Multiple linear regression analysis of the seasonal changes in the serum concentration of beta-cryptoxanthin

Assessing Repeated Urinary Proline Betaine Measures as a Biomarker of Usual Citrus Intake during Pregnancy: Sources of Within-Person Variation and Correlation with Reported Intake

Proline betaine (Pro-B) has been identified as a biomarker of dietary citrus intake, yet gaps remain in its validation as a quantitative predictor of intake during various physiological states. This study quantified sources of within-individual variation (WIV) in urinary Pro-B concentration during pregnancy and assessed its correlation with the reported usual intake of citrus fruit and juice. Pro-B concentrations were determined by 1H-NMR spectroscopy in spot and 24-h urine specimens (n = 255) collected throughout pregnancy from women participating in the MARBLES cohort study. Adjusted linear or log mixed effects models quantified WIV and tested potential temporal predictors of continuous or elevated Pro-B concentration. Pearson or Spearman correlations assessed the relationship between averaged repeated biomarker measures and usual citrus intake reported by food frequency questionnaires. The proportion of variance in urinary Pro-B attributable to WIV ranged from 0.69 to 0.74 in unadjusted and adjusted models. Citrus season was a significant predictor of Pro-B in most analyses (e.g., adjusted β [95% CI]: 0.52 [0.16, 0.88] for non-normalized Pro-B), while gestational age predicted only non-normalized Pro-B (adjusted β [95% CI]: -0.093 [-0.18, -0.0038]). Moderate correlations (rs of 0.40 to 0.42) were found between reported usual citrus intake and averaged repeated biomarker measurements, which were stronger compared to using a single measurement. Given the high degree of WIV observed in urinary Pro-B, multiple samples per participant are likely needed to assess associations between citrus consumption and health outcomes.

Anti-Obesity and Anti-Inflammatory Synergistic Effects of Green Tea Catechins and Citrus β-Cryptoxanthin Ingestion in Obese Mice

Chronic obesity causes various diseases, leading to an urgent need for its treatment and prevention. Using monosodium-glutamate-induced obesity mice, the present study investigated the synergistic obesity-reducing effects of tea catechins and the antioxidant β-cryptoxanthin present in mandarin oranges. The results show that the obese mice that ingested both tea catechin and β-cryptoxanthin for 4 weeks had a significantly decreased body weight, with no difference in body weight compared with control mice. Moreover, the blood biochemical test results were normal, and the body fat percentage was significantly decreased according to the histopathological analysis. Additionally, the abundance of M1 macrophages, which release pro-inflammatories, was significantly reduced in adipose tissue. Indeed, a significant decrease was detected in M1-macrophage-secreted tumor necrosis factor-alpha levels. Meanwhile, M2 macrophage levels were recovered, and adiponectin, which is released from adipocytes and involved in suppressing metabolic syndrome, was increased. Collectively, these results suggest that the combination of tea catechins and antioxidant foods can alleviate chronic obesity, indicating that a combination of various ingredients in foods might contribute to reducing chronic obesity.

Association between serum carotenoids and premature mortality in a population-based case-control study

Carotenoids are abundant pigments mainly contained in vegetables and fruits, and show antioxidant properties by quenching free radicals in human body. Few studies have investigated associations between serum carotenoid levels and premature mortality. The objective of this study was to investigate the association between serum carotenoid level and premature mortality in a Japanese population. This study included 446 Japanese adults (174 men, aged of 40-64) recruited as participants in the Japan Collaborative Cohort (JACC) Study. Serum carotenoid level was measured by high-performance liquid chromatography. Premature mortality was defined as death before 65 years old during the follow-up period. Premature mortality was ascertained in 60 men (34.5%) and 65 women (23.9%). In men, compared to the 1^st tertile of serum β-cryptoxanthin and provitamin A, those who were in the 3^rd tertile had lower risks of premature all-cause mortality (OR, 95% CI: 0.19, 0.07-0.47 for β-cryptoxanthin, and 0.24, 0.09-0.61 for provitamin A). In women, compared to the 1^st tertile of serum β-cryptoxanthin, those who were in the 3^rd tertile had higher risks of premature all-cause mortality (OR, 95% CI: 1.94, 1.00-4.03). These significant associations were observed in analyses for premature cancer mortality. We found significant associations between higher levels of serum β-cryptoxanthin and provitamin A and lower risks of premature mortality among Japanese men, while a different directional association was found in women. Although these findings suggest roles of serum carotenoids on premature mortality, further studies are needed to validate this association in other populations.

Association between Serum Concentration of Carotenoid and Visceral Fat

Consumption of fruits and vegetables rich in carotenoids has been widely reported to prevent cardiovascular diseases. However, the relationship between serum carotenoid concentrations and visceral fat area (VFA), which is considered a better predictor of cardiovascular diseases than the body-mass index (BMI) and waist circumference, remains unclear. Therefore, we examined the relationship in healthy individuals in their 20s or older, stratified by sex and age, to compare the relationship between serum carotenoid concentrations and VFA and BMI. The study was conducted on 805 people, the residents in Hirosaki city, Aomori prefecture, who underwent a health checkup. An inverse relationship between serum carotenoid concentrations and VFA and BMI was observed only in women. In addition, the results were independent of the intake of dietary fiber, which is mainly supplied from vegetables as well as carotenoids. This suggests that consumption of a diet rich in carotenoids (especially lutein and beta-carotene) is associated with lower VFA, which is a good predictor of cardiovascular disease, especially in women. This study is the first to comprehensively evaluate the association between serum carotenoid levels and VFA in healthy individuals.

High Vitamin C Intake with High Serum β-Cryptoxanthin Associated with Lower Risk for Osteoporosis in Post-Menopausal Japanese Female Subjects: Mikkabi Cohort Study

Recent epidemiological studies show that antioxidant vitamins and carotenoids might be beneficial to the maintenance of bone health. Recently, we found that serum carotenoids were inversely associated with the risk of developing osteoporosis in post-menopausal Japanese female subjects. However, little is known about the vitamin alone and/or the combination of the vitamin and carotenoid with the risk of osteoporosis. The objective of this study was to investigate longitudinally whether antioxidant vitamins and their combination with carotenoids are associated with the risk of developing of osteoporosis. We conducted a follow-up study on 187 post-menopausal female subjects from the Mikkabi prospective cohort study. Those who participated in previous bone mineral density (BMD) surveys and completed four years of follow-up were examined longitudinally. During a four-year follow-up, fifteen of the post-menopausal female subjects developed new-onset osteoporosis. After adjustment for confounders, the odds ratios (OR) for osteoporosis in the highest tertiles of vitamins C and E and retinol intakes against the lowest tertiles were 0.15 (95% confidence interval (CI): 0.02-0.99), 0.50 (CI: 0.08-3.23), and 1.49 (CI: 0.36-6.22), respectively. Furthermore, a significantly lower odds ratio was observed in the higher vitamin C intake group (169-625 mg/d) with higher serum β-cryptoxanthin (1.88-10.53 μM) against the lower vitamin C intake group (47-168 mg/d) with lower serum β-cryptoxanthin (0.24-1.84 μM) used for the reference group (p<0.05). The combination of β-cryptoxanthin and vitamin C is inversely associated with the risk of developing osteoporosis in post-menopausal Japanese female subjects.

[β-Cryptoxanthin and the risk for lifestyle-related disease: findings from recent nutritional epidemiologic studies]

  Antioxidant micronutrients, such as vitamins and carotenoids, exist in abundance in fruits and vegetables and have been known to contribute to the body's defense against reactive oxygen species. Numerous recent epidemiologic studies have demonstrated that a high dietary consumption of fruit and vegetables rich in carotenoids or with high serum carotenoid concentrations results in lower risks of certain cancers, diabetes, and cardiovascular disease. These epidemiologic studies have suggested that antioxidant carotenoids may have a protective effect against several lifestyle-related diseases. β-Cryptoxanthin is a carotenoid pigment found in Japanese mandarin (Citrus unshiu MARC.) fruit, which is mainly produced in Japan. Our nutritional epidemiologic survey, the Mikkabi Study, utilized data derived from health examinations of inhabitants performed in the town of Mikkabi in Shizuoka, Japan. In this survey, we measured serum β-cryptoxanthin as a specific biomarker to estimate the consumption of Japanese mandarin fruit. From the cross-sectional analyses from the Mikkabi Study, we found inverse associations of serum β-cryptoxanthin with the risks for atherosclerosis, insulin resistance, liver dysfunction, metabolic syndrome, low bone mineral density, and oxidative stress. In this review, recent epidemiologic studies about the associations between serum β-cryptoxanthin with the risk for several lifestyle-related diseases were reviewed.

Serum β-cryptoxanthin and β-carotene derived from Satsuma mandarin and brachial-ankle pulse wave velocity: The Mikkabi cohort study

BACKGROUND AND AIMS

Findings of observational studies suggest cardioprotective effects of antioxidant vitamins and carotenoids. However, recent meta-analyses failed to show the beneficial effects of supplemental intake of antioxidants on cardiovascular disease (CVD). We aimed to assess the association between CVD risk and β-cryptoxanthin in Japan, where Satsuma mandarin, a major source of β-cryptoxanthin, is widely consumed.

METHODS AND RESULTS

This was part of the Mikkabi cohort study. Surveys were conducted at baseline, in 2003 and 2005, and on follow-up in 2006, 2009, and 2013. We examined brachial-ankle pulse wave velocity (baPWV) with a high cut-off value set at 18.3 m s(-1). Hazard ratios (HR) and 95% confidence intervals for high baPWV were estimated using a Cox proportional hazards model with adjustment for potential confounders. A total of 635 participants with baPWV of less than 18.3 m s(-1) at baseline were included in the analysis. During the follow-up period of 57,921 person-months, 99 subjects developed high baPWV. After multivariate adjustment, the HR for high baPWV in the highest tertile compared with the lowest tertile was significantly low for β-cryptoxanthin, β-carotene, and total carotenoids. Serum concentrations of β-cryptoxanthin and β-carotene were higher in people who ate Satsuma mandarin frequently. Compared with <1/d intake of Satsuma mandarin, 3-4/d was associated with a low risk of high PWV.

CONCLUSION

This study indicated that β-cryptoxanthin and β-carotene derived from Satsuma mandarin are candidate micronutrients for preventing arteriosclerosis development. Further longitudinal and interventional studies will be required to validate the effect on CVD.

Protective Efficacy of the Ingestion of Mandarin Orange Containing β-Cryptoxanthin on Lipopolysaccharide-induced Acute Nephritis

β-cryptoxanthin is a common carotenoid pigment found in fruit, especially in Satsuma mandarins and in persimmons. After ingestion, β-cryptoxanthin is distributed to and accumulates in organs, such as the liver, lung, and kidney. Recent studies have reported that because of its antioxidant defense, β-cryptoxanthin performs several important functions in the preservation of human health and in the prevention of several diseases, including cancer and osteoporosis. The present study aims to determine whether β-cryptoxanthin has a protective effect on renal glomeruli during acute nephritis. To develop our acute nephritis mouse model, we induced kidney inflammation in mice using lipopolysaccharide. To analyze pathological changes in the renal glomeruli of these mice, tissue sections of the kidney were analyzed by hematoxylin-eosin and periodic acid-Schiff staining. In mice with acute nephritis, we observed a thickening of the basal membrane in the renal glomeruli. By ultrastructural analysis, abnormalities in the foot cells were also identified. In the β-cryptoxanthin-ingested mice, these pathological changes were decreased. Migration of urinal proteins occurred in mice with acute nephritis, but this was decreased in β-cryptoxanthin-ingested mice, such that it correlated with the blood concentration of β-cryptoxanthin. Furthermore, in β-cryptoxanthin-ingested mice, both the accumulation and activation of inflammatory cells were decreased in the renal glomeruli. These results suggest that β-cryptoxanthin ingestion may produce great improvement in acute nephritis. These findings provide new insights into β-cryptoxanthin and its protective effect, and provide a new target for pharmacological therapy in human disease.

High serum carotenoids are associated with lower risk for developing elevated serum alanine aminotransferase among Japanese subjects: the Mikkabi cohort study

Many recent studies have shown that antioxidant vitamins and/or carotenoids may reduce liver disease, but this association has not been well established with thorough longitudinal cohort studies. The objective of this study was to longitudinally investigate whether serum carotenoids at baseline are associated with the risk of developing elevated serum alanine aminotransferase (ALT) among Japanese subjects. We conducted a follow-up study of 1073 males and females aged between 30 and 79 years at baseline from the Mikkabi prospective cohort study. Those who participated in the baseline study and completed follow-up surveys were examined longitudinally. Exclusions included excessive alcohol consumption (≥60 g alcohol/d), hepatitis B and C and having a history of medication use for liver disease. A cohort of 213 males and 574 females free of elevated serum ALT (>30 IU/ml) at baseline was studied. Over a mean follow-up period of 7·4 (sd 3·1) years, thirty-one males and forty-nine females developed new elevated serum ALT. After adjustments for confounders, the hazard ratios for elevated serum ALT in the highest tertiles of basal serum β-carotene, β-cryptoxanthin and total provitamin A carotenoids against the lowest tertiles were 0·43 (95 % CI 0·22, 0·81), 0·51 (CI 0·27, 0·94) and 0·52 (CI 0·28, 0·97), respectively. For α-carotene and lycopene, borderline reduced risks were also observed; however, these were not significant. Our results further support the hypothesis that antioxidant carotenoids, especially provitamin A carotenoids, might help prevent earlier pathogenesis of non-alcoholic liver disease in Japanese subjects.

High serum carotenoids associated with lower risk for the metabolic syndrome and its components among Japanese subjects: Mikkabi cohort study

Recent epidemiological studies show the association of carotenoids with the metabolic syndrome (MetS), 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 of developing the MetS and its components in Japanese subjects. We conducted a follow-up study on 1073 men and women 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 men and 615 women) took part in the follow-up survey at least once. Over a mean follow-up period of 7·8 (sd 2·9) years, thirty-six men and thirty-one women developed new MetS. After adjustments for confounders, the hazard ratio (HR) for the MetS in the highest tertile of serum β-carotene against the lowest tertile was 0·47 (95 % CI 0·23, 0·95). On the other hand, significantly lower risks for dyslipidaemia were observed in the highest tertiles of serum α- and β-carotene and β-cryptoxanthin (HR 0·66; 95 % CI 0·46, 0·96; HR, 0·54; 95 % CI 0·37, 0·79; and HR 0·66; 95 % CI 0·44, 0·99, respectively). Other significant associations between the risks for obesity, high blood pressure and hyperglycaemia with serum carotenoids were not observed. Our results further support the hypothesis that eating a diet rich in carotenoids might help prevent the development of the MetS and its complications in Japanese subjects.

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.

β-Cryptoxanthin alleviates diet-induced nonalcoholic steatohepatitis by suppressing inflammatory gene expression in mice

Recent nutritional epidemiological surveys showed that serum β-cryptoxanthin inversely associates with the risks for insulin resistance and liver dysfunction. Consumption of β-cryptoxanthin possibly prevents nonalcoholic steatohepatitis (NASH), which is suggested to be caused by insulin resistance and oxidative stress from nonalcoholic fatty liver disease. To evaluate the effect of β-cryptoxanthin on diet-induced NASH, we fed a high-cholesterol and high-fat diet (CL diet) with or without 0.003% β-cryptoxanthin to C56BL/6J mice for 12 weeks. After feeding, β-cryptoxanthin attenuated fat accumulation, increases in Kupffer and activated stellate cells, and fibrosis in CL diet-induced NASH in the mice. Comprehensive gene expression analysis showed that although β-cryptoxanthin histochemically reduced steatosis, it was more effective in inhibiting inflammatory gene expression change in NASH. β-Cryptoxanthin reduced the alteration of expression of genes associated with cell death, inflammatory responses, infiltration and activation of macrophages and other leukocytes, quantity of T cells, and free radical scavenging. However, it showed little effect on the expression of genes related to cholesterol and other lipid metabolism. The expression of markers of M1 and M2 macrophages, T helper cells, and cytotoxic T cells was significantly induced in NASH and reduced by β-cryptoxanthin. β-Cryptoxanthin suppressed the expression of lipopolysaccharide (LPS)-inducible and/or TNFα-inducible genes in NASH. Increased levels of the oxidative stress marker thiobarbituric acid reactive substances (TBARS) were reduced by β-cryptoxanthin in NASH. Thus, β-cryptoxanthin suppresses inflammation and the resulting fibrosis probably by primarily suppressing the increase and activation of macrophages and other immune cells. Reducing oxidative stress is likely to be a major mechanism of inflammation and injury suppression in the livers of mice with NASH.

Comparison of bioavailability between β-cryptoxanthin and β-carotene and tissue distribution in its intact form in rats

The bioavailability of two intact carotenoids in several tissues of β-cryptoxanthin- and β-carotene-fed rats (20 mg/kg of diet) was investigated. Although metabolites of provitamin A are not included in our study, β-cryptoxanthin was found at higher concentrations in majority of the tissues. The results show that the bioavailability of intact β-cryptoxanthin seemed to be higher than that of β-carotene.

Absorption, storage and distribution of β-cryptoxanthin in rat after chronic administration of Satsuma mandarin (Citrus unshiu MARC.) juice

Fruits and vegetables contain numerous antioxidants, such as carotenoids. Recent epidemiologic studies have demonstrated that a high dietary consumption of fruit and vegetables rich in carotenoids or with high serum carotenoid concentrations results in lower risks of certain cancers, diabetes, and cardiovascular disease. These results indicate that absorbed carotenoids are stored in various organs. Previously, we found that β-cryptoxanthin, found especially in Satsuma mandarin (Citrus unshiu MARC.), is easily absorbed and can also survive for a relatively long time in the human body; however, little is known about the absorption, storage, and tissue distribution of β-cryptoxanthin. In this study, we measured serum and the content of β-cryptoxanthin in several rat tissues after chronic ingestion of Satsuma mandarin extract rich in β-cryptoxanthin. Rats were fed a standard commercial diet containing Satsuma mandarin extract (containing β-cryptoxanthin at 11.7 mg/kg diet) for eight weeks. After 3 h of fasting, serum, liver, spleen, kidney, lung, heart, testis, brain, and epididymal fat were collected. The concentrations of β-cryptoxanthin in serum and tissues were evaluated by high-performance liquid chromatography. There was a wide range in the tissue levels of β-cryptoxanthin; liver had the greatest value, with 1265.3 ng/g tissue, followed by spleen, kidney, lung, heart, brain, and testis. Epididymal fat had the lowest value, with 6.99 ng/g tissue. β-Cryptoxanthin was also detected in serum in a concentration of 5.76 ng/mL. These results indicate that β-cryptoxanthin is easily absorbed and accumulated in several organs.

Cancer chemoprevention by carotenoids

Carotenoids are natural fat-soluble pigments that provide bright coloration to plants and animals. Dietary intake of carotenoids is inversely associated with the risk of a variety of cancers in different tissues. Preclinical studies have shown that some carotenoids have potent antitumor effects both in vitro and in vivo, suggesting potential preventive and/or therapeutic roles for the compounds. Since chemoprevention is one of the most important strategies in the control of cancer development, molecular mechanism-based cancer chemoprevention using carotenoids seems to be an attractive approach. Various carotenoids, such as β-carotene, a-carotene, lycopene, lutein, zeaxanthin, β-cryptoxanthin, fucoxanthin, canthaxanthin and astaxanthin, have been proven to have anti-carcinogenic activity in several tissues, although high doses of β-carotene failed to exhibit chemopreventive activity in clinical trials. In this review, cancer prevention using carotenoids are reviewed and the possible mechanisms of action are described.

Mechanism of visceral fat reduction in Tsumura Suzuki obese, diabetes (TSOD) mice orally administered β-cryptoxanthin from Satsuma mandarin oranges (Citrus unshiu Marc)

The carotenoid β-cryptoxanthin (β-CRX) is abundant in Satsuma mandarins (Citrus unshiu Marc). Several studies have shown a relationship between Satsuma mandarin consumption and a low risk of several diseases, for example, diabetes, gout, and hypertension, suggesting β-CRX involvement in disease prevention. We investigated the effect of β-CRX on mildly obese males. β-CRX administration reduced visceral adipose tissue, body weight, and abdominal circumference. However, the detailed mechanism by which β-CRX mediates these changes remains unknown. To identify this mechanism, we used an obese model mouse (TSOD). Oral β-CRX administration repressed body weight, abdominal adipose tissue weight, and serum lipid concentrations in TSOD; these results are identical to previous human trial results. β-CRX administration significantly repressed adipocyte hypertrophy. Gene expression analysis strongly indicated that β-CRX can alter cytokine secretion and cell proliferation. These results suggest that β-CRX derived from Satsuma mandarins can help prevent obesity by repressing hypertrophy of abdominal adipocytes.

Prevention of Adiposity by the Oral Administration of β-Cryptoxanthin

β-Cryptoxanthin (β-CRX) is a carotenoid found in human blood. It is specifically rich in Satsuma mandarin (Citrus unshiu Marc.) but very little in other fruits or vegetables. Several reports indicate the health promoting benefits of β-CRX. As we had reported visceral fat reduction on mildly obese male by the oral administration of β-CRX, a detailed mechanism has not been identified. To identify the mechanism, obese model mouse, TSOD was used in the present study. Oral administration of β-CRX repressed body weight, abdominal adipose tissue weight, and serum lipid concentrations on TSOD mice. The outstanding observation is the significant repression of adipocyte hypertrophy. DNA microarray analysis strongly indicates that the oral administration of β-CRX represses the inflammatory cytokine secretion and improves the lipid metabolism and the energy consumption. It also suggests these effects are partly mediated by PPAR-α, not only lipid metabolism and adipocyte differentiation control but possibly internal circadian clock modulation.