Both the direct toxic effects of alcohol and alcoholism-associated vitamin deficiencies can cause mild to incapacitating sensorimotor polyneuropathy.

In a 10-site randomized, placebo-controlled trial, researchers assessed whether B vitamins could benefit 253 patients with alcohol dependence, sensory symptoms, signs of alcoholic neuropathy (as shown on nerve conduction studies), and diminished vibration perception at the big toe (determined by biothesiometry). 

People with other possible neuropathy etiologies or neuropathy lasting for more than 2 years were excluded.

Subjects were randomized to receive one of the following to be taken orally 3 times a day for 12 weeks: placebo, B vitamins (B1 250 mg, B2 10 mg, B6 250 mg, and B12 0.02 mg), or B vitamins plus folic acid (1 mg). Eighty-one percent of subjects completed the trial.

• Vibration perception at the big toe, the primary study endpoint, improved significantly more in both vitamin groups than in the placebo group (increase of approximately 1–2 points vs. 0.5 points on a scale from 0 to 8).
  
  
• Pain, sensory function, and eye-nose coordination with eyes closed also improved more in the vitamin groups.  
  
  
• The number of adverse events was similar in all groups.

 
Comments by Richard Saitz, MD, MPH:
These findings -- B vitamins have efficacy for alcoholic polyneuropathy -- are consistent with those reported in other studies.

It is difficult, however, to know whether patients will notice improvements with B vitamins or whether these improvements are detectable only via a sensitive research instrument (e.g., biothesiometry).

Nonetheless, with favorable safety profiles and low cost, B vitamins are a welcome treatment for people with this often troubling condition. 

Reprinted with permission from Alcohol and Health: Current Evidence.