Article Source : Natural Health Research Institute
Written by Angeline A. De Leon, Staff Writer.
Eight weeks of supplementation with tocotrienol improved diabetic peripheral neuropathy (DPN) in participating subjects compared to placebo.
Characterized by pain and numbness in the extremities, DPN is a complication associated with type 2 diabetes and the most common type of diabetic neuropathy 1. While approximately 50% of patients with DPN are asymptomatic, the other half typically presents with neuropathic pain or may develop diabetic foot ulcers, which can necessitate amputation 2. The pathogenesis of DPN is thought to involve a dysfunction of metabolic pathways, including those associated with oxidative stress, inflammation, and nerve growth factor (NGF), as a result of chronic hyperglycemia 1,3. Progression of DPN is also paralleled by demyelination and neuronal degeneration, reflected by diminished nerve conduction velocity 4. Although treatment of DPN has primarily focused on symptom management and/or enhancing glycemic control 5, supplementation with vitamin E represents a potential approach to directly improving DPN 6. Vitamin E, and its tocotrienol isoform specifically, are associated with neuroprotective and anti-inflammatory properties 7, and though scarce, evidence suggests that supplementation with tocotrienol-rich vitamin E (Tocovid) can enhance median motor nerve conduction velocity in patients with diabetes 8. Other studies also indicate that vitamin E intake in patients with DPN can effectively ameliorate neuropathic pain based on self-report measures 6,9. In a 2020 study 10 published in Nutrients, researchers evaluated the relationship between Tocovid intake and DPN, based on changes in nerve conduction parameters, in patients with type 2 diabetes.
A total of 77 diabetic patients (aged 35 to 75 years) were enrolled in a prospective, randomized, double-blind, placebo-controlled trial in which they were randomly assigned to receive 200 mg of either Tocovid or matching placebo twice daily for 8 weeks. At baseline and at 8-week follow-up, a nerve conduction study (NCS) was carried out (bilaterally on median and sural sensory nerves and the tibial motor nerve), and fasting venous blood samples were collected to determine serum biomarkers associated with DPN (malondialdehyde, MDA; nerve growth factor, NGF; serum thromboxane B2, TXB2).
At the end of 8 weeks, the Tocovid group demonstrated a significant increase in conduction velocity for the median (+1.25 m/s), sural (+1.60 m/s), and tibial (+0.75 m/s) nerves (p < 0.001 for all). No significant between-group differences were observed for amplitude of action potential for any of the nerves. After 8 weeks, serum levels of NGF were also found to be significantly higher for subjects in the Tocovid group, compared to placebo (p = 0.047). No significant between-group differences were detected for any of the other serum biomarkers.
Based on findings, researchers conclude that tocotrienol-rich vitamin E is capable of improving DPN in patients with type 2 diabetes, based on enhanced nerve conduction velocities. After 8 weeks of supplementation, Tocovid patients exhibited improved nerve conduction in the median, sural, and tibial nerves, reflecting the attenuation of demyelination associated with pre-clinical DPN 4. Improvements in nerve conduction parameters were also paralleled by elevations in serum NGF in Tocovid subjects, which may indicate amelioration of neuronal injury and enhancement of nerve function 11. It is hypothesized that Tocovid’s therapeutic effects against DPN may potentially involve NGF as a direct pathway, however, further studies are needed to confirm this. Results also require replication in subjects with confirmed cases of DPN. Despite a relatively short study duration and a limited sample size, general findings from the study provide valuable evidence to suggest that intake of tocotrienol-rich vitamin E may be capable of reversing the progression of DPN in its early stages.
Source: Ng, Yeek Tat, Sonia Chew Wen Phang, Gerald Chen Jie Tan, En Yng Ng, Nevein Philip Botross Henien, Uma Devi M Palanisamy, Badariah Ahmad, and Khalid Abdul Kadir. “The Effects of Tocotrienol-Rich Vitamin E (Tocovid) on Diabetic Neuropathy: A Phase II Randomized Controlled Trial.” Nutrients 12, no. 5 (2020): 1522.
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