Broadening the vaccine metaphor: The adequate balanced food (ABF) vaccine against tuberculosis (Acid-fast bacilli/AFB) and more.

Nutrition is essential to survival, health, and protection from disease across the lifespan. In the 1970s, an adequate diet was described as the most effective vaccine available for respiratory, diarrheal, and other common infections, as nutritional supplementation reduced these in the setting of undernutrition. Recently, the RATIONS (Reducing Activation of Tuberculosis through Improvement Of Nutritional Status) trial showed the efficacy of nutritional supplementation in reducing TB incidence in households by up to 50%, and an editorial used the metaphor of food as a vaccine for tuberculosis. This essay provides a historical overview of nutrition and TB prevention, with reports of reduced TB incidence from nutritional supplementation in World War II prisoner-of-war camps. This essay discusses additional evidence supporting McKeown's proposition that the historical decline of TB in countries like the UK was related to improvements in nutrition. Undernutrition is the leading risk for tuberculosis incidence globally, the underlying cause of 45% of 4.9 million deaths in children under five years annually. Undernutrition in early life is a risk factor for many non-communicable diseases, and its effect on cognition and growth perpetuates both undernutrition and poverty intergenerationally. The essay broadens the vaccine metaphor to describe adequate balanced food (ABF) as a vaccine for TB and many public health problems, with a unique product profile. It concludes with a reminder that nutrition acts by optimizing immune function - the most powerful system/vaccine we have for TB prevention; draws attention to emerging threats to food security like climate change and conflicts, and proposes that the answer to the prevention of TB may lie in better population health rather than only a war on the bacillus.