Lower carbohydrate diets for adults with type 2 diabetes.

In May 2021, the Scientific Advisory Committee on Nutrition (SACN) published a risk assessment on lower carbohydrate diets for adults with type 2 diabetes (T2D)(). The purpose of the report was to review the evidence on 'low'-carbohydrate diets compared with the current UK government advice on carbohydrate intake for adults with T2D. However, since there is no agreed and widely utilised definition of a 'low'-carbohydrate diet, comparisons in the report were between lower and higher carbohydrate diets. SACN's remit is to assess the risks and benefits of nutrients, dietary patterns, food or food components for health by evaluating scientific evidence and to make dietary recommendations for the UK based on its assessment(). SACN has a public health focus and only considers evidence in healthy populations unless specifically requested to do otherwise. Since the Committee does not usually make recommendations relating to clinical conditions, a joint working group (WG) was established in 2017 to consider this issue. The WG comprised members of SACN and members nominated by Diabetes UK, the British Dietetic Association, Royal College of Physicians and Royal College of General Practitioners. Representatives from NHS England and NHS Health Improvement, the National Institute for Health and Care Excellence and devolved health departments were also invited to observe the WG. The WG was jointly chaired by SACN and Diabetes UK.

Severity scoring of manganese health effects for categorical regression.

Characterizing the U-shaped exposure response relationship for manganese (Mn) is necessary for estimating the risk of adverse health from Mn toxicity due to excess or deficiency. Categorical regression has emerged as a powerful tool for exposure-response analysis because of its ability to synthesize relevant information across multiple studies and species into a single integrated analysis of all relevant data. This paper documents the development of a database on Mn toxicity designed to support the application of categorical regression techniques. Specifically, we describe (i) the conduct of a systematic search of the literature on Mn toxicity to gather data appropriate for dose-response assessment; (ii) the establishment of inclusion/exclusion criteria for data to be included in the categorical regression modeling database; (iii) the development of a categorical severity scoring matrix for Mn health effects to permit the inclusion of diverse health outcomes in a single categorical regression analysis using the severity score as the outcome variable; and (iv) the convening of an international expert panel to both review the severity scoring matrix and assign severity scores to health outcomes observed in studies (including case reports, epidemiological investigations, and in vivo experimental studies) selected for inclusion in the categorical regression database. Exposure information including route, concentration, duration, health endpoint(s), and characteristics of the exposed population was abstracted from included studies and stored in a computerized manganese database (MnDB), providing a comprehensive repository of exposure-response information with the ability to support categorical regression modeling of oral exposure data.

Nutrition issues in Codex: health claims, nutrient reference values and WTO agreements: a conference report.

BACKGROUND: Codex documents may be used as educational and consensus materials for member governments. Also, the WTO SPS Agreement recognizes Codex as the presumptive international authority on food issues. Nutrient bioavailability is a critical factor in determining the ability of nutrients to provide beneficial effects. Bioavailability also influences the quantitative dietary requirements that are the basis of nutrient intake recommendations and NRVs. HEALTH CLAIMS: Codex, EFSA and some national regulatory authorities have established guidelines or regulations that will permit several types of health claims. The scientific basis for claims has been established by the US FDA and EFSA, but not yet by Codex. Evidence-based nutrition differs from evidence-based medicine, but the differences are only recently gaining recognition. Health claims on foods may provide useful information to consumers, but many will interpret the information to mean that they can rely upon the food or nutrient to eliminate a disease risk. NUTRIENT REFERENCE VALUES: NRVs are designed to provide a quantitative basis for comparing the nutritive values of foods, helping to illustrate how specific foods fit into the overall diet. The INL-98 and the mean of adult male and female values provide NRVs that are sufficient when used as targets for individual intakes by most adults. WORLD TRADE ORGANIZATION AGREEMENTS: WTO recognizes Codex as the primary international authority on food issues. Current regulatory schemes based on recommended dietary allowances are trade restrictive. A substantial number of decisions by the EFSA could lead to violation of WTO agreements.

Dose-response relationships in multifunctional food design: assembling the evidence.

Demonstrating single and multiple functions attributable to foods or specific food components is a challenge. The International Life Sciences Institute Europe co-ordinated EU concerted actions, Functional Food Science in Europe (FUFOSE) and the Process for the Assessment of Scientific Support for Claims on Food (PASSCLAIM), respectively, addressed the soundness of the evidence and its coherence with a mechanistic schema comprising valid markers of exposure, intermediate and final outcomes and the quality and integrity of the evidence overall. Demonstrating causality often relies on randomized controlled trials (RCTs). However, in public health and biomedical science there is concern about the suitability of RCTs as sole standards of evidence-based approaches. Alternative and complementary approaches using updated Hill's viewpoints for appraising the evidence can be used in conjunction with evidence-based mechanistic reasoning and the quality criteria proposed in FUFOSE and PASSCLAIM to design studies and to assemble evidence exploring single or multiple benefits from food components and foods.

26th Hohenheim Consensus Conference, September 11, 2010 Scientific substantiation of health claims: evidence-based nutrition.

OBJECTIVE: The objective was to define the term evidence based nutrition on the basis of expert discussions and scientific evidence. METHODS AND PROCEDURES: The method used is the established Hohenheim Consensus Conference. The term "Hohenheim Consensus Conference" defines conferences dealing with nutrition-related topics. The major aim of the conference is to review the state of the art of a given topic with experts from different areas (basic science, clinicians, epidemiologists, etc.). Based on eight to 12 questions, the experts discuss short answers and try to come to a consensus. A scientifically based text is formulated that justifies the consensus answer. To discuss the requirements for the scientific substantiation of claims, the 26th Hohenheim Consensus Conference gathered the views of many academic experts in the field of nutritional research and asked these experts to address the various aspects of a claims substantiation process and the possibilities and limitations of the different approaches. RESULTS: The experts spent a day presenting and discussing their views and arrived at several consensus statements that can serve as guidance for bodies performing claims assessments in the framework of regulatory systems. CONCLUSION: The 26th Hohenheim Consensus Conference addresses some general aspects and describes the current scientific status from the point of view of six case studies to illustrate specific areas of scientific interest: carotenoids and vitamin A in relation to age-related macular degeneration, the quality of carbohydrates (as expressed by the glycemic index) in relation to health and well-being, probiotics in relation to intestinal and immune functions, micronutrient intake and maintenance of normal body functions, and food components with antioxidative properties and health benefits.

Food & health forum meeting: evidence-based nutrition.

The present report summarises a meeting held by the Food & Health Forum at the Royal Society of Medicine, London, on 27 May 2010. The objective of the meeting was to review the problems associated with the use of evidence-based nutrition and to discuss what constitutes the efficacy for foods and food constituents and how the strength and consistency of the evidence can be assessed and adapted to circumstances in which health claims are to be used on food products. The meeting highlighted the limitations with the present evidence-based nutrition models with the prospect that this may have long-term consequences for nutrition science and ultimately the consumer who may not benefit from new science that could have an impact on health.

An exposure-response curve for copper excess and deficiency.

There is a need to define exposure-response curves for both Cu excess and deficiency to assist in determining the acceptable range of oral intake. A comprehensive database has been developed where different health outcomes from elevated and deficient Cu intakes were assigned ordinal severity scores to create common measures of response. A generalized linear model for ordinal data was used to estimate the probability of response associated with dose, duration and severity. The model can account for differences in animal species, the exposure medium (drinking water and feed), age, sex, and solubility. Using this model, an optimal intake level of 2.6 mg Cu/d was determined. This value is higher than the current U.S. recommended dietary intake (RDI; 0.9 mg/d) that protects against toxicity from Cu deficiency. It is also lower than the current tolerable upper intake level (UL; 10 mg/d) that protects against toxicity from Cu excess. Compared to traditional risk assessment approaches, categorical regression can provide risk managers with more information, including a range of intake levels associated with different levels of severity and probability of response. To weigh the relative harms of deficiency and excess, it is important that the results be interpreted along with the available information on the nature of the responses that were assigned to each severity score.

Population reference intakes and micronutrient bioavailability: a European perspective.

The processes of setting population reference intakes in the European Union and elsewhere have highlighted the paucity of data for informing the assessments and the need to take the opportunity to establish transparent, physiologically based approaches to setting reference values for safe and adequate intakes, including considerations of excess exposures. The confusion arising from the European exercise contributed to a number of initiatives to rationalize approaches to setting reference levels and safe upper levels of intake. A biologically based approach to nutrient risk assessment, which has many features that could be extended advantageously to the creation of a similar approach to setting nutrient reference values, has been proposed. This approach has yet to be explored, but an additional product of the earlier confusion has been the development of proposals for the international harmonization of approaches to setting nutrient-based dietary standards that could lead to internationally agreed-upon standards for nutrient risk assessment and for setting key intake values.

Toxicity due to excess and deficiency.

Customary approaches to setting safe upper levels for the intake of nutrients use, as critical events, adverse health that which, when adjusted using uncertainty factors (UF), produce values that, when they are applied to population risk analysis, along with dietary reference values that have been independently derived using a different approach by nutritionists, may provide narrow and unrealistic safe ranges of dietary intake. This study describes the evolving concept of the risk assessment of nutrients in which the critical events are based on homeostatic health effects that occur at the upper extreme of the physiological range of intakes. These events can be envisaged as markers of failing adaptation to high exposures and as heralds of potential later adverse events. Such markers may be associated with smaller and more easily characterized uncertainties than those applied to the more gross toxicological architectural, functional, or reproductive health effects used in standard toxicological risk assessment. The study also outlines the potential extension of this homeostatic model to the determination of safe lower limits of intake for essential nutrients and the identification, when homeostasis fails, of thresholds for inadequate intakes that can be adjusted by using uncertainty factors (UF) to derive adequate reference intakes.

Development of a copper database for exposure-response analysis.

While its precise form has not yet been defined, it is assumed that the exposure-response curve for copper (Cu) is U-shaped, as both Cu deficiency and excess can produce adverse health effects. Exposure-response relationships provide the foundation for setting recommended levels of exposure to essential and nonessential substances. A group of toxicologists, biologists, and epidemiologists formed a working group in 2002 to review the literature on Cu excess and deficiency as well as possible exposure-response modeling strategies. It was decided that in order to conduct more complex modeling exercises with studies on Cu, the information had to be organized into a database for application of emerging analytical approaches in exposure-response assessment. The database would support both current as well as proposed methods for exposure-response assessment and accommodate a variety of reporting methods found in the literature. As there are multiple studies looking at a wide range of adverse health effects attributed to excess and deficiency, data were organized into ordered categories of severity to create a common measure of response. The present study (1) outlines the approach used to identify studies for the Cu database based on their quality and usefulness for exposure-response analyses; (2) provides an overview of the process used to define a common dose metric; and (3) describes the process used to categorize a diverse number of responses from Cu excess and deficiency to an ordinal severity score. Efforts are underway to use this database to define the exposure-response curve for Cu excess and deficiency; however, the comprehensive database can be used to carry out other in-depth analyses on Cu toxicity.

The process for the assessment of scientific support for claims on food.

The concerted action "The process for the assessment of the scientific support for claims on foods", PASSCLAIM, proposed criteria that could provide an international yardstick for the harmonised transparent assessment of evidence submitted to support a claim for a food or food component. The evidence would be systematically appraised against specific criteria: namely, (1) a characterisation of the food or food component to which the claimed effect is attributed; (2) human data, primarily from intervention studies that represent the target populations for the claim; (3) a dose response relationship; (4) evidence allowing for confounders such as lifestyle, consumption patterns, background diet and food matrix etc.; (5) an appropriate duration for the study; (6) a measure of compliance; (7) adequate statistical power to test the hypothesis. Validated and quality assured markers of intermediate or final outcomes could be used when ideal endpoints are not easily accessible for measurement as long as their relationship to the development of the principal outcome relevant to the claim is well characterised and substantiated. The overall coherence and totality of published and unpublished evidence should be considered in the process. Assessments for substantiation claims need expert judgement, weighting of the strength of the claim, and intelligent use of the criteria applied on an individual basis with respect both to gaps in the knowledge and to any need for new knowledge and data.

Criteria for substantiating claims.

Claims are used to support public health advocacy and marketing. Their evidence base is variable. Claims are made on (i) nutrient content, (ii) comparative merits, (iii) health benefits, and (iv) medical benefits. Experience with therapeutic agents has aided the development of recommendations for the substantiation of health claims for foods and food components, with which dietary supplements would be included. An EU Concerted Activity, Functional Food Science in Europe, suggested that such claims should be based on the general outcomes of 'enhanced function' and 'reduced risk of disease'. A further EU Concerted Activity, The Process for the Assessment of Scientific Support for Claims on Foods, proposed that the evidence base should provide: a characterization of the food or food component to which the claimed effect is attributed; human data, primarily from intervention studies that represent the target populations for the claim; a dose-response relationship: evidence of allowing for confounders including lifestyle, consumption patterns, background diet and food matrix; an appropriate duration for the study; a measure of compliance; and have adequate statistical power to test the hypothesis. When ideal endpoints are not easily accessible for measurement, validated and quality assured markers of the intermediate or final outcomes could be used, as long as their relationship is well characterized. Overall, the totality and coherence of published and unpublished evidence should be considered. Assessments for substantiation need expert judgement, weighting of the strength of the claim, and intelligent use of the criteria applied on an individual basis with respect both to gaps in knowledge and to any need for new knowledge and data.

Home percutaneous endoscopic gastrostomy feeding: perceptions of patients, carers, nurses and dietitians.

AIM: This paper is a report of a study to compare the perceptions of adult patients, family carers, nurses and dietitians regarding home percutaneous endoscopic gastrostomy feeding. BACKGROUND: Healthcare professionals have a major role in patient selection for gastrostomy placement and the provision of aftercare but it is not clear if patients, their carers and healthcare professionals have similar perceptions of the initiation and delivery of feeding and of the care in general. METHOD: A cross-sectional mixed-method study using purposive sampling, semi-structured interviews and questionnaires was performed. Interviews were undertaken during 2005 with adult patients and carers of adults receiving home feeding. A questionnaire containing comparable questions was distributed to the lead district nurse and dietitian providing the individual patient's care. Binomial regression was used to analyse any differences in perceptions across the groups of respondents. RESULTS: Nurses and dietitians had similar perceptions of gastrostomy feeding in adults. Family carers' perceptions matched those of professionals more closely than did those of patients. The greatest difference in perceptions was between patients and their family carers. Respondents' views about success of feeding and the appropriateness of the feeding regimen were similar, but greater differences existed regarding quality of life, withdrawal of feeding and choice in decision-making about tube placement. CONCLUSION: There is a need for increased patient and carer involvement in decision-making and for sufficient, appropriate information to facilitate informed decision-making. Practitioners who involve carers in decision-making, where patients lack capacity, need to be aware that carers may not represent the views of patients.

Nutrient risk assessment: setting upper levels and an opportunity for harmonization.

Upper levels are estimates of the quantity of a nutrient that can be ingested daily over a lifetime without appreciable risk to health. The approach to establishing upper levels for nutrients, nutrient risk assessment, has derived from the risk assessment of foreign chemicals that are deliberately added to foods, or are in food as contaminants. This process of risk assessment is rigorous and transparent, particularly in dealing with the uncertainty arising from the data available and their assessment and extrapolation to human populations. Hazard identification and characterization, i.e., a dose-response pattern, as applied to xenobiotics, are discussed first, and then the difficulties of applying this approach to nutrients are reviewed. Nutrients, in contrast to foreign chemicals, have specific and selective metabolic pathways and homeostasis, as well as specific functions. This is the source of differences in the nutrient risk assessments produced by various national and international advisory bodies. Although the same data are used in such exercises, different judgments are made about identifying adverse effects, the nature of uncertainties in the assessment, and in matching the upper levels with exposure assessments and dietary reference values. The establishment of different upper levels for different national and international communities is a source of confusion in public health policy and practice and a barrier to trade. It is proposed that a basis for harmonizing the existing approaches used in nutrient risk assessment would be the collaborative development of the model for establishing upper levels of intake for nutrients and related substances that has been recently described by a Joint Task Force of the World Health Organization and the Food and Agriculture Organization.

Feeding preterm infants after hospital discharge: a commentary by the ESPGHAN Committee on Nutrition.

Survival of small premature infants has markedly improved during the last few decades. These infants are discharged from hospital care with body weight below the usual birth weight of healthy term infants. Early nutrition support of preterm infants influences long-term health outcomes. Therefore, the ESPGHAN Committee on Nutrition has reviewed available evidence on feeding preterm infants after hospital discharge. Close monitoring of growth during hospital stay and after discharge is recommended to enable the provision of adequate nutrition support. Measurements of length and head circumference, in addition to weight, must be used to identify those preterm infants with poor growth that may need additional nutrition support. Infants with an appropriate weight for postconceptional age at discharge should be breast-fed when possible. When formula-fed, such infants should be fed regular infant formula with provision of long-chain polyunsaturated fatty acids. Infants discharged with a subnormal weight for postconceptional age are at increased risk of long-term growth failure, and the human milk they consume should be supplemented, for example, with a human milk fortifier to provide an adequate nutrient supply. If formula-fed, such infants should receive special postdischarge formula with high contents of protein, minerals and trace elements as well as an long-chain polyunsaturated fatty acid supply, at least until a postconceptional age of 40 weeks, but possibly until about 52 weeks postconceptional age. Continued growth monitoring is required to adapt feeding choices to the needs of individual infants and to avoid underfeeding or overfeeding.

Functional effects of food: what do we know in children?

The knowledge base underpinning the setting of nutrient requirements for children and adolescents is not very secure. The advent of the concepts of optimal nutrition and functional foods has encouraged the possible use of functional effects as criteria for adequate nutrition in this age group. Target functions have been identified for growth development and differentiation and for behavioural and cognitive development. However, ideal markers or effects for these are not generally available. Additionally, nutrition in young people should avoid predisposing them to diet-related disease in later life. It is suggested that functional effects should include markers of reduction of risks of disease (nutritional safety) as well of benefits for health and well-being. Such markers of functional effects should be expected to arise from fundamental studies of nutrient-gene interactions and post-genomic metabolism.