Protein quality as a complementary functional unit in life cycle assessment (LCA).

Goal and theoretical commentary: A number of recent life cycle assessment (LCA) studies have concluded that animal-sourced foods should be restricted-or even avoided-within the human diet due to their relatively high environmental impacts (particularly those from ruminants) compared with other protein-rich foods (mainly protein-rich plant foods). From a nutritional point of view, however, issues such as broad nutrient bioavailability, amino acid balances, digestibility and even non-protein nutrient density (e.g., micronutrients) need to be accounted for before making such recommendations to the global population. This is especially important given the contribution of animal sourced foods to nutrient adequacy in the global South and vulnerable populations of high-income countries (e.g., children, women of reproductive age and elderly). Often, however, LCAs simplify this reality by using 'protein' as a functional unit in their models and basing their analyses on generic nutritional requirements. Even if a 'nutritional functional unit' (nFU) is utilised, it is unlikely to consider the complexities of amino acid composition and subsequent protein accretion. The discussion herein focuses on nutritional LCA (nLCA), particularly on the usefulness of nFUs such as 'protein,' and whether protein quality should be considered when adopting the nutrient as an (n)FU. Further, a novel and informative case study is provided to demonstrate the strengths and weaknesses of protein-quality adjustment. Case study methods: To complement current discussions, we present an exploratory virtual experiment to determine how Digestible Indispensable Amino Acid Scores (DIAAS) might play a role in nLCA development by correcting for amino acid quality and digestibility. DIAAS is a scoring mechanism which considers the limiting indispensable amino acids (IAAs) within an IAA balance of a given food (or meal) and provides a percentage contribution relative to recommended daily intakes for IAA and subsequent protein anabolism; for clarity, we focus only on single food items (4 × animal-based products and 4 × plant-based products) in the current case exemplar. Further, we take beef as a sensitivity analysis example (which we particularly recommend when considering IAA complementarity at the meal-level) to elucidate how various cuts of the same intermediary product could affect the interpretation of nLCA results of the end-product(s). Recommendations: First, we provide a list of suggestions which are intended to (a) assist with deciding whether protein-quality correction is necessary for a specific research question and (b) acknowledge additional uncertainties by providing mitigating opportunities to avoid misinterpretation (or worse, dis-interpretation) of protein-focused nLCA studies. We conclude that as relevant (primary) data availability from supply chain 'gatekeepers' (e.g., international agri-food distributors and processors) becomes more prevalent, detailed consideration of IAA provision of contrasting protein sources needs to be acknowledged-ideally quantitatively with DIAAS being one example-in nLCA studies utilising protein as a nFU. We also contend that future nLCA studies should discuss the complementarity of amino acid balances at the meal-level, as a minimum, rather than the product level when assessing protein metabolic responses of consumers. Additionally, a broader set of nutrients should ideally be included when evaluating "protein-rich foods" which provide nutrients that extend beyond amino acids, which is of particular importance when exploring dietary-level nLCA.

Proceedings of the Rank Forum on Vitamin D.

The Rank Forum on Vitamin D was held on 2nd and 3rd July 2009 at the University of Surrey, Guildford, UK. The workshop consisted of a series of scene-setting presentations to address the current issues and challenges concerning vitamin D and health, and included an open discussion focusing on the identification of the concentrations of serum 25-hydroxyvitamin D (25(OH)D) (a marker of vitamin D status) that may be regarded as optimal, and the implications this process may have in the setting of future dietary reference values for vitamin D in the UK. The Forum was in agreement with the fact that it is desirable for all of the population to have a serum 25(OH)D concentration above 25 nmol/l, but it discussed some uncertainty about the strength of evidence for the need to aim for substantially higher concentrations (25(OH)D concentrations>75 nmol/l). Any discussion of 'optimal' concentration of serum 25(OH)D needs to define 'optimal' with care since it is important to consider the normal distribution of requirements and the vitamin D needs for a wide range of outcomes. Current UK reference values concentrate on the requirements of particular subgroups of the population; this differs from the approaches used in other European countries where a wider range of age groups tend to be covered. With the re-emergence of rickets and the public health burden of low vitamin D status being already apparent, there is a need for urgent action from policy makers and risk managers. The Forum highlighted concerns regarding the failure of implementation of existing strategies in the UK for achieving current vitamin D recommendations.

Research goals for folate and related B vitamin in Europe.

In the past decade, the understanding of folate bioavailability, metabolism and related health issues has increased, but several problems remain, including the difficulty of delivering the available knowledge to the populations at risk. Owing to the low compliance of taking folic acid supplements, for example, among women of child-bearing age who could lower the risk of having a baby with a neural tube defect, food-based strategies aimed at increasing the intake of folate and other B-group vitamins should be a priority for future research. These should include the development of a combined strategy of supplemental folate (possibly with vitamin B(12)), biofortification using engineered plant-derived foods and micro-organisms and food fortification for increasing folate intakes in the general population. Currently, the most effective population-based strategy to reduce NTDs remains folic acid fortification. However, the possible adverse effect of high intakes of folic acid on neurologic functioning among elderly persons with vitamin B(12) deficiency needs urgent investigation. The results of ongoing randomized controlled studies aimed at reducing the prevalence of hyperhomocysteinemia and related morbidity must be available before food-based total population approaches for treatment of hyperhomocysteinemia can be recommended. Further research is required on quantitative assessment of folate intake and bioavailability, along with a more thorough understanding of physiological, biochemical and genetic processes involved in folate absorption and metabolism.

The relationship between alpha-tocopherol and phospholipid fatty acids in rat liver subcellular membrane fractions.

(1) A method was devised for the subfractionation of normal rat liver and for the subfractionation of the mitochondrial fraction into inner and outer membrane fractions. The purity of the fractions was assessed using marker enzyme measurements. (2) alpha-Tocopherol was measured in all the fractions by a sensitive HPLC technique. Profiles of phospholipid fatty acids were also determined by gas-liquid chromatography in all the fractions, and these values were calculated in terms of the percentage of each fatty acid in the total fatty acid of the fraction, as well as of the mass of each fatty acid per mumol of phospholipid phosphorus. Tocopherol values were expressed as the mass of tocopherol per g wet liver and per mumol of phospholipid phosphorus. (3) The results show that the mitochondrial and microsomal fractions were the major tocopherol-containing fractions, and both the inner and outer mitochondrial fractions contained substantial amounts of alpha-tocopherol. (4) The mitochondrial and microsomal fractions also had the highest levels of polyunsaturated fatty acids (PUFA) in their phospholipid fraction, especially 20:4 and 22:6, which were particularly localised in the inner mitochondrial membrane fraction. The high inner mitochondrial and microsomal PUFA levels were particularly apparent when the sum of all the unsaturated fatty acids with three or more double bonds was calculated. (5) Calculation of molar ratios of of some phospholipid fatty acids to alpha-tocopherol gave values of the order of several thousand to one. (6) It is concluded that the protective effect of each molecule of alpha-tocopherol must be exerted towards a large number of molecules of membrane unsaturated fatty acids simultaneously. This perhaps implies specific localisation of tocopherol in regions of membrane particularly liable to attack, such as might be expected to occur close to respiratory enzymes that can donate electrons to molecular oxygen.

The alpha-tocopherol and phospholipid fatty acid content of rat liver subcellular membranes in vitamin E and selenium deficiency.

(1) Rats were given a diet deficient in vitamin E and selenium, or diets supplemented with either or both of these nutrients. The livers were subfractionated by standard procedures, and the purity of the fractions was assessed by marker enzyme techniques. alpha-Tocopherol was measured and profiles of phospholipid fatty acids were determined. (2) All the organelles studied were severely depleted of alpha-tocopherol in the rats deprived of vitamin E: no organelle was particularly severely depleted. There was a large rise in the alpha-tocopherol content in organelles of rats deprived of selenium but given adequate amounts of vitamin E, suggesting an increased uptake or mobilization of tocopherol to compensate for the detrimental effects of selenium deficiency. (3) The following general conclusions were reached from the results of the phospholipid fatty acid analyses. (i) vitamin E deficiency caused a consistent fall in the polyunsaturated fatty acid (PUFA) content (13-66% of the control level); (ii) selenium deficiency alone caused no consistent effect on phospholipid PUFA in the fractions studied; (iii) double deficiency of vitamin E and selenium caused a consistent rise in the proportion of PUFA in the fractions studied, ranging from 11 to 311%. (4) The result given in 3(i) is consistent with peroxidative destruction of membrane phospholipid PUFA during vitamin E deficiency. The result in 3(iii) is paradoxical: a possible explanation is that during severe disruption of antioxidant defences, there is an overshoot in the increased incorporation of unsaturated fatty acids into the membrane phospholipids, or in the chain-elongation and desaturation process required for the formation of PUFA, which may require vitamin E and/or selenium for its regulation.

Food and nutrition: attitudes, beliefs, and knowledge in the United Kingdom.

In a study of 1700 members of the UK general public in 1992 in which face-to-face interviews were conducted, factors thought important in a healthy diet were (in descending order) more fiber, less sugar, less fat, less salt, and more starchy foods. Of common nutritional terms there was most confidence in explaining the meaning of fiber and least in the meaning of monounsaturated fatty acids. Most nutritional information came from the media but the credibility of this information was low. Fifty-three percent said that a conversation with their general practitioner (GP) was a source of advice they trusted. In a survey of 150 GPs and 50 practice nurses in 1992, lack of confidence was found to be common concerning the meaning of several nutritional terms, especially extrinsic sugars, NSP (nonstarch polysaccharide), and trans fatty acids. GPs were confident they could explain the link between diet and heart disease but were not sure about the value of starch in the diet. Both GPs and practice nurses were dissatisfied with their training in nutrition, both before and after registration. General practice staff thought that personal ill health was the most important motivator for dietary change among their patients. They thought that apathy and dietary conservatism were the most common barriers to people changing their diet. However, the public positioned lack of knowledge as the biggest obstacle. Surveys reported here showed that people's knowledge of sources of fat, calcium, and iron is often unreliable.

The health benefits of eating foods containing omega-3 fatty acids.

The Department of Health recommends that people should eat two servings of fish a week, one of which should be oil-rich fish, in order to obtain essential omega-3 fatty acids. Some may be reluctant to do so, but education by nurses on the importance of these fatty acids to people with particular conditions, including heart disease, may encourage their uptake.

Vitamin D: An overview of vitamin D status and intake in Europe.

In recent years, there have been reports suggesting a high prevalence of low vitamin D intakes and vitamin D deficiency or inadequate vitamin D status in Europe. Coupled with growing concern about the health risks associated with low vitamin D status, this has resulted in increased interest in the topic of vitamin D from healthcare professionals, the media and the public. Adequate vitamin D status has a key role in skeletal health. Prevention of the well-described vitamin D deficiency disorders of rickets and osteomalacia are clearly important, but there may also be an implication of low vitamin D status in bone loss, muscle weakness and falls and fragility fractures in older people, and these are highly significant public health issues in terms of morbidity, quality of life and costs to health services in Europe. Although there is no agreement on optimal plasma levels of vitamin D, it is apparent that blood 25-hydroxyvitamin D [25(OH)D] levels are often below recommended ranges for the general population and are particularly low in some subgroups of the population, such as those in institutions or who are housebound and non-Western immigrants. Reported estimates of vitamin D status within different European countries show large variation. However, comparison of studies across Europe is limited by their use of different methodologies. The prevalence of vitamin D deficiency [often defined as plasma 25(OH)D <25 nmol/l] may be more common in populations with a higher proportion of at-risk groups, and/or that have low consumption of foods rich in vitamin D (naturally rich or fortified) and low use of vitamin D supplements. The definition of an adequate or optimal vitamin D status is key in determining recommendations for a vitamin D intake that will enable satisfactory status to be maintained all year round, including the winter months. In most European countries, there seems to be a shortfall in achieving current vitamin D recommendations. An exception is Finland, where dietary survey data indicate that recent national policies that include fortification and supplementation, coupled with a high habitual intake of oil-rich fish, have resulted in an increase in vitamin D intakes, but this may not be a suitable strategy for all European populations. The ongoing standardisation of measurements in vitamin D research will facilitate a stronger evidence base on which policies can be determined. These policies may include promotion of dietary recommendations, food fortification, vitamin D supplementation and judicious sun exposure, but should take into account national, cultural and dietary habits. For European nations with supplementation policies, it is important that relevant parties ensure satisfactory uptake of these particularly in the most vulnerable groups of the population.

Nutrition and health claims: the role of food composition data.

Regulation on nutrition and health claims number (EC) No. 1924/2006 came into force in the European Union (EU) in 2007. The Regulation aims to ensure that claims are truthful and do not mislead consumers. It also aims to stimulate innovation to produce healthier food products in the food industry. Nutrition claims are defined in an annex to the Regulation that states the wording of permitted claims and the conditions of use. The scientific support for potential health claims is being assessed by the European Food Safety Authority (EFSA), but consideration of other aspects and the final decision to accept or reject a claim lies with the European Commission. The final list of approved health claims was due to be published in early 2010, but work is behind schedule, and therefore decisions are being published in batches; the first batch of Article 13 claims based on generally accepted science was published in October 2009. Food composition data are vital in making accurate claims on food as the amount of the nutrient or food component in question must be defined. It is also important that the composition of a particular food or food category has been sufficiently defined in order for a health claim pertaining to this to be approved. In addition, to prevent claims being made on foods with a less healthy profile, nutrient profiles are being developed that will specify threshold amounts of saturated fat, sodium and sugar present in any product bearing a nutrition or health claim, and thus the composition of a food will be critical in determining whether it is eligible to carry a claim. Therefore, the access that the European Food Information Resource (EuroFIR) will provide to pan-European food composition data will be of great importance in making the Regulation workable. EuroFIR has been actively involved in EFSA's work on nutrient profiles, supplying data that have been used to develop the current profiling model. It is hoped that the EuroFIR Network and the not-for-profit organisation EuroFIR AISBL (Association Internationale Sans But Lucratif, that has been established to take forward EuroFIR's work) can continue to provide guidance to stakeholders as the Regulation develops.

Nutrient requirements and optimisation of intakes.

In 1991, dietary reference values were published in the UK. These refer to nutrients and provide the basis for dietary advice. To complement this, practical food-based guidance on how to plan a healthy and balanced diet has been developed. Interest continues in how best to establish guidance which helps individuals modify their diets so as to better match the dietary targets established as a means of promoting health and avoiding disease. Furthermore, in recent years, interest has grown in the potential to optimise nutrition and so promote health and well-being, rather than just avoiding deficiency. This has been accompanied by an awareness that many foods, particularly plant foods, contain substances that may have health promoting properties but are not, as yet, regarded as conventional nutrients.

A review of the MAFF Optimal Nutrition Status research programme: folate, iron and copper.

OBJECTIVE: The objective was to conduct a critical appraisal of research conducted within one of the UK government's research programmes, Optimal Nutrition Status, and to place the findings of this work in the context of the international research effort, to assist policy makers and advisers. Nine nutrients are addressed within the programme; the findings for three of these are reported here: folate/folic acid, iron and copper. DESIGN: To conduct the review, the researchers had access to all unpublished progress reports, submitted to officials, arising from the projects. The overall assessment criterion was whether the information generated by the research programme could be regarded as reliable experimental data of direct relevance to setting optimal dietary requirements for the particular micronutrients. However, findings were also assessed against specific scientific criteria concerning understanding of the bioavailability, interactions, development of functional markers and inter-individual variations in metabolism, for each of the nutrients scrutinised. RESULTS: The results of the review indicated that many important questions are indeed being addressed by the UK government's research programme, and that the work is contributing to the overall research effort being conducted world-wide on this important subject. CONCLUSIONS: Many major questions still need to be addressed before it will be possible to identify optimal intakes for various sub-populations. These priorities are summarised in the paper.

Curriculum design for professional development in public health nutrition in Britain.

OBJECTIVES: To describe how the Nutrition Society developed public health nutrition as a profession between 1992 and 1997, and to analyse the influences propelling on this professionalization. DESIGN: Qualitative case study. SETTING: Britain. RESULTS: The Nutrition Society of Britain consulted with various stakeholders (such as dietitians, researchers, professionals and practitioners and educators from the UK, and latterly from mainland Europe) to build a consensus about the definition, roles and functions of public health nutritionists and the need for, and scope of, this new profession. Building on this consensus, the Society developed a curriculum in line with British national nutrition policy. Analysis shows that the design and philosophy of the curriculum is explicitly international and European in orientation, in keeping with the tradition of the discipline and the Society. The curriculum is designed in terms of specialist competencies in public health nutrition, defining competency so that registered public health nutritionists are advanced practitioners or leaders: this is in keeping with contemporary trends in professional education generally and as expressed by the UNU/IUNS and at Bellagio, in nutrition in particular. CONCLUSIONS: Despite a unique relationship with British state and policy, this case of professionalization contributes to contemporary international inter- and intraprofessional debates about the nature of public health nutrition and is consistent with professional educational theory.

The Food Standards Agency's antioxidants in food programme--a summary.

BACKGROUND: In 2001, the British Nutrition Foundation (BNF) was contracted to evaluate projects from the Antioxidants in Food research programme, now funded by the Food Standards Agency and previously the Ministry of Agriculture, Fisheries and Food. The programme aimed at testing the 'antioxidant hypothesis'. METHODS: The evaluation was conducted with support and guidance from a Steering Group of experts. The final report sets out BNF's recommendations for the future of the Antioxidants in Food research programme. RESULTS: It was recommended that future research should consider a wider scope of potential mechanisms of action of substances within foods; more emphasis should be placed on studying bioavailability of a range of plant derived substances, and the impact of genotype, age and disease should be investigated. CONCLUSIONS: The research programme has been important as it has focused attention on disease prevention rather than on treatment, and has helped progress identification of biomarkers. From human observational and intervention studies there is evidence of an association between a diet rich in plant foods (particularly fruit and vegetables) and health benefits. However, as there is no evidence that any particular nutrient or class of bioactive substances makes a special contribution, currently the most prudent public health advice is to increase vegetable and fruit consumption.

A review of the epidemiological evidence for the 'antioxidant hypothesis'.

OBJECTIVE: The British Nutrition Foundation was recently commissioned by the Food Standards Agency to conduct a review of the government's research programme on Antioxidants in Food. Part of this work involved an independent review of the scientific literature on the role of antioxidants in chronic disease prevention, which is presented in this paper. BACKGROUND: There is consistent evidence that diets rich in fruit and vegetables and other plant foods are associated with moderately lower overall mortality rates and lower death rates from cardiovascular disease and some types of cancer. The 'antioxidant hypothesis' proposes that vitamin C, vitamin E, carotenoids and other antioxidant nutrients afford protection against chronic diseases by decreasing oxidative damage. RESULTS: Although scientific rationale and observational studies have been convincing, randomised primary and secondary intervention trials have failed to show any consistent benefit from the use of antioxidant supplements on cardiovascular disease or cancer risk, with some trials even suggesting possible harm in certain subgroups. These trials have usually involved the administration of single antioxidant nutrients given at relatively high doses. The results of trials investigating the effect of a balanced combination of antioxidants at levels achievable by diet are awaited. CONCLUSION: The suggestion that antioxidant supplements can prevent chronic diseases has not been proved or consistently supported by the findings of published intervention trials. Further evidence regarding the efficacy, safety and appropriate dosage of antioxidants in relation to chronic disease is needed. The most prudent public health advice remains to increase the consumption of plant foods, as such dietary patterns are associated with reduced risk of chronic disease.