Nutrition Research Highlights 3|2014
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This newsletter is published by the Nutrition & Health Group of the JRC’s Institute for Health and Consumer Protection. Regularly surveying the top nutrition and medical journals, we select the most recent news on nutrition research, relevant to current societal debates or policies. These are then summarized as “News” items or presented as a “View”, comprising an analysis and expert opinion. Enjoy your reading!
Have you ever started an antibiotic therapy and stopped because you were feeling better before the course had finished? Or exchanged antibiotics with your friends because “they were left in the cupboard”? At first glance these may look harmless but in fact, they constitute misuse of antimicrobial agents* and can contribute to antimicrobial resistance (AMR). AMR is the capacity of a microorganism (e.g. a bacterium) to resist the killing activity of an antimicrobial agent and recently the European Centre for Disease Prevention and Control (ECDC) estimates indicate that antimicrobial resistant infections result in at least 25000 deaths in Europe every year (1). In May 2014 the World Health Organization (WHO) published its first global report on AMR (2) where it calls for action to address AMR. The report largely focuses on the use of human antibiotics but emphasis is also put on antibiotics given to farm animals. These are used not only to treat disease (therapeutic purposes) but also in healthy, food-producing animals to prevent disease (prophylactic use) and in some instances promote growth.
In recent years there has been a growing concern over the transmission of antibiotic resistant bacteria and their resistance genes through the food chain and affecting human health. To protect both animals and humans, stricter rules on the use of antimicrobial agents have been put in place. For example, Regulation (EC) No 1831/2003 on feed additives bans the marketing and use of antibiotics as growth stimulator in Europe. In 2011, the European Commission launched the Action Plan against the rising threats from Antimicrobial Resistance (3) with important actions in the veterinary and animal farming sector. Denmark has a history of action in mitigating AMR that was recently highlighted in several fora (see (4) (5)). Legislation and guidance for prudent use of antimicrobials and good breeding practices are in place in this country together with measures to limit incentives to use antibiotics. For example, the recent "Yellow Card Initiative" flags individual farmers and veterinarians with exceptionally high use of antimicrobials prompting and supporting them to reduce usage within a given time period.
Preventing and controlling AMR both in humans and in farmed animals is a complex issue that involves many sectors. The Danish case illustrates that reductions in antimicrobials usage and in the presence of antimicrobial-resistant bacteria in farmed animals are possible. Targeted, creative and multi-factorial measures that mobilise all stakeholders appear to be key factors to this success story that can hopefully inspire others for better animal welfare and health! (AL & SC)
Cardiovascular disease (CVD) (specifically coronary heart disease and stroke) is the leading cause of death worldwide (1). Overweight and obesity (i.e. high body mass index (BMI)*) is one of the main risk factors for CVD. Other risk factors include high blood pressure, high blood glucose and high blood cholesterol. These risk factors can themselves be affected by high BMI, therefore their relative contribution is not entirely clear. This is an important question; answering it will clarify how much “cardiovascular health” one can gain by directly targeting blood pressure, cholesterol or glucose. A recent study set out to address this (2). It confirmed that overall, being both overweight and obese was associated with a much higher risk of developing CVD when compared to a healthy weight (2). Importantly, it estimated that approximately 50% of the excess risk** of coronary heart disease observed in individuals with high BMI, was mediated by these three metabolic risk factors. Their contribution is even higher in the case of stroke, where 75% of the excess risk of stroke associated with high BMI appears to be mediated by blood pressure, cholesterol and glucose levels. Blood pressure appears as the most important mediator, especially for stroke. Interestingly, the study noted that the metabolic factors mediated a greater share of risk for overweight individuals than for obese individuals. Hence, interventions aiming to control blood pressure, cholesterol and glucose are more likely to address the excess risk of CVD in those who are overweight. Although obese individuals could also benefit from such interventions, they continue to have significantly increased risk (2).
Future clinical and public health measures should consider these findings but additional research into other processes linking obesity and CVD is also needed. Preventative measures should combine reducing these modifiable risk factors with maintaining a healthy bodyweight. Dietary interventions aiming to improve dietary habits are a starting point (2) and together with enhanced physical activity, they are a good recipe for cardiovascular health! (FM)
* BMI is a measure of body mass, obtained from a person's weight (kg) divided by their height squared (m2). A healthy bodyweight is defined as a BMI between 18.5-25 kg/m2; overweight: between 25-30 kg/m2; and obese >30 kg/m2
** Excess risk: is an epidemiological measure of risk. In this case it quantifies to what extent the level of risk amongst people with high BMI exceeds that of healthy weight people (WHO 2009) (3).
If you sometimes wonder how much your food choices impact on climate change, land use or pollutant emissions (for example from nitrogen) across the European environment, the report “Nitrogen on the Table” may give you some answers (1). The report suggests that halving the consumption of red meat and dairy products consumed across Europe would reduce nitrogen pollution from agriculture, reduce greenhouse gas emissions, improve health and free up large areas of land (1).
Western diets are characterised by high intakes of meat, dairy and eggs, often resulting in intakes of saturated fat and red meat that exceed dietary recommendations. The livestock production needed to sustain these diets requires large areas of land for rearing and feed production, leading to high nitrogen and greenhouse gas emissions (1). Nitrogen is essential to life and to crop growth too (2). The natural depletion of nitrogen from soil which occurs during plant growth has led to artificial replacement of nitrogen through fertilisation. However, excess reactive nitrogen* in the environment pollutes water, soil and air (2).
Despite the EU's agricultural region being relatively nitrogen efficient**, 80% of all its reactive nitrogen emissions come from agriculture (6.5-8 million tonnes per year), the majority of which from livestock production (79-88%). The report above explored the effect on nitrogen emissions of different diets, for example, a 25 or 50% reduction in the intake of livestock products that were replaced with plant-based products (1). It shows that halving animal product intake in the EU would result in a 40% reduction in current European agricultural nitrogen emission, as well as a 25-40% reduction in greenhouse gas emissions. Additionally, large areas of land would be freed up for production of other crops (not destined as animal feed) or biofuels, overall increasing EU cereal exports from 3 million tonnes a year to 170 million tonnes per year and reducing soy (used in animal feed) imports to the EU by about 75% (1).
The cascade produced by such dietary changes would also benefit human health. On average, the current protein intake per person in the EU exceeds dietary recommendations set out by the European Food Safety Authority (3). The diets studied are better aligned with these current dietary recommendations. The report estimates that halving the consumption of animal products would reduce saturated fat intake by 40%, increase consumption of plant-based products and lower cardiovascular disease risk, without reducing caloric intakes (1).
Many people are making a conscious effort to reduce their meat consumption and have already signed up to the so called Demitarian diet (4). Maybe you'd like to give it a go? (FM)
* Reactive nitrogen: Nitrogen is essential for life, however its molecular form (N2) is unusable by most living organisms. Reactive nitrogen encompasses all forms of nitrogen which have been transformed into other molecular forms which are bioavailable to living organisms. These include nitrogen oxides (NOx), nitrous oxide (N2O), ammonia (NH3) and nitrate (NO3-) (2).
** Nitrogen efficiency is defined as the ratio between the nitrogen uptake of crops and the total nitrogen input, for example from fertilisers (5).
5. USDA (2007)
Trans fatty acids* (TFA), a particular type of unsaturated fatty acids, can be found as either of industrial origin (iTFA) or naturally occurring ruminant TFA (rTFA). Industrially produced partially hydrogenated oils (PHO) used in foodstuffs are the major source of iTFA in diets. They can be found in several food products including vegetable fats, bakery products, confectionary and some fried foods. rTFA, on the other hand, are produced in the rumen of animals such as cattle and sheep, and can be found in the fat of milk, butter, cheese and meat at levels of 2–9% of total fat (1, 2). Fresh foods such as fruit and vegetables do not contain TFA.
TFA do not serve any nutritional purpose (3). On the contrary, their intake is associated with increased risk of cardiovascular disease (4-6). Indeed, the European Food Safety Authority's recommends that 'TFA intakes should be as low as is possible within the context of a nutritionally adequate diet' (2) while the World Health Organization recommends a TFA intake of less than 1% of daily energy intake (7). The latest WHO 'Global action plan for the prevention and control of NCDs 2013-2020' recommends Member States to adopt policies at national level to 'virtually eliminate partially hydrogenated vegetable oils in the food supply, as appropriate, within the national context and national programmes' (8).
Approaches to minimise population dietary exposure to TFA
Since the detrimental effects of TFA on cardiovascular health hit the headlines more than two decades ago, a number of governments around the world have implemented several approaches to decrease the presence of TFA in food supply (e.g. voluntary TFA reduction agreements, mandatory TFA labelling, legal TFA limits (see examples in Figure 1**)) with various degrees of success (9). In 2003, Denmark became the first country in the world to adopt legislation (10) which limits the content of iTFA in foodstuffs destined for human consumption (maximum 2 g TFA per 100 g of total fat). Switzerland (11), Austria (12), Iceland (13), and most recently Hungary (14) and Norway (15) have followed. Within the framework of the Food Information to Consumers legislation (16), the EU is currently assessing the situation and options, and depending on such assessment and the views of Member States and European Parliament on the topic, further measures may be agreed upon. In the United States (US), last year the Food and Drug Administration (FDA) has “tentatively determined” that PHO are no longer to be considered as “generally recognized as safe” (GRAS) additives (17). Public consultation is now complete and if this is approved, US food manufacturers will not be permitted to sell PHO (directly or as ingredients in another food product) without the approval of the FDA for use as food additives (18). It has been suggested that eliminating the use of PHO could potentially reduce cardiovascular disease risk in the US (19).
Despite differences in country regulations, there is evidence to show a global decrease in TFA content in foods over the last twenty years, and therefore possible reductions in TFA population intakes and in plasma TFA circulating levels (20). A recent study investigated whether products containing PHO could easily be found in European supermarkets and what PHO amounts these products contained (21). The authors did not find products with significant TFA amounts in selected supermarkets in Berlin (Germany), Copenhagen (Denmark), London (UK), Oslo (Norway), Paris (France), Stockholm (Sweden) and Vienna (Austria) in 2013; however, in South-Eastern European countries popular foods (e.g. pre-packaged biscuits/cakes wafers) can be found in supermarkets that contain well above the 2 g of TFA per 100 g fat aforementioned limit. The same products could be found in ethnic shops in countries with a limit on TFA content in foods in place, e.g. Denmark.
Figure 1 TFA policies around the world, 2005-2012 (9)
The results of this study indicate that while some countries and food producers appear to have successfully addressed the problem of high content of iTFA in foods, others have not and particular population groups may still be at risk of high TFA intake. Our own work confirms these observations (22). Policy makers from both sides of the Atlantic appear to be currently looking at their TFA-related policy options aiming to further improve their citizen's foods and diets. We look forward to the outcomes and wish them success in this endeavour (TM).
* Codex Alimentarius defines TFA as 'all the geometrical isomers of monounsaturated and polyunsaturated fatty acids having non-conjugated, interrupted by at least one methylene group, carbon-carbon double bonds in the trans configuration'
** Reproduced with permission (9)
10. Executive Order No. 160 of 11 March 2003 on the Content of Trans Fatty Acids in Oils and Fats Danish Veterinary and Food Administration, Danish Ministry of Food, Agriculture and Fisheries, Denmark
13. Regulation on the Maximum Levels for Trans Fatty Acids in Foods 21 December 2010, Ministry of Fisheries and Agriculture, Republic of IcelandRegulation on the Maximum Levels for Trans Fatty Acids in Foods 21 December 2010, Ministry of Fisheries and Agriculture, Republic of Iceland
14. Draft Decree of the Ministry of Human Resources on the highest permitted amount of trans fats in food products, the conditions of and inspections by the authorities on the distribution of food products containing trans fats and the rules for tracking the population's consumption of trans fats H. Ministry of Human Resources, 2013, Hungary
15. Draft Regulations relating to trans fatty acids in foods - Notification 2013/9013/N - C50A 2013, The Norwegian Food Safety Authority, Royal Ministry of Trade and Industry, Department for Industrial and Trade Issues, Norway
May– June 2014
Nutrition Research Highlights is a bi-monthly publication prepared by the Nutrition Team of the DG-Joint Research Centre, Institute for Health and Consumer Protection. Sandra Caldeira, Anastasia Livaniou, Tsz Ning Mak, Theodora Mouratidou, Flaminia Mussio, Stefan Storcksdieck genannt Bonsmann and Jan Wollgast contributed to this issue.
The views expressed here do not necessarily reflect the opinion of the European Commission.
© European Union, 2014. Reproduction of articles (excluding photographs) is authorised, except for commercial purposes, provided that the source is mentioned.