNA concentrations by a colorimetric assay or ELISA, and 3) calculation of %HMA. Proof-of-concept experiments, using serum and plasma samples of 4 adult volunteers, showed that the estimated value of %HMA obtained by this analytical method was significantly correlated with the theoretical value of %HMA determined by HPLC. The subsequent validation experiment, using 86 serum samples of pregnant women in the Japanese participants of SMILE Iwamizawa, also confirmed the significant association between the estimated and theoretical values of %HMA. This analytical method can be a basis to determine %HMA without using HPLC or LC-MS, contributing to the universalization of %HMA measurement as a clinical test.

Niacin is involved in many biological reactions relating energy metabolism, redox reactions, DNA repair and longevity, and low NAD levels with aging and feeding high fat diets develop and progress age-related diseases. Although recent findings suggest the requirement of niacin insufficient animal model to further study, appropriate animal models have not been established yet because niacin is biosynthesized from tryptophan via tryptophan-nicotinamide pathway. To establish model mice to evaluate niacin nutritional status, we used kynurenine 3-monooxygenase knock out (KMO^-/-) mice which lack NAD biosynthesis pathway from tryptophan. To determine the niacin requirement and assess niacin nutritional markers, 4 wk old KMO^-/- mice were fed 2-30 mg/kg nicotinic acid containing diets for 28 d. More than 4 mg/kg but not less than 3 mg/kg nicotinic acid containing diets induced maximum growth, and niacin nutritional markers in the blood, liver and urine increased with increase of dietary nicotinic acid. These results showed that several niacin nutritional markers reflect niacin nutritional status, niacin nutritional status can be controlled by dietary nicotinic acid, and niacin requirement for maximum growth is 4 mg/kg nicotinic acid diets in the KMO^-/- mice. This animal model useful to investigate pathophysiology and mechanism of niacin deficiency, clarify the relationships between niacin nutritional status and age-related and lifestyle diseases, and evaluate factors affecting niacin nutritional status.

Zinc (Zn) deficiency is one of the most common nutritional deficiencies worldwide. It is associated with reduced nutritional status and has been reported in cases of growth retardation, alopecia, and decreased serum alkaline phosphatase (ALP). It has also been reported to occur during total parenteral nutrition (TPN) administration and is associated with various diseases, such as liver diseases, diabetes, and kidney disease. We used Zn-deficient mice of ICR and C57BL/6J strains to investigate the various effects of Zn deficiency on the body, assuming that a healthy person may also become deficient in Zn either due to an unbalanced diet or malabsorption. The results showed that a Zn-deficient diet suppressed body weight gain and increased the tissue weight of the kidneys and cecum in both strains of mice. Biochemical data showed no decrease in serum ALP activity in either strain. Furthermore, in C57BL/6J mice, a Zn-deficient diet caused alopecia, loss of villi in the small intestine, and eventually affected the intestinal mucosa, which could be a risk factor for poor nutritional status. Although previous reports have shown that serum ALP activity is decreased during Zn deficiency, this is the first study that used 4-wk-old mice of ICR and C57BL/6J strains to show that serum ALP activity, which is a Zn deficiency marker, did not decrease in the two strains of Zn-deficient mice; furthermore, a Zn-deficient diet causes various symptoms.

Rat Cyp27b1 was successfully expressed in HepG2 cells using an adenovirus vector. High vitamin D 1α-hydroxylation activity was detected in them, whereas no activity was observed in non-infected cells. Similarly, vitamin D 1α-hydroxylation activity was also observed in HepG2 cells expressing Cyp27b1-Flag, which is tagged with a Flag at the C-terminus of Cyp27b1. Western blot analysis using an anti-Flag antibody showed a clear band of Cyp27b1-Flag. Next, we screened three types of anti-Cyp27b1 antibodies, which consist of two commercially available antibodies and our self-made antibody using Cyp27b1- or Cyp27b1-Flag expressing HepG2 cell lysate as a positive control. Surprisingly, Western blot analysis revealed that two commercially available antibodies did not detect Cyp27b1 but specifically detect other proteins. In contrast, our self-made antisera specifically detected Cyp27b1 and Cyp27b1-Flag in the HepG2 cells expressing Cyp27b1 or Cyp27b1-Flag. These commercially available antibodies have been used for the detection of Cyp27b1 by Western blotting and immunohistochemistry. Our results suggest that those data should be reanalyzed.