Abstract
Background: Although the micronutrients (vitamins and trace minerals) essential for growth and normal physiological function are obtained from the diet, a substantial fraction of the human population is deficient in one or more micronutrients due to inadequate nutrition and/or malabsorption. Methods: This narrative review examines evidence that airborne micronutrients ('aeronutrients') are readily absorbed by the lungs, and preclinical and clinical evidence that inhaled iodine and vitamins A, B12 and D can enter the bloodstream. Results: Inhaled vitamin B12 resolves the symptoms and haematological features of pernicious anaemia with a bioavailability comparable to intramuscular injections and superior to oral formulations. Inhaled nebulised vitamin A restores serum levels in children with retinol deficiency. Randomised controlled trials have reported that inhalation of nebulised preparations of vitamins A, B12, magnesium and zinc are well tolerated and not associated with adverse health effects. Aeronutrient formulations have untapped potential for the therapeutic treatment of nutritional deficits, particularly in individuals with malabsorption or a low tolerance of injections. Aeronutrient therapy should be regarded as a medical intervention and be regulated accordingly, with efficacy and safety supported by scientific evidence, unlike the 'vitamin vapes' marketed by the wellness industry. Conclusions: Before this potential can be realised, a regulatory framework will need to be developed for aeronutrients. The high effectiveness of the pulmonary route introduces concerns regarding overdosing and toxicity which can best be addressed by categorising these formulations as prescription drugs that require regular monitoring of nutritional and health status.