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Carotenoids, vitamin A, and their association with the metabolic syndrome: a systematic review and meta-analysis.
Beydoun, MA, Chen, X, Jha, K, Beydoun, HA, Zonderman, AB, Canas, JA
Nutrition reviews. 2019;(1):32-45
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Abstract
CONTEXT Modifiable factors that reduce the burden of the metabolic syndrome (MetS), particularly plant-derived biomarkers, have been a recent focus of rising interest. OBJECTIVE This systematic review and meta-analysis, which follows PRISMA guidelines, evaluates evidence from a period of 20 years that links vitamin A and carotenoids with the occurrence of MetS and following the PRISMA guidelines. DATA SOURCES PubMed and Cochrane databases (January 1997 through March 2017) were systematically assessed for studies, including case-control, cross-sectional, and cohort studies, that evaluated the associations of MetS with carotenoids and retinyl esters and retinol (vitamin A). DATA EXTRACTION Key measures of associations were harmonized into odds ratios (ORs) and 95% confidence intervals (95%CI) of MetS per 1 standard deviation (SD) of exposure using forest plots and random effects models that pooled data points from 11 cross-sectional studies. Begg's funnel and harvest plots were constructed. RESULTS An inverse association between total carotenoids and MetS was found [ORpooled, 0.66; 95%CI, 0.56-0.78; 1 SD ∼ 0.82 µmol/L; n = 5 studies]. This association was the strongest for β-carotene, followed by α-carotene and β-crypotoxanthin. No association was detected between retinol and MetS (ORpooled, 1.00; 95%CI, 0.88-1.13; 1 SD ∼ 2.14 µmol/L; n = 6 studies). Publication bias was absent, and harvest plots indicated consistency upon replication for β-carotene and total carotenoid exposures. CONCLUSIONS This review and meta-analysis suggests that, unlike retinol, total and individual carotenoids were inversely related to MetS.
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The effects of crocin on the symptoms of depression in subjects with metabolic syndrome.
Jam, IN, Sahebkar, AH, Eslami, S, Mokhber, N, Nosrati, M, Khademi, M, Foroutan-Tanha, M, Ghayour-Mobarhan, M, Hadizadeh, F, Ferns, G, et al
Advances in clinical and experimental medicine : official organ Wroclaw Medical University. 2017;(6):925-930
Abstract
BACKGROUND Studies have suggested that metabolic syndrome (MetS) is associated with increased depressive symptoms, and reducing depression in subjects with MetS is important. Crocin, an active component of saffron, has useful properties for subjects with MetS, including antidepressant properties. OBJECTIVES The aim of the study was to assess the effect of a preparation of crocin on the symptoms of depression in subjects with MetS, and the relationship between changes in those symptoms and the serum pro-oxidant/anti-oxidant balance (PAB). MATERIAL AND METHODS This sub-study was carried out on 34 subjects with MetS from the authors' previous randomized double-blind controlled clinical trial (RCT), all of whom met the inclusion criteria for this study. The subjects were randomly assigned to treatment and placebo groups (n = 17 in each group) and received each 30 mg of crocin (2 tablets of 15 mg) or placebo for 8 weeks. Depressive symptoms were assessed using the Beck Depression Inventory (BDI). The BDI questionnaire was completed for each subject at the baseline and at the end of the 8th week of treatment. Blood samples were taken from the subjects before and after the intervention period. Statistical analyses were performed using the SPSS for Windows, v. 16 (SPSS Inc., Chicago, USA). RESULTS Out of the 34 participants enrolled, 33 completed the trial. The degree of depression decreased significantly in the crocin group (p = 0.005), but not in the placebo group (p > 0.05), and the difference between the 2 groups was statistically significant (p = 0.013). No significant relationship was observed between changes in depression symptoms and changes in the serum PAB (p > 0.05). CONCLUSIONS This study demonstrates that at a dose of 30 mg per day for 8 weeks, crocin reduced the symptoms of depression in subjects with MetS compared to the control group, and this effect was independent of its effect on the serum PAB.
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Saffron aqueous extract prevents metabolic syndrome in patients with schizophrenia on olanzapine treatment: a randomized triple blind placebo controlled study.
Fadai, F, Mousavi, B, Ashtari, Z, Ali beigi, N, Farhang, S, Hashempour, S, Shahhamzei, N, Bathaie, SZ
Pharmacopsychiatry. 2014;(4-5):156-61
Abstract
OBJECTIVE The aim of this study was to assess whether saffron aqueous extract (SAE) or its active constituent, crocin, prevents olanzapine-induced metabolic syndrome (MetS) and insulin resistance in patients with schizophrenia. METHODS 66 patients diagnosed with schizophrenia who were on olanzapine treatment (5-20 mg daily) were randomly allocated to receive a capsule of SAE (n=22; 30 mg daily), crocin (n=22; 30 mg daily) or placebo (n=22) in a 12-week triple-blind trial. Patients were screened not to have MetS at baseline and further assessment was done at weeks 6 and 12. Measurement of fasting blood glucose (FBS) and serum lipids were repeated at weeks 2, 6 and 12. Fasting blood levels of insulin and HbA1c were also measured at baseline and week 12. HOMA-IR and HOMA-β were determined to evaluate insulin resistance. RESULTS 61 patients completed the trial and no serious adverse effects were reported. Time-treatment interaction showed a significant difference in FBS in both SAE and crocin groups compared to placebo (p=0.004). In addition, SAE could effectively prevent reaching the criteria of metabolic syndrome (0 patients) compared to crocin (9.1%) and placebo (27.3%) as early as week 6. CONCLUSION SAE could prevent metabolic syndrome compared to crocin and placebo. Furthermore, both SAE and crocin prevented increases in blood glucose during the study.
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A carotenoid health index based on plasma carotenoids and health outcomes.
Donaldson, MS
Nutrients. 2011;(12):1003-22
Abstract
While there have been many studies on health outcomes that have included measurements of plasma carotenoids, this data has not been reviewed and assembled into a useful form. In this review sixty-two studies of plasma carotenoids and health outcomes, mostly prospective cohort studies or population-based case-control studies, are analyzed together to establish a carotenoid health index. Five cutoff points are established across the percentiles of carotenoid concentrations in populations, from the tenth to ninetieth percentile. The cutoff points (mean ± standard error of the mean) are 1.11 ± 0.08, 1.47 ± 0.08, 1.89 ± 0.08, 2.52 ± 0.13, and 3.07 ± 0.20 µM. For all cause mortality there seems to be a low threshold effect with protection above every cutoff point but the lowest. But for metabolic syndrome and cancer outcomes there tends to be significant positive health outcomes only above the higher cutoff points, perhaps as a triage effect. Based on this data a carotenoid health index is proposed with risk categories as follows: very high risk: <1 µM, high risk: 1-1.5 µM, moderate risk: 1.5-2.5 µM, low risk: 2.5-4 µM, and very low risk: >4 µM. Over 95 percent of the USA population falls into the moderate or high risk category of the carotenoid health index.