Inositol’s and other nutraceuticals’ synergistic actions counteract insulin resistance in polycystic ovarian syndrome and metabolic syndrome: state-of-the-art and future perspectives

Abstract

The incidence of metabolic syndrome (MetS), type II diabetes (T2D) and polycystic ovarian syndrome (PCOS) has been progressively increasing. Insulin resistance (InsR) seems to play a key role in a majority of phenotypes of these conditions, altering metabolic homeostasis, within muscle, liver, adipose and other tissues. Hyperinsulinemia is often associated with InsR and causes hormonal imbalances especially within ovaries and adrenals. Inositol is a polyalcohol, naturally occurring as nine stereoisomers, including D-chiro-inositol (DCI) and myo-inositol (MI), which have prominent roles in the metabolism of glucose and free fatty acids. MI and DCI have been classified as insulin-sensitizers and seem to adequately counteract several InsR-related metabolic alterations with a safe nutraceutical profile. Based on our analysis of selected studies that investigated MI and/or DCI, we conclude that supplementation with MI and/or DCI complement each other in their metabolic actions and act in synergy with other insulin sensitizing drugs and/or nutraceuticals. Nevertheless, considering the possible severe bias due to different methodologies across published studies, we conclude that there is a need for further studies on larger cohorts and with greater statistical power. These should further clarify outcomes and suitable therapeutic dosages of MI and DCI, possibly based on each patient’s clinical status.

Chinese abstract

代谢综合征（MetS）,II型糖尿病（T2D）和多囊卵巢综合征（PCOS）的发病率在持续增加。胰岛素抵抗（InsR）似乎在打破肌肉、肝脏、脂肪等组织的代谢平衡产生这些疾病的外在症状的过程中发挥关键作用。高胰岛素血症常与InsR相联系，并导致激素失衡特别是卵巢和肾上腺激素的失衡。肌醇是一种多元醇，一般以9种立体异构体的形式出现,包括D-手-肌糖（DCI）和肌醇（MI）,对葡萄糖和游离脂肪酸的代谢有明显的作用。MI和DCI被列为胰岛素致敏剂，作为安全的营养食品它们似乎能够充分抵消与InsR相关的代谢改变。根据我们选定的调查DCI和/或MI的研究分析得出结论：在协同与其他代谢行为和胰岛素增敏的药物或营养品方面，MI和/或DCI相辅相成。然而,考虑到已发表研究中由于方法不同可能导致的严重偏差,我们认为有必要进行大型的队列研究,以获取更强的统计支持。这些可以进一步证实我们的结论并根据每个病人的临床状态制定合适的MI和DCI的治疗剂量。

• Diabetes
• insulin
• insulin resistance
• insulin sensitizer
• polycystic ovary syndrome

Declaration of interest

All the authors have no proprietary, financial, professional or other personal interest of any nature in any product, service, or company other than what is declared for each author under credentials. C. Paul provides research consulting services to Designs For Health, Inc but has no particular financial interest in any product containing ingredients mentioned in this article. The authors alone are responsible for the content and writing of this article. No specific funding was obtained.