White as milk: Biocentric bias in the framing of lactose intolerance and lactase persistence.

The majority of the world population is lactose intolerant, as 65%-70% of people lose the enzymes to digest lactose after infancy. Yet, in the United States, where lactose intolerance is predicted to affect only 36% of people, this phenomenon is often framed as a deficiency as opposed to the norm. This is because the United States has a higher prevalence of people who are lactase persistent. Lactase persistence is a genetic trait most common among Europeans and some African, Middle Eastern and southern Asian groups with a history of animal domestication and milk consumption. In this study, we take the case of lactose intolerance to examine how popular media maintains biocentric biases. Analysing relevant articles published in The New York Times and Scientific American between 1971 and 2020, we document how ideas about milk, health and race evolve over time. Over this fifty-year period, writers shifted from framing lactose intolerance as racial difference to lactase persistence as evolutionary genetics. Yet, articles on the osteoporosis 'epidemic' and vitamin D deficiency worked to perpetuate lactose intolerance as a health concern and standardise the dairy-heavy American diet. Studying media portrayals of lactose intolerance and lactase persistence, we argue that popular discourses normalise biocentric biases through messages about eating behaviours and health.