Nutrition Research Highlights 4|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!
- Taking a moment to enjoy your food
- Mother's nutrition lives on…
- The schools of thought on vitamin supplements
You have probably been told - while rushing through your lunch - not to eat so fast! Is there a scientific basis for this kind of advice though?
A recent study (1) reviewed the latest literature on this topic with the aim of assessing if and how eating rate affects energy intake, hunger levels or both. The analysis suggests that indeed a slower eating rate results in reduced concurrent energy intake. However, hunger levels 2-3 hours after the meal were not affected by changing eating rate (1). Why this may happen is not clear as the links between eating rate and hunger or satiety are still elusive. For example, some suggest that the speed of eating and the frequency of chewing our food affect the satiety hormones involved in the control of hunger. Others support the idea that eating more slowly could influence the amount we eat by affecting our stomach distension, which sends 'fullness' signals to our brain (2). Another proposed mechanism suggests that increasing the number of bites of food whilst maintaining eating rate constant also causes us to eat less (3). Likewise, it has been suggested that some of us have acquired a learned association between the number of bites, chews or sips we take during a meal and the feeling of fullness that brings the meal to an end (1).
Despite all the questions on the linkages between eating rate, food intake and hunger, it appears as though reducing eating rate could be used as a behavioural strategy to reduce energy intake (1). So feel free to take your time while enjoying a nice meal this summer! (FM)
Many studies, mostly epidemiological or in animal models, have linked adverse exposures in utero or in early life to subsequent metabolic ill-health. Prolonged starvation is such an adverse event, and adult diabetes and obesity are possible outcomes. Indeed, great attention is given to future mothers' nutrition and health status and to the first years of life of children*. It is interesting that characteristics acquired in such an early period can later be transmitted to other generations. Two recent studies strengthen further the evidence supporting this concept and highlight the role that males in particular can play in the inter-generational effects of maternal malnutrition (1, 2).
In both studies, researchers underfed mice during pregnancy. The pups were born underweight and later in life developed several metabolic problems such as glucose intolerance**. Importantly, the male pups (generation 2 mice) grew up to become fathers of equally underweight pups (generation 3 mice). Like their fathers, these generation 3 mice developed glucose intolerance. When the researchers compared the sperm DNA of the generation 2 mice born to underfed mothers to that of similar mice born to normally-fed mothers they saw specific differences in the methylation patterns***. These changes are likely to have occurred in utero during the development of generation 2 pups and were perpetuated to the next generation of mice (generation 3).
How exactly undernutrition during pregnancy impairs metabolic health across multiple generations, remains to be shown. But by analogy, all efforts to protect mothers and their future babies may have long lasting trans-generational benefits we should strive to secure. (SC)
** "Glucose intolerance is an umbrella term for metabolic conditions which result in higher than normal blood glucose levels" (taken from: http://www.diabetes.co.uk/glucose-intolerance.html, accessed 4 August 2014)
Should we be taking supplements regularly as a preventative measure for health? If you ask scientists, they are likely to give you different answers and their views cannot be more divided. Back in December 2013, a group of researchers had published a paper that caused a stir with many - they called for a stop to waste money on vitamin and mineral supplements among the well-nourished adults* (1). Since then, many scientists have fought back with claims that vitamin deficiencies are still widespread across developed nations such as the US (2) and Europe (3) (see our previous article) and supplements are needed to help close these nutritional gaps (4).
So why the different schools of thought on vitamin supplements? A recent article in Nature explored this question (4). The answer boils down to vitamin studies not producing agreeable results - some studies have demonstrated effectiveness but most studies haven't. And why don't they agree? Because studies have different designs, methods of investigation (e.g. different dose and forms of a vitamin), and contained sample populations with very different genetic variations.
In April 2014, the U.S. Preventive Services Task Force reviewed the evidence on the efficacy of multivitamin or mineral supplements in the general adult population** for the prevention of cardiovascular disease and cancer, and concluded: "the current evidence is insufficient to assess the balance of benefits and harms of multivitamins, single- or paired-nutrient supplements for the prevention" of such diseases (5). The Task Force also recommended against beta-carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer. Unfortunately, research to date cannot provide a definitive answer to our question of whether we should take supplements. Hence, for the time being it is best to stick to the current recommendations (6) and get our micronutrients from the most natural (and probably cheapest) sources - food! (TNM)
* Note that women of child-bearing age are recommended to take 400 micrograms of supplemental folic acid daily for at least one month before and up to three months after conception (6).
** This recommendation applies to healthy adults without special nutritional needs (typically aged 50 years or older). It does not apply to children, women who are pregnant or may become pregnant, or persons who are chronically ill or hospitalised or have a known nutritional deficiency.
We reported earlier on the issue of childhood obesity and the adoption of the EU Action Plan on Childhood Obesity 2014-2020 (1). Since then, the Director-General of the World Health Organization (WHO) has established the high-level Commission on Ending Childhood Obesity (2), and June saw the release of the Council conclusions on nutrition and physical activity (3). Diet and lifestyle can have a huge impact on health, and habits form early in life. Consequently, schools are a key setting for the young to experience the importance of eating well and being active.
Since the Council conclusions (3) and the Childhood Obesity Action Plan (1) are the most explicit on the school setting, let's take a look at the proposed actions and how this compares with what guidance the individual Member States are offering.
Council conclusions and the Childhood Obesity Action Plan
The Council (3) acknowledges the important role of "healthy nutrition options in childcare facilities and schools" and sees potential benefits for the whole family. At the same time it notes that schools can help to "protect and support the most vulnerable members of society." Consequently, it invites the Member States to:
- promote policies and initiatives aiming at healthy diet and sufficient physical activity, including in school environments;
- work with stakeholders to make healthier dietary options easily accessible, easy to choose and affordable for all citizens and provide opportunities and places for daily physical activity at schools (among other places);
- promote healthy environments, especially in schools, pre-schools and sport facilities, by encouraging the supply of healthy dietary options based on nutritional standards, addressing excessive access to and intake of salt, saturated fats, trans fatty acids and sugar, as well as frequent consumption or consumption in high amounts of sugar sweetened and/or caffeinated soft drinks and encouraging children and adolescents to be physically active on a regular basis.
The Childhood Obesity Action Plan (1) reflects the above in a number of ways and dedicates one of its eight areas for action to promoting healthier environments, especially at schools and pre-schools. To this end, it defines operational objectives, corresponding actions, responsible parties, appropriate indicator(s), required data collection and assessment mechanisms as well as the time frame to reach certain targets.
Evidence on school-based interventions
The scientific evidence supports interventions in school focused on improving both diet and physical activity through various means and at different levels (4). Specialised educational curricula, trained teachers, supportive school policies, a formal physical education programme, healthy food and beverage options, and a parental/family aspect are included in the most promising approaches. Also of likely benefit are school garden programmes, including nutrition and gardening education and hands-on gardening experiences, as well as programmes that provide free fruit and vegetables to students during the school day. As reported previously, dietary intakes in school children may be improved by making the more desirable food choices at school more attractive and prominent.
In line with such evidence, WHO Europe in 2006 issued a tool for developing school food and nutrition policy (5). This tool offers a comprehensive list of suggestions from which countries, authorities and schools are invited to choose those "most appropriate and applicable to their circumstances."
Mapping national school food policies across Europe
Against this backdrop, and to facilitate exchange between policy-makers, the JRC assessed if and what school food policies exist in the EU (6). The good news is that all 30 countries considered, i.e. the EU28 plus Norway and Switzerland, have some form of school food policy in place. This may range from a list of (dis)allowed foods to be sold on school premises (Cyprus) to extensive voluntary guidance (e.g. Germany, Italy) or mandatory standards (e.g. Finland, Slovenia) for food provision and related aspects. The vast majority (>90%) of school food policies employ food-based standards such as how much fruit and vegetables to serve per day or how often to include fatty fish in the menu. About 75% of policies place clear restrictions on soft drinks, sweet treats, and savoury snacks, and 65% limit the provision of (deep-)fried and processed products. Menu composition and portion size is commonly guided by energy and nutrient reference points, the major focus being on total calories and fat content in line with age-appropriate requirements.
Overall, school food policies are voluntary in 15 countries and mandatory in the remaining 15 countries (6). Ministries of Health or Education, either alone or in unison, are the most common governmental departments primarily responsible for developing the policy. Primary aims of these policies are to improve child nutrition, teach healthy diet and lifestyle habits and reduce or prevent obesity. Other aspects addressed are restrictions on food marketing and vending machines, the importance of training catering and other staff involved in handling food, and whether nutrition education is a mandatory part of the national school curriculum.
Notably, the analysis (6) revealed that less than 60% of the European national school food policies define outcome measures such as the uptake rate for school meals, the actual food provision, or the nutritional status of the child. Considering that the Childhood Obesity Action Plan (1) lists 'Monitoring and Evaluation' as one of its eight Areas for Action, more and standardised efforts are needed to assess whether the school food policies achieve their stated objectives. In May 2014, the JRC organised a workshop entitled 'European School Food and Nutrition: policies, interventions and their impact', which brought together European stakeholders from governments, academia, and non-governmental organisations. Participants exchanged success stories in the area of school food provision and shared ideas on how to move the field forward, including monitoring and surveillance. Concrete examples in terms of recipes for success were: 1) the building of partnerships; 2) local engagement and co-creation (the co-involvement of head-teachers was seen as crucial); and 3) increasing the availability of healthier options.
Regarding suggestions on how to move school nutrition forward, the workshop participants highlighted various measures at many different levels from revisiting portion sizes to having benchmarking tools and comparable data. Monitoring and evaluation of school food policies and their implementation and effects were seen as essential. Progress indicators discussed ranged from school food intake and uptake to education attainment and absenteeism. Additional proposed measures included nutrition education, school gardens, hand-washing programmes, preparing and eating school food, dental hygiene, and even using schools to act on health inequalities. The full workshop report will be made available on the dedicated website.
From policy to action
Creating a supportive policy environment for school-based interventions to reduce childhood obesity is important. However, as Ursula O'Dwyer, Irish representative on the EU High Level Group on Nutrition and Physical Activity and lead on the Childhood Obesity Action Plan puts it: "By putting everything into place, we've done the equivalent of buying a gym membership. But no one ever got fit by just becoming a gym member - they have to actually use it" (7). We fully concur and close with our own words: "Providing tasty and nutritious school food requires strong commitment by a multitude of stakeholders. But if done right, the time and money we spend on it today will reward us with social, economic, and health gains many times the initial investment" (6). (SSgB)
2. WHO website, News releases section. Accessed 21 July 2014
7. Health-EU newsletter 134 - Focus. Accessed 18 July 2014.
Image: Boy eating healthy school lunch.
July - August 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, 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.