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The adaptive shift that favored stone tool–assisted behavior in hominins began by 3.3 million years ago. However, evidence from early archaeological sites indicates relatively short-distance stone transport dynamics similar to behaviors observed in nonhuman primates. Here we report selective raw material transport over longer distances than expected at least 2.6 million years ago. Hominins at Nyayanga, Kenya, manufactured Oldowan tools primarily from diverse nonlocal stones, pushing back the date for expanded raw material transport by over half a million years. Nonlocal cobbles were transported up to 13 kilometers for on-site reduction, resulting in assemblage patterns inconsistent with accumulations formed by repeated short-distance transport events. These findings demonstrate that early toolmakers moved stones over substantial distances, possibly in anticipation of food processing needs, representing the earliest archaeologically visible signal for the incorporation of lithic technology into landscape-scale foraging repertoires. 

Abstract Background and objectivesWater is essential for proper physiological function. As temperatures increase, populations may struggle to meet water needs despite adaptations or acclimation; chronic dehydration can cause kidney damage. We evaluate how daily water requirements are associated with ambient temperature (ambT), wet bulb globe temperature (WBGT), urine specific gravity (USG; marker of hydration status), and albumin:creatinine ratio (ACR; kidney function biomarker) among Daasanach pastoralists living in a hot, dry northern Kenyan climate. MethodologyWater turnover (WT), USG, and ACR were measured using deuterium depletion (WT), refractometry (USG), and urine dipstick (ACR) for 76 participants aged 5–68 years in June 2022–23. Relationships between WT, ambT, WBGT, USG, and ACR were evaluated using linear and generalized linear models. ResultsAdult WT was higher than mean values worldwide, peaking around 7 l/day. Water demands increase from childhood through middle age before falling in later life. Adult WT was not correlated with ambT or WBGT. About 2/11 children’s and 7/36 adults’ USG indicated dehydration; USG was not correlated with child WT but was negatively correlated with adult WT when accounting for body size. WT was lower among adults with high (≥30 mg/g) ACR; high ACR was associated with higher USG. Conclusions and implicationsHigh Daasanach WT is likely driven by hot, semi-arid conditions, and lifestyle, rather than by compromised kidney function. Most participants were well-hydrated. Despite nonsignificant correlations between temperature and adult WT, high WT highlights the physiological demands of hot, dry climates. As climate change increases the global population exposed to hotter temperatures, global water needs will likely increase. 

ABSTRACT ObjectivesIn subsistence populations, high physical activity is typically maintained throughout pregnancy. Market integration shifts activity patterns to resemble industrialized populations, with more time allocated to sedentary behavior. Daasanach semi‐nomadic pastoralists living in northern Kenya face lifestyle heterogeneity due to the emergence of a market center. We investigate how Daasanach women manage the energetic demands of pregnancy with subsistence labor tasks and how market integration relates to variation in energetic demands, physical activity, and coping strategies. MethodsWe conducted nine focus group discussions with 72 pregnant women. We also deployed wrist‐worn fitness trackers with 21 pregnant women in two community types: central or peripheral to the market center to capture variation in market integration. Data from focus group discussions were analyzed using thematic analysis. We used multiple linear regression to examine the relationship between gestational age and physical activity. ResultsWe identified themes of increased fatigue, diet restrictions, and assistance with labor tasks during pregnancy. Gestational age negatively predicted mean daily steps, with a decrease of 1160 ± 437 steps per day with each consecutive pregnancy month. Stratified by community type, gestational age only negatively predicted mean daily steps for peripheral communities, with a decrease of 1443 ± 629 steps per day with each consecutive pregnancy month. ConclusionsResults suggest that physical activity differs with market integration early, but not late, in pregnancy. Daasanach women cope with the energetic demands of pregnancy by reducing physical activity late in pregnancy and receiving assistance with labor tasks from family and neighbors. 

Background: Pastoralists live in challenging environments, which may be accompanied by unique activity, energy, and water requirements. Aim: Few studies have examined whether the demands of pastoralism contribute to differences in total energy expenditure (TEE) and water turnover (WT) compared to other lifestyles. Subjects and methods: Accelerometer-derived physical activity, doubly labelled water-derived TEE and WT, and anthropometric data were collected for 34 semi-nomadic Daasanach adults from three northern Kenyan communities with different levels of pastoralist activity. Daasanach TEEs and WTs were compared to those of other small-scale and industrialised populations. Results: When modelled as a function of fat-free-mass, fat-mass, age, and sex, TEE did not differ between Daasanach communities. Daasanach TEE (1564–4172 kcal/day) was not significantly correlated with activity and 91% of TEEs were within the range expected for individuals from comparison populations. Mean WT did not differ between Daasanach communities; Daasanach absolute (7.54 litres/day men; 7.46 litres/day women), mass-adjusted, and TEE-adjusted WT was higher than most populations worldwide. Conclusions: The similar mass-adjusted TEE of Daasanach and industrialised populations supports the hypothesis that habitual TEE is constrained, with physically demanding lifestyles necessitating trade-offs in energy allocation. Elevated WT in the absence of elevated TEE likely reflects a demanding active lifestyle in a hot, arid climate. 

BACKGROUND:Salt leaching into freshwater is an emerging global environmental health concern. We tested the associations between drinking water salinity and blood pressure, hypertension, and albuminuria. METHODS:We conducted a 2-year panel study in 2022 and 2023 with 434 observations among 327 Daasanach adults aged >18 years in northern Kenya. Water sources were analyzed for overall salinity and ionic composition (sodium; chloride; calcium, potassium, magnesium). We measured resting blood pressure and classified hypertension stage 1 and stage 2. Urine samples were analyzed for albuminuria (≥30 mg/g albumin-to-creatinine ratio). RESULTS:Drinking water salinity was driven by sodium-chloride (mean=162.6 mg/L, SD=77.1), with low concentrations of calcium, potassium, and magnesium (mean=45 mg/L, SD=13.5). Across 2022 and 2023, 40.1% of adults had at least hypertension stage 1, 13.5% had hypertension stage 2, and 42.2% had albuminuria. Using random effects linear and logistic panel regressions fully adjusted for confounders, each 100 mg/L of drinking water sodium-chloride was associated with 4.5 mm Hg (95% CI, 2.4–6.6) and 3.3 mm Hg (95% CI, 2.2–4.5) increases in systolic and diastolic blood pressure, 3.0× the odds of at least hypertension stage 1 (95% CI, 1.49–5.83), 3.6× the odds of hypertension stage 2 (95% CI, 1.93–6.81), and 2.0× the odds of albuminuria (95% CI, 1.28–3.06). Calcium, potassium, and magnesium were unassociated with any outcomes. Hypertension stage 2 (but not hypertension stage 1) was associated with 2.6× (95% CI, 1.19–5.77) the odds of albuminuria. CONCLUSIONS:Drinking water sodium-chloride was associated with resting blood pressure, hypertension, and albuminuria in a population with few traditional lifestyle risk factors for chronic disease. Measuring specific salts in water helps untangle associations with hypertension. 

Abstract Background and objectivesNon-communicable disease risk and the epidemic of cardiometabolic diseases continue to grow across the expanding industrialized world. Probing the relationships between evolved human physiology and modern socioecological conditions is central to understanding this health crisis. Therefore, we investigated the relationships between increased market access, shifting subsistence patterns and cardiometabolic health indicators within Daasanach semi-nomadic pastoralists who vary in their engagement in traditional lifestyle and emerging market behaviors. MethodologyWe conducted cross-sectional socioecological, demographic and lifestyle stressor surveys along with health, biomarker and nutrition examinations among 225 (51.6% female) Daasanach adults in 2019–2020. We used linear mixed-effects models to test how differing levels of engagement in market integration and traditional subsistence activities related to blood pressure (BP), body composition and blood chemistry. ResultsWe found that systolic and diastolic BP, as well as the probability of having high BP (hypertension), were negatively associated with distance to market, a proxy for market integration. Additionally, body composition varied significantly by socioeconomic status (SES), with significant positive associations between BMI and body fat and higher SES among adults. Conclusions and implicationsWhile evidence for evolutionary mismatch and health variation have been found across a number of populations affected by an urban/rural divide, these results demonstrate the effects of market integration and sedentarization on cardiometabolic health associated with the early stages of lifestyle changes. Our findings provide evidence for the changes in health when small-scale populations begin the processes of sedentarization and market integration that result from myriad market pressures. 

Abstract Objective: Water plays a critical role in the production of food and preparation of nutritious meals, yet few studies have examined the relationship between water and food insecurity. The primary objective of this study, therefore, was to examine how experiences of household water insecurity (HWI) relate to experiences of household food insecurity (HFI) among a pastoralist population living in an arid, water-stressed region of northern Kenya. Design: We implemented the twelve-item Household Water Insecurity Experiences (HWISE, range 0–36) Scale and the nine-item Household Food Insecurity Access Scale (HFIAS, range 0–27) in a cross-sectional survey to measure HWI and HFI, respectively. Data on socio-demographic characteristics and intake of meat and dairy in the prior week were collected as covariates of interest. Setting: Northern Kenya, June–July 2019. Participants: Daasanach pastoralist households ( n 136) from seven communities. Results: In the prior 4 weeks, 93·4 % and 98·5 % of households had experienced moderate-to-severe HWI and HFI, respectively. Multiple linear regression analyses indicated a strong association between HWI and HFI. Each point higher HWISE score was associated with a 0·44-point (95 % CI: 0·22, 0·66, P = 0·003) higher HFIAS score adjusting for socio-economic status and other covariates. Conclusions: These findings demonstrate high prevalence and co-occurrence of HWI and HFI among Daasanach pastoralists in northern Kenya. This study highlights the need to address HWI and HFI simultaneously when developing policies and interventions to improve the nutritional well-being of populations whose subsistence is closely tied to water availability and access.