When speaking about nerve health, vitamin B complex is an essential nutrient. These vitamins play a significant role in energy production in the body.
They include thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), pyridoxine (vitamin B6), biotin (vitamin B7), folate (vitamin B9), and cobalamin(vitamin B12).
Vitamin B deficiency is the most common cause of neurological disorders worldwide. Poor diet, excessive alcohol consumption, vegan diet plans, gastric disorders, severely compromised immunity, etc. are few of the risk factors for vitamin B deficiency.
B complex vitamins are water soluble, and they partner with coenzymes to sustain various biochemical pathways in the brain. These biochemical pathways are necessary for few functions such as:
• Producing energy in the cells
• Production of neurotransmitters
• Metabolism of amino acids
• Development of nerve and brain cells
• Development of myelin- the coating or insulation around nerve cells
• Optimum functioning of central and peripheral nervous system
Let’s explore the role of B complex vitamins in neuropathy.
How does vitamin B complex deficiency cause neuropathy?
Nutritional neuropathies arise from nutrient deficiencies. Diets deficient in B complex vitamins could cause neuropathies or other neurological disorders.
Deficiency in B complex vitamins could also occur due to reduced absorption from the intestine or due to increased alcohol intake or therapy with conventional drugs.
Vitamin B complex supports neurite outgrowth or extension of the tail like structures of the neuron. Vitamin B1, B6, and B12 are actively involved in this growth.
Thiamine deficiency can be responsible for polyneuropathy (affecting multiple nerves) in the lower limbs resembling a ‘burning feet’ sensation.
Malabsorption of vitamin B2 (riboflavin) in the intestine has been linked with neuropathy.
Excessive alcohol intake or treatment with certain drugs (such as isoniazid, an antibiotic) can cause a vitamin B5 (pyridoxine) deficiency. This deficiency may cause reduced nerve fiber density contributing to neuropathy.
Vitamin B6 (folate) deficiency has been linked with sensory rather than motor neuropathy. It can lead loss of axons (tail-like endings of nerve cells).
Quick Gist: Vitamins from the B complex family are involved in various aspects of nerve health such as nerve conduction, development of myelin sheath and other structural aspects. Dietary or another risk factors-induced deficiency of these vitamins contributes to nerve damage and neuropathic pain.
5 Proven Benefits of Vitamin B Complex for Neuropathy
Now that we have understood the importance of vitamin B for nerve health let’s explore some studies investigating this vitamin group’s benefit in peripheral neuropathy.
1. Vitamin B supplementation can help rectify its deficiency
Vitamin B complex deficiencies can be related to a particular vitamin in the group. Folate deficiency neuropathy differs from thiamine deficiency neuropathy; it is slowly progressing and can affect sensory neurons significantly.
Vitamin B6 or pyridoxine deficiency (or even excess) is identified as a causative factor of peripheral neuropathy.
Levodopa treated Parkinson’s patients may experience neuropathy. One of the causes for this is that levodopa may disturb vitamin B12 metabolism. Hence, supplementation of folate and vitamin B12 is recommended.
Early or continuous supplementation with vitamin B can reduce the risk of developing neuropathy with levodopa treatment.
Bariatric surgery may contribute to vitamin B deficiency induced neurological disorders such as polyneuropathy.
Such drug or health condition induced B complex deficiencies can be alleviated with supplementation and aid in reversing neuropathies.
Quick Gist: B vitamin complex deficiencies can be attributed to a deficiency of a single or combination of vitamins in the group. These deficiencies could be caused by factors such as alcoholism, levodopa therapy or chemotherapy or even due to diet-related deficiencies.
2. B complex vitamins can help relieve neuropathic pain
Complex B vitamins are intricately involved in the pain mechanism. Their antioxidant effect, ability to regulate cellular mechanisms and their involvement in neurotransmitter synthesis contributes to their pain relieving effect.
Analgesic or pain-relieving medications prescribed for neuropathic pain appear to be ineffective at times.
Quick Gist: Supplementation with a combination of B vitamins can help reduce neuropathic pain significantly within 2-3 months. B complex vitamins can increase the pain-relieving effect of steroid and analgesics if taken together.
4. B complex vitamins increase therapeutic outcome of standard treatment in neuropathy
Gabapentin and pregabalin are the most commonly prescribed drugs for treating neuropathy.
Allodynia refers to pain response to a stimulus that would not cause pain in normal conditions.
An experimental study reveals that co-administration of vitamin B complex with gabapentin can increase its anti-allodynic effect and relieve neuropathic pain.
Similarly, the combination of thiamine (vitamin B1) and pregabalin are found to have an additive pain-relieving effect and can benefit in the treatment of neuropathic pain.
A study was conducted where patients with diabetic neuropathy were treated with gabapentin alone or in combination with vitamin B complex.
Significant reduction in pain and improvement in the quality of life was observed. The only side effect noted in both groups was dizziness.
The Journal of Diabetes Research, 2016 published a very interesting study. A comparison was drawn between the combination of vitamin B + gabapentin and pregabalin alone.
The treatment was as follows:
• Gabapentin + vitamin B group: Starting with 300mg gabapentin to 3600mg at the last visit and 100mg vitamin B1 and 20mg vitamin B12.
• Pregabalin group: Starting with 75mg/day to 600mg/day.
Significant reduction in pain intensity was observed in both groups. The vitamin B group showed 30% reduction in symptoms which was comparable to the effect of 900mg/day of pregabalin. The incidence of vertigo and dizziness was less in the vitamin B group.
Gabapentin and B complex vitamin combination helped achieved pain reduction as effectively as pregabalin.
Researchers also noted that pregabalin alone could help achieve pain reduction at 50% of the minimum dose of gabapentin.
Quick Gist: Combination of vitamin B with conventional drugs such as gabapentin or pregabalin increases their therapeutic effect in neuropathy.
4. Vitamin B12 benefits in peripheral neuropathy as an antioxidant
The Cochrane Database of Systemic Reviews, 2008 reported that there is insufficient data to comment on vitamin B’s efficacy in peripheral neuropathy.
However, they also noted that high-dose vitamin B could help resolve pain and numbness.
Vitamin B12 plays an important role in maintaining nerve health. It helps in neurite outgrowth (extension of the tail like the structure of nerve cell) and protects nerve cells from cell death.
Treatment with vitamin B12 or its active form (methylcobalamin) can reverse neuropathy and support clinical recovery.
A study published in Nutritional Neuroscience, 2014 revealed that 3-6 month therapy with cyanocobalamin helped improve nerve conduction and support clinical recovery in patients with vitamin B12 deficiency induced neuropathy.
Another clinical study demonstrated that vitamin B12 in combination with folic acid and nucleotide uridine monophosphate (The drug name is Keltican) was found to be effective in reducing pain in all types of peripheral neuropathy.
77.4% of the patients stopped using NSAIDs or painkillers after initiation of this therapy.
Irrespective of vitamin B12 deficiency, certain neuropathies may respond to vitamin B12 therapy owing to its antioxidant nature.
Quick Gist: Vitamin B12 deficiency is a common causative factor of neuropathy, and its supplementation can help reverse peripheral neuropathy. In some cases, neuropathies may respond to vitamin B12 treatment even in the absence of deficiency. This is attributed to the vitamin’s antioxidant nature.
5. Vitamin B12 supplementation reduces symptoms of Diabetic neuropathy
A review study published in 2005 revealed that vitamin B12 supplementation help alleviates pain in diabetic neuropathy. No significant improvement in physiological parameters such as electrical activity of the nerve was observed.
But researchers did comment that there is a need for further good quality research studies.
Treatment with vitamin B complex and Allithiamine (a garlic-derived soluble form of vitamin B1) for nine months was found to improve parameters such as vibration perception and nerve conduction velocity( related to transmission of nerve impulses) in diabetic neuropathy.
A study published in International Journal Of Food Sciences and Nutrition, 2009 demonstrated that vitamin B12 supplementation is as effective as nortriptyline (a tricyclic antidepressant used to relieve pain in neuropathy).
A significant reduction in pain, pins and needles sensation and tingling sensation was observed. However, no change in electric activity was observed in both groups.
A recent study published in Journal of Diabetes Investigation, 2016 compared the effects of acetyl-l-carnitine with vitaminB12 in diabetic neuropathy.
A 24-week therapy with these therapeutic agents led to a reduction in symptoms of neuropathy and also reduced disability associated with it.
It also improved neurophysiological parameters. Acetyl-l-carnitine was found to be as effective as vitamin B12 in improving diabetic neuropathy.
Quick Gist: Due to chronic use of anti-diabetes medication such as metformin, vitamin B12 deficiency is observed in the patients. This causes nerve damage. Supplementation with methylcobalamin (B12) is proven to provide symptomatic relief in this condition.
Some studies suggest that vitamin B therapy may not be effective in some cases
Chronic kidney failure patients with peripheral polyneuropathy are found to respond to vitamin B6 therapy rather than vitamin B12 supplementation even if no vitamin B6 deficiency was observed.
Interestingly high-dose vitamin B6 or pyridoxine supplementation is found to cause neuropathy.
The Cochrane Database of Systemic Reviews, 2008 stated that there is insufficient evidence to comment on vitamin B’s effectiveness in peripheral neuropathy.
They found vitamin B is less efficacious than therapeutic agents like alpha-lipoic acid, cilostazol or cytidine triphosphate as far as clinical improvement in parameters like nerve conduction was concerned.
A recent review study published in Singapore Medical Journal, 2016 suggested that no evidence proves that use of oral vitamin B12 supplements benefits in neuropathy.
Quick Gist: A few studies have found that oral vitamin B supplementation may not be effective in neuropathy. This could be explained by the fact that severe cases may require vitamin B injections and some may require supplementation with a particular vitamin from the B complex group.
Also, most studies mentioned earlier report that vitamin B helps relieve pain due to nerve damage, but these have not translated into an improvement in electrical activity of the nerves. But it does provide symptomatic relief.
Long-term studies should be conducted to assess their action on nerve’s electric activity.
High-dose vitamin B6 (more than 50mg/day) may cause neuropathy, and hence the dose should be determined with the help of a health practitioner.
Dietary Sources of Vitamin B complex
Though neuropathy treatment would require vitamin B supplementation, it is great to include to certain vitamin B rich foods in the diet.
Thiamine or vitamin B1 can be obtained from whole grain foods, poultry, lean meats, seafood, nuts, soy foods, etc. Vitamin B12 is not found in plant foods. It can be obtained from milk, eggs and meat products.
Vitamin B6 is mostly found in organ meats, fish, poultry and starchy vegetables. Folate can be obtained from dark leafy greens, fruits, poultry, dairy products, and meats.
Dosage of vitamin B complex for neuropathy
The dose of vitamin B complex for peripheral neuropathy treatment is dependent on the severity and nature of the condition. It is important to identify which vitamins one is deficient in.
Vitamin B12 dose (i.e., cyanocobalamin) ranges from 20 mcg to 1,840 mcg daily while for methylcobalamin, it is 4 mg and 1,500 mg daily.
Intramuscular injections may be necessary in some cases.
Benfotiamine ( a bioavailable form of thiamine) at high doses of 150-320 mg per day is effective in diabetic neuropathy.
It is best to consult a health practitioner about the dosage of vitamin B complex before initiating therapy.
B complex vitamins are safe if taken in recommended dosages. However, vitamin B6 at high doses can cause toxicity and even neuropathy.
Vitamin B12 may interact with medications like chloramphenicol, proton pump inhibitors, histamine antagonists, metformin, etc.
Thiamine may interact with digoxin, diuretics, and phenytoin. Please consult a health practitioner before taking vitamin B supplements.
Vitamin B complex can help reduce neuropathic pain significantly. In some cases, it can even reverse neuropathy.
However, some studies do suggest that it may not improve the electric activity of the nerve. Further research in the form of long-term studies should investigate this aspect.
Combination of B complex vitamins with conventional treatment (gabapentin and pregabalin) can improve therapeutic outcome.
B complex vitamins are essential for maintaining good nerve health. One can test for vitamin B deficiency to identify which vitamin supplement could benefit.
However, some neuropathies may respond to vitamin B therapy even in the absence of a deficiency.
Please consult a health practitioner before taking vitamin B supplements for neuropathy to ascertain the dosage and combination that would suit your condition.