number of exposures to antibiotics in infancy (Shao et al. 2017). The same is true for
psychiatric (Köhler-Forsberg et al. 2019), and allergic disorders (Strzępa et al. 2018),
and there is perhaps an association between antibiotic use and some autoimmune
diseases (Strzępa et al. 2018; Dydensborg Sander et al. 2019; Kemppainen et al.
2017). These findings are particularly worrying because a recent study of 8 low- and
middle-income countries revealed an average of 11 antibiotic prescriptions by the
age of 2 years (Fink et al. 2019). This will hasten the switch to a Western pattern of
metabolic, psychiatric, and inflammatory disorders.
However, this essay concentrates on the role of exposure to the microbiota of the
natural environment, and mentions the human microbiotas only when exposure to
the natural environment is a major determinant of the constitution, integrity, and
function of the human microbiota. For example, the natural environment can supply
organisms to replace those eliminated by antibiotics. Many epidemiological studies
suggest that exposure to the green environment is beneficial for health, and evidence
is particularly strong for the same three types of health problems that are affected by
antibiotic use, as summarised below: metabolic, psychiatric, and inflammatory
disorders.
18.2.1 Metabolic Syndrome and Obesity
Metabolic syndrome, obesity, and cardiovascular disease constitute one of the major
groups of health problem that plague modern humans. A longitudinal study based on
Fig. 18.1 The microbial world of mankind. The various microbiotas have co-evolved with us as
partners that play essential roles in all aspects of our physiology. Thus, we are in a state of evolved
dependence on their presence. These organisms come from mother and family, but also from the
natural environment. In addition to the organisms themselves, they supply data and signals that are
needed for setting up the immune system, and in particular, for fine-tuning the mechanisms that
regulate the immune system
18 Darwinian Medicine: We Evolved to Require Continuing Contact with the. . .
333
psychiatric (Köhler-Forsberg et al. 2019), and allergic disorders (Strzępa et al. 2018),
and there is perhaps an association between antibiotic use and some autoimmune
diseases (Strzępa et al. 2018; Dydensborg Sander et al. 2019; Kemppainen et al.
2017). These findings are particularly worrying because a recent study of 8 low- and
middle-income countries revealed an average of 11 antibiotic prescriptions by the
age of 2 years (Fink et al. 2019). This will hasten the switch to a Western pattern of
metabolic, psychiatric, and inflammatory disorders.
However, this essay concentrates on the role of exposure to the microbiota of the
natural environment, and mentions the human microbiotas only when exposure to
the natural environment is a major determinant of the constitution, integrity, and
function of the human microbiota. For example, the natural environment can supply
organisms to replace those eliminated by antibiotics. Many epidemiological studies
suggest that exposure to the green environment is beneficial for health, and evidence
is particularly strong for the same three types of health problems that are affected by
antibiotic use, as summarised below: metabolic, psychiatric, and inflammatory
disorders.
18.2.1 Metabolic Syndrome and Obesity
Metabolic syndrome, obesity, and cardiovascular disease constitute one of the major
groups of health problem that plague modern humans. A longitudinal study based on
Fig. 18.1 The microbial world of mankind. The various microbiotas have co-evolved with us as
partners that play essential roles in all aspects of our physiology. Thus, we are in a state of evolved
dependence on their presence. These organisms come from mother and family, but also from the
natural environment. In addition to the organisms themselves, they supply data and signals that are
needed for setting up the immune system, and in particular, for fine-tuning the mechanisms that
regulate the immune system
18 Darwinian Medicine: We Evolved to Require Continuing Contact with the. . .
333