cryptoxanthins and Metabolic-Syndrome

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. It is characterized by a wide spectrum of hepatic changes, which may progress to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is considered a hepatic manifestation of metabolic syndrome; however, mechanisms underlying the onset and progression of NAFLD are still unclear. Resident and recruited macrophages are key players in the homeostatic function of the liver and in the progression of NAFLD to NASH. Progress has been made in understanding the molecular mechanisms underlying the polarized activation of macrophages. New NAFLD therapies will likely involve modification of macrophage polarization by restraining M1 activation or driving M2 activation. Carotenoids are potent antioxidants and anti-inflammatory micronutrients that have been used to prevent and treat NAFLD. In addition to their antioxidative action, carotenoids can regulate macrophage polarization and thereby halt the progression of NASH. In this review, we summarize the molecular mechanisms of macrophage polarization and the function of liver macrophages/Kupffer cells in NAFLD. From our review, we propose that dietary carotenoids, such as β-cryptoxanthin and astaxanthin, be used to prevent or treat NAFLD through the regulation of macrophage polarization and liver homeostasis.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Beta-Cryptoxanthin; Carotenoids; Cell Polarity; Disease Models, Animal; Disease Progression; Homeostasis; Humans; Kupffer Cells; Liver; Macrophage Activation; Metabolic Syndrome; Micronutrients; Non-alcoholic Fatty Liver Disease; Randomized Controlled Trials as Topic; Xanthophylls

Citrus fruits are known for their beneficial health effects associated with the prevention of metabolic syndrome/type 2 diabetes that is mainly attributed to flavonoids. Few investigations have reported the potential anti-diabetic effects of retinoids from the bioconversion of β-cryptoxanthin (bcx), a citrus carotenoid. Therefore, the present study explored the anti-diabetic effect of a citrus functional food, obtained by membrane eco-technology of a citrus clementina juice, especially enriched in bcx but also in flavonoids and pectin. We assessed the in vivo effect of citrus bcx absorption and its bioconversion into retinoids in metabolic syndrome/type 2 diabetic fructose rats. Fructose-fed rats were used as a prediabetic control, and a prediabetic group was treated with the citrus concentrate for 8 weeks. The citrus-based food treatment improved glucose tolerance, dyslipidemia and blood pressure, in prediabetic rats. Although these effects were in part due to the synergy between enriched phytonutrients (bcx, hesperidin, pectin) of the citrus matrix, the role of bcx and its bioconversion into retinoids were highlighted. We showed that prediabetic rats absorbed less bcx and the bioconversion was less efficient. Bcx from citrus-based food was able to restore vitamin A status in prediabetic rats suggesting that the absorption/bioconversion of bcx may have a key role in improvement of metabolic syndrome/type 2 diabetes.

Topics: Animals; Beta-Cryptoxanthin; Citrus; Diabetes Mellitus, Type 2; Functional Food; Glucose; Humans; Male; Metabolic Syndrome; Rats; Retinoids

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.

Topics: Adult; Aged; beta Carotene; Carotenoids; Cohort Studies; Cryptoxanthins; Female; Follow-Up Studies; Humans; Japan; Longitudinal Studies; Lutein; Lycopene; Male; Metabolic Syndrome; Middle Aged; Prospective Studies; Risk Factors; Zeaxanthins

The association between serum carotenoids and the metabolic syndrome (MetS) remains uncertain, and little is known about this relationship in the Chinese population. The present study examined the association between serum carotenoid concentrations and the MetS in Chinese adults. We conducted a community-based cross-sectional study in which 2148 subjects (1547 women and 601 men) aged 50-75 years were recruited in urban Guangzhou, China. Dietary data and other covariates were collected during face-to-face interviews. Blood pressure, waist circumference, blood lipids, glucose and serum carotenoids (α-, β-carotene, β-cryptoxanthin, lycopene and lutein/zeaxanthin) were examined. We found dose-response inverse relationships between individual serum carotenoid concentrations and total carotenoids and the prevalence of the MetS after adjusting for potential confounders (P for trend < 0.001). The OR of the MetS for the highest (v. lowest) quartile were 0.31 (95% CI 0.20, 0.47) for α-carotene, 0.23 (95% CI 0.15, 0.36) for β-carotene, 0.44 (95% CI 0.29, 0.67) for β-cryptoxanthin, 0.39 (95% CI 0.26, 0.58) for lycopene, 0.28 (95% CI 0.18, 0.44) for lutein+zeaxanthin and 0.19 (95% CI 0.12, 0.30) for total carotenoids. Higher concentrations of each individual carotenoid and total carotenoids were significantly associated with a decrease in the number of abnormal MetS components (P for trend < 0.001-0.023). Higher serum carotenoid levels were associated with a lower prevalence of the MetS and fewer abnormal MetS components in middle-aged and elderly Chinese adults.

Topics: Aged; Asian People; beta Carotene; Blood Glucose; Blood Pressure; Carotenoids; China; Cross-Sectional Studies; Cryptoxanthins; Diet; Dose-Response Relationship, Drug; Female; Humans; Lipids; Lutein; Lycopene; Male; Metabolic Syndrome; Middle Aged; Odds Ratio; Prevalence; Waist Circumference; Xanthophylls; Zeaxanthins

Several epidemiological studies have shown that circulating antioxidant levels are inversely associated with metabolic syndrome status. The purpose of this study was to examine the association of serum carotenoid levels, which have potent antioxidant effects, with metabolic syndrome and metabolic syndrome components in Japanese subjects.. We conducted a cross-sectional study of 931 subjects (318 men and 613 women), aged 39-70 years, who attended a health examination. Metabolic syndrome was defined according to the diagnostic definition from the Japanese Examination Committee of Criteria for Metabolic Syndrome, which was released in 2005. Serum carotenoids were measured by high-performance liquid chromatography.. A significantly lower odds ratio (OR) for metabolic syndrome was observed in the highest tertile of serum β-cryptoxanthin (OR:0.45; 95% CI:0.22-0.93 in men and 0.41; 0.17-0.93 in women) and β-carotene (OR:0.45; 95% CI:0.21-0.95 in men and 0.37; 0.15-0.83 in women) compared to the lowest tertiles, in both sexes, but no significant association was found in male smokers. In women, moreover, OR for metabolic syndrome in the highest tertile of serum zeaxanthin/lutein (OR:0.37; 95% CI:0.16-0.84) was significantly lower than in the lowest tertile. Serum levels of β-cryptoxanthin, α-carotene, and β-carotene were significantly decreased with an increasing number of metabolic syndrome components in both sexes.. These findings indicate that carotenoids may be important factors in the prevention of metabolic syndrome in nonsmokers, but further studies are required in smokers.

Topics: Adult; Aged; beta Carotene; Carotenoids; Cross-Sectional Studies; Cryptoxanthins; Female; Humans; Japan; Male; Metabolic Syndrome; Middle Aged; Practice Guidelines as Topic; Prevalence; Sex Factors; Smoking; Surveys and Questionnaires; Waist Circumference; Xanthophylls

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.

Topics: Adult; Aged; Antioxidants; Carotenoids; Cross-Sectional Studies; Cryptoxanthins; Female; Humans; Male; Metabolic Syndrome; Middle Aged; Smoking; Xanthophylls