The Chemical Ecology of Human Ingestive Behaviors

Johns, Timothy

doi:10.1146/annurev.anthro.28.1.27

Cited by 49 publications

(32 citation statements)

References 106 publications

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“…The diets of early hominids that were dependent upon plant-based foods included the woody parts of plants such as leaves, stems, bark and roots, which are especially high in antioxidants [88,89]. However, with the transition to a meatbased diet, the intake of plant-based antioxidants decreased, exacerbating the problems arising from an increased production of health-eroding free radicals.…”

Section: Do Humans Get Sick More Often Than Animals and Hence Engage mentioning

confidence: 99%

“…However, with the transition to a meatbased diet, the intake of plant-based antioxidants decreased, exacerbating the problems arising from an increased production of health-eroding free radicals. As time went on, humans started to explore farming, selecting against bitter-tasting plants with antioxidants [88,89]. Thus, once farming began, humans would have become even more likely to get sick, as indicated by the tell-tale skeletal remains alluded to above [64].…”

Section: Do Humans Get Sick More Often Than Animals and Hence Engage mentioning

confidence: 99%

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Behavioural defences in animals against pathogens and parasites: parallels with the pillars of medicine in humans

Hart

2011

Phil. Trans. R. Soc. B

157

139

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No other theme in animal biology seems to be more central than the concept of employing strategies to survive and successfully reproduce. In nature, controlling or avoiding pathogens and parasites is an essential fitness strategy because of the ever-present disease-causing organisms. The diseasecontrol strategies discussed here are: physical avoidance and removal of pathogens and parasites; quarantine or peripheralization of conspecifics that could be carrying potential pathogens; herbal medicine, animal style, to prevent or treat an infection; potentiation of the immune system; and care of sick or injured group members. These strategies are seen as also encompassing the pillars of human medicine: (i) quarantine; (ii) immune-boosting vaccinations; (iii) use of medicinal products; and (iv) caring or nursing. In contrast to animals, in humans, the disease-control strategies have been consolidated into a consistent and extensive medical system. A hypothesis that explains some of this difference between animals and humans is that humans are sick more often than animals. This increase in sickness in humans leading to an extensive, cognitively driven medical system is attributed to an evolutionary dietary transition from mostly natural vegetation to a meat-based diet, with an increase in health-eroding free radicals and a dietary reduction of free-radical-scavenging antioxidants.

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Section: Do Humans Get Sick More Often Than Animals and Hence Engage mentioning

confidence: 99%

Section: Do Humans Get Sick More Often Than Animals and Hence Engage mentioning

confidence: 99%

Behavioural defences in animals against pathogens and parasites: parallels with the pillars of medicine in humans

Hart

2011

Phil. Trans. R. Soc. B

157

139

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“…By the very definition of the field, practitioners of chemical ecology have crossed traditional disciplinary boundaries from the beginning. Building upon a solid framework for human chemical ecology (Johns 1990(Johns , 1999, chemical ecologists should be able to, and indeed must, rise to these new challenges.…”

Section: Introductionmentioning

confidence: 99%

Chemical ecology in coupled human and natural systems: people, manioc, multitrophic interactions and global change

et al. 2010

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Chemical ecology provides unique perspectives for managing plant/human interactions to achieve food security. Allelochemicals function as chemical defences of crop plants, enhancing yields. While ingested allelochemicals can confer health benefits to humans, at higher concentrations they are often toxic. The delicate balance between their positive and negative effects in crop plants is influenced by many factors. Some of these-how environment affects optimal levels of defence, how metabolic interactions with nutrients affect toxicity of ingested allelochemicals-are the province of chemical ecology. These biological factors, however, interact with social factors, and neither can be studied independently. Chemical ecologists must work together with social scientists to understand the overall system. Here, we illustrate such an integrative approach, analysing the interactions between people and the major tropical crop manioc, which contains cyanogenic glucosides. Polymorphism for cyanogen levels in manioc facilitates analysis of how costs and benefits of crop defences vary among social systems. We first show how people/ manioc interactions diversified in this crop's Amazonian homeland, then turn to the remarkable cultural adaptations of African farmers since manioc's introduction 400 years ago. Finally, we evaluate new coevolutionary challenges in parts of Africa where people are still unfamiliar with a potentially dangerous crop. Current environmental and social catastrophes have restricted farmers' options, resulting in acute problems in health of humans and ecosystems. We show that high cyanogen levels confer important agronomic advantages, but also impose costs and constraints that can only be understood when biology is coupled with analysis of social, cultural and economic factors. Detoxifying manioc technologically requires know-how, time, water and other resources. Detoxifying residual dietary cyanogens metabolically depends on being able to grow, or to buy, the nutrients required for detoxification, primarily sulphur-rich proteins. Solutions that appear adaptive today may not be in the future, as changing climate, rising atmospheric CO 2 levels and decreased access to fertilizers affect productivity of crops and the nutrient and allelochemical composition of the foods they are used to produce.

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“…The healthfulness of pica continues to be debated. Proponents of pica suggest potential benefits such as mineral supplementation (especially iron and calcium), relief of gastrointestinal distress and detoxification, particularly of plant secondary compounds (Johns, 1999;Profet, 1992;Wiley and Katz, 1998). Others posit a range of harmful effects, including geohelminth infection, caloric displacement, constipation, dental damage, eclampsia, fatigue, hypertension, intestinal blockage, iron deficiency, lead poisoning, peritonitis and, most frequently, anaemia (Halsted, 1968;Key et al, 1982;Rothenberg et al, 1999;Sayetta, 1986).…”

Section: Introductionmentioning

confidence: 99%

Geophagia is not associated with Trichuris or hookworm transmission in Zanzibar, Tanzania

Young

Goodman

Farag

et al. 2007

Transactions of the Royal Society of Tropical Medicine and Hygi

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SummaryGeophagia may be harmful as a method for the transmission of geohelminths. In this study, we pose two questions in a representative sample of 970 pregnant women from Pemba Island, Zanzibar, Tanzania. Can consumed earth be a vector for geohelminth infection? And do geophagists have differential parasitic infection? The parasitological content of 59 non-food substance samples was analysed. Cross-sectional data regarding pica behaviour were collected through interviews conducted by local researchers. Ascaris, Trichuris and hookworm status was ascertained through Kato-Katz smears. The prevalence of geophagia at baseline was 5.6% and the overall prevalence of Ascaris, Trichuris and hookworm infection was 5.6%, 33.2% and 32.9%, respectively. No consumed soil samples contained infectious parasitic stages, and only one of the consumed pica substances (charcoal) contained parasites of potential risk to human health. Neither the prevalence nor the intensity of infection with Ascaris, Trichuris or hookworm differed significantly by geophagia status. Furthermore, in multivariate models, geophagia was not a significant predictor of helminth infection status. We conclude that geophagia is not a source of Trichuris or hookworm infection among pregnant women in Pemba (insufficient power to evaluate the effect of Ascaris), which is in contrast to existing findings of helminth infection and geophagia. KeywordsPica; Geophagia; Helminthiasis; Pregnancy; Parasites; Zanzibar * Corresponding author. Tel.: +1 607 351 0172; fax: +1 607 255 1033. E-mail address: sly3@cornell.edu (S.L. Young). Authors' contributions: SLY conceived the substudy design, oversaw sample collection, collected ethnographic data and drafted the paper; DG determined sample preservation methods, examined pica samples, interpreted parasitology results and wrote the parasitology methods; THF designed and supervised the parasitological sample collection and analysis, and assisted with data analysis and drafting the paper; SMA assisted with substudy design, researcher training and pica sample collection;

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The Chemical Ecology of Human Ingestive Behaviors

Cited by 49 publications

References 106 publications

Behavioural defences in animals against pathogens and parasites: parallels with the pillars of medicine in humans

Behavioural defences in animals against pathogens and parasites: parallels with the pillars of medicine in humans

Chemical ecology in coupled human and natural systems: people, manioc, multitrophic interactions and global change

Geophagia is not associated with Trichuris or hookworm transmission in Zanzibar, Tanzania

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