Dietary Shifts Research Articles

Partial substitution of red or processed meat with plant-based foods and colorectal cancer risk

Abstract Background Consumption of plant-based foods, particularly whole grains, may decrease colorectal cancer (CRC) risk, while red and processed meat consumption increases it. Moreover, shifting to more plant-based diets promotes sustainable food systems. Yet, few studies have examined the impact of dietary shifts towards more plant-based diets on CRC risk. We modelled a partial substitution of red or processed meat with whole grains, vegetables or fruits in relation to CRC risk in Finnish adults. Methods Our data comprised 43 788 participants (79% men) aged ≥25 years from five Finnish cohorts. The median follow-up was 29 years, during which 1124 CRC cases were diagnosed. Diet was assessed by a validated food frequency questionnaire. We modelled substitutions of 100g/week of red meat or 50g/week of processed meat with an equivalent amount of plant-based foods. In a two-stage meta-analysis, cohort-specific hazard ratios (HR) were calculated using Cox proportional hazards model and pooled together. We adjusted the analyses for sex and other relevant confounders. Results We observed a small decrease in CRC risk when red or processed meat was partially substituted with vegetables (red meat: HR 0.97, 95% CI 0.94-0.99, P = 0.008; processed meat: 0.99, 0.98-1.00, P = 0.029) or fruits (red meat: 0.97, 0.94-0.99, P = 0.007; processed meat: 0.99, 0.98-1.00, P = 0.036). No association occurred between the partial substitution of red or processed meat with whole grains and CRC risk. Conclusions Our results suggested that already small and easily implemented substitutions of red or processed meat with vegetables or fruits could reduce CRC risk in Finnish adults. The findings highlight the need for effective nutrition policy actions to promote the shift towards more plant-based diets that would benefit both public health and sustainable food systems. Further research on similar substitutions in relation to CRC risk is required in different populations and real-life settings. Key messages • Already small and easily implemented substitutions of 100g/week of red meat or 50g/week of processed meat with vegetables or fruits could reduce colorectal cancer risk in Finnish adults. • The findings highlight the need for effective nutrition policy actions to promote the shift towards more plant-based diets that would benefit both public health and the sustainability of food systems.

Dietary shifts drive the slowdown of declining methylmercury related health risk in China

Chinese population suffers severe health risk from dietary methylmercury (MeHg) exposure. However, the temporal change of such risk and socioeconomic driving factors remain unknown. This study investigates this issue by compiling time-series inventory of China's MeHg-related health risk at the provincial scale and revealing critical socioeconomic influencing factors through structural decomposition analysis. Results show that the per-fetus IQ decrements from dietary MeHg exposure have declined by 60% nationally during 2004–2019. Such decline results from the joint effects of dietary shifts (contributing 44%) and the decrease of MeHg concentrations in foods consumed (contributing 56%). However, the declining trend has slowed down since 2014 and even leveled off after 2016, which is mainly affected by dietary pattern changes. Especially, the increased intake level and proportion of fishes in underdeveloped provinces of China have dominated the slowdown of declining trend after 2016. Moreover, the affluence and education levels have significantly negative associations with per-fetus IQ decrements. Rich and well-educated people have higher ability of risk perception, which indicates the importance of rational consumption patterns. Our findings can help develop socioeconomic regulatory policies on reducing per-fetus IQ decrements from dietary MeHg exposure in China.

Function of Cytochrome P450s and Gut Microbiome in Biopesticide Adaptation of Grapholita molesta on Different Host Diets.

Insects that feed on various host plants possess diverse xenobiotic adaptations; however, the underlying mechanisms are poorly understood. In the present study, we used Grapholita molesta, which shifts feeding sites from peach shoots to apple fruits, as a model to explore the effects of shifts in host plant diet on the profiles of cytochrome P450s and the gut bacteria microbiome, as well as their effects on biopesticide adaptation. We found that the sensitivity of the fruit-feeding G. molesta to emamectin benzoate biopesticide was significantly lower than that of the shoot-feeding larvae. We also found that the P450 enzyme activity and the expression of nine cytochrome P450s were enhanced in G. molesta fed on Fuji apples compared to those fed on peach shoots. The survival rates of G. molesta exposed to emamectin benzoate significantly decreased as each of three of four emamectin benzoate-inducted cytochrome P450 genes were silenced. Furthermore, we discovered the gut bacteria dynamics of G. molesta changed with the host shift and the structure of the gut bacteria microbiome was determined by the final diet ingested; additionally, the dysbiosis of the gut microbiota induced by antibiotics could significantly increase the sensitivity to emamectin benzoate. Taken together, our results suggest that the expression of P450s and the composition of the gut bacteria microbiome promote adaptation to emamectin benzoate in G. molesta, providing new insights into the molecular mechanisms underlying xenobiotic adaptation in this notorious pest.

Airborne magnetite nanoparticles induced early vascular pathologies by disrupting lipid metabolism under high-fat dietary patterns.

Magnetite nanoparticles (MNPs) have been extensively detected in the atmospheric environment and implicated as a prominent threat to atherosclerosis, a chronic vascular inflammatory disease. Due to globalization and economic development, the dramatic shift in diet from traditional to high-fat dietary patterns aggravated atherosclerosis progression induced by environmental factors. However, limited knowledge is available regarding vascular risks and underlying mechanisms of airborne MNPs in high-risk populations with high-fat dietary habits. Herein, we demonstrated that MNPs exerted a proatherogenic effect under high-fat dietary patterns, leading to aortic wall thickening, elastic fiber disorganization, macrophage infiltration, and local inflammation. Based on the correlation analysis between MNPs and PM group, we identified that MNPs might be a key PM component in atherogenic toxicity. MNPs exposure disturbed the dynamic process of lipid metabolism, manifested as aortic lipid accumulation, dyslipidemia, and hepatic lipid metabolism disorder, which was modulated by the JAK-STAT pathway. Overall, these findings provide new insight into understanding the cardiovascular risks and mechanisms of MNPs among high-risk populations.

Gut microbial shifts in vampire bats linked to immunity due to changed diet in human disturbed landscapes

Anthropogenic land-use change alters wildlife habitats and modifies species composition, diversity, and contacts among wildlife, livestock, and humans. Such human-modified ecosystems have been associated with emerging infectious diseases, threatening human and animal health. However, human disturbance also creates new resources that some species can exploit. Common vampire bats (Desmodus rotundus) in Latin America constitute an important example, as their adaptation to human-modified habitats and livestock blood-feeding has implications for e.g., rabies transmission. Despite the well-known links between habitat degradation and disease emergence, few studies have explored how human-induced disturbance influences wildlife behavioural ecology and health, which can alter disease dynamics. To evaluate links among habitat disturbance, diet shifts, gut microbiota, and immunity, we quantified disturbance around roosting caves of common vampire bats in Costa Rica, measured their long-term diet preferences (livestock or wildlife blood) using stable isotopes of carbon and nitrogen, evaluated innate and adaptive immune markers, and characterized their gut microbiota. We observed that bats from roosting caves with more cattle farming nearby fed more on cattle blood. Moreover, gut microbial richness and the abundance of specific gut microbes differed according to feeding preferences. Interestingly, bats feeding primarily on wildlife blood harboured a higher abundance of the bacteria Edwardsiella sp., which tended to be associated with higher immunoglobulin G levels. Our results highlight how human land-use change may indirectly affect wildlife health and emerging infectious diseases through diet-induced shifts in microbiota, with implications for host immunity and potential consequences for susceptibility to pathogens.

Diversity among flexitarian consumers; stratifying meat reducers by their underlying motivations to move to a plant-based diet

Concerns surrounding environmental and health impacts of meat production and consumption have motivated consumers to reduce their intake of animal-based products, with many adopting a ‘flexitarian’ diet that involves reduction of animal-based products, without complete abstinence. The underlying motivations driving this dietary shift remain unclear.Two online studies investigated whether subgroups of flexitarian consumers could be identified through individual differences in psychological traits that were hypothesised to be related to flexitarianism. Consumer subgroups were compared on their self-reported meat consumption and factors important to their dietary choices.In Study 1, self-identified flexitarians (N = 353) completed questionnaires comprising validated items related to psychological aspects of food choices (e.g., food-neophobia, food-involvement, health-consciousness). Consumer segments were created based on clusters of differences in motivations to follow a flexitarian diet. Study 2 (N = 297) sought to validate these initial clusters in a naïve sample of self-identified flexitarians.In Study 1, consumers grouped into three distinct clusters defined as ‘health-driven’, ‘trend-cautious’, and ‘adventurous’ flexitarians. Differences in food choice motivations and the importance of reducing meat intake were observed between clusters, but not reflected in differences in meat consumption. In Study 2, four consumer segments were defined as ‘health-only’, ‘traditional trend-cautious’, ‘adventurous’ and ‘health-focused’ flexitarians. Again, differences in food motivations, health interest, justifications for meat consumption and the importance of reducing meat intake were observed between clusters, but not reflected in differences in meat consumption.We provide a novel description of the diverse motivations among flexitarian consumers to reduce animal-based product intake.

Simulating impacts of fishing toothfish on the pelagic community in the Cooperation Sea, Southern Ocean

There is increasing attention to the use of Antarctic toothfish (Dissostichus mawsoni) and Patagonian toothfish (Dissostichus eleginoides). Understanding the responses of toothfish and other species to fishing activities favors the sustainable use of natural resources. We developed an end-to-end model OSMOSE-CooperationSea to simulate the food web dynamics in the Cooperation Sea and evaluate the impact of toothfish fishery. Fishes and cephalopods played important roles in the energy pathways from krill species and other zooplankton species to toothfish and Weddell seal (Leptonychotes weddellii) whose trophic levels were higher than 5.0. Adélie penguin (Pygoscelis adéliae), Crabeater seal (Lobodon carcinophaga), and Baleen whales were strongly krill-reliant. The spawning stock of toothfish decreased more quickly than the recruitments with increasing fishing pressure. Fishing impacts on the recruitments of toothfish were hysteretic due to the fishing selectivity. The model considered an ontogenetic diet shift of toothfish that mesopelagic fish was influential to toothfish juveniles. The overexploitation of toothfish stock might result in a trophic cascade that mesopelagic fish biomass increased and krill biomass declined. Adélie penguin, Crabeater seal, and Baleen whales preyed on more small fishes in response to the decline of krill biomass. Considering the impacts of changes in Antarctic krill availability, the biomass of Adélie penguin, Crabeater seal, and Baleen whales declined with a heavy toothfish fishery. The study highlights the importance of precautionary and ecosystem-based management to toothfish fishery.

The Belt and Road initiative and food consumption in countries along the route

AbstractThe economic impact of the Belt and Road (B&R) initiative has received extensive academic attention, but few existing assessments have focused on the impact of the initiative on consumer welfare. Therefore, this paper empirically investigates the impact of the B&R initiative on food consumption levels and dietary diversity in B&R countries and its inherent channels through the difference‐in‐differences model with the propensity score matching method (PSM‐DID). The results indicate that the B&R initiative has a significant positive effect on improving food consumption levels and dietary diversity in B&R countries, and the promotion‐effect is stronger for the Maritime Silk Road countries. Further, the B&R initiative has led to a dietary shift in B&R countries, with a decrease in the calorie share of cereals and an increase in the calorie share of fruits and vegetables, oils and fats, and meat, eggs and milk. The mechanism analysis reveals that income and prices may be important channels for the impact of the initiative on food consumption in B&R countries, and that the B&R initiative may have led to changes in tastes in B&R countries. [EconLit Citations: D12, F13, Q11].

Is a Fishing Moratorium Needed in Lake Honghu, Southern China? A Stomach Content Analysis of the Anchovy (Coilia brachygnathus)

Since 2017, a fishing moratorium has been enforced in Lake Honghu as part of Chang–Jiang’s biodiversity conservation strategy. However, given that the lake is a semi-closed aquatic ecosystem and no longer serves as a habitat for certain fishes of the mid–lower Chang–Jiang basin, the efficacy of this moratorium remains uncertain. To address the question from a trophic ecology perspective, a stomach content analysis was performed on captured anchovies of C. brachygnathus, a current predominant species in Lake Honghu, from November 2020 to October 2021. The results showed that copepods, shrimps, and macrophytes were the main components of this anchovy’s diet, and there were size-related shifts in diets. The dominance of C. brachygnathus, a pelagic–littoral omnivore in this lake, implies a lacustrine environment shift triggered by continued human disturbances. The utilization of macrophytes as the main food items by large-sized anchovies of Lake Honghu has partially contributed to the rapid degradation of submerged vegetation. This highlights the need to remove large-sized individuals of C. brachygnathus and Carassius auratus, another benthic-omnivorous dominant fish, in order to effectively restore the aquatic vegetation and ecosystem of Lake Honghu. The current implementation of fishing moratoriums in subtropical shallow floodplain lakes such as Lake Honghu should be reviewed critically.

Seasonal riverine inputs may affect diet and mercury bioaccumulation in Arctic coastal zooplankton

Climate change driven increases in permafrost thaw and terrestrial runoff are expected to facilitate the mobilization and transport of mercury (Hg) from catchment soils to coastal areas in the Arctic, potentially increasing Hg exposure of marine food webs. The main aim of this study was to determine the impacts of seasonal riverine inputs on land-ocean Hg transport, zooplankton diet and Hg bioaccumulation in an Arctic estuary (Adventfjorden, Svalbard). The Adventelva River was a source of dissolved and particulate Hg to Adventfjorden, especially in June and July during the river's main discharge period. Stable isotope and fatty acid analyses suggest that zooplankton diet varied seasonally with diatoms dominating during the spring phytoplankton bloom in May and with increasing contributions of dinoflagellates in the summer months. In addition, there was evidence of increased terrestrial carbon utilization by zooplankton in June and July, when terrestrial particles contributed substantially to the particulate organic matter pool. Total (TotHg) and methyl Hg (MeHg) concentrations in zooplankton increased from April to August related to increased exposure to riverine inputs, and to shifts in zooplankton diet and community structure. Longer and warmer summer seasons will probably increase riverine runoff and thus Hg exposure to Arctic zooplankton.

Consumers’ meat commitment and the importance of animal welfare as agricultural policy goal

Animal welfare is one of the key agricultural policy goals and is considered extremely important by consumers. With the increasing urgency for a sustainable and healthy dietary shift, it could be one of the key motivators for behaviour change. Therefore, we investigate how consumers perceive the importance of animal welfare not only as an agricultural policy goal but also in comparison to conflicting goals, such as domestic food production, farmers’ income, and consumer prices. We investigate how the weighing of animal welfare as an agricultural policy goal is related to individual behaviour (i.e. meat consumption), values and attitudes, such as meat commitment, the perceptions of farmers and the Ecological Welfare scale (which includes animal welfare and environment protection). Thus, we conducted an online survey in October 2022, recruiting a sample of 1542 participants (51.5% women) in equal parts from the German-, French-, and Italian-speaking parts of Switzerland. Participants were asked to evaluate the importance of increased animal welfare in three situations with the following conflicting policy goals: (1) increasing domestic food production, (2) reducing consumer food prices, and (3) increasing farm incomes. Regression analysis revealed that the influential predictors in all three models were similar. Being a woman, politically left leaning, and less committed to meat eating, having a more negative perception of farmers, and assigning more importance to ethical food consumption increased the probability of putting more weight on animal welfare in all three goal conflicts described above. The finding that participants who were more committed to meat eating tended to assign less importance to animal welfare when weighing the three conflicting agricultural policy goals is well-aligned with the current literature. Implications for agricultural policy are discussed.

Determinants of dietary diversity and drivers of food choice among low-income consumers in urban Kenya, Malawi and Zimbabwe.

Rapid urbanisation affects lifestyle and eating habits, predominantly causing a dietary shift that adds challenges to meet dietary recommendations within a complex food system. This research investigated dietary diversity and food choice drivers among low-income consumers in three urban settlements (Nairobi, Kenya; Bulawayo, Zimbabwe and Lilongwe, Malawi, representing rapid, moderate and slow urban growth patterns, respectively) as a first step towards improving diets across cultures and geographies. Mixed methods data collection was employed for this study. Qualitative methods such as rapid foodscape appraisal workshops and food stories in selected low-income settlements in Nairobi, Bulawayo and Lilongwe were utilised to collect information on the food environments (food balances, infrastructure, safety, policies and institutions). Quantitative data such as socio-demographic characteristics and dietary diversity were collected via structured questionnaires using Cognitive Edge's SenseMaker® (n = 890, 450 and 440 for Nairobi, Bulawayo and Lilongwe, respectively). The dietary intake of respondents was assessed using a 24-h recall, which was then converted to the food group diversity score (FGDS). Different levels of compounded stress affected dietary diversity and quality, including high food prices, concerns about sanitation and hygiene and the role of food standards regulation bodies. The mean FGDS across all locations was lower than the recommended cut-off of 5 (4.5, 2.8 and 2.6 across Nairobi, Zimbabwe and Lilongwe, respectively). Additionally, in Nairobi, there were gender differences in diet diversity, with men having a higher dietary diversity score than women (4.6% vs. 4.3%; p = 0.004). The majority of respondents in Lilongwe (65%) reported price as the most important driver of food choice, compared to 38% in Nairobi and 42% in Bulawayo. Our observation of poor-quality diets provides further evidence of the need for food policies that are cognisant of the nutrition and health of the growing population of the urban poor. Such policies would focus on lowering the costs of nutritious foods as well as ensuring food safety within the complex food system observed in the urban low-income environment.

Assessing juvenile swordfish (Xiphias gladius) diet as an indicator of marine ecosystem changes in the northwestern Mediterranean Sea

To preserve marine biodiversity, we need reliable early warning indicators that inform changes in marine ecosystems. As reliable samplers of mid-trophic level communities, studying the trophodynamics of large pelagic fish can contribute to monitoring these changes. Here, we combined stomach content and stable isotope analyses to reconstruct the diet of juvenile swordfish (Xiphias gladius) in the northwestern Mediterranean Sea, in a time-lapse of almost a decade (2012 and 2020). Overall, our study showed that swordfish fed on a wide range of fish and cephalopod species from both pelagic and demersal habitats. A dietary shift towards increasing consumption of cephalopods and decreasing consumption of Gadiformes had been observed between 2012 and 2020. Stable isotope approaches revealed that gelatinous organisms were also important prey, particularly for smaller-sized swordfish. We underline the importance of combining multiple and complementary approaches to better reconstruct the diet of generalist species. Our findings highlight the generalist and opportunistic diet of Mediterranean swordfish, which makes them good candidates for monitoring changes in the ecosystem.

The response of stream ecosystem properties to two size classes of herbivorous minnow species.

Losses in freshwater fish diversity might produce a loss in important ecological services provided by fishes in particular habitats. An important gap in our understanding of ecosystem services by fishes is the influence of individuals from different size classes, which is predicted based on known ontogenetic shifts in metabolic demand and diet. I used 20 experimental stream mesocosms located at Konza Prairie Biological Station (KPBS), KS, USA, to assess the influence of fish size on ecosystem properties. Mesocosms included two macrohabitats: one riffle upstream from one pool filled with consistent pebble and gravel substrate. There were four experimental and one control treatment, each replicated four times (N = 20). I used two size classes of central stonerollers (Campostoma anomalum) and southern redbelly dace (Chrosomus erythrogaster). Five ecosystem properties were assessed: algal filament length (cm), benthic chlorophyll a (μg/cm2), benthic organic matter (g/m2), macroinvertebrate biomass (g/m2), and stream metabolism (g O2/m2/day-1). Size structure of fish populations affected some, but not all, ecosystem properties, and these effects were dependent upon species identity. Size structure of both species had effects on algal filament lengths where stonerollers of both size classes reduced algal filaments, but only small redbelly dace kept filaments short. A better understanding of the relationship between these prairie stream minnows and their small stream habitats could be useful to both predict changes in stream properties if species are lost (redbelly dace are a Species In Need of Conservation) or size structure shifts.

Chiropteran diversity and diet of fruit bats in a tropical dry forest of northern South America

Remnants of Tropical Dry Forest persist in urban and peri-urban areas and are essential for maintaining biodiversity and ecosystem services. However, the challenges facing the conservation of these respective forests have intensified with the encroachment of the urban frontier, mining activities, deforestation, and cattle ranching. In this context, our study aims to estimate the diversity of the order Chiroptera and characterize the diet of the family Phyllostomidae. This approach allows us to gain insights into the ecological dynamics and assess the status of Tropical Dry Forest fragments located within the urban and peri-urban areas of Cúcuta, Colombia. Field sampling was conducted from January to September 2018, with a total sampling effort of 2,160 hours/meter/net. Bats were sexed, morphometrically characterized, and had their feces collected for diet analysis before being tagged and released. We identified three families, nine genera, and 11 species. A total of 276 individuals were captured. Seven species were observed in the urban area and ten in the peri-urban zone; Artibeus lituratus and Carollia perspicillata were the most abundant species in both locations. The diet included seeds from the families Moraceae, Anacardiaceae, and Rosaceae. Our findings reveal that in areas with dense vegetation, such as peri-urban zones, frugivorous bats prefer to consume fruits of domesticated species, including economically significant fruits like guava and tomato. This dietary shift could alter seed dispersal patterns and the dynamics of the Tropical Dry Forest, highlighting the ecological importance of these flying mammals in ecosystem regeneration.

Gut microbiota parallelism and divergence associated with colonisation of novel habitats.

An organism's gut microbiota can change in response to novel environmental conditions, in particular when colonisation of new habitats is accompanied by shifts in the host species' ecology. Here, we investigated the gut microbiota of three lizard species (A. inornata, H. maculata and S. cowlesi) from their ancestral-like habitat in the Chihuahuan desert and two colonised habitats with contrasting geological and ecological compositions: the White Sands and Carrizozo lava flow. The host species and the lizards' environment both shape gut microbiota composition, but host effects were overall stronger. Further, we found evidence that colonisation of the same environment by independent host species led to parallel changes of the gut microbiota, whereas the colonisation of two distinct environments by the same host species led to gut microbiota divergence. Some of the gut microbiota changes that accompanied the colonisation of the White Sands were associated with shifts in diet (based on diet information from previous studies), which is congruent with the general observation that trophic ecology has a strong effect on gut microbiota composition. Our study provides insights into how shifts in host ecology accompanying colonisation of novel environments can affect gut microbiota composition and diversity.

Advanced glycation end products promote intervertebral disc degeneration by transactivation of matrix metallopeptidase genes

Examine the mechanism by which advanced glycation end products (AGEs) induce intervertebral disc degeneration (IDD) in C57BL/6J mice. Matrix metallopeptidase (MMP) gene mRNA levels were assessed using RT-qPCR. Immunoprecipitation and co-immunoprecipitation were performed to identify the transcriptional complex regulating MMP expression due to AGEs. The preventive effects of inhibitors targeting this complex were tested in mice on high AGE diets. IDD and AGE accumulation were evident in mice on high-AGE diets (HAGEs), persisting across dietary shifts but absent in mice exclusively on low-AGE diets. Molecularly, HAGEs activated p21-activated kinase 1 (PAK1), prompting peroxisome proliferator-activated receptor gamma coactivator-related protein 1 (PPRC1) phosphorylation. Ubiquitin-specific protease 12 (USP12) interacted with the phosphorylated PPRC1 (pPPRC1), safeguarding it from proteasomal degradation. This pPPRC1, in collaboration with two histone acetyltransferases p300/CREB-binding protein (CBP) and a transcription factor activator protein 1(AP1), enhanced the expression of 12 MMP genes (MMP1a/1b/3/7/9/10/12/13/16/19/23/28). In vitro AGE exposure on nucleus pulposus and annulus fibrosus cells replicated this gene activation pattern, driven by the PAK1/pPPRC1-p300/CBP-AP1 pathway. The application of PAK1, p300, and AP1 inhibitors reduced pPPRC1-p300/CBP-AP1 binding to MMP promoters, diminishing their expression. These inhibitors effectively thwarted IDD in HAGE mice. Our results revealed that HAGEs instigate IDD via the PAK1/pPPRC1-p300/CBP-AP1 signaling pathway. This insight can guide therapeutic strategies to slow IDD progression in prediabetic/diabetic patients.

Coping with extremes: Alternations in diet, gut microbiota, and hepatic metabolic functions in a highland passerine

In wild animals, diet and gut microbiota interactions are critical moderators of metabolic functions and are highly contingent on habitat conditions. Challenged by the extreme conditions of high-altitude environments, the strategies implemented by highland animals to adjust their diet and gut microbial composition and modulate their metabolic substrates remain largely unexplored. By employing a typical human commensal species, the Eurasian tree sparrow (Passer montanus, ETS), as a model species, we studied the differences in diet, digestive tract morphology and enzyme activity, gut microbiota, and metabolic energy profiling between highland (the Qinghai-Tibet Plateau, QTP; 3230 m) and lowland (Shijiazhuang, Hebei; 80 m) populations. Our results showed that highland ETSs had enlarged digestive organs and longer small intestinal villi, while no differences in key digestive enzyme activities were observed between the two populations. The 18S rRNA sequencing results revealed that the dietary composition of highland ETSs were more animal-based and less plant-based than those of the lowland ones. Furthermore, 16S rRNA sequencing results suggested that the intestinal microbial communities were structurally segregated between populations. PICRUSt metagenome predictions further indicated that the expression patterns of microbial genes involved in material and energy metabolism, immune system and infection, and xenobiotic biodegradation were strikingly different between the two populations. Analysis of liver metabolomics revealed significant metabolic differences between highland and lowland ETSs in terms of substrate utilization, as well as distinct sex-specific alterations in glycerophospholipids. Furthermore, the interplay between diet, liver metabolism, and gut microbiota suggests a dietary shift resulting in corresponding changes in gut microbiota and metabolic functions. Our findings indicate that highland ETSs have evolved to optimize digestion and absorption, rely on more protein-rich foods, and possess gut microbiota tailored to their dietary composition, likely adaptive physiological and ecological strategies adopted to cope with extreme highland environments.

Feeding climate and biodiversity goals with novel plant-based meat and milk alternatives

Plant-based animal product alternatives are increasingly promoted to achieve more sustainable diets. Here, we use a global economic land use model to assess the food system-wide impacts of a global dietary shift towards these alternatives. We find a substantial reduction in the global environmental impacts by 2050 if globally 50% of the main animal products (pork, chicken, beef and milk) are substituted—net reduction of forest and natural land is almost fully halted and agriculture and land use GHG emissions decline by 31% in 2050 compared to 2020. If spared agricultural land within forest ecosystems is restored to forest, climate benefits could double, reaching 92% of the previously estimated land sector mitigation potential. Furthermore, the restored area could contribute to 13-25% of the estimated global land restoration needs under target 2 from the Kunming Montreal Global Biodiversity Framework by 2030, and future declines in ecosystem integrity by 2050 would be more than halved. The distribution of these impacts varies across regions—the main impacts on agricultural input use are in China and on environmental outcomes in Sub-Saharan Africa and South America. While beef replacement provides the largest impacts, substituting multiple products is synergistic.

Model-based scenarios for achieving net negative emissions in the food system

Most climate mitigation scenarios point to a combination of GHG emission reductions and CO2removal for avoiding the most dangerous climate change impacts this century. The global food system is responsible for ~1/3 of GHG emissions and thus plays an important role in reaching emission targets. Consumers, technology innovation, industry, and agricultural practices offer various degrees of opportunity to reduce emissions and remove CO2. However, a question remains as to whether food system transformation can achieve net negative emissions (i.e., where GHG sinks exceed sources sector wide) and what the capacity of the different levers may be. We use a global food system model to explore the influence of consumer choice, climate-smart agro-industrial technologies, and food waste reductions for achieving net negative emissions for the year 2050. We analyze an array of scenarios under the conditions of full yield gap closures and caloric demands in a world with 10 billion people. Our results reveal a high-end capacity of 33 gigatonnes of net negative emissions per annum via complete food system transformation, which assumes full global deployment of behavioral-, management- and technology-based interventions. The most promising technologies for achieving net negative emissions include hydrogen-powered fertilizer production, livestock feeds, organic and inorganic soil amendments, agroforestry, and sustainable seafood harvesting practices. On the consumer side, adopting flexitarian diets cannot achieve full decarbonization of the food system but has the potential to increase the magnitude of net negative emissions when combined with technology scale-up. GHG reductions ascribed to a mixture of technology deployment and dietary shifts emerge for many different countries, with areas of high ruminant production and non-intensive agricultural systems showing the greatest per capita benefits. This analysis highlights potential for future food systems to achieve net negative emissions using multifaceted “cradle-to-grave” and “land-to-sea” emission reduction strategies that embrace emerging climate-smart agro-industrial technologies.