Nutrition Research Highlights 6|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!
- A cup of cocoa a day?
- Diets shape the future
- Uncovering 'hidden' hunger
- What if obesity weighed down school grades?
- Fewer calories in commercial foods and drinks for children – will this halt the obesity epidemic?
News on the benefits of chocolate or cocoa consumption for brain function is always welcome, especially for the many chocolate lovers out there! This is perhaps the reason why a recent study by Brickman and colleagues (1) was widely covered in a broad range of news media. In this study, the authors built on previous evidence to hypothesise that high doses of flavanols*, possibly combined with aerobic exercise, might improve the function of a specific region of the brain, the dentate gyrus. After optimising the tools needed, the authors set up a three-month randomised controlled trial** to test their hypothesis; since age-related changes linked to functional integrity have been observed in dentate gyrus, the authors recruited healthy but sedentary adults aged between 50 and 69 years. The subjects were split into a high-flavanol intake group (~1 gram daily of cocoa flavanols) and a low-flavanol intake group (~1 milligram daily), and each group divided further into with or without aerobic exercise (1h per day, 4 days a week). Participants took a visual test which involved rapidly displaying complex images and identify them among multiple similar choices. Their brains were also scanned to assess the cerebral blood volume in the dentate gyrus – a measure that correlates with neuronal metabolism in that brain region.
The high-flavanol group responded faster than the low-flavanol group on the visual test indicating improved cognitive performance. The authors also observed that the high-flavanol group showed an increase in the cerebral blood volume of the dentate gyrus and that aerobic exercise did not seem to have any effect. All together, the results indicate that 'dietary cocoa flavanol consumption enhanced dentate gyrus function in the aging human hippocampus'. Because the study involved a small number of people and because it is not clear what the observed effects mean for day-to-day cognition activities, more work is needed before we start emptying the cocoa product shelves from the nearest food store! In addition, the high amount of flavanols provided in the study would not be easily obtained through cocoa consumption within the context of a balanced diet (2). So, you might as well keep on having your occasional mug of cocoa or piece of chocolate and enjoy it for what it is. And keep on exercising for your health and well-being! (PM)
* Flavanols (flavan-3-ols) are a group of compounds found in plants such as cocoa and include substances such as catechins and epicatechins.
** A clinical study design 'where people are randomly allocated to receive (or not) a particular intervention (this could be two different treatments or one treatment and a placebo). This is the best type of study design to determine whether a treatment is effective'. Source: National Health Service glossary
Image: Cocoa beans from Wikimedia Commons, courtesy of Graham Crumb
We may not think about it while enjoying a delicious meal but our dietary choices can actually shape our individual health, the health of our planet and the health of our countries' finances. Two recent publications (1, 2) highlight this point and show how dietary and lifestyle choices can influence the future in 2050. The first article (1) compiles impressive amounts of data on the environmental impact of foods and diets, – calculated as greenhouse gas (GHG) emissions and cropland usage, and the health implications of particular diets – quantified as reduction in relative risk of developing type II diabetes, cancer, coronary mortality and all-cause mortality. The authors considered four diets– a typical omnivorous diet described for each world region including all food groups – and three alternative diets: a Mediterranean diet (rich in vegetables, fruit and seafood), a pescetarian (including fish and no meat) or a vegetarian (including dairy and eggs but no fish or meat). Their analysis shows that the alternative diets have health benefits in reducing the relative risk for developing type II diabetes, cancer and coronary mortality and each has considerable environmental benefits as well. Projecting their analyses to 2050, the authors conclude that consumption of the alternative diets could have clear environmental benefits related to GHG emissions and land usage from food production. The composition of a reference 2050 diet and alternative diets is depicted in the figure here represented. The authors calculate that GHG emissions could be halved when comparing the vegetarian diet with the reference 2050 diet. Our own foresight report Tomorrow's healthy society: research priorities for foods and diets (2) also illustrates how different 2050 choices linked to diet and lifestyle co-exist with very different scenarios. The report depicts four scenarios that differ primarily in societal values (individualistic societies or societies with a strong community spirit) and agricultural commodity prices (more or less affordable quality food). The report illustrates how these two drivers can greatly affect population dietary patterns, and the scenarios developed therein – 'healthy new world', 'heal the world', 'me, myself and I' and 'eat to live' – clearly reflect this impact. The report goes on to propose ten research priority areas that will help Europe cope with the challenges ahead; however, individual choices can make a difference too.
The complexity of the issues above and the uncertainty about many of the future developments imply that a certain degree of simplification is needed when discussing the future 'diet-health-environment trilemma' (1). Nevertheless, the message encompassed in both studies is certainly strong enough to get us all thinking. Diets characterised by higher fruit and vegetable and lower animal protein intake appear to have health and environmental benefits (1) for both individuals and societies. (SC)
Image: Characterisation of a 2050 reference diet (reference diet a forecast based on the past 50 yrs of data on global dietary trends and GDP) and 3 alternative diets analysed in Tilman & Clark, 2014 (1). Reproduced with permission from (3)
While many have heard about vitamin A or iron deficiencies in low-income countries of the world, the existence of hidden hunger in developed countries including some in Europe may come as a surprise. In the 3rd World Congress of Public Health Nutrition (WCPHN) (1) the keynote lectures by Prof. Hans Konrad Biesalski alerted to 'Hidden hunger in the "First World" - how is economic crisis affecting under nutrition?'. Biesaslki described hidden hunger as a chronically inadequate dietary supply of micronutrients such as vitamin A, iron, zinc, iodine and folate. Such micronutrients contribute to the majority of nutrient deficiency cases worldwide and can affect human health before clinical signs of malnutrition become obvious (2).
Despite popular belief, hidden hunger does exist in developed countries and has an impact on childhood development and diseases later in life. Biesalski presented results of the latest Life in Transition Survey (LiTS) where participating households affected by the recent economic crisis report spending less on staple foods such as fruits, vegetables, milk and bread (3). The resulting inadequate diet in terms of both quality and diversity is the basis for this hidden hunger. As poverty and limited nutritional knowledge are the main reasons for hidden hunger, long-term actions and policies to address this challenge are needed. Actions to reduce hidden hunger affecting poor people in the developed world were called for and Biesalski suggested that school lunches and nutritional education of medical doctors form good steps forward. We look forward to future actions and policies challenging and eventually overcoming hidden hunger. (TM)
Biesalski, Hans Konrad. 'Der verborgene Hunger' (Springer Spektrum), 2012, ISBN 978-3-8274-2952-0.
Image: Pike Place Market. Courtesy of: Wikimedia Commons
Among the various negative consequences of obesity in childhood and adolescence, impaired academic attainment has been discussed for some years, yet with little scientific support (1). However, findings from the Avon Longitudinal Study in Parents and Children (ALSPAC) now strengthen the evidence which links teenage obesity with poorer school grades (2). Based on weight status measurements of nearly 6 000 pupils at ages 11 and 16 and their school grades at ages 11, 13 and 16, Booth and colleagues (2) calculated the independent impact of being obese on students' grades in English, Science and Maths. The researchers observed that girls who were obese at age 11 had significantly worse marks at age 16 than their non-obese peers, even after controlling for various confounders*. Results for boys showed a similar trend but did not reach statistical significance.
If these results can be confirmed by more research, these ALSPAC findings would add yet another reason why reducing the levels of childhood obesity is important. Physical activity (PA), one of the key pillars in any obesity prevention and weight management strategy, may have a double benefit here. In addition to keeping one in shape, it may also improve children's cognitive performance and brain function. Indeed, when children aged 7-9 years participated in a 9-month course of almost daily physical activity, they showed enhanced performance on complex cognitive tasks compared to control children not following the PA course (3). Nevertheless, further studies will be needed to understand if and how this may translate into better academic performance. In the meantime, being physically active is a smart thing to do, regardless of school grades or gender! (SSgB)
* Confounders 'get in the way' of the comparison between groups that one tries to make and ultimately affect study outcomes. Confounding is defined as 'a situation in which the effects of two processes are not separated'. Text adapted from: https://epilab.ich.ucl.ac.uk/coursematerial/statistics/introduction/planning_study/confounding.html (accessed 13 Nov 2014)
Image: Smiling Girl Pointing Towards The Camera. Courtesy of Stock Images
In strategic policy documents, a common approach to address diet-related risk factors and health issues (such as obesity, high blood pressure, diabetes, and cardiovascular disease), is to reduce the availability and consumption of less healthy food options; this refers to those foods that 'contain high levels of nutrients for which there is evidence that excess consumption in European populations might influence diet-related adverse health conditions: total fat, saturated fatty acids, trans-fatty acids, sugars and salt' (1). In Europe, many companies are already voluntarily increasing the amount of healthier options in their portfolios by changing the composition of foods or introducing new products with healthier nutrient profiles (2). In the United States, where childhood obesity rates are even more alarming than in Europe, the focus has primarily been on reducing the energy content of packaged foods and beverages. In 2009, the 16 leading US consumer packaged goods (CPG) food and beverage manufacturers joined the Healthy Weight Commitment Foundation (HWCF) and pledged to collectively remove 1 trillion calories from their products by 2012 against a 2007 baseline. This pledge is currently being comprehensively evaluated by external researchers receiving independent funding to ensure this analysis is as independent as possible. Preliminary results indicate that the manufacturers participating in the HWCF pledge have greatly exceeded the commitment. As a matter of fact, in 2012, they sold 6.4 trillion calories less than in 2007, much more than the initial target of 1 trillion (3). This sounds like a great success story of voluntary food reformulation. However, in order to understand the impact of this reduction in food and beverage calories sold, further examination is needed.
Food and beverage manufacturers participating in the HWCF pledge (from here on referred to as: 'HWCF brands') sold products containing a total of 60.4 trillion calories throughout 2007. This corresponds to an estimated share of 25% of total energy consumed (i.e. approximately 240 trillion calories) in the US for that year (4); reducing by 6.4 trillion calories over the 5 year period equates to a 10% overall reduction in calories sold by HWCF brands. This gives a first indication of the scale of this achievement. This reduction translates into a decrease of 78 kcal/capita/day* sold in HWCF brands products in 2012 as compared to 2007 (3). Although the latter values are more tangible, do they also indicate progress towards reducing the epidemic of childhood obesity?
Calculations suggest that average daily energy intake levels in children from 2007-8 would need to be reduced by 184 kcal/capita/day if the US government's Healthy people 2020 goal of a 10% reduction in childhood obesity is to be achieved (5). While the numbers now seem to suggest that almost half of the necessary energy reduction has been accomplished in only 5 years, care needs to be taken in not jumping to conclusions too quickly: the 78 kcal/capita/day reduction refers to calories sold, while the necessary reduction of 184 kcal/capita/day refers to the average daily intake in children. A second study of the HWCF evaluation (6) estimated the trend in daily calories purchased in US households with children in 2012 against the 2007 baseline. Overall, a reduction of 66 kcal/capita/day was seen, which by and large confirms the magnitude of the decline observed in HWCF calories sold. Nevertheless, it will only be possible to evaluate the real impact of the HWCF pledge when the results of the third evaluation study on the actual daily calories consumed by children in 2011/2012 become available. In order to understand what voluntary agreements by only a part of CPG manufacturers can achieve, it is important to consider not only calories consumed from HWCF brand products, but also calories consumed from all foods (packaged and not packaged) in order to explore possible compensation effects in children's energy intake.
Nevertheless, looking at results from past studies may temper enthusiasm. Despite possible early signs of improvements in childhood obesity rates, observed declines in US children's energy intake from 2003-4 through 2007-8 have not continued through 2009-10. As a matter of fact, there is even evidence to suggest an increase in energy intakes among adolescents (7). Moreover, total energy intakes remained significantly higher among pre-school children and children from low-income families in 2009-10 compared to 1989-91 (8) suggesting that specific population groups need particular attention. Furthermore, it should be noted that according to the second HWCF evaluation study (6) in 2009-10 US households with children purchased fewer calories from HWCF brands, as well as from other packaged foods and beverages, as compared to 2007-8. Together, packaged foods and beverages account for nearly two-thirds of the calories Americans consume (3). Hopefully the third part of the HWCF evaluation, which will look at 2011-12 energy consumption data in children, will provide further answers as to why the reduced calories purchased with packaged foods and beverages do not also translate into reduced energy intake in children.
Apparently, one can view the reported effects on HWCF brand calories sold and purchased by households with children as a glass half-full or half-empty. A view reflecting the former welcomed the achieved reductions in calorie contents as an important contribution towards fighting childhood obesity, albeit calling for continued efforts affecting all parts of the population (9). In contrast, a critical comment urged vigilance about the true intentions of the industry and wondered whether the HWCF pledge actually was a 'marketing ploy' given that ongoing reductions in caloric contents of HWCF brands products per year prior to the pledge were similar to the pledged reductions over the entire 5-year (2007 to 2012) period (10). In any case, reducing the energy intake of packaged foods and beverages can only be one piece of the puzzle when addressing overall diet quality. More independent, rigorous and transparent evaluations are needed as a basis for critically monitoring the implementation and effect of measures addressing diet-related health issues, whilst making actors, whether private or public, accountable. (JW)
* For comparison: the commonly used reference daily energy intake of an average adult is 2000 kcal (Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers)
Image: 'Candy' by usamedeniz. Courtesy of Free Digital Photos
November – December 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, Tsz Ning Mak, Petros Maragkoudakis, 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.