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Some snakes are the only vertebrates able to engulf prey with cross-sectional areas several times larger than the area encompassed by the snake’s jaws at peak gape. This ability is conferred by modifying soft tissues ventral to the axial musculoskeletal system for extraordinary extensibility between the mandibles and stomach. Moving large prey into the gut depends on structural decoupling of toothed jaws from the braincase. In all living snakes, kinetic jaws form mobile ratchets. In scolecophidians, transverse maxillary or dentary ratchets have evolved to move small prey into the gut. In alethinophidians, longitudinal palatopterygoid ratchets move the head and body of the snake over the prey. Evidence from extant snakes shows that streptostyly, prokinesis, rhinokinesis and loss of all ventral skeletal elements connected to the axial skeleton were critical to evolution of the upper-jaw ratchet on which macrostomy is based. The existing fossil record gives tantalizing clues that suggest the ancestor of snakes might have been macrostomous. Resolution of this issue will require structural details of the snout, braincase, and toothed ratchets in both ‘basal’ extant snakes and fossils.
Genomic studies have elucidated some molecular underpinnings for adaptations during the early history of snakes, but studies of dietary adaptations remain sparse. Snakes differ from most other squamates by tending towards diets of vertebrate prey (carnivory), whereas arthropods are common in diets of most other squamates (insectivory). To test whether a shift from insectivory to carnivory occurred early in snake history, I examined chitinase genes (CHIAs) in 19 squamates. Previous studies on mammals found that contraction in the number of CHIAs, which enzymatically digest arthropod chitinous exoskeletons, correlates with transitions from insectivory to carnivory or herbivory. I found evidence that CHIAs have a long history in Squamata, with at least seven paralogs inferred in their last common ancestor. Retention of these CHIAs seems to be commonplace for arthropod-eating squamates, but snakes likely lost six CHIAs between diverging from other toxicoferans and the origin of afrophidian snakes. This genomic signal corresponds with an inferred major shift towards carnivory during the origin and evolution of early snakes, which may have contributed to their successful radiation.
The Covid-19 pandemic has impacted college students’ lifestyles and placed them at a greater risk of obesity and food insecurity. The purpose of the systematic review was to consolidate evidence for the effect of Covid-19 on students’ dietary quality, dietary habits, body weight, and food security status. A comprehensive literature search was conducted utilizing various databases including Google Scholar, MEDLINE, ScienceDirect, Embase, and Scopus to identify relevant studies. To be incorporated in this review, studies had to include higher education students, measure the prevalence of food insecurity, and assess the dietary and body weight changes during the Covid-19 pandemic. The studies showed that the diet quality of college students was compromised during the pandemic in many nations due to the decrease in the intake of whole grains, dairy products, legumes, nuts, fruits, and vegetables and the increase in consumption of alcohol, confectionery products, and refined grains. There was an increase in the frequency of cooking, binge eating, breakfast skipping, and unhealthy snacking. These modifications, in return, were associated with body weight changes, with no less than 20 to 30 % of students gaining weight during the pandemic. The pandemic also impacted food security status of students, with over 30% being food insecure worldwide. The Covid-19 outbreak has exacerbated the students’ diet quality and dietary habits and placed them under high risk of weight gain and food insecurity. Higher education institutions and governments should improve students’ access to nutritious foods and incorporate nutrition education interventions in the curricula.
To investigate perceptions of iTaukei Fijian women and men around diet and the ability to consume a healthy diet.
Design:
Six focus groups conducted with women and men, separately. Six to 10 women and men participated in each group. Discussions were recorded, transcribed, translated, and thematically analysed. Themes were mapped to an intersectionality framework to aid interpretation.
Setting:
Four villages in Viti Levu, Fiji.
Participants:
Twenty-two women and 24 men.
Results:
Seven overarching themes were identified, including generational changes in food behaviour, strong gendered beliefs around food and food provision, cultural and religious obligations around food, the impact of environment change on ability to consume a healthy diet, perceptions of the importance of food, food preferences and knowledge. Participants across focus groups identified that it was the “duty” of women to prepare food for their families. However, some women reflected on this responsibility being unbalanced with many women now in the formal workforce. Changes between generations in food preferences and practices were highlighted, with a perception that previous generations were healthier. Power dynamics and external factors, such as environmental changes, were identified by women and men as crucial influences on their ability to eat a healthy diet.
Conclusion:
Embedded traditional perceptions of gendered roles related to nutrition were misaligned with other societal and environmental changes. Given factors other than gender, such as power dynamics and environmental factors were identified as influencing diet, viewing nutrition-related issues through an intersectional lens is important to inform equitable food policy in Fiji.
During the first millennium ad, Europe saw much socio-environmental change, which is reflected in the archaeological and palaeoecological evidence. Using published and new isotope data from across western Europe, the author examines changing resource use from c.ad 350 to 1200. The geographical limits of millet and substantial marine consumption are identified and comparisons between childhood and adult diets made across regions. Cross-cultural interaction at a broad scale is emphasized and patterns within early medieval England form the subject of an in-depth case study. While doubt is cast onto the uptake of marine resource consumption in England following the Fish Event Horizon, changes in agricultural practices, the impact of Christianization, and the role of freshwater fish in diets are explored. The author's hierarchical meta-analytical approach enables identification of human–environment interactions, with significant implications for changing foodways in Europe during the first millennium ad.
It is unclear whether there is any association between psychological distress and unhealthy dietary habits among adolescents in low- and middle-income countries. We aimed to estimate the prevalence of these factors in South-East Asia region and investigate their associations. We used data from the Global School-based Health Survey for nine South-East Asian countries. Psychological distress was defined by presence of ≥ 2 factors from loneliness, anxiety, suicide ideation, suicide planning and suicide attempt. We assessed inadequate fruit intake, inadequate vegetable intake, daily soft drink and weekly fast-food consumption. We used random-effects meta-analysis to estimate pooled prevalence. Logistic regressions were used to estimate OR of unhealthy dietary behaviours for psychological distress. Among 30 013 adolescents (56 % girls) aged 12–15 years, the prevalence of psychological distress was 11·0 %, with girls reporting slightly higher than boys (11·8 % v. 10·1 %). The prevalence of inadequate fruit intake, inadequate vegetable intake, daily soft drink consumption and weekly fast-food consumption was 42 %, 26 %, 40 % and 57 %, respectively. Psychological distress was associated with inadequate fruit intake (pooled OR = 1·20, 95 % CI 1·03, 1·40), inadequate vegetable intake (pooled OR = 1·17, 1·05, 1·31) and daily soft drink consumption (pooled OR = 1·14, 1·03, 1·26); but not with weekly fast-food consumption (pooled OR = 1·13, 0·96, 1·31). We observed substantial cross-country variations in prevalence and OR estimates. In conclusion, South-East Asian adolescents have significant burden of psychological distress and unhealthy dietary behaviours, with those having psychological distress are more likely to have unhealthy dietary behaviours. Our findings will guide preventative interventions and inform relevant policies around adolescent nutrition in the region.
Some evidence suggests that breastfeeding may modify food preferences in the later years of life. The present study aimed to provide a systematic review of observational studies investigating the association between exposure to breastmilk and its duration with data-driven or hypothesis-driven (or diet quality scores) dietary patterns over one year of age. The databases of PubMed, Scopus, and Web of Science were searched for observational studies published from January 2010 until July 2021, which led to the identification of 22 eligible articles. There was considerable heterogeneity between studies in terms of assessment of exposure and outcome. Of the 11 studies that assessed data-driven dietary patterns, ten reported a significant association for at least one identified dietary pattern. Overall, being breastfed as well as a longer duration of any/exclusive breastfeeding were associated with higher scores on healthy dietary patterns characterized mainly by high loadings of fruits, vegetables, and whole grains. In comparison, a negative association was found for unhealthy dietary patterns rich in foods with high content of added sugar, salt, and saturated fats. In terms of diet quality scores, nine out of 11 studies reported a significant positive association between the duration of any breastfeeding and adherence to recommended healthy diets or dietary guidelines. In conclusion, the evidence from this review was generally in support of the hypothesis indicating breastfeeding is associated with healthy dietary patterns at later ages. However, due to the methodological limitations in the available studies, further research is warranted to elucidate solid evidence on this topic.
The transition of foods during toddlerhood and the suboptimal diets consumed in the Middle East make children susceptible to malnutrition and micronutrient deficiencies. Based on international recommendations, coupled with the merits of clinical studies on the application of young child formula (YCF), a group of fourteen experts from the Middle East reached a consensus on improving the nutritional status of toddlers. The recommendations put forth by the expert panel comprised twelve statements related to the relevance of YCF in young children; the impact of YCF on their nutritional parameters and functional outcomes; characteristics of the currently available YCF and its ideal composition; strategies to supply adequate nutrition in young children and educational needs of parents and healthcare professionals (HCPs). This consensus aims to serve as a guide to HCPs and parents, focusing on improving the nutritional balance in toddlers in the Middle Eastern region. The panellists considere YCF to be one of the potential solutions to improve the nutritional status of young children in the region. Other strategies to improve the nutritional status of young children include fortified cow's milk and cereals, vitamin and mineral supplements, early introduction of meat and fish, and the inclusion of diverse foods in children's diets.
The wetlands inhabited by the southern river otter Lontra provocax in Chile are subject to anthropogenic disturbances. As a result of the modification and destruction of its habitat, caused by loss of riparian vegetation, and other threats, the species is categorized as Endangered on the IUCN Red List. We monitored the river otter and its diet during September 2020–January 2021 in a swamp forest fragment in southern Chile. We obtained evidence of river otter presence from the upper part of the wetland to the confluence with the Bueno River, suggesting inter-population connectivity of the species in an extensive hydrographic basin. Faeces and food remains showed a predominance of native macrocrustaceans, with introduced fish present at lower levels. The detection of the southern river otter in a fragment of threatened swamp forest suggests a low abundance in environmentally degraded freshwater environments. The identification of subpopulations such as the one reported here provides valuable data to support the conservation of the species in threatened wetlands.
The NOVA classification of food items has become increasingly popular and is being used in several observational studies as well as in nutritional guidelines and recommendations. We propose that there is a need for this classification and its use in the formulation of public health policies to be critically discussed and re-appraised. The terms ‘processing’ and ‘ultra-processing’, which are crucial to the NOVA classification, are ill-defined, as no scientific, measurable or precise reference parameters exist for them. Likewise, the theoretical grounds of the NOVA classification are unclear and inaccurate. Overall, the NOVA classification conflicts with the classic, evidence-based evaluation of foods based on composition and portion size because NOVA postulates that the food itself (or how much of it is eaten) is unimportant, but rather that dietary effects are due to how the food is produced. We contend that the NOVA system suffers from a lack of biological plausibility so the assertion that ultra-processed foods are intrinsically unhealthful is largely unproven, and needs further examination and elaboration.
In this study we present new carbon (δ13C) and nitrogen (δ15N) stable isotope data of human (n=13) and animal (n=40) bone and/or dentine collagen samples, alongside accelerator mass spectrometry radiocarbon (AMS 14C) dates of human remains (n=16). The studied material was sampled from Lithuanian sites dating from the Late Mesolithic to the pre-Roman Iron Age. For the first time, we present δ13C and δ15N data from Lithuanian freshwater fish as well as AMS 14C, δ13C, and δ15N measurements of human remains from six disturbed graves at the Donkalnis cemetery and from two pre-Roman Iron Age graves. According to the new results, human diet derived protein from the Late Mesolithic to Subneolithic (ca. 7000–2900 cal BC) was primarily based on freshwater fish. While previous macrobotanical and stable isotope studies has suggested that C4 plants, i.e., millet, became more widely used from the Late Bronze Age (1100–500 cal BC), our data suggests that millet consumption may have decreased during the pre-Roman Iron Age (500–1 cal BC) in the southeastern Baltic.
To explore associations between maternal pre-pregnancy exposure to arsenic in diet and non-cardiac birth defects.
Design:
This is a population-based, case–control study using maternal responses to a dietary assessment and published arsenic concentration estimates in food items to calculate average daily total and inorganic arsenic exposure during the year before pregnancy. Assigning tertiles of total and inorganic arsenic exposure, logistic regression analysis was used to estimate OR for middle and high tertiles, compared to the low tertile.
Setting:
US National Birth Defects Prevention Study, 1997–2011.
Participants:
Mothers of 10 446 children without birth defects and 14 408 children diagnosed with a non-cardiac birth defect.
Results:
Maternal exposure to total dietary arsenic in the middle and high tertiles was associated with a threefold increase in cloacal exstrophy, with weak positive associations (1·2–1·5) observed either in both tertiles (intercalary limb deficiency) or the high tertile only (encephalocele, glaucoma/anterior chamber defects and bladder exstrophy). Maternal exposure to inorganic arsenic showed mostly weak, positive associations in both tertiles (colonic atresia/stenosis, oesophageal atresia, bilateral renal agenesis/hypoplasia, hypospadias, cloacal exstrophy and gastroschisis), or the high (glaucoma/anterior chamber defects, choanal atresia and intestinal atresia stenosis) or middle (encephalocele, intercalary limb deficiency and transverse limb deficiency) tertiles only. The remaining associations estimated were near the null or inverse.
Conclusions:
This exploration of arsenic in diet and non-cardiac birth defects produced several positive, but mostly weak associations. Limitations in exposure assessment may have resulted in exposure misclassification. Continued research with improved exposure assessment is recommended to identify if these associations are true signals or chance findings.
This exploratory study investigated the effects of early v. delayed time-restricted eating (TRE) plus caloric restriction (CR) on body weight, body composition and cardiometabolic parameters in adults with overweight and obesity. Adults (20–40 years) were randomised to one of three groups for 8 weeks: early time-restricted eating (eTRE; 08.00–16.00) plus CR, delayed time-restricted eating (dTRE; 12.00–20.00) plus CR or only CR (CR; 08.00–20.00). All groups were prescribed a 25 % energy deficit relative to daily energy requirements. Thirteen participants completed the study in the eTRE and CR groups and eleven in the dTRE group (n 37). After the interventions, there was no significant difference between the three groups for any of the outcomes. Compared with baseline, significant decreases were observed in the body weight (eTRE group: −4·2 kg; 95 % CI, −5·6, −2·7; dTRE group: −4·8 kg; 95 % CI, −5·9, −3·7; CR: −4·0 kg; 95 % CI, −5·9, −2·1), fat mass (eTRE group: −2·9 kg; 95 % CI, −3·9, −1·9; dTRE group: −3·6 kg; 95 % CI, −4·6, −2·5; CR: −3·1 kg; 95 % CI, −4·3, −1·8) and fasting glucose levels (eTRE group: −4 mg/dl; 95 % CI, −8, −1; dTRE group: −2 mg/dl; 95 % CI, −8, 3; CR: −3 mg/dl; 95 % CI, −8, 2). In a free-living setting, TRE with a energetic deficit, regardless of the time of day, promotes similar benefits in weight loss, body composition and cardiometabolic parameters. However, given the exploratory nature of our study, further investigation is needed to confirm these findings.
Sleep habits are directly related to risk of obesity, and this relationship may be partly mediated through food choices and eating behaviour. Short sleep duration, impaired sleep quality and suboptimal sleep timing are all implicated in weight gain and adverse cardiometabolic health, at least partly mediated through their associations with diet quality. Short-term sleep restriction leads to increased energy intake, and habitually short sleepers report dietary intakes that indicate a less healthy diet compared with adequate sleepers. Evidence is emerging that sleep extension interventions in short sleepers may reduce intake of sugars and overall energy intake. Poor sleep quality, night shift work patterns and social jetlag are also associated with lower diet quality and consumption of energy-dense foods. Incorporating sleep advice into weight management interventions may be more effective than energy-restricted diets and exercise advice alone. However, there are a lack of intervention studies that aim to lengthen sleep, improve sleep quality or adjust irregular sleep timing to investigate the impact on dietary intakes and eating behaviour in participants aiming to lose weight or maintain weight loss. Finally, future research should take account of individual characteristics such as age, sex, life stage and changing working practices when designing combined lifestyle interventions including sleep behaviour change for health and well-being.
One potential mechanism by which diet and lifestyle may affect chronic disease risk and subsequent mortality is through chronic systemic inflammation. In this study, we investigated whether the inflammatory potentials of diet and lifestyle, separately and combined, were associated with all-cause, all-CVD and all-cancer mortality risk. We analysed data on 18 484 (of whom 4103 died during follow-up) Black and White men and women aged ≥45 years from the prospective REasons for Geographic and Racial Differences in Stroke study. Using baseline (2003–2007) Block 98 FFQ and lifestyle questionnaire data, we constructed the previously validated inflammation biomarker panel-weighted, 19-component dietary inflammation score (DIS) and 4-component lifestyle inflammation score (LIS) to reflect the overall inflammatory potential of diet and lifestyle. From multivariable Cox proportional hazards models, the hazards ratios (HR) and their 95 % CI for the DIS–all-cause mortality and LIS–all-cause mortality risk associations were 1·32 (95 % CI (1·18, 1·47); Pfor trend < 0·01) and 1·25 (95 % CI (1·12, 1·38); Pfor trend < 0·01), respectively, among those in the highest relative to the lowest quintiles. The findings were similar by sex and race and for all-cancer mortality, but weaker for all-CVD mortality. The joint HR for all-cause mortality among those in the highest relative to the lowest quintiles of both the DIS and LIS was 1·91 (95 % CI 1·57, 2·33) (Pfor interaction < 0·01). Diet and lifestyle, via their contributions to systemic inflammation, separately, but perhaps especially jointly, may be associated with higher mortality risk among men and women.
Stable isotopes are a powerful tool for reconstructing the past. However, environmental factors not previously considered can lead to misinterpretations. Our study presents a novel analysis of the feeding behavior of the megafauna that inhabited the Pilauco ecosystem in south-central Chile during the last glacial termination. We analyzed a suite of modern plant and animal samples from closed-canopy forests to establish an isotopic baseline with which to compare stable isotope results from fossil megafauna. Using the modern samples as a reference, the δ13C results from the Pilauco megafauna indicate feeding behaviors in forested areas. These results were then calibrated with dental calculus samples and coprolites, which suggest the coexistence of graze- and grass-dominated mixed-feeder diets. The δ15N values found in Pilauco megafauna are not consistent with modern reference data sets or with the low δ15N values of extinct proboscideans from other contemporaneous and nearby sites. Probably, the δ15N values of the Pilauco ecosystem were not primarily affected by climate, but rather by disturbance factors (e.g., grazing effect). Our results indicate that the Pilauco megafauna fed mainly on arboreal vegetation; however, non-isotopic proxies indicate that they were also eating open vegetation (e.g., herbs and grasses).
To systematically review evidence from systematic reviews of interventions to improve dietary behaviours and reduce food wastage in secondary school pupils.
Design:
CINAHL, Cochrane Reviews, EMBASE, MEDLINE, PsychINFO and Web of Science were searched for systematic reviews of school-based dietary interventions from 2000 to 2020 published in a peer-reviewed journal in English. Articles were reviewed independently by two authors. AMSTAR-2 was used for quality assessment.
Setting:
Secondary school dietary interventions.
Participants:
Adolescents (aged 11–18).
Results:
In total, thirteen systematic reviews of dietary interventions in secondary schools met the inclusion criteria. A number of key characteristics of interventions that contributed to improvements in food choices in secondary school pupils were identified. These included the combination of education and environmental restructuring, incorporation of computer-based feedback, media or messaging, peer and/or parent involvement, an increase in the availability of healthy foods and the use of behavioural theory as a basis to the intervention. Intervention components that contributed specifically to a reduction in sugar-sweetened beverage intake or an increase in fruit and vegetable consumption, which are particularly relevant to adolescents, could not be determined. Similarly, evidence for interventions that improve nutritional knowledge and attitudes was limited.
Conclusions:
This systematic review of systematic reviews has identified a number of components of dietary interventions that can be explored to improve dietary behaviours in secondary school environments and, if demonstrated to be effective, be considered for inclusion in policies and strategies to improve the school food environment and promote dietary change.
Circulating branched-chain amino acids (BCAAs), a subgroup of the nine essential amino acids, have been associated to pancreatic cancer risk. The aim of this study is to estimate the relation between BCAA intake from diet and pancreatic cancer risk.
We analysed data from a multicentric Italian case-control study, including 326 pancreatic cancer cases and 652 controls, matched to cases by study centre, sex and age. A validated food-frequency questionnaire was used to collect the participants’ usual diet before cancer diagnosis (or hospital admission for controls) and to compute dietary intakes of various nutrients, including BCAAs. Odds ratios (ORs) and corresponding confidence intervals (CIs) were computed through logistic regression models conditioned on the matching variables and adjusted for major confounding factors, including total energy intake.
We found a positive association between the BCAA intake and pancreatic cancer risk (OR for the third quartile=1.88, 95% CI=1.08-3.26; OR for the fourth quartile =2.17, 95% CI=1.17-4.06), with a significant trend in risk. The association persisted after excluding subjects with diabetes and family history of pancreatic cancer, and across strata of selected covariates.
These data support and quantify the association between dietary BCAAs and pancreatic cancer, previously suggested by studies on circulating BCAAs.
Different methods of dietary intake assessment are frequently used to assess a population’s diet. In this study, we aimed to compare the adherence to Swiss food-based dietary guidelines as depicted in two Swiss population-based surveys using different methods of dietary assessment.
Design:
Two population-based, cross-sectional surveys were compared. In the Swiss Health Survey (SHS), diet was assessed via a short set of questions on specific food groups, while in menuCH by two non-consecutive 24-h dietary recall interviews.
Setting:
To compare the diet depicted in these surveys, we used the Swiss food-based dietary guidelines on vegetable, fruit, dairy product, meat and meat product, fish and alcohol. The weighted proportion of responders meeting these guidelines was calculated for both surveys and was compared overall and by selected characteristics.
Participants:
Residents of Switzerland, selected from a stratified random sample of the non-institutionalised residents, who agreed to participate in the respective survey. To ensure comparability between the surveys, the age of the study populations was restricted to 18–75 years.
Results:
In menuCH, approximately 2 % of responders met ≥4 of the selected Swiss food-based dietary guidelines. In the SHS, using a cruder dietary assessment, the corresponding percentage was 20 %. In both surveys, more women and never smokers were meeting ≥4 food-based dietary guidelines compared to men and current or former smokers, respectively.
Conclusions:
Our study comparing the diet in two population-based, representative surveys detected large variations in guideline adherence depending on the dietary assessment method used.