Nutritional and Acquired Deficiencies in Inositol Bioavailability. Correlations with Metabolic Disorders

Abstract

Communities eating a western-like diet, rich in fat, sugar and significantly deprived of fibers, share a relevant increased risk of both metabolic and cancerous diseases. Even more remarkable is that a low-fiber diet lacks some key components—as phytates and inositols—for which a mechanistic link has been clearly established in the pathogenesis of both cancer and metabolic illness. Reduced bioavailability of inositol in living organisms could arise from reduced food supply or from metabolism deregulation. Inositol deregulation has been found in a number of conditions mechanistically and epidemiologically associated to high-glucose diets or altered glucose metabolism. Indeed, high glucose levels hinder inositol availability by increasing its degradation and by inhibiting both myo-Ins biosynthesis and absorption. These underappreciated mechanisms may likely account for acquired, metabolic deficiency in inositol bioavailability.

Inositol and antioxidant supplementation: Safety and efficacy in pregnancy

“…Inositol (cyclohexanehexol), a cyclic carbohydrate with six hydroxyl groups, was originally isolated in 1850 from muscle extracts by Scherer and named Myo‐inositol (Myo), from the Greek word meaning “muscle.” Myo can be obtained through biosynthetic mechanisms and from dietary sources. Although Myo was initially considered as an essential nutrient belonging to the vitamin B family, it has been observed that the liver and the kidneys are able to produce up to 4 g/day of inositol.…”

“…Inositol deficiency may arise through a plethora of different mechanisms, including reduced intake, increased catabolism and excretion, decreased biosynthesis, and an inhibition of intestinal and cellular uptake. Inositol deficiency can significantly affect several human pathological conditions . Myo is a precursor for many inositol‐containing compounds, playing critical and different roles in signal transduction, in membrane biogenesis, in vesicle trafficking, and in chromatin remodelling …”

“…As a matter of fact, Myo and DCI seem to be both implicated in glucose homeostasis, since abnormalities in the metabolism of both has been associated to insulin resistance and diabetes . Conversely, glucose can interfere with Myo metabolism at different levels, both increasing Myo degradation and inhibiting its biosynthesis and absorption, thus contributing to the Myo depletion observed in diabetes …”

“…Inositol is actively transported into the cell through two different mechanisms, primarily involving sodium ion‐coupled (SMIT1 and SMIT2) and proton‐coupled transporters (HMIT1) . SMIT1/2 are influenced in different ways by glucose and by glucose‐dependent metabolic pathways . For instance, inhibitors of the sodium/glucose transporter 1/2 prevent both inositol and glucose uptake in hepatocytes, probably because this transporter system is common to these molecules .…”

Myo‐inositol in health and disease: its impact on semen parameters and male fertility

“…It has been established that MI, its phosphate derivatives, and associated lipids are present in different food types (corns, beans, fruits, nuts) and are widely distributed in several animal tissues (Clements & Darnell, 1980;Schlemmer et al, 2009;Dinicola et al, 2017). MI is mainly present in animals in its free form or as phosphatidylinositol (PI); in breast milk, is found in its free form and as 6-b-galactinol (Naccarato & Wells, 1974).…”