Mamoru Nishimuta

Natural S-equol decreases bone resorption in postmenopausal, non-equol-producing Japanese women: a pilot randomized, placebo-controlled trial.

Objective: Equol is a metabolite of the isoflavone daidzein and may play a critical role in preventing bone loss by soy isoflavones in postmenopausal women. However, results from clinical trials have not been published. The aim of this study was to investigate the effects of equol on bone metabolism and serum sex and thyroid hormone levels in postmenopausal Japanese women. Methods: We performed a 1-year double-blind, randomized, placebo-controlled trial with natural S-equol supplements for 93 non-equol-producing menopausal Japanese women. Participants were randomly assigned to four groups receiving the following: placebo, 2 mg of equol supplement per day, 6 mg of equol supplement per day, and 10 mg of equol supplement per day. Results: Equol intervention increased equol concentrations in serum and urine in a dose-dependent manner. Urinary deoxypyridinoline was significantly decreased, with a −23.94% change in the group that received 10 mg of equol supplement per day as compared with a −2.87% change in the group that received placebo after 12 months of intervention (P = 0.020). Thus, 10 mg/day of equol supplement markedly inhibited bone resorption. Treatment with 10 mg/day of equol prevented a decrease in bone mineral density in the entire body in postmenopausal women after 12 months. Sex and thyroid hormone concentrations in serum did not differ among the four groups after intervention. Conclusions: These findings suggest that 10 mg/day of natural S-equol supplementation contributes to bone health in non-equol-producing postmenopausal women without adverse effects.

Influence of dental occlusion on physical fitness decline in a healthy Japanese elderly population

The aim of this study was to clarify the relationship between dental occlusion and physical fitness by a longitudinal survey. A sample of 348 subjects (171 men and 177 women) aged 71 was investigated by Eichner index (EI) as an occlusal condition (Class A: no loss; Class B: partial loss; Class C: complete loss) and five types of physical fitness tests and were re-examined 8 years later. The upper 50% were sampled to analyze the correlation between each physical fitness decline and the EI at the baseline by logistic regression models. Logistic regression analyses revealed that leg extensor power (Class B vs. Class A; odds ratio=OR=4.61, p=0.010) and one-leg standing time with eyes open (Class C vs. Class A; OR=4.27, p=0.031) showed significant correlations with the EI at the baseline. In this study, partial or complete loss of occlusion was associated with a decline in leg extensor power or a decrease in one-leg standing time with eyes open. These findings suggest that maintenance of dental occlusion may prevent a decrease in activities of daily living in the elderly.

Physical Function Is Weakly Associated with Angiotensin-Converting Enzyme Gene I/D Polymorphism in Elderly Japanese Subjects

Background: The turning point in the deterioration of physical function seems to occur between the ages of 70 and 80 years. In particular, muscle strength may decline even more in subjects older than 75. A recent study found that the angiotensin-converting enzyme (ACE) genotype also affects physiological left ventricular hypertrophy. A very limited number of papers have examined genetic differences in resistance and endurance forms of a single sporting discipline. Objective: The purpose of this study was to evaluate the relationship between ACE genotype and physical function by controlling the known confounding factors including dental status. Methods:We selected 431 subjects who were aged 76 years and did not require special care for their daily activities. We conducted a medical examination, followed by 5 physical function tests, as follows: (1) maximum hand grip strength, (2) maximal isometric knee extensor strength, (3) maximal stepping rate for 10 s, (4) one-leg standing time with eyes open and (5) 10-meter maximum walking speed. Subjects were genotyped for the ACE intron 16 Alu insertion. In addition, serum concentrations of total cholesterol, total protein, IgA and IgG were measured at a commercial laboratory. The Eichner index was used as an indicator of occlusal condition. Multiple linear regression analysis was performed to evaluate the relationship between the ACE gene insertion/deletion (I/D) polymorphism and physical function considering confounding factors. Results: The ACE gene I/D polymorphism was positively associated with hand grip strength and 10-meter maximum walking speed. Betas of hand grip strength were 0.09 for I/D (p = 0.022) and 0.12 for insertion/insertion (I/I; p = 0.004). Betas of 10-meter walking speed were –0.11 for I/D (p = 0.093) and –0.14 for I/I (p = 0.039). Dental status such as Eichner index class C was significantly associated with one-leg standing time with eyes open (beta –0.11; p = 0.028). Conclusion: This study suggests that there is a significant relationship between ACE genotype and physical function. In particular, subjects with the ACE deletion/deletion genotype were associated with upper extremities.

Fluoride Intake from Food and Liquid in Japanese Children Living in Two Areas with Different Fluoride Concentrations in the Water Supply

The purpose of this study was to estimate the average daily amount of fluoride from the diet ingested by Japanese children of ages susceptible to dental fluorosis in two areas with different fluoride concentrations in the water supply. Thirty-eight children aged 2–8 years participated in a survey of fluoride intake. Twenty-one out of 38 children lived in an area in which the community water fluoride concentration was an average of 0.555 ppm (moderate fluoride area: MFA), and 17 lived in a low fluoride area (LFA), which ranged between 0.040 and 0.131 ppm. To measure the fluoride intake, diets were collected with a duplicate-diet technique. The fluoride concentrations in each sample were measured using the diffusion technique of Taves and the electrode technique. Meanwhile, after clinical examinations for dental caries and fluorosis, 228 subjects aged 13–15 years were selected for analysis from the same communities. The mean DMFT in the MFA was significantly lower than that in the LFA. The severest grade of dental fluorosis observed was ‘very mild’ according to Dean’s fluorosis index in both areas. The total daily fluoride intakes were 0.0252–0.0254 mg F/kg/day in the MFA and 0.0126–0.0144 mg F/kg/day in the LFA. Differences in the fluoride concentration of drinking water in this study were reflected in the fluoride intake from the diet in a typical Japanese diet.

Physical performance and 10-year mortality in a 70-year-old community-dwelling population.

Background and aims: Poor physical performance is known to be inversely related to mortality. The purpose of the present study was to determine whether an association between physical performance and 10-year mortality could be extended to a Japanese 70-year-old community-dwelling population, and to compare findings with those found in an octogenarian population. Methods: Seventy- year-old subjects residing in Niigata city, Japan, participated. Baseline examinations, including a physical performance test of four tests of muscle strength, one test of balance, and one test of agility, were carried out in June 1998 for 600 participants, and these individuals were then followed for 10 years. Results: During the 10-year follow up, 80 subjects died. Cox regression analysis with adjustment for confounding factors showed that high scores in muscle strength tests for lower extremities, such as single-leg and double-leg extensor strength and isokinetic leg extensor power, were found to be related to decreases in total cause mortality. Conclusions: In an elderly 70-year-old Japanese community-dwelling population, poor muscle strength was found to be an independent predictor of total mortality. Together with our previous findings in an 80-year-old population, the association between poor strength and high mortality may have effects at 70 but not 80 years of age.

Balance of Magnesium Positively Correlates with That of Calcium

Background and Objective: In a prior study [1], we showed no significant relationship between intake and balance of magnesium (Mg). Subsequent further investigation [2] disclosed that intakes of both Ca and P were positively correlated with their respective balances, whereas intake of Mg did not show any significant correlation with Mg balance. In this paper, we show positive correlations between intake of Mg and balances of both Ca and P. Methods and Results: Using these correlations, the mean value and upper limit of the 95% confidence interval (from the regression equation between Mg intake and either the balances of Ca or that of P, when each balance is equal to zero) were 4.584 and 4.802 (against Ca balance), 4.554 and 4.785 (against P balance) mg/kg BW/d, respectively. Balances of Mg and Ca correlated with each other.

Tracking of Pedometer-Determined Physical Activity in Healthy Elderly Japanese People.

BACKGROUND Tracking refers to the tendency for an individual to maintain their rank within a group over time. This study longitudinally investigated the 8-year tracking of pedometer-determined physical activity among physically independent elderly Japanese people aged 72 to 80 years. METHODS Steps/day were measured when participants were aged 72 and assessed again after 2, 5, and 8 years. The number of participants with a 2-year follow-up (72 to 74 years) was 177 (101 males, 76 females), with a 5-year follow-up (72 to 77 years) was 183 people (110 males, 73 females), and with an 8-year follow-up (72 to 80 years) was 145 people (91 males, 54 females). Step counts were continuously measured for 1 week in January, April, July, and October during each year of assessment. RESULTS A high rank correlation coefficient for steps/day exceeding 0.60 was obtained at the 2-, 5- and 8-year follow-up examinations for both males and females. CONCLUSION This study suggests that the rank within a group of pedometer-determined steps/day remains stable over up to 8 years in healthy Japanese people aged between 72 to 80 years old.

Influence of beverage and food consumption on fluoride intake in Japanese children aged 3-5 years.

This study was conducted to estimate the relative contribution of particular foods and drinks to dietary fluoride intake in 94 preschool Japanese children in low-fluoride areas. The mean daily fluoride intake from all beverages (548 ± 162 g) was 0.108 mg (SD = 0.082), accounting for 37% of the total dietary fluoride; tea beverages showed the highest value, 0.093 mg (SD = 0.081), 32%. That from staple food and side dishes was 0.183 mg (SD = 0.146), 63%, followed by cereals (12%), fish (8%) and bean products (5%). In conclusion, the contribution of beverages excluding tea to dietary fluoride intake is small in Japanese children.

Dietary Salt (Sodium Chloride) Requirement and Adverse Effects of Salt Restriction in Humans

Inevitable sodium loss under sodium restriction must not be construed as evidence for the estimated average requirement (EAR) for sodium (Na) in humans. We conducted human mineral balance studies to determine the EAR for some minerals (Na, K, Ca, Mg, P, Zn, Fe, Cu and Mn). Na concentration in arm sweat was low while those of calcium (Ca) and magnesium (Mg) were high, during relatively heavy bicycle-ergometer exercise under relatively low Na intake (100 mmol/d). This suggests that Na was released from the bone, the sole pool of Na, with Ca and Mg. Additionally, the negative balances of Ca and Mg was observed under a relatively low sodium intake (100 mmol/d) even with the sufficient supply and intake of Ca and Mg into human body. Finally, we found no correlation between the Na intake and the Na balance, while the Na-intake was correlated significantly to the balances of K, Ca and Mg. The Na intake necessary to keep the balances of Ca and Mg positive was calculated to be 68 mg/kg body weight/d. To learn the signs and symptoms of low sodium intake, we compared the results of a metabolic study in which subjects consumed diets with 6 g and 12 g salt/d respectively. The blood pressure decreased only with the 6 g/d group. Fecal moisture contents of the 6 g/d group were lower than for the 12 g/d group, suggesting the fecal Na was strongly reabsorbed with water when the dietary Na was insufficienct. Indiscriminate Na restriction may have adverse effects on health.

Dentition status and frailty in community‐dwelling older adults: A 5‐year prospective cohort study

To examine the longitudinal association between dentition status and incidence of frailty in older adults.