How functional medicine leverages systems biology and epigenetic science to treat the microbiome and reverse chronic disease. Each body is a system within a system--an ecology within the larger context of social, political, economic, cultural, and environmental factors. This is one of the lessons of epigenetics, whereby structural inequalities are literally encoded in our genes. But our ecological embeddedness extends beyond DNA, for each body also teems with trillions of bacteria, yeast, and fungi, all of them imprints of our individual milieus. Nested Ecologies asks what it would mean to take seriously our microbial being, given that our internal ecologies are shaped by inequalities embedded in our physical and social environments. Further, Rosalynn Vega argues that health practices focused on patients' unique biology inadvertently reiterate systemic inequities. In particular, functional medicine--which attempts to heal chronic disease by leveraging epigenetic science and treating individual microbiomes--reduces illness to problems of "lifestyle," principally diet, while neglecting the inability of poor people to access nutrition. Functional medicine thus undermines its own critique of the economics of health care.

Drawing on novel digital ethnographies and reflecting on her own experience of chronic illness, Vega challenges us to rethink not only the determinants of well-being but also what it is to be human.