Matching roots to their environment

Background Plants form the base of the terrestrial food chain and provide medicines, fuel, fibre and industrial materials to humans. Vascular land plants rely on their roots to acquire the water and mineral elements necessary for their survival in nature or their yield and nutritional quality in agriculture. Major biogeochemical fluxes of all elements occur through plant roots, and the roots of agricultural crops have a significant role to play in soil sustainability, carbon sequestration, reducing emissions of greenhouse gasses, and in preventing the eutrophication of water bodies associated with the application of mineral fertilisers. ● Scope This article provides the context for a Special Issue of Annals of Botany on ‘Matching Roots to Their Environment’. It first examines how land plants and their roots evolved, describes how the ecology of roots and their rhizospheres contributes to the acquisition of soil resources, and discusses the influence of plant roots on biogeochemical cycles. It then describes the role of roots in overcoming the constraints to crop production imposed by hostile or infertile soils, illustrates root phenotypes that improve the acquisition of mineral elements and water, and discusses high-throughput methods to screen for these traits in the laboratory, glasshouse and field. Finally, it considers whether knowledge of adaptations improving the acquisition of resources in natural environments can be used to develop root systems for sustainable agriculture in the future.

Soil, food security and human health: a review

Direct effects of soil or its constituents on human health are through its ingestion, inhalation or absorption. The soil contains many infectious organisms that may enter the human body through these pathways, but it also provides organisms on which our earliest antibiotics are based. Indirect effects of soil arise from the quantity and quality of food that humans consume. Trace elements can have both beneficial and toxic effects on humans, especially where the range for optimal intake is narrow. We focus on four trace elements (iodine, iron, selenium and zinc) whose deficiencies have substantial effects on human health. As the world’s population increases issues of food security become more pressing, as does the need to sustain soil fertility and minimize its degradation. Lack of adequate food and food of poor nutritional quality lead to differing degrees of under-nutrition, which in turn causes ill health. Soil and land are finite resources and agricultural land is under severe competition from other uses. Relationships between soil and health are often difficult to extricate because of the many confounding factors present. Nevertheless, recent scientific understanding of soil processes and factors that affect human health are enabling greater insight into the effects of soil on our health. Multidisciplinary research that includes soil science, agronomy, agricultural sustainability, toxicology, epidemiology and the medical sciences will facilitate the discovery of new antibiotics, a greater understanding of how materials added to soil used for food production affect health and deciphering of the complex relationships between soil and human health.

Prediction of nutrient digestibility and energy concentrations in fresh grass using nutrient composition

Improved nutrient utilization efficiency is strongly related to enhanced economic performance and reduced environmental footprint of dairy farms. Pasture-based systems are widely used for dairy production in certain areas of the world, but prediction equations of fresh grass nutritive value (nutrient digestibility and energy concentrations) are limited. Equations to predict digestible energy (DE) and metabolizable energy (ME) used for grazing cattle have been either developed with cattle fed conserved forage and concentrate diets or sheep fed previously frozen grass, and the majority of them require measurements less commonly available to producers, such as nutrient digestibility. The aim of the present study was therefore to develop prediction equations more suitable to grazing cattle for nutrient digestibility and energy concentrations, which are routinely available at farm level by using grass nutrient contents as predictors. A study with 33 nonpregnant, nonlactating cows fed solely fresh-cut grass at maintenance energy level for 50 wk was carried out over 3 consecutive grazing seasons. Freshly harvested grass of 3 cuts (primary growth and first and second regrowth), 9 fertilizer input levels, and contrasting stage of maturity (3 to 9 wk after harvest) was used, thus ensuring a wide representation of nutritional quality. As a result, a large variation existed in digestibility of dry matter (0.642-0.900) and digestible organic matter in dry matter (0.636-0.851) and in concentrations of DE (11.8-16.7 MJ/kg of dry matter) and ME (9.0-14.1 MJ/kg of dry matter). Nutrient digestibilities and DE and ME concentrations were negatively related to grass neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents but positively related to nitrogen (N), gross energy, and ether extract (EE) contents. For each predicted variable (nutrient digestibilities or energy concentrations), different combinations of predictors (grass chemical composition) were found to be significant and increase the explained variation. For example, relatively higher R(2) values were found for prediction of N digestibility using N and EE as predictors; gross-energy digestibility using EE, NDF, ADF, and ash; NDF, ADF, and organic matter digestibilities using N, water-soluble carbohydrates, EE, and NDF; digestible organic matter in dry matter using water-soluble carbohydrates, EE, NDF, and ADF; DE concentration using gross energy, EE, NDF, ADF, and ash; and ME concentration using N, EE, ADF, and ash. Equations presented may allow a relatively quick and easy prediction of grass quality and, hence, better grazing utilization on commercial and research farms, where nutrient composition falls within the range assessed in the current study.

"When I go to bed hungry and sleep, I'm not hungry": children and parents' experiences of food insecurity

Evidence demonstrates food insecurity has a detrimental impact on a range of outcomes for children, but little research has been conducted in the UK, and children have rarely been asked to describe their experiences directly. We examined the experiences of food insecure families living in South London. Our mixed-methods approach comprised a survey of parents (n = 72) and one-to-one semi-structured interviews with children aged 5-11 years (n = 19). The majority of parents (86%) described their food security during the preceding year as very low. Most reported they had often or sometimes had insufficient food, and almost all had worried about running out of food. Two thirds of parents had gone hungry. Most parents reported they had been unable to afford a nutritionally balanced diet for their children, and just under half reported that their children had gone hungry. Four themes emerged from the interviews with children: sources of food; security of food, nutritional quality of food, and experiences of hunger. Children's descriptions of insufficient food being available indicate that parents are not always able to shield them from the impact of food insecurity. The lack of school-meals and after-school clubs serving food made weekends particularly problematic for some children. A notable consequence of food insecurity appears to be reliance on low-cost takeaway food, likely to be nutritionally poor.

Survey of canteens and food services in Victorian schools

Objective: To examine the characteristics of food services in Victorian government primary and secondary schools.

Design and methods: A cross-sectional postal survey of all high schools and a random sample of one quarter of primary school respondents in Victoria. A `School Food Services and Canteen' questionnaire was administered by mail to the principal of each school.

Subjects: Respondents included principals, canteen managers and home economics teachers from 150 primary and 208 secondary schools representing response rates of 48% and 67%, respectively.

Main outcome measures: Responses to closed questions about school canteen operating procedures, staff satisfaction, food policies and desired additional services.

Data analyses: Frequency and cross-tabulation analyses and associated χ²-tests.

Results: Most schools provided food services at lunchtime and morning recess but one-third provided food before school. Over 40% outsourced their food services, one-third utilised volunteer parents, few involved students in canteen operations. Half of the secondary schools had vending machines; one in five had three or more. Secondary school respondents were more dissatisfied with the nutritional quality of the food service, and expressed more interest in additional services than primary respondents. Schools with food policies wanted more service assistance and used volunteer parents, student and paid canteen managers more than schools without policies.

Conclusion: Most schools want to improve the nutritional quality of their food services, especially via school food policies. There is a major opportunity for professional organisations to advocate for the supply of healthier school foods.

Globalisation, food and health in Pacific Island countries

Pacific Island countries (PICs) are experiencing an epidemic of obesity and consequent chronic diseases. Despite investment in the development of National Plans of Action for Nutrition (NPANs) and interventions to promote healthy eating and physical activity, nutritional status appears to show little improvement. This paper presents a synthesis of the findings from two research papers that were prepared for a 2003 food safety and quality meeting in Nadi, Fiji. The findings indicate that although lifestyle behaviours might be the immediate cause of dietary imbalances, greater attention should focus on omnipresent influences of globalisation as a critical element of the nutrition transition in the Pacific. In particular, those aspects of globalisation mediated through the World Trade Organization (WTO) Agreements that are placing pressures on food security and fostering increased dependence on imported food of poor nutritional quality. Rapid, significant and sustainable improvements in public health in PICs require interventions that can tackle these underlying contributors to ill health. There are opportunities to explore the use of food regulatory approaches to influence the composition, availability and accessibility of food products. Within the context of the WTO Agreements the legitimacy of food regulatory approaches will depend upon the case to demonstrate the relationship between the intervention and the protection of food security and public health nutrition. The challenges in realising these opportunities are: 1) to have the capacity to construct a case, 2) meet the technical and financial demands to administer and enforce regulatory approaches, and 3) to take advantage of opportunities available and to be able to fully participate in the international policy-making process.

The health equity dimensions of urban food systems

There is increasing recognition that the nutrition transition sweeping the world’s cities is multifaceted. Urban food and nutrition systems are beginning to share similar features, including an increase in dietary diversity, a convergence toward “Western-style” diets rich in fat and refined carbohydrate and within-country bifurcation of food supplies and dietary conventions. Unequal access to the available dietary diversity, calories, and gastronomically satisfying eating experience leads to nutritional inequalities and diet-related health inequities in rich and poor cities alike. Understanding the determinants of inequalities in food security and nutritional quality is a precondition for developing preventive policy responses. Finding common solutions to under- and overnutrition is required, the first step of which is poverty eradication through creating livelihood strategies. In many cities, thousands of positions of paid employment could be created through the establishment of sustainable and self-sufficient local food systems, including urban agriculture and food processing initiatives, food distribution centers, healthy food market services, and urban planning that provides for multiple modes of transport to food outlets. Greater engagement with the food supply may dispel many of the food anxieties affluent consumers are experiencing.

Invoice methodology

An innovative method for measuring the impact of an environmental food service intervention on the nutritional quality of the food supply was developed and implemented at five food services in Victoria as part of a Catering Improvement Program trial. This study used the invoice data to investigate changes in food supply at these food services.

Tongan adolescents' eating patterns : opportunities for intervention

The purpose of this mixed methods study was to examine the sources of food and dietary patterns of Tongan adolescents (n = 2084) and their perceptions of sociocultural influences. The study incorporated anthropometric measurements, a behavioral survey, and qualitative interviews. More adolescent Tongan females (82.5%) than males (74.3%) reported sourcing morning tea and/or lunch (females 81.9%, males 72.6%) from school canteens or nearby food outlets. More females than males reported consuming obesity-promoting foods such as packaged snack foods (females 38.2%, males 21.3%), chocolates (females 24.7%, males 15.0%), and soft drinks (females 55.3%, males 50.4%). Food purchased for consumption at schools was predominantly energy dense and nutrient poor. Ensuring that students have access to foods of high nutritional quality sourced from school or home, and restricting access to local food outlets that supply unhealthy products would improve the nutrition status of adolescents in Tonga. Furthermore, it is important that obesity prevention interventions are informed by culture-specific influences to optimize uptake of healthy diets.

Interventions for preventing obesity in children (review)

Background

Prevention of childhood obesity is an international public health priority given the significant impact of obesity on acute and chronic diseases, general health, development and well-being. The international evidence base for strategies that governments, communities and families can implement to prevent obesity, and promote health, has been accumulating but remains unclear.
Objectives

This review primarily aims to update the previous Cochrane review of childhood obesity prevention research and determine the effectiveness of evaluated interventions intended to prevent obesity in children, assessed by change in Body Mass Index (BMI). Secondary aims were to examine the characteristics of the programs and strategies to answer the questions "What works for whom, why and for what cost?"
Search methods

The searches were re-run in CENTRAL, MEDLINE, EMBASE, PsychINFO and CINAHL in March 2010 and searched relevant websites. Non-English language papers were included and experts were contacted.
Selection criteria

The review includes data from childhood obesity prevention studies that used a controlled study design (with or without randomisation). Studies were included if they evaluated interventions, policies or programs in place for twelve weeks or more. If studies were randomised at a cluster level, 6 clusters were required.
Data collection and analysis

Two review authors independently extracted data and assessed the risk of bias of included studies. Data was extracted on intervention implementation, cost, equity and outcomes. Outcome measures were grouped according to whether they measured adiposity, physical activity (PA)-related behaviours or diet-related behaviours. Adverse outcomes were recorded. A meta-analysis was conducted using available BMI or standardised BMI (zBMI) score data with subgroup analysis by age group (0-5, 6-12, 13-18 years, corresponding to stages of developmental and childhood settings).
Main results

This review includes 55 studies (an additional 36 studies found for this update). The majority of studies targeted children aged 6-12 years. The meta-analysis included 37 studies of 27,946 children and demonstrated that programmes were effective at reducing adiposity, although not all individual interventions were effective, and there was a high level of observed heterogeneity (I2=82%). Overall, children in the intervention group had a standardised mean difference in adiposity (measured as BMI or zBMI) of -0.15kg/m2 (95% confidence interval (CI): -0.21 to -0.09). Intervention effects by age subgroups were -0.26kg/m2 (95% CI:-0.53 to 0.00) (0-5 years), -0.15kg/m2 (95% CI -0.23 to -0.08) (6-12 years), and -0.09kg/m2 (95% CI -0.20 to 0.03) (13-18 years). Heterogeneity was apparent in all three age groups and could not explained by randomisation status or the type, duration or setting of the intervention. Only eight studies reported on adverse effects and no evidence of adverse outcomes such as unhealthy dieting practices, increased prevalence of underweight or body image sensitivities was found. Interventions did not appear to increase health inequalities although this was examined in fewer studies.
Authors' conclusions

We found strong evidence to support beneficial effects of child obesity prevention programmes on BMI, particularly for programmes targeted to children aged six to 12 years. However, given the unexplained heterogeneity and the likelihood of small study bias, these findings must be interpreted cautiously. A broad range of programme components were used in these studies and whilst it is not possible to distinguish which of these components contributed most to the beneficial effects observed, our synthesis indicates the following to be promising policies and strategies:

· school curriculum that includes healthy eating, physical activity and body image

· increased sessions for physical activity and the development of fundamental movement skills throughout the school week

· improvements in nutritional quality of the food supply in schools

· environments and cultural practices that support children eating healthier foods and being active throughout each day

· support for teachers and other staff to implement health promotion strategies and activities (e.g. professional development, capacity building activities)

· parent support and home activities that encourage children to be more active, eat more nutritious foods and spend less time in screen based activities

However, study and evaluation designs need to be strengthened, and reporting extended to capture process and implementation factors, outcomes in relation to measures of equity, longer term outcomes, potential harms and costs.

Childhood obesity prevention research must now move towards identifying how effective intervention components can be embedded within health, education and care systems and achieve long term sustainable impacts.

Monitoring the impacts of trade agreements on food environments

The liberalization of international trade and foreign direct investment through multilateral, regional and bilateral agreements has had profound implications for the structure and nature of food systems, and therefore, for the availability, nutritional quality, accessibility, price and promotion of foods in different locations. Public health attention has only relatively recently turned to the links between trade and investment agreements, diets and health, and there is currently no systematic monitoring of this area. This paper reviews the available evidence on the links between trade agreements, food environments and diets from an obesity and non-communicable disease (NCD) perspective. Based on the key issues identified through the review, the paper outlines an approach for monitoring the potential impact of trade agreements on food environments and obesity/NCD risks. The proposed monitoring approach encompasses a set of guiding principles, recommended procedures for data collection and analysis, and quantifiable 'minimal', 'expanded' and 'optimal' measurement indicators to be tailored to national priorities, capacity and resources. Formal risk assessment processes of existing and evolving trade and investment agreements, which focus on their impacts on food environments will help inform the development of healthy trade policy, strengthen domestic nutrition and health policy space and ultimately protect population nutrition.

Food sources of total energy and nutrients among U.S. infants and toddlers: national health and nutrition examination survey 2005-2012

Understanding the dietary intakes of infants and toddlers is important because early life nutrition influences future health outcomes. The aim of this study was to determine the dietary sources of total energy and 16 nutrients in a nationally representative sample of U.S. infants and toddlers aged 0-24 months. Data from the 2005-2012 National Health and Nutrition Examination Survey were analyzed. Dietary intake was assessed in 2740 subjects using one 24-h dietary recall. The population proportion was used to determine the contribution of foods and beverages to nutrient intakes. Overall infant formulas and baby foods were the leading sources of total energy and nutrients in infants aged 0-11.9 months. In toddlers, the diversity of food groups contributing to nutrient intakes was much greater. Important sources of total energy included milk, 100% juice and grain based mixed dishes. A number of foods of low nutritional quality also contributed to energy intakes including sweet bakery products, sugar-sweetened beverages and savory snacks. Overall non-flavored milks and ready-to-eat cereals were the most important contributors to micronutrient intakes. In conclusion this information can be used to guide parents regarding appropriate food selection as well as inform targeted dietary strategies within public health initiatives to improve the diets of infants and toddlers.

Child and adolescent obesity: part of a bigger picture

The prevalence of childhood overweight and obesity has risen substantially worldwide in less than one generation. In the USA, the average weight of a child has risen by more than 5 kg within three decades, to a point where a third of the country's children are overweight or obese. Some low-income and middle-income countries have reported similar or more rapid rises in child obesity, despite continuing high levels of undernutrition. Nutrition policies to tackle child obesity need to promote healthy growth and household nutrition security and protect children from inducements to be inactive or to overconsume foods of poor nutritional quality. The promotion of energy-rich and nutrient-poor products will encourage rapid weight gain in early childhood and exacerbate risk factors for chronic disease in all children, especially those showing poor linear growth. Whereas much public health effort has been expended to restrict the adverse marketing of breastmilk substitutes, similar effort now needs to be expanded and strengthened to protect older children from increasingly sophisticated marketing of sedentary activities and energy-dense, nutrient-poor foods and beverages. To meet this challenge, the governance of food supply and food markets should be improved and commercial activities subordinated to protect and promote children's health.

Seasonal variations in chemical composition and stable isotopes of farmed and wild Brazilian freshwater fish

This study examined variations in the Fulton condition factor, chemical composition, and stable isotopes of carbon and nitrogen in the Brazilian freshwater fish cachara (Pseudoplatystoma fasciatum), comparing farmed and wild fish in different seasons. Values for energy, protein, moisture, and Fulton's condition factor were higher for farmed than for wild fish in the rainy season, indicating better nutritional quality; however, these differences were not observed in the dry season. Likewise, we found significant enhancement of delta(15)N in farmed fish in the rainy season but not in the dry season, whereas enhancement of delta(13)C was observed in both seasons. The combined measurement of delta(13)C and delta(15)N provided traceability under all conditions. Our findings show that stable isotope analysis of C and N can be used to trace cachara origin, and that seasonal variations need to be considered when applying chemical and isotopic authentication of fish and fish products. (C) 2010 Elsevier Ltd. All rights reserved.