Mieko Nakamura

Bone mineral density in post-menopausal female subjects is associated with serum antioxidant carotenoids

SummaryHigh intake of fruit and vegetables may reduce the risk of osteoporosis. Carotenoids exist in abundance in these foods. This study showed the association of bone mineral density with serum carotenoids. The findings suggest that β-cryptoxanthin and β-carotene might provide benefits to bone health in post-menopausal female subjects.IntroductionAntioxidant carotenoids are abundant in fruit and vegetables. Recent epidemiological studies show that high intakes of fruit and vegetables may reduce the risk of osteoporosis, but little is known about the association of bone mineral density (BMD) with serum carotenoids.MethodsA total of 699 subjects (222 males and 477 females) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Radial BMD was measured using dual-energy X-ray absorptiometry (DXA). The associations of serum carotenoid concentrations with the radial BMD were evaluated cross-sectionally.ResultsIn male and pre-menopausal female subjects, the six serum carotenoids were not associated with the radial BMD. On the other hand, in post-menopausal female subjects, serum β-cryptoxanthin and β-carotene were weakly but positively correlated with the radial BMD. After adjustment for confounders, the odds ratio (OR) for the lowest quartile of BMD in the high groups (Q2–Q4) of serum β-cryptoxanthin against the lowest quartile (Q1) was 0.45 (95% confidence interval: 0.22–0.95) in post-menopausal female subjects. However, this association was not significant after further adjusting for intakes of minerals and vitamins.ConclusionsAntioxidant carotenoids, especially β-cryptoxanthin, significantly but partly associate with the radial BMD in post-menopausal female subjects.

Dietary patterns of antioxidant vitamin and carotenoid intake associated with bone mineral density: findings from post-menopausal Japanese female subjects

SummaryRecent studies show that antioxidants may reduce the risk of osteoporosis. This study showed the associations of bone mineral density with dietary patterns of antioxidant vitamins and carotenoids. The findings suggest the combination of vitamin C and β-cryptoxanthin intakes might provide benefit to bone health in post-menopausal Japanese female subjects.IntroductionRecent epidemiological studies show antioxidants may reduce the risk of osteoporosis, but little is known about the dietary patterns of antioxidant vitamin and carotenoid intakes and their relation with bone mineral density (BMD).MethodsA total of 293 post-menopausal female subjects who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Radial BMD was measured using dual-energy X-ray absorptiometry. Dietary intakes of antioxidant vitamins and carotenoids were assessed by using a validated food-frequency questionnaire. Dietary patterns were identified on a selected set of antioxidants through principal component factor analysis.ResultsThree dietary patterns were identified. The “retinol” pattern, characterized by notably high intakes of preformed retinol, zeaxanthin, and vitamin E, was positively associated with the risk for low BMD. In contrast, the “β-cryptoxanthin” pattern, characterized by notably high intakes of β-cryptoxanthin and vitamin C, was negatively associated with low BMD. The odds ratios for low BMD in the highest tertiles of dietary intakes of preformed retinol, vitamin C, and β-cryptoxanthin against the lowest tertiles were 3.22 [95% confidence interval (CI), 1.38–7.51], 0.25 (CI, 0.10–0.66), and 0.40 (CI, 0.17–0.92), respectively, after adjustments for confounders. However, negative associations of vitamin C and β-cryptoxanthin with low BMD were not significant after further adjustment for intake of β-cryptoxanthin or vitamin C, respectively. Higher intakes of both vitamin C and β-cryptoxanthin were significantly associated with low BMD (P < 0.05).ConclusionsThe combination of vitamin C and β-cryptoxanthin may be associated with radial BMD in post-menopausal Japanese female subjects.

The Homeostasis Model Assessment-insulin Resistance Index Is Inversely Associated with Serum Carotenoids in Non-diabetic Subjects

BACKGROUND Carotenoids may reduce the risk for diabetes mellitus, but little is known about the association of insulin resistance with serum carotenoids in non-diabetic subjects. This study aimed to investigate whether the homeostasis model assessment-insulin resistance (HOMA-IR) index would be lower in the presence of high serum carotenoid concentrations in non-diabetic subjects. METHODS A total of 812 subjects (256 males and 556 females) who had received health examinations in 2003 participated in the study. The associations of the serum-carotenoid concentrations and HOMA-IR were evaluated cross-sectionally. The multivariate-adjusted geometric means of HOMA-IR by the tertiles of the serum carotenoid concentration were calculated after adjusting for age, body mass index, systolic blood pressure, total cholesterol, triacylglycerols, current tobacco use, regular alcohol intake, exercise habits and total energy intake. Associations among high HOMA-IR (3.0+ mU×mmol/L2) across tertiles of serum carotenoid concentration were assessed by tests for logistic regression analysis. RESULTS In male subjects, the multivariate adjusted geometric mean of HOMA-IR was inversely associated with the serum β-cryptoxanthin concentrations. In female subjects, an inverse association of the serum carotenoid concentration and HOMA-IR was observed in lycopene, β-cryptoxanthin, and zeaxanthin. The confounding factor-adjusted odds ratios (OR) for high HOMA-IR on the highest tertiles of serum α-carotene, β-carotene, β-cryptoxanthin, and zeaxanthin were 0.18 [95% confidence interval (CI): 0.06-0.52], 0.22 (95% CI: 0.07-0.67), 0.34 (95% CI: 0.12-0.96), and 0.30 (95% CI: 0.11-0.79), respectively, in male subjects. On the other hand, in female subjects, the adjusted OR for high HOMA-IR on the highest tertiles of serum lycopene and β-cryptoxanthin were 0.39 (95% CI: 0.21-0.73) and 0.51 (95% CI: 0.28-0.95), respectively. CONCLUSIONS The serum antioxidant carotenoids were inversely associated with HOMA-estimated insulin resistance in non-diabetic subjects.

High Serum Carotenoids Associated with Lower Risk for Bone Loss and Osteoporosis in Post-Menopausal Japanese Female Subjects: Prospective Cohort Study

Introduction Recent epidemiological studies show that high intakes of carotenoids might be useful to maintain bone health, but little is known about the association of serum carotenoids with change of bone mineral density (BMD). The objective of this study was to investigate longitudinally whether serum carotenoids are associated with bone loss. Methods We conducted a follow-up on 146 male and 99 pre- and 212 post-menopausal female subjects from the Mikkabi study. Those who participated in previous BMD surveys and completed four years of follow-up were examined longitudinally. Results During a 4-year follow-up, 15 of the post-menopausal female subjects developed new-onset osteoporosis. In contrast, none of the male and pre-menopausal female subjects did. In male and pre-menopausal female subjects, the six serum carotenoids at the baseline were not associated with bone loss. On the other hand, in post-menopausal female subjects, the 4-year bone loss of radius was inversely associated with the serum carotenoid concentrations, especially in β-carotene. After adjustments for confounders, the odds ratios (OR) for osteoporosis in the highest tertiles of serum β-carotene and β-cryptoxanthin against the lowest tertiles were 0.24 (95% confidence interval 0.05–1.21) and 0.07 (CI: 0.01–0.88), respectively. Serum β-cryptoxanthin was also inversely associated with the risk for osteopenia and/or osteoporosis (P for trend, 0.037). In addition, our retrospective analysis revealed that subjects who developed osteoporosis and/or osteopenia during the survey period had significantly lower serum concentrations of β-cryptoxanthin and β-carotene at the baseline than those in the normal group. Conclusions Antioxidant carotenoids, especially β-cryptoxanthin and β-carotene, are inversely associated with the change of radial BMD in post-menopausal female subjects.

Associations of serum carotenoid concentrations with the metabolic syndrome: interaction with smoking

Recent epidemiological studies show the associations of serum antioxidant status with the metabolic syndrome. Oxidative stress may play an important role in the pathogenesis of diabetes and CVD. Actually, smoking is a potent oxidative stressor in man, but little is known about the interaction of serum carotenoids and the metabolic syndrome with smoking status. In this study, the associations of the serum carotenoids with the metabolic syndrome stratified by smoking habit were evaluated cross-sectionally. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Among total subjects, the OR for the metabolic syndrome in the highest tertile of serum beta-carotene was 0.41 (95 % CI 0.18, 0.92) after adjusting confounders. In current smokers, significantly lower OR were observed in the middle (OR 0.10; 95 % CI 0.01, 0.72) and highest (OR 0.06; 95 % CI 0.01, 0.73) tertiles of serum beta-carotene. Furthermore, lower OR were observed in accordance with tertiles of serum alpha-carotene and beta-cryptoxanthin in current smokers (P for trend 0.042 and 0.036, respectively). In contrast, in non-smokers, a significantly lower OR was observed in the highest tertile of serum beta-carotene (OR 0.30; 95 % CI 0.10, 0.89) after multiple adjustment. Inverse associations of serum carotenoids with the metabolic syndrome were more evident among current smokers than non-smokers. These results support that antioxidant carotenoids may have a protective effect against development of the metabolic syndrome, especially in current smokers who are exposed to a potent oxidative stress.

Dietary supplement use by community-living population in Japan: data from the National Institute for Longevity Sciences Longitudinal Study of Aging (NILS-LSA).

BACKGROUND There are few studies about dietary supplement use and nutrient intake from these products in Japan. The purpose of this study was to clarify (1) the prevalence of dietary supplement use, (2) the characteristics of dietary supplement users, (3) nutrient intake from dietary supplements, and (4) the existence of dietary supplement users who took excessive nutrients from these products. METHODS To collect the information on dietary supplement use in the previous year and nutrient intake from these products, we conducted a self-administered dietary supplement frequency questionnaire. The subjects were 2,259 people aged 40-82 years. Dietary supplements were grouped into 8 major categories. A dietary supplement database was developed to estimate nutrient intake from these products. Excess users were defined as people who consumed more nutrient than the tolerable upper intake level of the Dietary Reference Intakes for Japanese. RESULTS In the previous year, 55 % of males and 61 % of females consumed dietary supplements. Dietary supplement use was especially prevalent in females, subjects who felt unhealthy, and subjects who were more careful of maintaining an appropriate weight, though the association was affected by the frequency of dietary supplement use. The most common dietary supplements were drink type in males and vitamins in females. Some nutrient values obtained from dietary supplements were higher than those from food. Excess users were found for intake of vitamin A, B6, K, niacin, iron, and magnesium. CONCLUSIONS It is important to clarify dietary supplement use and to estimate nutrient intake from these products.

Consumption of dairy products and death from cardiovascular disease in the Japanese General Population: The NIPPON DATA80

Background Recent Western studies show an inverse association between milk and dairy product intake and cardiovascular disease (CVD). We studied the association between consumption of milk and dairy products and CVD death in Japan. Methods Men and women aged 30 years or older were followed for 24 years. All had participated in a national nutrition survey in 300 health districts throughout Japan in 1980. The Cox proportional hazards model was used to assess mortality risk according to tertiles of milk and dairy product intake, with the high consumption group as reference. Hazard ratios (HRs) per 100-g/day increase in consumption were also estimated. Results During the 24-year follow-up period, there were 893 CVD deaths, 174 deaths from coronary heart disease (CHD), and 417 stroke deaths among 9243 participants. For women, the HRs for death from CVD, CHD, and stroke in the low consumption group were 1.27 (95% CI: 0.99–1.58; P for trend = 0.045), 1.67 (0.99–2.80; P = 0.02), and 1.34 (0.94–1.90; P = 0.08), respectively, after adjustment for age, body mass index, smoking status, alcohol drinking habits, history of diabetes, use of antihypertensives, work category, and total energy intake. With each 100-g/day increase in consumption of milk and dairy products, HRs tended to decrease for deaths from CVD (HR, 0.86; 95% CI, 0.74–0.99), CHD (0.73; 0.52–1.03), and stroke (0.81; 0.65–1.01) in women. No significant association was observed in men. Conclusions Consumption of milk and dairy products was inversely associated with CVD death among women in Japan.

Synergistic interaction of cigarette smoking and alcohol drinking with serum carotenoid concentrations: findings from a middle-aged Japanese population

Previous studies have indicated low serum carotenoid concentrations among cigarette smokers and/or alcohol drinkers, but little is known about the interaction of smoking and drinking with serum carotenoids. We tested the hypothesis that smoking and drinking reduce serum carotenoid concentrations synergistically. A total of 1073 subjects (357 male and 716 female) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. The subjects were divided into six groups according to alcohol intake (non-drinkers, < 1 g/d; light drinkers, > or = 1, < 25 g/d; moderate-to-heavy drinkers, > or = 25 g/d) and smoking status (non-smokers and current smokers). The dietary intakes and serum concentrations of six carotenoids (lycopene, alpha-carotene, beta-carotene, lutein, beta-cryptoxanthin and zeaxanthin) within each group were evaluated cross-sectionally. The dietary intakes of all carotenoids did not differ in the six groups after adjusting for age and sex. The multivariate-adjusted means of the serum carotenoid concentrations in non-drinkers did not differ between non-smokers and current smokers. In contrast, the adjusted means of serum alpha-carotene, beta-carotene and beta-cryptoxanthin were significantly lower than those with increased alcohol intake, and these lower serum carotenoids among alcohol drinkers were more evident in current smokers than in non-smokers. Serum lycopene of moderate-to-heavy drinkers was significantly lower than that of non-drinkers, but it was not influenced by smoking. Neither smoking nor drinking was associated with the serum concentrations of lutein and zeaxanthin. These results suggest that smoking and drinking may reduce the serum alpha-carotene, beta-carotene and beta-cryptoxanthin concentrations in a synergistic manner.

High-serum carotenoids associated with lower risk for developing type 2 diabetes among Japanese subjects: Mikkabi cohort study

Objective Recent epidemiological studies show the association of antioxidant carotenoids with type 2 diabetes, but thorough longitudinal cohort studies regarding this association have not been well conducted. The objective of this study was to investigate longitudinally whether serum carotenoids are associated with the risk for developing type 2 diabetes among Japanese subjects. Research design and methods We conducted a follow-up study on 1073 males and females aged 30–79 years at the baseline from the Mikkabi prospective cohort study. Those who participated in the baseline and completed follow-up surveys were examined longitudinally. Over the 10-year period, 910 subjects (295 males and 615 females) took part in the follow-up survey at least one time. A cohort of 264 males and 600 females free of diabetes at baseline was studied. Results Over a mean follow-up period of 7.8 years (SD=2.9), 22 males and 33 females developed new type 2 diabetes. After adjustments for confounders, the HRs for type 2 diabetes in the highest tertiles of serum α-carotene, β-cryptoxanthin, and total provitamin A carotenoids against the lowest tertiles were 0.35 (95% CI 0.15 to 0.82), 0.43 (CI 0.20 to 0.92) and 0.41 (CI 0.19 to 0.90), respectively. For β-carotene and zeaxanthin, borderline reduced risks were also observed, but these were not significant. Conclusions Our results further support the hypothesis that eating a diet rich in carotenoids, especially provitamin A carotenoids, might help prevent the development of type 2 diabetes in Japanese patients. Trial registration number NIFT-2013001.

Association between food group intake and serum total cholesterol in the Japanese population: NIPPON DATA 80/90.

Background Dietary habit is one of the important determinants of health. Investigation of the association between diet and blood lipids at the food product level is more advantageous than that at the nutrient level because the results can be applied more directly to improving dietary habits for disease prevention. Methods The integrated datasets of the NIPPON DATA and National Nutrition Surveys in Japan conducted in 1980 and 1990 were used for analysis. The association between serum total cholesterol concentration and food group intake was examined by multiple linear regression analysis separately for sex and survey year with data adjusted for age, body mass index and total energy intake. Results Intakes of rice, sugar, sweets and snacks, fruit and vegetables other than green and yellow ones were lower and intakes of green and yellow vegetables, mushrooms, seaweed, eggs and milk were higher in the 1990 survey than in the 1980 survey. Intakes of meat, milk and eggs showed a positive association with serum total cholesterol concentration in both sexes while intake of legumes showed a negative association only in men in both the 1980 and 1990 surveys. Conclusions Sex- and age-specific food group intakes for 1980 and 1990 were identified, and positive and negative associations between serum total cholesterol concentration and food group intake were revealed in a representative sample of the Japanese population. The results provide some insights into the improvements in dietary habits that can be made for disease prevention in Japan.