Dietary myo-inositol intake and peripheral nerve function in diabetic neuropathy

Abstract

The effect of variations in dietary myo-inositol intake upon plasma myo-inositol concentrations, urinary myo-inositol excretion, motor nerve conduction velocities in the median and peroneal nerves, and sensory nerve conduction velocities in the median and sural nerves was studied in six nondiabetic subjects and in twenty patients with symptomatic distal symmetrical diabetic polyneuropathy. Diets were developed which provided either a low, a normal, or a high intake of myo-inositol. In control subjects, the low- myo-inositol diet was found to decrease, while the high- myo-inositol diet increased both the preprandial plasma myo-inositol concentrations and the daily urinary excretion of myo-inositol. These diets had little effect upon measured nerve function in the control subjects, although the high- myo-inositol diet appeared to slightly reduce the median sensory nerve conduction velocity in this group. In the neuropathic diabetics, the low- and high- myo-inositol diets were found to have similar effects upon the plasma myo-inositol concentrations and urinary myo-inositol excretion, but did not affect the plasma glucose concentrations. When analyzed by groups, no statistically significant changes were observed in any of the measured nerve conduction velocities in the diabetic patients. However, when the change in nerve conduction velocity was analyzed, it was found that the ingestion of the high- myo-inositol diet resulted in a statistically significant increase in the median sensory (+1.92 m/sec, p < 0.001) and the sural sensory nerve conduction velocity (+6.67 m/sec, p < 0.001). In contrast, ingestion of the low- myo-inositol diet produced a statistically significant decrease in the median motor (−2.35 m/sec, p < 0.001) and the peroneal motor nerve conduction velocity (−1.18 m/sec, p < 0.001). Thus, ingestion of a diet enriched in myo-inositol may have a salutory effect upon peripheral nerve function in the patient with symptomatic diabetic neuropathy and appears to be without significant side effects in this patient group.