Consumer understanding of nutrition and health claims is a key aspect of current regulations in the European Union (EU). In view of this, qualitative and quantitative research techniques were used to investigate consumer awareness and understanding of product claims in the UK, focusing particularly on nutrition claims relating to sugars. Both research methods identified a good awareness of product claims. No added sugars claims were generally preferred to reduced sugars claims, and there was a general assumption that sweeteners and other ingredients would be added in place of sugars. However, there was little awareness of the level of sugar reduction and the associated calorie reduction in products when reduced sugars claims were made on pack. In focus groups, participants felt deceived if sugar reduction claims were being made without a significant reduction in calories. This was reinforced in the quantitative research which showed that respondents expected a similar and meaningful level of calorie reduction to the level of sugar reduction. The research also identified consumer confusion around the calorie content of different nutrients, including over-estimation of the calorie content of sugars. This is crucial to consumers' expectations as they clearly link sugar to calories and therefore expect a reduction in sugar content to deliver a reduction in calorie content.
Metabolomics describes the measurement of the full complement of the products of metabolism in a single biological sample and correlating these metabolomic profiles with known physiological or pathological states. The metabolome offers the possibility of finding unique fingerprints responsible for different phenotypes. Analytical techniques such as nuclear magnetic resonance or mass spectrometry measure thousands of compounds within the metabolome simultaneously and appropriate data mining and database tools allow the finding of significant correlations between the measured metabolomes. The first direct outcome of nutritional metabolomics will be the discovery of biomarkers, which can reveal changes in health and disease but also indicate short term and long-term dietary intake. The concerted actions of nutrigenomics and metabolomics will play a crucial role in understanding how specific interactions of single nucleotide polymorphisms (SNP) influence a person's response to a diet. Finally, systems biology approaches to human nutrition combine transcriptomics, proteomics and metabolomics with the aim of understanding how diets interact within the human being.
The multitude of difficulties associated with measuring physical activity emphasises the need for validation studies. Validity is defined as the extent to which a measurement instrument assesses the true exposure of interest, which is different to repeatability – the extent to which an instrument gives the same result on different occasions. Both validity and repeatability are important. The ideal validation instrument would objectively measure the true exposure without correlated error (systematic error in the same direction) with the method being validated. An assessment method should be validated against another tool that measures exactly the same exposure. So if a questionnaire is designed to measure total energy expenditure then the validation tool should also measure total energy expenditure (Rennie & Wareham 1998). Many inappropriate comparison methods have been used in this field. For example, Fogelholm et al. (2006) investigated the validity of the short format of the IPAQ questionnaire against fitness. The authors were surprised to find that the dose–response relationship between physical activity and cardiorespiratory fitness disappeared in those classified most active by IPAQ, but put this down to over-reporting of physical activity. Studies using questionnaires which focus on vigorous physical activity may find higher correlations with VO2max than those that attempt to measure total daily physical activity, because vigorous activities, which are related to fitness, are more reliably recalled in questionnaires. This does not imply that these questionnaires can be used to measure the totality of physical activity.
The National Diet and Nutrition Survey: young people aged 4–18 years, published in June 2000, is the most detailed survey yet to be undertaken in this age group in Britain. It has revealed that Britain's young people are largely inactive and, although the majority appears to have adequate intakes of most vitamins, intakes tended to be lowest in families on benefit. This was particularly the case for folate and vitamin C, reflecting lower intakes of fruit and vegetables. Thirteen per cent of 11–18-year-olds had low vitamin D status, the vitamin usually provided via exposure to sunlight and essential for the development of healthy bones. A sizeable proportion of children may have inadequate intakes of a number of minerals, including zinc, calcium, potassium, magnesium and iron. For example, 25% of 11–14-year-old girls and 19% of those aged 15–18 years had intakes of calcium that were likely to be inadequate (i.e. lower than the LRNI); in all age and gender groups there was evidence of low zinc intakes; and 14% of girls and 13% of boys had low ferritin levels, suggesting low iron stores and an increased risk of anaemia. On the positive side, fat intakes were close to the population goal of 35% of dietary energy, but intakes of saturated fatty acids exceeded the recommended population level for adults of 11% of energy, and intakes of sugars and salt were also high in many children. This article discusses some of the public health implications of this major survey.
The 1981 FAO/WHO/UNU report on protein and energy requirements makes significant advances in the application of science. Here it is summarized and reviewed with emphasis on areas of uncertainty and differences in approach since 1971. The convenient procedures for making estimates of energy requirements leave out some important minor factors, thus allowing debate and reconsideration of when and how they can be accounted for properly. Judgements are made when appropriate data is unavailable, for example protein requirements in the elderly. A controversial issue may be a health judgement, which could be interpreted to mean that increased physical activity rather than low-calorie diets is the route to lowering the prevalence of obesity and improving long-term health.
Linking nutritional factors to medical conditions involves the assessment of dietary intakes of individuals, but the development of a much needed valid short cut method has proved somewhat intractable.
In relating the diet of individuals to the development of coronary heart disease, for example, different approaches have been used. Metabolic studies have indicated the importance of a high ratio of polyunsaturated fatty acids to saturated fatty acids in the diet - to lower blood cholesterol levels. Intervention studies based on high P/S ratios followed. Most prospective studies have shown the importance of energy intake in relation to the development of CHD.
Recommendations have been based on between-country data rather than on individual dietary data. The DHSS COMA report of 1984 identified several risk factors including insufficient physical activity.
The Joint Advisory Committee on Nutrition Education took up the challenge made by the COMA committee that “Means should be found to educate the general population of the UK in habits of eating and physical activity that will minimize the risk of cardiovascular disease and of obesity”.
The publication by the BNF and HEC, “Eating for a Healthier Heart”, seeks to do this by stimulating interest in food and by the understanding of balance, both in output and intake and within intake of foods necessary for health.
The European Community is fortunate to have sufficient food to be able to address the issues of quality, safely and choice rather than sufficiency alone. When the EC was founded in 1958, agricultural issues dominated, with the need to secure a regular supply of food high on the political agenda. It was that concern which produced the Common Agricultural Policy. Now, in a more prosperous, high tech age, consumers are able to concentrate on how food is produced, what they want to buy, and the level of safety appropriate. It is in this context that the European Community's food policy, and the action necessary if the Community (that is the 12 Member States, with their 350 million consumers) is to establish a food policy which will suit the twenty-first century, is considered.
Agriculture has been subject to European influence via the Common Agricultural Policy since 1962. Goods like grain and milk already circulate relatively freely in Europe. Transport of goods will benefit from the lifting of restrictions and the opening of the Channel Tunnel. The removal of monetary Compensatory Amounts will benefit British farmers if currency fluctuations are removed. The abolition of frontier health checks on plants and animals in favour of checks by exporting countries is alarming, but experts are confident about the prospects of greatly reducing the incidence of serious disease. The impact of 1992 on farming will be slight compared with the effect on the food industry. The question is will 1992 bring an efficient low-cost food industry on the American model or will Europe's diversify be retained?
Completion of the Internal Market in 1992, or whenever, could have significant economic implications for food consumers and food businesses. Food companies will face greater competition and might be expected to operate on a pan-European, rather than national, scale. Consumers, it is hoped, will be offered a wider choice of quality food products at lower prices.
However, the progression towards a single European economic space is not without its dangers: the principal fears being that consumers could be faced by a bewildering range of quite different, but apparently comparable, products; and that manufacturers could find that their ability to compete effectively against products imported from other member states is constrained by the retention of obsolete national legislative provisions.
The essential purpose of food law is consumer protection while quality judgement is a matter for the individual, based on informative labelling.
Although the Council has agreed major frameworks directives, much detailed work is still required including; an agreed common list of food additives; the problems of the constituents of packaging materials and their possible migration into food; the assessment of quality of dietary products for their declared aims; limits for environmental contaminants; the approach to be adopted for biotechnology products and the labelling of foods containing ingredients which have been irradiated.
According to a recent survey*, ‘British companies are not perceived to be a major threat by rival European firms. In contrast, the UK is a heavily targeted market for foreign companies’.
Real expenditure on food is increasing but at a lower rate than total consumer spending. Food expenditure as a percentage of total consumer spending has dropped to 14% in the UK. This is the lowest of any European country but still a few points higher than in the USA.
Expenditure on food consumed outside the home is also increasing at a much faster rate than expenditure on food for consumption at home. This type of expenditure now amounts to 30% (much less in terms of the quantity of food consumed, of course) of consumer spending, compared with 45% in the USA and is still growing.
Within household food consumption, an increasing proportion of expenditure is going on convenience products.
Throughout Europe similar trends are apparent — increased opportunities for prepared products offering high quality, high nutritional value, freshness' and convenience. The balance between the various attributes most valued by consumers has varied over time within countries and differs between countries at any given time.
The UK is one of the most developed markets in terms of expenditure on convenience foods, ownership of freezers and microwave ovens. (Fig. 1) This provides home companies with a large base from which to export and an attractive target for continental companies looking for diversification from staple products.
The Dietary Guidelines for Americans form the foundation of US federal nutrition policy. The Food Guide Pyramid, the most widely distributed and best-recognised nutrition education tool ever produced in the US, is based partially on the Dietary Guidelines. In addition, every federal nutrition programme in the United States uses the Dietary Guidelines as part of their nutrition standards. Federal law requires that the guidelines be reviewed every five years. The Dietary Guidelines Advisory Committee was charged with answering the question, ‘what should Americans eat to be healthy?’ After rigorously reviewing the scientific, peer-reviewed literature the committee recommended a new set of guidelines for the year 2000. The guidelines are intended for healthy children (ages 2 years and older) and generally healthy adults of any age. The guidelines were expanded from seven in 1995 to ten in 2000. The 2000 Dietary Guidelines for Americans are; (1) aim for a healthy weight; (2) be physically active each day; (3) let the pyramid guide your food choices; (4) eat a variety of grains daily, especially whole grains; (5) eat a variety of fruits and vegetables daily; (6) keep foods safe to eat; (7) choose a diet that is low in saturated fat and cholesterol and moderate in total fat; (8) choose beverages and foods that moderate your intake of sugars; (9) choose and prepare foods with less salt; and (10) if you drink alcoholic beverages, do so in moderation.
Summary Dietary habits learnt during childhood form the foundations for behaviour throughout the rest of life. With the ever-increasing challenge of childhood overweight and obesity, finding ways to promote healthy behaviours in the family environment is a key factor in both the prevention and treatment of these conditions. This study was carried out by Kellogg's in order to explore barriers to healthy eating and physical activity and to identify possible triggers to participation in these health behaviours. This article provides a review of the study, and outlines its key findings and their implications for healthcare professionals.
Summary The period between adolescence and adulthood is a time of great change, mentally, physically and socially. Such changes can have a profound impact on nutrient intake. Yet whilst some short-term studies have attempted to assess dietary change during adolescence, few have considered how diet changes over the longer term, spanning the transition between adolescence and adulthood. This article describes the findings of the first British study to assess the change in macronutrient and micronutrient intake from early adolescence into adulthood. The study sample comprised 202 participants of a dietary survey carried out on Northumberland 12 years olds in 1979–80 who were followed up at 33 years old. At both time-points dietary intake was measured using two 3-day food diaries with follow-up interviews to record estimated portion size. The most notable findings were that between 12 and 33 years old, for both males and females, % food energy intakes of fat, total sugars and carbohydrate had fallen and protein intakes had risen, whilst absolute intakes of unavailable carbohydrate and all micronutrients considered (vitamin C, iron, calcium, vitamin D), with the exception of retinol equivalents, had increased. These changes in intake were generally consistent in direction between males and females. In conclusion, nutrient intake undergoes considerable change between adolescence and adulthood and, in most respects, this is in a direction in line with dietary recommendations. This does not imply that efforts should not be made to improve childhood and adolescent diet given the importance of diet on health in adolescence and later in life and evidence that dietary intake is, to some extent, established at an early age.
• Forewords• Timeline• Introduction• Section 1: The interaction between diet and public health○ 1.1: Changing patterns of mortality in the UK○ 1.2: Changing patterns of disease and links with diet• Section 2: The role of government○ 2.1: Overview of government departments related to food and nutrition○ 2.2: Recommendations for healthy diets○ 2.3: Nutrition-related health policies• Section 3: Trends in dietary patterns and nutrient intake○ 3.1: Measuring dietary patterns and nutrient intake○ 3.2: Dietary patterns○ 3.3: Nutrient intake• Section 4: Factors influencing food access and availability○ 4.1: Government policies○ 4.2: Advances and innovations of the food industry○ 4.3: Consumer-led changes• Conclusions• Acknowledgements• ReferencesSummary Throughout the 20th century, average life expectancy has been increasing. This is primarily a result of a change in disease patterns, as infectious diseases have declined, and chronic diseases have become the nation's main killers. A number of factors are recognised to influence the risk of chronic disease, including diet and lifestyle. Therefore, dietary guidelines have been developed to help people follow a diet that can maximise their health and longevity. These guidelines complement more detailed dietary reference values, which were first established in 1950. Since then, these values have stayed much the same, and today they are used to asses thenutritional adequacy of the diet using data from dietary surveys, such as the National Diet and Nutrition Survey. The National Food Survey is another important source of information about what the population are eating. This survey has collected data on food purchased for consumption in the home since 1940 and therefore can provide invaluable information on trends in estimated food, energy and nutrient intake for the general population. Figures estimated from the National Food Survey suggest that since the 1970s, total energy intake has been falling in line with falling levels of energy expenditure. Nevertheless, this decline in energy expenditure has left individuals prone to gaining weight, yet the dietary guidelines in use today still focus on the need to monitor intake of fat and saturates. On the face of it, the British diet has been remarkably stable over the past 60 years. However, what has been evident is a shift towards a lower fat diet with lower fat meats, such as poultry overtaking beef, pork and lamb as the most popular meats and semi-skimmed milk dominating the milk category since its introduction in the 1980s.There are a number of factors that have affected the trends in food consumption, some of which can be attributed to specific events; for example, the drought from 1975 to 1976 caused a shortage of potatoes, resulting in a high market price, which in turn led to a decline in potato consumption. It is beyond the scope of this Briefing Paper to explain all of the variations and changes in food intake over the past 60 years. However, this paper does provide an overview of the factors (namely government policies, advances and innovations of the food industry and consumer-led changes) that have influenced food availability and access since the 1940s. For example, a significant policy that has had influence is the Common Agricultural Policy (CAP), which was devised by six nations of the European Economic Community in response to the effects of war, in particular world food shortages. Many of the original objectives of CAP had been met by the time the UK joined in 1973. However, through various reforms the policy has continued and has had a significant impact on food supply, food prices and the environment. More recent government policies regarding food availability have focused on improving the nutrient profile of foods and promoting a healthy balanced diet.The food and farming industry's compliance with CAP has strongly influenced the way in which foods have been produced and the direction of the agricultural industry. For example, intensification has been essential to meet the required productivity and has relied upon the use of inorganic fertilisers, herbicides and pesticides. However, some producers have opted to produce foodstuffs organically, which has been supported by some consumers and become somewhat of a niche market.Since their popularisation in the 1960s, the buying power of supermarkets, and fast turnover of foods, has meant it became possible to stock a larger variety of produce from across the world at more affordable prices. The increasing floor space opened a door for manufacturers and retailers to showcase a widening range of products and gave consumers an opportunity to compare products and select their preferred choice. The wide variety of food products available since the 1960s has been the result of new food technologies and more recently new ingredients and novel foods. These advances have been coupled with an increase in the ownership of domestic appliances, including fridges (1960s), freezers (1970s) and microwave ovens (from the 1980s).Since the 1980s, there has been an increase in the proportion of women who worked; therefore, convenience became a driving factor for consumer purchasing. These social trends were reflected in the increased popularity of eating out. Convenience has remained an important determinant of consumer purchasing choice, and advances in food technology and manufacture have meant that today it is possible to cook a meal in minutes. Advances in food science and technology have also enabled health-promoting products, so-called functional foods, to be produced, and for many health-conscious individuals these have proved very popular. For some consumers, the health benefits of a food have been a driver for food purchasing habits, and advertisers have taken advantage of this for decades. In particular, the association between food and health was becoming well recognised during the 1980s. This was fuelled by the publication of dietary guidelines and research reports, such as those advocating the importance of a diet low in saturates. Over the past 20 years, other ethical concerns surrounding food manufacture have been high on the agenda of food companies and consumers alike.
Summary COST (European Cooperation in the field of Scientific and Technical Research) Action 926 is a networking partnership funded by the European Union through the European Science Foundation. Scientists involved have evaluated whether or not the new ‘omic’ technologies can offer a means of obtaining the scientific evidence to underpin the established consensus that increased consumption of fruit, vegetables and wholegrain products is beneficial to human health. The effects of processing on the bioavailability of bioactive components in food have also been reviewed in this paper and recommendations made to ensure that maximum benefit is obtained from the diet.
Summary Among the components likely to be used in functional foods, prebiotics show interesting properties, and some are already recognised and used as food ingredients. A prebiotic has been defined as ’a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health’. Inulin and oligofructose are the best-studied prebiotics so far. They are selectively fermented by the microflora in the human colon leading to a bacterial composition that is dominated by bifidobacteria, a perceived health-promoting genus. In this paper, the effects of these prebiotics, especially oligofructose-enriched inulin, on calcium absorption and bone metabolism are reviewed.
Summary An adequate supply of folate minimises the risk of neural tube defects, vascular disease (CHD, stroke) and possible cancers. Whilst the USA, Canada and Chile have a policy of mandatory fortification of white flour with folic acid, most countries of the EU do not permit the fortification of foodstuffs with folic acid. The UK allows folic acid fortification and in practice this has been mainly limited to some breakfast cereals and breads. Governments can only assess whether an optimal folate intake can be achieved through food sources alone if the proportion of food folate actually absorbed can be accurately established. Our recent use of stable-isotope-labelled folates has now questioned the reliability of experimental methods used for the past four decades to estimate the ‘relative absorption’ of food folates. Historically, the plasma 5-methyltetrahydrofolic acid response to oral test doses of food folates are compared to the plasma response induced by a similar sized ‘reference’ dose of folic acid. We have found that a significant part of the plasma response does not actually originate from the test dose, and the accepted understanding of the initial site of biotransformation of folic acid upon which the experimental approach depends may be incorrect.
Breakfast clubs are not a new resource for parents and children, but interest in them has heightened, because of both the need for improvement in school food and political interest in their availability across the devolved countries. It has been suggested that concrete scientific evidence as to their benefits to academic performance be required before a breakfast club should be available for children across the UK. It is inappropriate to correlate crude measures such as Standard Assessment Test (SAT) scores and exam results with breakfast club provision, and the focus of analysis should be individual pupil benefit (both scholastically and socially), nutrient intake, meal provision and even assisting working parents with child care. There is limited data available to investigate the adequacy of food provision in school breakfast clubs, but there is now sufficient information available for breakfast club organisers to provide a nutritionally balanced breakfast. A body of evidence is emerging that demonstrates the benefits of breakfast club attendance to mental performance and social development. However, it is unclear whether such benefits are derived from the consumption of breakfast per se, the environment or a combination of the two. It is reasonably safe to conclude that the benefits of breakfast clubs are more pronounced in deprived areas, and efforts of charities to support breakfast clubs should focus in these areas. Given the role and importance of school breakfast clubs, ContinYou, a leading national charity, pledged support in establishing 200 more school breakfast clubs over 2009 and 2010.
There has been little systematic study by experimental psychologists of what determines an individual's food choices, and work in nutrition and the food sciences has not recognised adequately the importance of the behavioural processes surrounding food perception and motivation. The scientific measurement of the sensory influences on food acceptance and, particularly, the effects of attitude on the senses, is now developing. A collaboration between those who formulate food products, those who aim to improve eating habits and those who study food acceptance behaviour could yield benefits for all.
This paper outlines the principles of the methods of measuring acceptance, with examples from current work on sugar, salt and milk fat preferences, and discusses the potential for changes in choice.
Summary The proportion of older people in the UK population is rising, and those aged 65 years and over are particularly at risk of malnutrition. This is caused by factors such as underlying disease, poor oral health, decreased mobility, limited transport to local shops, social isolation and poverty. Older men, particularly those who live alone, may be even more at risk of an inadequate diet. This paper presents findings from a subset of the Low Income Diet and Nutrition Survey, a national survey of materially deprived individuals aged 2 years and over in the UK. The influence of social, physical and other factors on foods consumed and nutrient intake in 234 men (unweighted sample) aged 65 years and over who either lived alone or with other(s) of retirement age is investigated. Mean energy intakes fell below the estimated average requirement (84%), while mean intakes of several micronutrients fell below the reference nutrient intake (vitamin D 35%, magnesium 77%, potassium 75%, and zinc 88%). Men living in households where the person mainly responsible for shopping and preparing food had poorer cooking skills had a lower consumption of vegetables, wholemeal bread and fish and fish dishes, and lower intakes of energy and selected nutrients. Men who experienced difficulty in chewing consumed less fruit, vegetables, wholemeal bread and meat and meat dishes, and had lower intakes of protein and selected nutrients. Interventions need to focus on improving cooking skills, especially in men who live or eat alone, and on increasing the consumption of fruit and vegetables in those with poor oral health, especially those who have difficulty chewing.
Amongst women in exercise training, the female athlete triad is on the increase. This is the combination of disordered eating, amenorrhoea and osteoporosis. However, the effects of exercise training on bone mineral accumulation in youngsters is not fully known. Bone mass increases rapidly during childhood and adolescence until peak bone mass (PBM) is attained. PBM is an important determinant of adult bone mineral density (BMD) and therefore optimisation of PBM is valuable in the prevention of osteoporosis. This paper reviews the effects of exercise training on the accumulation of bone mineral in girls.
Summary Dietary supplements and special diets that purportedly enhance cognitive function are widely promoted in many countries. Nutritional interventions claiming to relieve stress and depression, increase energy or improve memory are common. Limited regulatory requirements for marketing dietary supplements or special diets, particularly in comparison with drugs, place substantial responsibility on scientists conducting research in this area. Agreement on scientific standards for the conduct and evaluation of research is clearly desirable, so that scientists can achieve consensus regarding such claims. Many of the methods used to assess dietary supplements and other nutritional factors are similar to those used in other fields, such as psychopharmacology, and are widely accepted by investigators conducting nutrition and behaviour research. Key methods in common include use of double-blind procedures, dose–response studies and placebo treatments. Some of these procedures can be difficult or impossible to implement in nutritional studies. Other critical methods, such as selection of appropriate tests to assess cognitive performance and mood state, are more controversial among scientists working in this and other areas, and difficult to standardise. Scientific consensus on these issues will ensure availability of safe and efficacious dietary supplements and help eliminate dangerous or ineffective products.
Summary Awareness of the increased prevalence of heart disease, obesity and type 2 diabetes has resulted in research being focused on simple and robust approaches to their prevention. One rationale for dealing with these potentially major public health problems is via a better understanding of the contribution of diet to progression towards these diseased states. As a response to these concerns, major research efforts in this area have been funded under the auspices of the European Union. In particular, studies are aimed at providing the scientific basis for improving health through diet, with a focus on understanding how polyunsaturated fish oils can be a positive (i.e. protective) component of diet against metabolic syndrome (the descriptor for progression towards diseases such as obesity and type 2 diabetes). This review will consider the health implications of the rise in metabolic syndrome, as well as new approaches to the provision of beneficial polyunsaturated oils.
Summary The very long chain (VLC) n-3 polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are widely recognised to have beneficial effects on human health. However, recommended intakes of VLC n-3 PUFA (450 mg/day) are not being met by the diet in the majority of the population mainly because of low consumption of oil-rich fish. Current mean intake of VLC n-3 PUFA by adults is estimated to be about 282 mg/day with EPA and DHA contributing about 244 mg/day. Furthermore, the fact that only about 27% of adults eat any oil-rich fish (excluding canned tuna) and knowledge of the poor conversion of -linolenic acid to EPA and DHA in vivo, particularly in men, leads to the need to review current dietary sources of these fatty acids. Animal-derived foods are likely to have an important function in increasing intake and studies have shown that feeding fish oils to animals can increase the EPA and DHA content of the resulting food products. This paper highlights the importance of examining current and projected consumption trends of meat and other animal products when exploring the potential impact of enriched foods by means of altering animal diets. When related to current food consumption data, potential dietary intakes of EPA+DHA from foods derived from animals fed enriched diets are calculated to be about 231 mg/day. If widely consumed, such foods could have a significant impact on progression of conditions such as cardiovascular disease. Consideration is also given to the sources of VLC n-3 PUFA in animal diets, with the sustainability of fish oil being questioned and the need to investigate the use of alternative dietary sources such as those of algal origin.
ProSafeBeef is a 5-year integrated project funded by the European Commission under the sixth Framework Programme. The overall aim is to advance beef safety and quality across Europe and the work programme spans seven integrated “pillars”. Pillar 3 is concerned with producing safe beef and beef products with enhanced nutritional and eating quality characteristics. A particular focus is on the development of strategies to enhance the concentrations in beef of those fatty acids considered to be of benefit to human health, without causing a detrimental effect on the appearance, shelf-life or eating quality of the beef. There is accumulating evidence of the importance of long-chain n-3 (omega-3) polyunsaturated fatty acids (PUFAs) for human health and disease prevention, and also evidence from experimental studies that has shown anticarcinogenic, antiatherogenic, and anti-obesity effects of two isomers of conjugated linoleic acid (CLA). Based on this evidence, the major focus of research efforts to improve the nutritional value of beef has been on increasing the concentration of the n-3 PUFAs and CLA. Considerable progress has been made within pillar 3 of ProSafeBeef to meet this aim, primarily by manipulating the diet of cattle. Fundamental information on ruminal lipid metabolism and on the control and/or prevention of ruminal hydrogenation of dietary lipids arising from research within ProSafeBeef will facilitate the production of beef with a ‘healthier’ fatty acid profile. Moreover, strategies will be defined for industry on how to optimise nutritional and sensory properties and oxidative quality of beef products, by combining the nutritional enhancement made in the live animal together with target levels of functional ingredients to be added during processing.
Summary‘Trans’ fatty acids are unsaturated acids with special structural features that occur naturally in dietary fats from animal and plant sources and in fats processed by catalytic hydrogenation. They are readily metabolized by the human body. Thus, although when consumed in the diet they are incorporated into body fat (including depot and milk fats), they are subject to rapid ‘turnover’. In physical properties, trans monounsaturatedfatty acids are intermediate between cis-monounsaturated and saturated acids, and they tend to be treated either as saturated or cis-monounsaturated acids in metabolic pathways. The author argues in this article that any adverse effects on health or metabolism that may have been observed can be ascribed to an imbalance between the intake of trans and essential fatty acids. Such imbalances, could also occur with non-essential fatty acids other than trans fats. Normally, the amounts eaten in average diets would not pose serious problems and only when products have excessively high trans contents and make a significant contribution to the diet need trans acids be highlighted on labels.
Summary1Introduction2What are unsaturated fatty acids?2.1 The chemistry of fatty acids2.2 Digestion, absorption and metabolism2.3 Functions of unsaturated fatty acids3Unsaturated fatty acids in the UK diet3.1 Sources of fat in the diet3.2 Dietary recommendations for fat3.3 Intakes of unsaturated fatty acids3.4 Major contributors to unsaturated fatty acid intake3.5 Trends in intake4Unsaturated fatty acids in health and disease4.1 Unsaturated fatty acids and cardiovascular disease4.2 Unsaturated fatty acids and diabetes4.3 Unsaturated fatty acids and cancer4.4 Unsaturated fatty acids and inflammatory conditions4.5 Unsaturated fatty acids in fetal and infant development4.6 Unsaturated fatty acids and cognitive function and behaviour4.7 Emerging aspects of unsaturated fatty acids and health5Unsaturated fatty acids and public health5.1 Labelling of unsaturated fatty acids5.2 Are current UK recommendations adequate?5.3 Opportunities to increase intake of long chain n-3 PUFAs5.4 Implications of optimising intakes of unsaturated fatty acids6Conclusions
AcknowledgementsReferencesAppendix 1Summary Fat provides energy; indeed it is the most energy dense of all the macronutrients, with 1 g providing 37 kJ (9 kcal). However, the constituent parts of fat, fatty acids, are required by the body for many other functions than simply as an energy source, and there is an increasing awareness of the potential health benefits of specific types of fatty acids. Fatty acids are long hydrocarbon chains, with a methyl group at one end (the omega or n-end) and an acid group at the other. Unsaturated fatty acids are hydrocarbon chains containing at least one carbon–carbon double bond; monounsaturated fatty acids contain one double bond, and polyunsaturated fatty acids (PUFAs) contain many double bonds. The position of the double bond relative to the omega end determines whether a PUFA is an n-3 (omega 3) or an n-6 (omega 6) fatty acid.Most fatty acids can be synthesised in the body, but humans lack the enzymes required to produce two fatty acids. These are called the essential fatty acids and must be acquired from the diet. In humans, the essential fatty acids are the n-3 PUFA α-linolenic acid and the n-6 PUFA linoleic acid. Although humans can elongate dietary α-linolenic acid to the long chain n-3 PUFAs eicosapentaenoic acid and docosahexaenoic acid, the rate of synthesis may not be sufficient to meet requirements, and it is, therefore, recommended that good sources of these fatty acids, namely, oil-rich fish, are also included in the diet.Fat is found in most food groups, and foods containing fat generally provide a range of different fatty acids, both saturated and unsaturated. In the UK, the major dietary sources of unsaturated fatty acids include meat & meat products, cereals & cereal products and potatoes & savoury snacks; primarily as a result of the vegetable oil used in processing. Recommended intakes of both total fat and the different types of fatty acids have been set for the UK population, and it is possible to monitor fat intake from the data collected in nationwide dietary surveys. As a population, we are not currently meeting these recommendations, so there is still scope for dietary change. In Western diets, n-6 fatty acids are the predominant PUFAs, and this is in line with current dietary advice to consume a minimum of 1% energy as n-6 PUFAs and 0.2% energy as n-3 PUFAs. The balance of n-3 and n-6 PUFAs in Western diets has changed substantially over the last 100 years or so, and as the two families of PUFAs share a common metabolic pathway, concerns have been raised that this might be detrimental to health; what is becoming increasingly clear is that both n-3 and n-6 PUFAs have independent health effects in the body, and as intakes of the n-6 PUFAs are within the guidelines for a healthy diet, concerns about the n-6 to n-3 ratio are driven by low intakes of n-3 rather than high intakes of n-6. Currently in adults n-6 PUFAs contribute to 5.3% energy.Detecting associations between components of the diet and risk of various diseases is notoriously complex and in many cases, the evidence is still accumulating. Cardiovascular disease, characterised by hardening and narrowing of blood vessels and/or the development of blood clots, is one of the leading causes of mortality and morbidity worldwide. The type and total amount of dietary fat has a clear part to play in affecting an individual’s disease risk, yet the precise mechanisms by which unsaturated fatty acids reduce cardiovascular disease risk are still unclear. A number of mechanisms whereby dietary fatty acids could influence the progression of cardiovascular disease and its risk factors have been identified. These include effects on blood lipid concentrations, blood pressure, inflammatory response, arrhythmia and endothelial function, along with many other effects, both known and as yet undefined. A well-established risk factor for cardiovascular disease is an elevated plasma low density lipoprotein (LDL) cholesterol concentration. Replacing saturated fatty acids with either monounsaturated fatty acids or n-6 PUFAs reduces LDL (the ‘bad’) cholesterol, and so reduces the risk of developing the disease. Unsaturated fatty acids, such as linoleic acid or monounsaturated fatty acids, also slightly raise high density lipoprotein (HDL) (the ‘good’) cholesterol, which assists in the removal of triacylglycerols from the bloodstream. Interest in the health effects of the long chain n-3 PUFAs found in fish oils is also increasing. There is strong supportive, but not yet conclusive, evidence that these fatty acids protect against fatal heart disease. On the basis of this conclusion, in 2004 the Scientific Advisory Committee on Nutrition advised the UK government to adopt the population-wide dietary recommendation to eat at least two portions of fish per week, of which one should be oil-rich, equivalent to 0.45 g of the long chain n-3 PUFAs per day. In recent years, the potential health benefits of α-linolenic acid has attracted attention, and evidence is mounting on the role that this n-3 fatty acid may play in preventing the progression of cardiovascular disease, although it is currently unclear what, if any, association exists.Brain cells are especially rich in certain long chain PUFAs. This has led to the suggestion that dietary status of these long chain fatty acids might influence cognitive function and behaviour. Research in this field is still in its early stages, but there is a small amount of evidence to suggest improvements in cognitive function following fatty acid supplementation. In contrast, it is well established that pregnant women must have an adequate supply of the long chain n-3 PUFAs before and throughout pregnancy and lactation to support normal growth, neurological development and cognitive function of the baby. As n-6 PUFAs are more abundant in the diet, achieving an adequate intake is less problematic. However, this is not the case for the n-3 PUFAs; increasing fish consumption beyond two servings of oil-rich fish per week or relying on fish oil supplementation is not appropriate during pregnancy due to the potential problems associated with heavy metal contamination of fish, or the high vitamin A level in some fish oil supplements.Unsaturated fatty acids have also been associated with a number of other diseases and although the evidence is by no means conclusive, it is an area that is attracting a huge amount of interest. Dietary fat affects a number of different metabolic pathways, including those involved with glycaemic control, so the types and amounts of dietary fat may have a role to play in the management of type 2 diabetes. Unsaturated fatty acids may also be associated with a reduced risk of developing certain cancers, including cancers of the colon, breast and prostate, although currently the level of evidence is not deemed sufficient by authoritative bodies, such as the World Cancer Research Fund, World Health Organization and the Department of Health, to make any specific dietary recommendations. There are a number of inflammatory conditions, such as asthma, Crohn’s disease and arthritis, which could potentially be alleviated by dietary modification. The fatty acid composition of cell membranes can be altered by consumption of both n-3 and n-6 PUFAs, and this can result in reduced inflammatory activity. However, whether this effect brings about a significant reduction in clinical symptoms is still unclear. It is also important to note that there are concerns that the beneficial effects on certain disease outcomes are only observed with very high intakes of unsaturated fatty acids, which could realistically only be achievable by supplementation. Few nutritionists would be comfortable recommending supplement use as the only alternative to fish, as this can be expensive and goes against the idea that all the nutrients that our bodies require can be obtained from the food that we eat if the right choices are made.Unsaturated fatty acids are now a nutritional hot topic, and their presence in foods has attracted both public and industrial interest. There is currently no specific legislation to control the use of health claims relating to the fatty acid content of foods. However, a European Union (EU) Directive is expected imminently which will formally set down the criteria that a product will have to meet in order to make any nutrition or health claim. With regards to the current recommendations, those for the UK are in line with those around the world. However, as a population, we need to increase our consumption of long chain n-3 PUFAs and decrease intake of saturated fatty acids. To facilitate this, food technologists are looking at ways in which the fatty acid profile of a food can be modified in order to bring dietary improvements without requiring a major change in dietary habits. However, public health messages surrounding the optimum intakes of fatty acids must be clear and consistent to ensure that a favourable change in the fatty acid profile of the UK diet occurs.
Summary Food composition data are essential for a wide variety of activities, including public health nutrition, research, food labelling and government policy. Food composition data play a particularly important role in four sectors in Europe, namely health, trade regulation and legislation, agriculture and the environment. The need to continue the harmonisation of food composition data already achieved through European collaboration can be clearly identified and evidenced. Harmonisation is not exclusively a technical issue, but also entails creating durable and sustainable structures to maintain the viability of food composition data. These and related issues are currently being addressed by the EuroFIR Network of Excellence (project number FP6-513944, http://www.eurofir.net).
In 2007, the World Cancer Research Fund/American Institute for Cancer Research produced food, nutrition and physical activity recommendations for personal and public health goals for reducing cancer risk. A companion publication, Policy and Action for Cancer Prevention, addresses the external influences on people's eating and physical activity habits over a lifetime and evaluates potential actions to change these behaviours. The Policy Report makes recommendations for policies and actions that will help achieve the public health goals for reducing cancer risk. The recommendations are addressed to policy-makers and decision-takers at international, national and local level. These recommendations, if implemented, will help influence and change the lifestyle choices that people make, thereby reducing the risk of cancer and other chronic diseases within the population. The overarching message of the Policy Report is that public health is everyone's business. The protection and improvement of public health does not happen by accident – it requires policies and actions to be implemented by all relevant sectors of society.
Summary The food industry is currently under pressure from the Food Standards Agency (FSA) to deliver reductions in the salt intake of the population through the introduction of lower salt levels in processed foods (Gilbert & Heisler 2004 in same issue). Government research indicates that meat and meat products as a category are the second largest contributor to dietary salt after cereal products. This use of a combined category of ‘meat and meat products’ is misleading, as carcase meat is naturally low in sodium and therefore salt. Salt is added to meat products for a variety of technical reasons, including microbiological safety. There is evidence that consumers are confused about the difference between the terms ‘sodium’ and ‘salt’. Analysis of products for labelling purposes therefore requires careful consideration to ensure that misleading information is not presented. While the debate about the role of salt in blood pressure control will no doubt continue, the British meat industry has committed to reducing the salt, or more specifically sodium, content of its products. To this end an action plan for sodium reduction in meat products has been developed which focuses on those products with the highest sodium contents and encourages producers to seek opportunities to reduce the sodium content of all meat products.
Summary The aim of this intervention was to affect a change in the food choices of adolescents (11–16 years old) at school by giving pupils more control over the food provision in their school through the establishment of the School Nutrition Action Groups. The study compared food selections and pupils’ views of the catering service between 12 schools implementing School Nutrition Action Groups and 12 control schools. Schools were selected to reflect educational achievement, ethnic mix and gender. Pupils completed a baseline and a 2-year follow-up questionnaire. In addition, data of the sales of food in the school dining rooms in all schools were collected at baseline and follow-up. There was a significant increase in the sales of main meals and snack meals in the intervention schools suggesting that School Nutrition Action Groups can be an effective and relevant way of changing food choices in schools.
Summary The notion that sweetness is ‘addictive’ endures in the scientific literature and in the popular press. The most common targets of food cravings and addictions are energy-dense foods that are sweet, high in fat, or both. In clinical studies, the consumption of sweet and high-fat foods has been selectively reduced by opiate antagonists, suggesting a link between hedonic pleasure response and the brain systems of reward. Recent brain imaging studies have further implicated the dopamine system in mediating the pleasure response to food as well as a range of addictive behaviours. However, suggestions that sugar and fat have a permanent impact on the neurobiology of food preference are in sharp contrast with the view that the vast majority of food addictions are simply a matter of misattribution. Dietary restraint, coupled with ambiguous attitudes towards good-tasting but energy-dense foods, may lead consumers to claim that some aspects of eating behaviour are beyond their control. This distinction between addiction and attribution has implications for obesity-related lawsuits. The chief attraction of addiction theory for the plaintiff’s counsel lies in the claim of diminished personal responsibility and abrogation of free choice. However, sugar and sweets do not appear to meet the current criteria for substance dependence as formulated in the Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition. Examining scientific literature on sweet food ‘addictions’ and their putative links to the obesity epidemic is the topic of this review.