Vitamin B12, Sulfites and Bronchospasm

Sulfites have been implicated as the cause of bronchospasm in some subjects with asthma. However, there is still no universally accepted explanation of the pathogenesis of these reactions.

In a clinical trial, weekly intramuscular injections of 1,000 mcg of vitamin B12 (cyanocobalamin) produced significant improvements in asthma patients. 18 of 20 patients showed decreased shortness of breath on exertion and improvement in appetite, sleep, and general condition.⁷⁹

B Anibarro, et al., studied five children with asthma with metabisulfite intolerance confirmed by oral challenge testing. The challenge test with metabisulfite was repeated after premedication of all the patients with 1.5 mg of oral cyanocobalamin - vitamin B12. 

In four of the five patients treated with cyanocobalamin, bronchospasm did not develop in the second metabisulfite challenge.⁸⁰

It is suggested that oral supplementation with 1 to 3 milligrams of vitamin B12 daily may provide a benefit similar to that provided by the injectable form.⁸¹