Table 1.
Included experimental animal studies on the nerve-regenerating effect of neurotropic B vitamins.
| Reference | Studied B vitamin(s) | Species | Main findings/conclusion | Nerve-regenerating effect shown? |
|---|---|---|---|---|
| Studies on vitamin B1 (thiamine) only | ||||
| Song 2009 [33] | B1 | Rat | Thiamine suppressed thermal hyperalgesia, reduced hyperexcitability, and lessened alterations of sodium currents in injured dorsal root ganglion neurons. | Yes |
| Stracke 2001 [29] | B1 | Rat | In comparison to water-soluble thiamine nitrate, early administration of liposoluble vitamin B1 (benfotiamine) prevented formation of advanced glycation end-products and functional nerve damage to a much higher degree than when given later during experimental diabetes. | n/a, neuroprotection |
|
| ||||
| Studies on vitamin B6 (pyridoxine) only | ||||
| Yang 2009 [36] | B6 | Rat | Vitamin B6 inhibited glutamate release from rat cortical synaptosomes through the suppression of presynaptic voltage-dependent Ca2+ entry and protein kinase C activity. | n/a, neuroprotection |
|
| ||||
| Studies on vitamin B12 (cobalamin) only | ||||
| Albay 2020 [58] | B12 | Rat | B12 attenuated sciatic nerve injury. B12 and cholecalciferol synergistically improved functional and histopathological nerve healing. | Yes |
| Horasanli 2017 [48] | B12 | Rat | Vitamin B12 promoted functional recovery, improved axonal regeneration, and attenuated edema and myelin sheath degeneration after sciatic nerve injury. | Yes |
| Wang 2015 [56] | B12 | Rat | Vitamin B12 had an antiapoptotic effect and possibly promoted nerve regeneration by inhibiting the apoptosis of damaged neurons and creating conditions for the recovery of nerve function. | n/a |
| Gan 2014 [47] | B12 | Mouse | High-dose vitamin B12 promoted functional recovery of nerves (sciatic nerve) after peripheral nerve injury. It also promoted morphological recovery, possibly by upregulation of neurotrophic factors. | Yes |
| Romano 2014 [69] | B12 | Rat | Vitamin B12 treatment accelerated reepithelization and corneal reinnervation after mechanical injury (removal of corneal epithelium). | Yes |
| Tamaddonfard 2014 [42] | B12 | Rat | High-dose vitamin B12 increased functional recovery and promoted peripheral nerve regeneration by reducing Wallerian degeneration responses after tibial nerve crush injury. | Yes |
| Sun 2012 [52] | B12 | Rat | Dexamethasone and vitamin B12 synergistically promoted peripheral nerve repair after sciatic nerve injury through the upregulation of brain-derived neurotrophic factor expression and were more effective in combination than both of the treatments alone. | Yes |
| Jian-bo 2010 [30] | B12 | Rat | Vitamin B12 delayed the onset of diabetic peripheral neuropathy via upregulation of neural insulin–like growth factor 1 gene expression, particularly together with good glycemic control. | Yes |
| Liao 2010 [41] | B12 | Rat | Vitamin B12 facilitated functional recovery, enhanced motor end plate innervation, and augmented the diameters and myelin thickness of regenerated axons following end-to-end neurorrhaphy. | Yes |
| Okada 2010 [57] | B12 | Rat | High-dose vitamin B12 promoted neurite outgrowth and neuronal survival and increased extracellular signal-regulated kinases and Akt signaling after sciatic nerve injury. It also promoted functional recovery of nerves. | Yes |
| Yuan 2010 [46] | B12 | Mouse | Vitamin B12 promoted functional recovery and histological regeneration of the injured sciatic nerve and its target muscle after sciatic nerve injury. | Yes |
| Watanabe 1994 [50] | B12 | Rat | High-dose vitamin B12 promoted functional recovery and increased nerve fiber density, numbers of small- and medium-sized myelinated fibers, and fiber diameters in acrylamide-induced peripheral neuropathy. | Yes |
| Yamazaki 1994 [49] | B12 | Mouse | Vitamin B12 promoted regeneration of degenerating nerve terminals in gracile axonal dystrophy, possibly by acting both on motorneurons and Schwann cells. | Yes |
| Mikhaĭlov 1987 [51] (translated from Russian into English) | B12 | Rat | Vitamin B12 accelerated the reinnervation of skeletal muscles after experimental mechanical damage. | Yes |
| Yamatsu 1976 [53] (translated from Japanese into English) | B12 | Rat | Vitamin B12 enhanced protein metabolism in Schwann cells at the initial stages of axonal regeneration after sciatic nerve injury and thereby possibly facilitated axonal regeneration. | n/a |
|
| ||||
| Studies on vitamin B complex (including at least B1, B6, B12) and possibly further B vitamins | ||||
| Al-Saaeed 2019 [65] | B1, B6, B12 | Rat | Results confirmed that vitamin B12 played an essential role in neuronal regeneration through myelination of the injured nerve. It promoted nerve regeneration better than the other B vitamins and better than the combination. | Yes |
| Ehmedah 2019 [68] | B1, B2, B3, B5, B6, B12 | Rat | Vitamin B complex treatment attenuated local inflammation after peripheral nerve injury. | Yes |
| Nedeljković 2017 [67] | B1, B2, B3, B5, B6, B12 | Rat | Treatment with vitamin B complex (B1, B2, B3, B6, B12) immediately after injury and reconstruction of the peripheral motor nerve improved recovery of the injured nerve. Vitamin B complex attenuated muscle atrophy and the increase in nerve and muscle nuclear density, which was observed after injury of the femoral nerve and its target muscle. | Yes |
| Altun 2016 [63] | B1, B6, B12 | Rat | Tissue levels of vitamin B complex and vitamin B12 varied with progression of crush-induced sciatic nerve injury. Supplementation of these vitamins in the acute period may help accelerate nerve regeneration. | n/a |
| Jolivalt 2009 [28] | B1, B6, B12 | Rat | In experimental diabetes, repeated daily treatment with vitamin B complex (B1, B6, B12) ameliorated tactile allodynia and formalin-evoked hyperalgesia in a dose-dependent manner and improved sensory nerve conduction velocity. None of the individual B vitamins was as effective as the combination in restoring nerve function (nerve conduction velocity). | Yes |
| Fujii 1996 [62] | B1, B6, B12 | Rat, mouse | Vitamin B complex (B1, B6, B12) promoted neurite outgrowth and effectively treated acrylamide-induced neuropathy. It played an important role in growth and repair of nerve fibers. | Yes |
| Becker 1990 [66] | B1, B6, B12 | Rabbit | Vitamin B complex (B1, B6, B12) increased the number of regenerated axons, especially of myelinated fibers, and decreased the occurrence of degradation products in the degenerated nerve section after cold lesion of the N. saphenous compared with placebo. | Yes |
| Stotzem 1988 [64] | B1, B6, B12 | Rat | Vitamin B complex slightly increased nerve regeneration after sciatic nerve injury but the difference vs. control was not statistically significant. | Small, statistically nonsignificant difference |
n/a: not applicable.