Carpal Tunnel Syndrome and Vitamin B6

Carpal Tunnel Syndrome (CTS) is a common condition usually associated with repetitive strain from jobs that require a fast, constant movement of the arms and hands (such as working on an assembly line). Up to 9% of adult women develop CTS and the incidence increases after age 50. A common medical treatment approach has been a combination of drugs (including corticosteroids), diuretics, splinting at night, and modifying activities, often including a “light duty” status until the symptoms calm down. Prior to accepting surgery as, “…the only option left,” an “alternative treatment” approach of vitamin B6 (and of course, chiropractic manual therapies) is chosen by many. Many treatment approaches have been previously discussed; however, today, we’ll take a closer look at the vitamin B6 /CTS connection.

Research regarding the use of vitamin B6 or, pyridoxine, can be traced way back into the ‘70s and ‘80s when it was reported that B6 is involved in several metabolic pathways, including neural function (“neurotransmission”). This is how it helps CTS patients since CTS occurs as the consequence of a pinched (median) nerve at the wrist. Findings from the initial studies, though quite small in terms of the number of subjects, suggested B6 improved the symptoms of CTS (such as, numbness and tingling into the 2nd to 4th palm-side fingers) by raising the pain threshold (that is, the point when symptoms occurred). Another study reported improvements in pain scores and mild improvements in electromyography and nerve conduction velocity (EMG-NCV) studies. Another study reported that at least 7 patients in their study were B6 deficient when blood tested. Regarding the dose, one study reported that taking only 2mg of B6 was enough to improve the patient’s CTS symptoms, but 100mg was needed for the avoidance of surgery. In a large “retrospective literature review” of 994 CTS patient files, it was reported that when 494 patients were treated with 100mg twice a day, the rate of symptom alleviation was 68%, much higher than group that did not receive B6 (only 14.3%). Yet, controversy is still reported about the effectiveness of B6 and firm conclusions are lacking. Despite this uncertainty, 200 mg of vitamin B6 is frequently included as part of the non-surgical “package” (along with NSAIDs like ibuprofen, nighttime splints, and an ergonomic workstation evaluation).

So, how much B6 is “enough?” The recommended daily intake is only 2 mg or less for all ages, genders and lifestyles with an upper limit set at 100 mg/day. The main toxicity issue is sensory neuropathy, which (oddly) is very similar to the symptoms caused by CTS! The good news is that CTS symptoms rapidly disappear at doses < 1000 mg/day and most studies indicate no toxic neuropathy by taking doses between 40 and 500 mg/day. Hence, it is recommended to never exceed 500mg/day and most recommendations are in the 100-200 mg/day range. If symptoms improve, a gradual reduction in the dose after about 3 months is advised. Closer monitoring of symptoms in those taking >200mg/day is recommended, especially since the symptoms of toxicity and CTS are so similar. Other B6 toxicity symptoms include depression, fatigue, impaired memory, irritability, headaches, altered walking, and bloating. So, keep your eyes open if doses >200mg/day are taken. Other micronutrients to consider that are anti-inflammatory in nature include omega 3 fatty acids, vitamin D, magnesium (often in combination with calcium), Co-Q10, proteolytic enzymes, and herbs such as ginger, tumeric, boswellia, white willow bark and more.