Frozen chicken for wild fish: nutritional transition in the Brazilian Amazon region determined by carbon and nitrogen stable isotope ratios in fingernails

Disaster victim identification: Stable isotope analysis and the identification of unknown decedents

Within the complex world of disaster victim identification, or DVI, forensic science practitioners use a variety of investigative techniques to work toward a common goal: identification of the decedents, bringing closure to the affected communities. Identification is a complex undertaking; the event (disaster) also can be extraordinarily complex, as it may be an acute event, or one that spans months or years. Compounding this time issue, remains may be heavily fragmented, dispersed, commingled, or otherwise disrupted by either the perpetrators or the disaster itself. To help solve these complexities, we explore the use of stable isotope analysis (SIA) in DVI events. SIA can be used with a variety of body tissues (hair, nail, bone, and teeth), and each represents different time depths in a decedent's life. Bone collagen and tooth enamel carbonate are useful to reconstruct an individual's diet and source water intakes, respectively, leading to likely population or geographic origin determinations. Additionally, the carbon and nitrogen isotopic signatures of bone collagen have calculated intraperson ranges. These facts allow investigators to determine likely origin of remains using isotopic data and can be used to link skeletal elements (to an individual), or perhaps more importantly, show that remains are not linked. Application of SIA can thus speed remains identification by eliminating individuals from short lists for identification, linking or decoupling remains, and reducing the need for some DNA testing. These strategies and hypothesis tests should commence early in the DVI process to achieve maximum effectiveness.

South American Archaeological Isotopic Database, a regional-scale multi-isotope data compendium for research

The South American Archaeological Isotopic Database (SAAID) is a comprehensive open-access resource that aggregates all available bioarchaeological stable and radiogenic isotope measurements, encompassing data from human individuals, animals, and plants across South America. Resulting from a collaborative effort of scholars who work with stable isotopes in this region, SAAID contains 53,781 isotopic measurements across 24,507 entries from individuals/specimens spanning over 12,000 years. SAAID includes valuable contextual information on archaeological samples and respective sites, such as chronology, geographical region, biome, and spatial coordinates, biological details like estimated sex and age for human individuals, and taxonomic description for fauna and flora. SAAID is hosted at the PACHAMAMA community within the Pandora data platform and the CORA repository to facilitate easy access. Because of its rich data structure, SAAID is particularly well-suited for conducting spatiotemporal meta-analyses. It serves as a valuable tool for addressing a variety of research topics, including the spread, adoption, and consumption intensification of food items, paleo-environmental reconstruction, as well as the exploration of mobility patterns across extensive geographic regions.

Evaluation of exposure to multiple organic pollutants in riparian communities of the Brazilian Amazon: Screening levels and potential health risks

Organic pollutants are widely distributed in the environment. Due to their physical and chemical characteristics, they tend to be biomagnified in food chains, mainly in aquatic organisms. Therefore, food consumption is a significant route of lifelong exposure. Although the Amazon River basin contains the highest freshwater biodiversity on Earth, there is scarce literature focusing on the levels of organic pollutants in the local population. The present study was aimed at assessing the levels of several environmental pollutants (polycyclic aromatic hydrocarbons, bisphenols, parabens, and benzophenones) in urine samples from riverside communities along the Tapajós and Amazon Rivers in the Brazilian Amazon region. The results show a 100 % detection of naphthalene metabolites (namely, 1-hydroxy-naphthalene (1OH-NAP), 2-hydroxy-naphthalene (2OH-NAP)), with the highest levels belonging to benzylparaben (BzP) (17.3 ng/mL). Gender-specific analysis revealed that women had significantly higher levels of certain PAH metabolites (i.e., 1OH-NAP and 2-hydroxy-fluorene (2OH-FLU)) than men. In turn, most of the evaluated compounds were higher in urine samples from people living near the Amazon River, which presents increased traffic of boats and ships than the Tapajós River. On the other hand, the human health risk assessment suggested that all communities are at risk of suffering non-carcinogenic effects from exposure to PAHs. At the same time, they are also at risk of carcinogenic effects from exposure to benzo[a]pyrene metabolites. Thus, further studies are needed in order to evaluate the potential health effects of exposure to a mixture of these organic pollutants and other contaminants present in the area, such as mercury.

Changes in dietary carbohydrate and lipid quality indices between 2008 and 2018: Analysis of the Brazilian dietary surveys

The aim of the study was to evaluate characteristics and changes over a decade in dietary carbohydrate and lipid quality according to socio-demographic variables. Data was obtained from two Brazilian National Dietary Surveys 2008-2009 (n = 34 003) and 2017-2018 (n = 46 164) examining a nationwide representative sample of individuals ≥10 years old. Food intake was assessed by means of two non-consecutive diet records (2008-2009) and 24 h diet recalls (2017-2018). Carbohydrate Quality Index is a score ranging from 4 to 20 calculated from fibre intake, global dietary glycaemic index, solid/total carbohydrate (CHO) and whole grains/total grains CHO. Lipid Quality Index was estimated by dividing the sum of the dietary content of monounsaturated and polyunsaturated fatty acids by the sum of saturated and trans fatty acids. Indices were categorised into five categories (1 for lowest and 5 for highest quality). Socio-demographic variables were sex, age, income, urban/rural area and place of food consumption. The estimates (95% CI) were generated separately for each survey and then compared to identify changes in time. Our main findings refer to changes in diet quality according to income. At the lowest income level, the proportions of individuals in the best carbohydrate and lipid quality categories reduced from 26.9% to 20.6% and from 30.0% to 24.9%, respectively. Alternatively, at the highest income level, these proportions increased from 22.9% to 26.6% and from 11.9% to 15.7%, respectively. Furthermore, the quality of lipids improved in women and among individuals reporting some away-from-home food consumption, while the quality of carbohydrates was reduced among adolescents and in rural areas.

BITACORA: An isotopic database of modern human tissues (keratin, teeth) for Argentina

As a consequence of the recent history of Argentina related to crimes against humanity, the country has positioned itself as a leader on Forensic Anthropology in human rights contexts. To some extent it can even be argued that Forensic Genetics for human identification had its origins in human rights work in the early 1980s in Argentina. However, there are still hundreds of unidentified human remains recovered from the dictatorial regimes' crimes. Additionally, every year there are dozens of unidentified deceased buried in public cemeteries. Thus, there is an urgent need to adopt new techniques that could increase the biological profile of a person, and therefore increase the chances of positive identifications. One of such initiatives is the development of isotopic databases and models that can provide information on the population and region of origin of unidentified victims. We present the development of an isotopic database of modern human tissues named BITACORA (from its name in Spanish: Base de Información Isotópica de Tejidos Actuales Como Referencia Argentina). BITACORA holds isotopic data (δ18O, δ2H, δ13C, δ15N and δ34S values) from teeth (enamel and dentine) and keratin tissues (scalp hair, beard and fingernails) obtained from volunteers of known origin, as well as individual information of the donors (age, gender, biometrics, dietary preferences, and relocation history). BITACORA is associated with a tap water isotope database. Currently, we have 345 keratin, 273 teeth and 287 tap water samples gathered from across the country. We present preliminary analyses on the geographic distribution of these isotopic markers, and provide an overall discussion of the current status and future development of the databases.

Evolution of household availability of regional foods in Amazonas

OBJECTIVE

To evaluate the evolution of household availability of regional foods in the state of Amazonas, their distribution according to sociodemographic characteristics, and potential differences when compared to the remaining areas of Brazil.

METHODS

Data on food acquisition for home consumption from the 2002-2003, 2008-2009, and 2017-2018 Pesquisa de Orçamentos Familiares (POFs - Consumer Expenditure Surveys) were analyzed, covering, respectively, 48,470, 55,970, and 57,920 households in Brazil, of which 1,075, 1,344, and 1,833 are in Amazonas. Foods were categorized into three groups: cassava and its derivatives, freshwater fish, and regional fruits. The study analyzed the amount of regional food purchased, expressed in relative household caloric share, for the entire area of Amazonas. Additionally, the data was stratified and analyzed according to sociodemographic variables, with differences assessed through the overlapping of 95% confidence intervals.

FINDINGS

The household caloric share of the total regional foods in Amazonas was 22.54% in 2002-2003, 18.18% in 2008-2009, and 6.49% in 2017-2018. Across Brazil, those percentages were much lower in the same period: 3.67%, 3.34%, and 1.82%, respectively. Changes in Amazonas were primarily attributed to the steep drop in the cassava and derivatives group, which decreased from 14.30% in 2002-2003 to 12.74% in 2008-2009 and further declined to 3.09% in 2017-2018. Additionally, there was a gradual decline in household availability of freshwater fish, decreasing from 7.30% in 2002-2003 to 4.85% in 2008-2009 and reaching 2.90% in 2017-2018. Households in rural areas and with lower per capita income presented a higher proportion of calories from total regional foods; this particular stratum also experienced the most significant reductions in their consumption.

CONCLUSION

During the study period, there was a significant decrease in the consumption of regional foods in Amazonas, particularly in lower income households in rural areas. Among them, the family reference person was typically a younger male with a lower educational background.

Examination of amino acid hydrogen isotope measurements of scalp hair for region-of-origin studies

RATIONALE

Hydrogen isotope (δ2 H) analysis of keratinaceous bulk tissues has been used in forensic science to reconstruct an individual's travel history or determine their region-of-origin. Here, we use a compound-specific approach to examine patterns of individual amino acid δ2 H values in relation to those of local tap water, bulk scalp hair tissues, and region-of-origin.

METHODS

We measured δ2 H values of amino acids in anonymously collected scalp hair (n = 67) and tap water from 28 locations in the United States. Samples were hydrolyzed into their constituent amino acids, derivatized alongside in-house reference materials, and analyzed in triplicate using a GC-C-IRMS system.

RESULTS

Non-essential amino acid (AANESS ) δ2 H values and their corresponding tap water samples varied systematically across continental regions. Hydrogen isotope values of alanine, glutamic acid, and glycine were significantly correlated with tap water and an estimated 42%-51% of the hydrogen atoms in these AANESS were derived from tap water. We used linear discriminate analysis (LDA) to explore regional patterns in scalp hair bulk tissue and amino acid δ2 H values. For the model that included AANESS data, 87% of the variance was explained by the first linear discriminant axis (LD1), and was driven by bulk hair tissue, alanine, and proline. This model had an overall 72% successful reclassification with samples from the south and northwest regions reclassifying correctly 92% and 78% of the time, respectively. For the model that included AAESS data, LD1 explained 81% of the variation and was driven bulk hair, threonine, valine, phenylalanine, and isoleucine. The overall reclassification rate for the model that included AAESS was 70%.

CONCLUSIONS

Our findings suggest that δ2 H analyses of AANESS and AAESS could help improve geolocation models for human and wildlife forensics by simultaneously providing information about both dietary and tap water inputs of hydrogen to tissue synthesis.

Consumption and Preferences for Wild and Domestic Meat in Indigenous Communities in the Brazilian Atlantic Forest

Wild animals have traditionally been the main sources of protein available, if not the only, to numerous indigenous populations worldwide. However, greater access to markets, reduced availability or access to wildlife, and policies in support of agricultural development, have shifted food habits toward domestic and industrial sources of protein. In this study, we evaluated consumption patterns and preferences/avoidances for wild animals (wildmeat, crustaceans, and fish) in comparison to domestic sources of protein among the Potiguara living on the Brazilian coast. Using data from 843 semi-structured interviews applied to students from 28 indigenous villages, we found that domestic meats were more consumed and preferred as compared to wild animals (aquatic and game animals), despite the high abundance of fish and crustacean resources in the surveyed area. Consumption and preference for game were higher among male students while avoidance was higher among female students. The avoidance of domestic meats and fish was low for both genders. The occupation of the fathers affected students’ food habits, in those nature-related occupations (farmer, fisherman/woman, sugarcane worker) conditioned greater consumption of wildmeat and fish, while non-nature related occupations lead to greater consumption of protein from domestic sources. The consumption of protein from all sources increased with the distance between villages and a protected area. Our results indicate that the younger generation of Potiguaras does not regularly consume wildmeat and fish and their preference for domestic sources of protein is shaped by the socio-environmental context, access to different types of meat, and taste preferences.

Reproductive life histories: can incremental dentine isotope analysis identify pubertal growth, pregnancy and lactation?

BACKGROUND

There are few reliable osteological indicators to detect parity or infer puberty in skeletal remains. Nitrogen (δ¹⁵N) and stable carbon (δ¹³C) isotope ratios in human tissues can be affected by metabolically unbalanced states engendered by pregnancy or rapid growth, offering potential biomarkers.

AIM

This pilot study explores the potential of incremental dentine-collagen isotope ratio analysis to identify puberty and gestation.

SUBJECTS AND METHODS

Incremental dentine δ¹⁵N and δ¹³C profiles were produced by analysing third molars extracted as part of dental treatment of 10 individuals living in Sudan. Demographic and anthropometric data at the time of tooth extraction was available. Medical histories were unknown.

RESULTS

Isotopic signatures potentially related to pubertal growth, with an average δ¹⁵N reduction of 0.78 ± 0.29‰, are indicated. Six isotopic signals suggestive of pregnancy, with an average δ¹⁵N decrease of 0.48 ± 0.22‰, are also observed. The timing, speed and amplitude of post-partum δ¹⁵N patterns seemingly infer infant feeding practices and maternal nutritional status.

CONCLUSION

This pilot study highlights the potential of incremental dentine isotope analysis for the reconstruction of early reproductive histories in skeletal remains. However, controlled studies with a larger human cohort are needed to validate these findings, establish isotopic signals linked to puberty and lactation, and improve chronology accuracy.

[Patterns of food consumption in riverine communities in the mid-Solimões river region - Amazonas - Brazil]

This is a cross-sectional study conducted with 492 riverine residents in the rural area of Coari (AM) to identify food patterns in the mid-Solimões river region and associated factors. Food intake was evaluated using a brief Food Frequency Questionnaire (FFQ), and principal component analysis was used to identify dietary patterns. The association with socioeconomic variables was evaluated using generalized linear models. Four dietary patterns were identified: "vegetables" (vegetables, tubers, fruit); "Brazilian" (chicken, eggs, rice, beans); "traditional riverine" (fish, flour, milk); "meat and candies" (game and pork, candies). The "vegetable" pattern was associated with education (p = 0.001), number of rooms in the house (p = 0.005) and greater proximity to urban areas (p = 0.004). The "Brazilian" pattern was associated with the female sex (0.013), higher income (p < 0.001) and greater proximity to urban areas (p = 0.001). The "traditional riverine" pattern was associated with distance from the urban area (p < 0.001), and the "meat and candies" pattern was associated with age (p = 0.029), education (p < 0.001) and proximity to urban areas (p = 0.003). The extractive nature of riverine food intake is still present in more isolated communities, and consumption of other food items was associated with better social conditions.

Wild meat consumption in tropical forests spares a significant carbon footprint from the livestock production sector

Whether sustainable or not, wild meat consumption is a reality for millions of tropical forest dwellers. Yet estimates of spared greenhouse gas (GHG) emissions from consuming wild meat, rather than protein from the livestock sector, have not been quantified. We show that a mean per capita wild meat consumption of 41.7 kg yr⁻¹ for a population of ~ 150,000 residents at 49 Amazonian and Afrotropical forest sites can spare ~ 71 MtCO₂-eq annually under a bovine beef substitution scenario, but only ~ 3 MtCO₂-eq yr⁻¹ if this demand is replaced by poultry. Wild meat offtake by these communities could generate US$3M or US$185K in carbon credit revenues under an optimistic scenario (full compliance with the Paris Agreement by 2030; based on a carbon price of US$50/tCO₂-eq) and US$1M or US$77K under a conservative scenario (conservative carbon price of US$20.81/tCO₂-eq), representing considerable incentives for forest conservation and potential revenues for local communities. However, the wild animal protein consumption of ~ 43% of all consumers in our sample was below the annual minimum per capita rate required to prevent human malnutrition. We argue that managing wild meat consumption can serve the interests of climate change mitigation efforts in REDD + accords through avoided GHG emissions from the livestock sector, but this requires wildlife management that can be defined as verifiably sustainable.

The Urban River Syndrome: Achieving Sustainability Against a Backdrop of Accelerating Change

Human activities have been affecting rivers and other natural systems for millennia. Anthropogenic changes to rivers over the last few centuries led to the accelerating state of decline of coastal and estuarine regions globally. Urban rivers are parts of larger catchment ecosystems, which in turn form parts of wider nested, interconnected systems. Accurate modelling of urban rivers may not be possible because of the complex multisystem interactions operating concurrently and over different spatial and temporal scales. This paper overviews urban river syndrome, the accelerating deterioration of urban river ecology, and outlines growing conservation challenges of river restoration projects. This paper also reviews the river Thames, which is a typical urban river that suffers from growing anthropogenic effects and thus represents all urban rivers of similar type. A particular emphasis is made on ecosystem adaptation, widespread extinctions and the proliferation of non-native species in the urban Thames. This research emphasizes the need for a holistic systems approach to urban river restoration.

Impacts of market economy access and livelihood conditions on agro-food transition in rural communities in three macro-regions of Brazil

Urbanization has threatened rural communities' livelihoods worldwide, changing their agro-food systems from locally produced traditional items to industrialized foodstuffs. The main objective was to investigate the relationship between livelihood conditions and the agro-food transition process in rural communities of the Center-West, Northeast, and Amazon regions of Brazil. We hypothesized that traditional agroecosystems and local food habits changed with greater access to market economies. The study was conducted with semi-structured questionnaire interviews to verify agro-food patterns, subsistence farming, natural resource use, and socioeconomic conditions. Moreover, we used stable isotope ratios from the inhabitants' fingernails to determine the food source and trophic chain diversity. Data from questionnaires were analyzed using a Bayesian clustering model to characterize the socioeconomic conditions and agro-food patterns among rural and urban communities. The isotopic data were appraised through a nonparametric model to assess food differences among Brazilian regions and different community types. The Bayesian model allowed us to determine the optimal number of groups according to descriptive socioeconomic and agro-food variables sorted by each specific location. We also verified a food change from C₃ (more natural) to C₄ (more processed) with an increase in δ ¹³C and a decrease in δ ¹⁵N in the city and town localities. This indicates a livelihood shift from locally produced foods to processed items toward urban areas. Although remote villages showed more maintenance of their agro-food systems, increased access to market economies and the supermarket diet is changing the livelihood conditions of rural communities, which can compromise their traditional farming and food sovereignty.

Substitution of inland fisheries with aquaculture and chicken undermines human nutrition in the Peruvian Amazon

With declining capture fisheries production, maintaining nutrient supplies largely hinges on substituting wild fish with economically comparable farmed animals. Although such transitions are increasingly commonplace across global inland and coastal communities, their nutritional consequences are unknown. Here, using human demographic and health information, and fish nutrient composition data from the Peruvian Amazon, we show that substituting wild inland fisheries with chicken and aquaculture has the potential to exacerbate iron deficiencies and limit essential fatty acid supplies in a region already experiencing high prevalence of anaemia and malnutrition. Substituting wild fish with chicken, however, can increase zinc and protein supplies. Chicken and aquaculture production also increase greenhouse gas emissions, agricultural land use and eutrophication. Thus, policies that enable access to wild fisheries and their sustainable management while improving the quality, diversity and environmental impacts of farmed species will be instrumental in ensuring healthy and sustainable food systems.

Assessing geographic controls of hair isotopic variability in human populations: A case-study in Canada

Studying the isotope variability in fast-growing human tissues (e.g., hair, nails) is a powerful tool to investigate human nutrition. However, interpreting the controls of this isotopic variability at the population scale is often challenging as multiple factors can superimpose on the isotopic signals of a current population. Here, we analyse carbon, nitrogen, and sulphur isotopes in hair from 590 Canadian resident volunteers along with demographics, dietary and geographic information about each participant. We use a series of machine-learning regressions to demonstrate that the isotopic values in Canadian residents' hair are not only influenced by dietary choices but by geographic controls. First, we show that isotopic values in Canadian residents' hair have a limited range of variability consistent with the homogenization of Canadian dietary habits (as in other industrialized countries). As expected, some of the isotopic variability within the population correlates with recorded individual dietary choices. More interestingly, some regional spatial patterns emerge from carbon and sulphur isotope variations. The high carbon isotope composition of the hair of eastern Canadians relative to that of western Canadians correlates with the dominance of corn in the eastern Canadian food-industry. The gradient of sulphur isotope composition in Canadian hair from coast to inland regions correlates with the increasing soil pH and decreasing deposition of marine-derived sulphate aerosols in local food systems. We conclude that part of the isotopic variability found in the hair of Canadian residents reflects the isotopic signature associated with specific environmental conditions and agricultural practices of regional food systems transmitted to humans through the high consumption rate of intra-provincial food in Canada. Our study also underscores the strong potential of sulphur isotopes as tracers of human and food provenance.

Increased in carbon isotope ratios of Brazilian fingernails are correlated with increased in socioeconomic status

High δ¹³C in human tissues in Brazil indicate high consumption of C₄-based sources due to the consumption of highly processed food and animal protein. The significant positive correlation between the human developed index (HDI) developed by the United Nations Development Program, and fingernail δ¹³C at the county level proved to be useful as a new proxy in tracking human nutrition. Regions with higher HDI are those with higher consumption of highly processed food.

Mapping carbon and nitrogen isotopic composition of fingernails to demonstrate a rural-urban nutrition transition in the Center-West, Northeast, and Amazon regions of Brazil

OBJECTIVE

The main objective of this study is to investigate diet patterns among rural and urban populations of the Center-West, Northeast, and Amazon regions of Brazil through the carbon and nitrogen isotopic composition of fingernails, recognizing that the extent of market integration is a key driver of food consumption.

MATERIALS AND METHODS

In the Center-West, Northeast, and Amazon regions of Brazil, fingernails were sampled in clusters encompassing a major city, town, and rural village. A total of 2,133 fingernails were analyzed. Fingernails were clipped by donors using fingernail clippers. In the laboratory, samples were cleaned then weighed in small tin capsules before being isotopically analyzed for carbon and nitrogen.

RESULTS

The overall mean δ¹³ C and δ¹⁵ N were -19.7 ± 2.8‰ and 10.6 ± 1.1‰, respectively. In the more remote villages, where access to food markets is more challenging, lower δ¹³ C prevails, suggesting that Brazilian staple foods (rice, beans, and farinha) still dominate. In areas with easier access to food markets, δ¹³ C values were higher, suggesting a change to a diet based on C₄ plants, typical of a Brazilian supermarket diet. The variability among inhabitants in the same location expressed by a significant inverse correlation between δ¹³ C and δ¹⁵ N fingernail values suggested that "market integration" does not affect everyone equally in each community.

DISCUSSION AND CONCLUSION

The nutrition transition has not yet reached some remote villages in these regions of Brazil or that the nutrition transition has not yet reached all residents of these remote villages. On the other hand, in several villages there is a considerable adherence to the supermarket diet or that some residents of these villages are already favoring processed food.

Rural development and shifts in household dietary practices from 1999 to 2010 in the Tapajós River region, Brazilian Amazon: empirical evidence from dietary surveys

BACKGROUND

Research on changing dietary practices is rare in lower and middle income countries, and understanding the impact of global economic processes on population health and nutrition is important, especially of rural communities. We analyzed the diet of 22 families in Brasília Legal, a riverside community in the Tapajós River region of the Brazilian Amazon, using nonparametric tests to compare dietary surveys taken in 1999 and 2010.

RESULTS

Data from the two surveys show that food obtained through commercial supply chains became more frequent in household diets, corresponding to significant increases in daily consumption of food items rich in energy, protein, and sugar. At the same time, there was a decline in traditional Amazonian food intake.

CONCLUSIONS

Comparing these results with household socio-economic characteristics and drawing on open-ended interviews, we consider the multiple influences that economic development processes may have had on local diets. The introduction of new income sources and employment opportunities, infrastructural and transportation expansion, as well as environmental change appear to have influenced the observed dietary shifts. Such shifts are likely to have important implications for the nutritional status of communities in the Amazon, highlighting concerning trade-offs between current development trajectories and human health. Public policies and health education programs must urgently consider the interactions between sustainable development priorities in order to address emerging health risks in this rapidly changing region.

Tooth wear as an indicator of acculturation process in remote Amazonian populations

Riverine populations are typical of the Amazon region that depend on nature for subsistence. These people are considered an intermediate population between the urban and indigenous, the original Amazon habitants. The aim of this cross-sectional study was to evaluate the relationship between tooth wear and age in a remote riverine population from the Amazon, located by the Tucumanduba River (n = 94), and to compare them to previous findings obtained from semi-isolated indigenous (n = 223) and urban populations (n = 40) from the Amazon region, which were examined using the same methodology. Using linear regression, tooth wear explained 54.5% of the variation in the ages of the riverine subjects (p<0.001). This coefficient is mid-way between those obtained in semi-isolated indigenous populations (65–86%) and urban subjects (12%) living in the Amazon. Our findings suggest that tooth wear, a direct evidence of what an individual ate in the past, may be an indicator of the acculturation process in remote populations.

Carbon and Nitrogen Isotope Ratios of Food and Beverage in Brazil

Several previous studies on targeted food items using carbon and nitrogen stable isotope ratios in Brazil have revealed that many of the items investigated are adulterated; mislabeled or even fraud. Here, we present the first Brazilian isotopic baseline assessment that can be used not only in future forensic cases involving food authenticity, but also in human forensic anthropology studies. The δ13C and δ15N were determined in 1245 food items and 374 beverages; most of them made in Brazil. The average δ13C and δ15N of C3 plants were -26.7 ± 1.5‱, and 3.9 ± 3.9‱, respectively, while the average δ13C and δ15N of C4 plants were -11.5 ± 0.8‱ and 4.6 ± 2.6‱, respectively. The δ13C and δ15N of plant-based processed foods were -21.8 ± 4.8‱ and 3.9 ± 2.7‱, respectively. The average δ13C and δ15N of meat, including beef, poultry, pork and lamb were -16.6 ± 4.7‱, and 5.2 ± 2.6‱, respectively, while the δ13C and δ15N of animal-based processed foods were -17.9 ± 3.3‱ and 3.3 ± 3.5‱, respectively. The average δ13C of beverages, including beer and wine was -22.5 ± 3.1‱. We verified that C-C4 constitutes a large proportion of fresh meat, dairy products, as well as animal and plant-based processed foods. The reasons behind this high proportion will be addressed in this study.

Conditional Cash Transfers in the Amazon: From the Nutrition Transition to Complex Dietary Behavior Change

Nutrition transition theory describes a progressive substitution of local staples for industrialized processed foods in local diets, a process documented diversely across world regions, and increasingly observed in rural areas of the global south. Here we examine the role of conditional cash transfer programs, in particular the emblematic Brazilian Bolsa Família (BFP), in driving nutritional transition in rural areas of the Amazon. Based on ethnographic research with both participating and nonparticipating women in the Amanã Sustainable Development Reserve (SDR), our analysis integrates Food Frequency Questionnaires (FFQ), seasonal 24-hour food intake recalls, and stable isotope ratios in fingernails to examine dietary behavioral change. Contrary to dietary changes observed elsewhere in the Amazon, participation in the BFP is not associated with a significant substitution of local staples for industrialized processed foods in Amanã. While an increase in the consumption of some industrialized foods was observed, it has been selective and it has not changed the structure of diets. Factors such as social and cultural value of local staples, resident's involvement with the SDR, their relationship with lake and upland forest and agricultural environments, and limited market access have buffered the expansion of industrialized processed foods as observed elsewhere.

In urban, but not rural, areas of Madre de Dios, Peru, adoption of a Western diet is inversely associated with selenium intake

Road development has been a major driver of the transition from traditional to calorie-dense processed 'Western' diets in lower and middle-income countries. The paving of the Interoceanic Highway (IOH) facilitated rapid development to the Madre de Dios (MDD) region in the Peruvian Amazon. As traditional foods such as Brazil nuts and fish are known to be rich in the essential micronutrient selenium, people further along the nutrition transition to a Western diet may have lower selenium (Se) intake. To test this hypothesis, in 2014 the Investigacion de Migracion, Ambiente, y Salud (IMAS Study) (Migration, Environment, and Health Study) collected household surveys from 310 households in 46 communities along the IOH and nails for Se analysis from 418 adults. Principal component analysis of 25 commonly consumed food items identified a factor resembling Western diet, which was used to calculate household Western diet weighted sum factor scores (WSFS). WSFS means were interpolated into a 10 km buffer around the IOH using inverse distance weighting. Western diet adoption was higher in urban compared to rural areas (p < 0.0001), and geographic variation was observed between mining and agricultural areas. Mean nail Se was 730 ng/g, SD 198 ng/g (range: 200-1390 ng/g). Generalized estimating equation (GEE) models assessed the association between food consumption and nail Se. Household chicken consumption was positively associated with Se in rural areas only. Urban/rural status modified the effect of western diet adoption on nail Se, and Se was inversely associated with WSFS in urban areas only. Conclusion: In urban, but not rural, areas of Madre de Dios, Peru, adoption of a Western diet is inversely associated with selenium intake. As the essential micronutrient selenium is a vital part of antioxidant proteins, lower intake could compound the chronic health effects that may result from transition to a calorie-dense diet.

Is the 'canine surrogacy approach' (CSA) still valid for dogs and humans in market-oriented and subsistence-oriented communities in Brazil?

Based on the assumptions that human food is available for dogs and isotope diet-tissue differences are similar in dogs and humans, the 'canine surrogacy approach' (CSA) has been used to infer patterns of ancient populations. The goal of this study was to test the CSA in urban (Brasília and Piracicaba) and in rural (Ubatuba and Maraã) areas. The hair C and N isotope ratios of modern dogs were compared with those of human fingernails from different regions of Brazil. Our CSA results showed a correlation between dog and human isotopes values: in rural areas δ¹⁵N of humans and dogs was not statistically different; contrarily, in urban centres, δ¹⁵N of humans was approximately 1 ‰ higher (p < 0.01) than δ¹⁵N of dogs; humans had lower δ¹³C values (p < 0.01) than dogs in Brasília, Piracicaba and Ubatuba. In Maraã, there was not any significant difference between dogs and humans. We concluded that CSA is still valid as a first approach in modern societies. However, isotopic differences found suggest that in modern societies processed dog food is increasingly disconnecting human and dog, jeopardising the use of CSA in the future if the trend of increasing processed dog food consumption continues to occur.

Carbon and nitrogen isotopic composition of commercial dog food in Brazil

BACKGROUND

Brazil is a low- to medium-income country and has the second largest pet food market in the world with 8% of world pet food consumption. The lowest-income social class spends around 17% of their domestic budget on pet food and other items related to pets. Consumers are frequently misled by advertising as there is no precise information about the main sources of protein, carbohydrates and fat in the labels, and the Brazilian pet food industry can legally claim that their products contain certain items like salmon or beef even if they use just a flavoring compound.

METHODS

The stable isotope methodology compares the stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) between source and product. The 13C/12C ratio of a specific product (e.g., dog food) reveals the proportions of C4 (maize) and C3 (soybean, rice and wheat) plants in that product and the 15N/14N ratio reveals the proportion of the compounds derived from animals. With this isotopic data, we used MixSIAR, a Bayesian stable isotope-mixing model, to estimate the proportion of maize, grains, poultry and beef in dog food.

RESULTS

The δ13C values of dry dog food ranged from -24.2‰ to -12.8‰, with an average (± standard-deviation) of -17.1‰ ± 2.8‰. The δ13C values of wet pet food ranged from -25.4‰ to -16.9‰, with an average (± standard-deviation) of -21.2‰ ± 2.4‰, which was significantly lower (p < 0.01). The δ15N values of the dry and wet food ranged from 1.7‰ to 4.2‰, and from 0.5‰ to 5.5‰, respectively. The average δ15N values of dry food (2.9‰ ± 0.5‰) was not higher than the wet food (2.6‰ ± 1.3‰) (p > 0.01). The output of the MixSIAR showed a low proportion of bovine products in dry dog food samples. On the other hand, poultry was obviously the dominant ingredient present in most of the samples. Maize was the second dominant ingredient. Wet and dry dog food showed similar isotopic analysis results. The only difference was a lower proportion of maize and higher proportion of grains in wet dog food.

DISCUSSION

The main finding is that dog food in Brazil is mostly made of approximately 60% (ranging from 32% to 86%) animal-based and 40% (ranging from 14% to 67%) plant-based products. Poultry and maize are the main ingredients. Poultry is added as a by-product or meal, which avoids competition between dogs and humans for meat products, while they can compete for maize. On the other hand, a large proportion of plant-based products in dog food decreases the energy and environmental footprint, since plant-based food products tend to be less harmful compared to animal-based products. Labels can mislead consumers by showing pictures of items that are not necessarily part of the product composition and by not showing the detailed information on the proportion of each ingredient. This information would allow customers to make their own choices considering their pet's nutrition, the competition between animals and humans for resources and environmental sustainability.

Applying the principles of isotope analysis in plant and animal ecology to forensic science in the Americas

The heart of forensic science is application of the scientific method and analytical approaches to answer questions central to solving a crime: Who, What, When, Where, and How. Forensic practitioners use fundamentals of chemistry and physics to examine evidence and infer its origin. In this regard, ecological researchers have had a significant impact on forensic science through the development and application of a specialized measurement technique-isotope analysis-for examining evidence. Here, we review the utility of isotope analysis in forensic settings from an ecological perspective, concentrating on work from the Americas completed within the last three decades. Our primary focus is on combining plant and animal physiological models with isotope analyses for source inference. Examples of the forensic application of isotopes-including stable isotopes, radiogenic isotopes, and radioisotopes-span from cotton used in counterfeit bills to anthrax shipped through the U.S. Postal Service and from beer adulterated with cheap adjuncts to human remains discovered in shallow graves. Recent methodological developments and the generation of isotope landscapes, or isoscapes, for data interpretation promise that isotope analysis will be a useful tool in ecological and forensic studies for decades to come.

Global spatial distributions of nitrogen and carbon stable isotope ratios of modern human hair

RATIONALE

Natural stable carbon (δ(13)C) and nitrogen isotope ratios (δ(15)N) of humans are related to individual dietary habits and environmental and physiological factors. In forensic science the stable isotope ratios of human remains such as hair and nail are used for geographical allocation. Thus, knowledge of the global spatial distribution of human δ(13)C and δ(15)N values is an essential component in the interpretation of stable isotope analytical results.

METHODS

No substantial global datasets of human stable isotope ratios are currently available, although the amount of available (published) data has increased within recent years. We have herein summarised the published data on human global δ(13)C andδ(15)N values (around 3600 samples) and added experimental values of more than 400 additional worldwide human hair and nail samples. In order to summarise isotope ratios for hair and nail samples correction factors were determined.

RESULTS

The current available dataset of human stable isotope ratios is biased towards Europe and North America with only limited data for countries in Africa, Central and South America and Southeast Asia. The global spatial distribution of carbon isotopes is related to latitude and supports the fact that human δ(13)C values are dominated by the amount of C4 plants in the diet, either due to direct ingestion as plant food, or by its use as animal feed. In contrast, the global spatial distribution of human δ(15)N values is apparently not exclusively related to the amount of fish or meat ingested, but also to environmental factors that influence agricultural production.

CONCLUSIONS

There are still a large proportion of countries, especially in Africa, where there are no available data for human carbon and nitrogen isotope ratios. Although the interpretation of modern human carbon isotope ratios at the global scale is quite possible, and correlates with the latitude, the potential influences of extrinsic and/or intrinsic factors on human nitrogen isotope ratios have to be taken into consideration.

Stable isotope composition of human fingernails from Slovakia

Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ(13)C and δ(15)N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in (13)C and (15)N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ(13)C and δ(15)N values. These data were compared to previously published δ(13)C and δ(15)N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking.