Nutrition Research Highlights 3|2012
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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!
- The fast way
- Suggesting the better food choice to consumers
- Social networks & ICT to tackle childhood obesity
We all heard the sentence 'You are what you eat'… But a recent study in mice suggests that it is not only the what and the calories in there but also the when they are consumed that affects weight (1). The study compared two groups of mice on a high fat diet – the first had access to food 24 hours per day and the second only 8 hours per day during their nocturnal active period. The results showed that, although all mice consumed the same amount of calories, mice that ate night and day gained more weight, had liver damage and higher blood glucose and cholesterol levels than those eating during their active period and fasting for the remainder 16 hours. After 100 days this later group even outperformed a control group fed a normal diet in an exercise test. Several observations can explain these results. Firstly, different feeding patterns affect the metabolism of these mice. Also the authors propose that when eating frequently, the signal to burn fat is absent and therefore the body continuously stores fat. In addition, the mice under the time-restricted regimen appeared to be more active during the end of the night leading to the burning of more calories. As mice are obviously not humans the question is whether humans would also benefit from time restricted feeding, in particular from long (16h) fasting periods (e.g. by not eating late at night). Longer fasting could even have the opposite effect, leading to increased appetite which in a lurking obesogenic environment could result in overeating. Indeed, after fasting for 18 hours people tend to pick starchy foods rather than vegetables for example (2). Importantly, the authors caution that the implication of their study is not that fasting counterbalances an unhealthy diet. What we should retain from this study is that the time of eating deserves serious consideration in human nutritional studies addressing obesity and weight management. (RG)
Photo: Late night canteen (wikimedia commons)
The ever increasing pressure that chronic diseases are imposing on our health systems and economies require politicians to consider stepping up their efforts against modifiable risk factors such as dietary choices. In this context, it is noteworthy that a series of studies from the US Institute of Medicine (the 'health arm of the National Academy of Sciences') indicate that to develop a single, standardised front of pack (FOP) labelling system "that is easily understood by most age groups and appears on all food products would best maximize the effectiveness in encouraging consumers to make healthier food choice and purchase decisions" (1,2). They also recommend providing a "one symbol system information about calorie content and serving size and targeted information related to nutrients that are strongly associated with public health concerns" including saturated fat and trans fats, sodium and added sugars (2,3). While the expert committee acknowledges that one flawless FOP system does not exist, the main benefits of such a single system would be to facilitate consumer's comparisons of nutritional value within and across food categories and also to encourage food product reformulation. We have previously discussed the fact that even in the presence of factual clear information, humans are not always rational and often make sub-optimal decisions. FOP systems are likely to strongly direct consumer's food choice. An EU funded research consortium has also come to the conclusion that consistent FOP systems providing energy and key nutrients would increase consumer's attention and use of nutrient labels (4). In Europe, there are several voluntary FOP systems but mandatory FOP labelling has been excluded from recent legislation. Nevertheless, it seems worthwhile to continue exploring front of pack labelling to suggest better food choices to consumers. (JW)
The most recent WHO World health statistics 2012 report (1) has just re-confirmed that obesity continues being a major health threat worldwide: 12% of the world’s adult population is obese. What about children and teenagers though? Data presented by the International Association for the Study of Obesity (IASO) show that the levels of overweight children and adolescents in many European countries are well above 25% (2). Because of these troublesome statistics, the Joint Research Centre has decided to organise a workshop on "Countering obesity by combining behavioural insights and novel ICT tools" There is plenty of ongoing research in these areas and many questions popping up too. Christakis and Fowler (3) have raised the point that social networks are relevant to the "spread of obesity". In the adult American population that they studied, a person's chances of becoming obese increased by nearly 60% if s/he had a friend who became obese in a given time frame. So, if obesity could spread among friends can healthy eating habits and physical activity spread too? And can one take advantage of information and communication technologies (ICT) to promote them? A recent review of the literature (4) suggests so; text messaging or smart phone applications showed benefits in interventions aiming at reduction of physical inactivity and/or overweight/obesity. These phenomena can be exploited in online social network platforms like Facebook to encourage the spreading of healthy behaviours. Most sports brands have gadgets that allow tracking of physical activity, even sharing it in real-time with all network friends. Friends become sources of inspiration and motivation towards better health. That happens offline too but considering that the average number of friends of a Facebook user is around 250, 'spreading' could be more efficient. Other interesting possibilities for 'spreading' physical activity are active video games (AVG, also called exergames) in the form of sports, dancing or gaming competitions for example. A recent study (5) did show that exergaming in children elevates their energy expenditure to moderate or vigorous levels and importantly is liked by children of various BMI levels. Whether all these are effective complementary measures to address childhood obesity will surely be a topic of discussion at the workshop. Should these measures work, how can they be made more accessible to all? Can they also be exploited to promote healthier eating habits? We invite you to visit the workshop website and leave additional comments and suggestions for transforming this promising field into concrete ideas that can help tackle childhood obesity. (SC)
Image: An ideal FOP system as described in the IOM reports
In the latest issue of the American Journal of Clinical Nutrition, a letter to the editor discussing the effects of saturated fats intake on blood lipid levels sparked a scientific debate on the field (1), the latest in a series of many (2). Hence, we thought that it would be useful to shed a bit of light on this seemingly controversial issue and clear the confusion that surrounds it.
There are two different types of fats, saturated and unsaturated (poly and mono-unsaturated), with different impacts on human health. Saturated fatty acids*, or SFAs for short, have received a lot of attention because their high intakes have been linked to the development of coronary heart disease. Foods with a high content of saturated fat include animal origin products such as full fat dairy (butter, cheese, cream,), fatty meat (lard, beef, pork), baked goods and fried foods, as well as some plant oils, such as palm and coconut oil.
In the EU, the European Food Safety Authority (EFSA) recommends an SFA intake that is "as low as possible" (3) while the United States Department of Agriculture (USDA) and the Food and Agriculture Organisations (FAO) of the United Nations together with the World Health Organisation (WHO) specify (4,5) that the saturated fats should provide at most 10% of total consumed energy (calories). In spite of these recommendations, saturated fat consumption in the U.S. amounts from 11 to 13.5% of total calories (6). In Europe, the average ranges from 11 to 15% of total energy consumption, and even if there is a trend for lower saturated fat consumption in South Europe (9-13%), it is still, on average, above the recommendations (7,8).
But why do the major health authorities recommend drastically reducing SFA consumption? Well, there is a direct link between the intake of SFAs and the increase of blood low density lipoprotein (LDL) cholesterol concentrations (3,4). LDL cholesterol is often called "bad" cholesterol because it is a risk factor for cardiovascular disease, while high density lipoprotein (HDL) cholesterol has been known as the "good" cholesterol. In very simple terms, the most accepted line of thought currently is that the higher the HDL/LDL concentration ratio in blood is the better. Hence, "red light" on anything that increases LDL in blood, like SFAs, and "green light" on foods that increase HDL. Of course not all that straightforward in this scientific field, since, as mentioned above, there are scientists that dispute the relationship between cholesterol, SFAs and heart disease risk (9,10). The general consensus however agrees to what we have just described above. Although SFAs are needed for several physiological and structural functions, our organism can synthesise the amount of SFAs that it needs, and therefore we do not need them in the diet.
So, how can we reduce SFAs and what can we substitute them with in our diet? There is convincing evidence that decreasing the consumption of products rich in SFAs and replacing them with products rich in polyunsaturated fatty acids (without changing total fat intake) decreases the risk of cardiovascular disease (3,4,5). In addition, replacing SFAs with mono-unsaturated fatty acids results in increased HDL concentrations (the green lights!) and a decrease in the risk of heart disease3. In light of these, bodies like EFSA, USDA and FAO/WHO recommend reducing SFA intake and replacing them with poly- and mono- unsaturated fats. We have told you above which foods are rich in SFAs, but which foods contain these blessed unsaturated fats? Foods rich in polyunsaturated fats are fish, nuts and seeds, including their respective oils, as well as leafy green vegetables like spinach, lettuce or broccoli. Olive oil is the main dietary source of mono-unsaturated fats, which can also be found in canola or corn oil as well as eggs.
Lets see what happened when the scientific recommendations about SFA consumption where put into practice. Public health campaigns in Finland and Iceland have included SFA reduction as part of a holistic approach (e.g. smoking and salt intake reduction) to improve diets and lifestyles and have seen dramatic decreases in coronary heart mortality, 80% (1972-2007) and 66% (1981-2006) respectively (11,12,13). In both countries, half of the reduced mortality was due to lowering of blood cholesterol. The Finnish scientists went one step further and identified that the lowered blood cholesterol was mainly due to diet-related factors (as opposed to medication). Of those dietary factors, the most important ones was the decrease in dietary intake of SFA coupled with the increased intake of poly-unsaturated fatty acid, and to a smaller extent decreases in dietary cholesterol and trans fats. This was mainly achieved by substituting butter with vegetable oils and by reducing consumption of full fat dairy products and substituting some of them with low-fat alternatives. Dr. Pekka Puska from the Finnish National Institute for Health and Welfare estimated that, due to the described intervention, Finns gained approx. 10 years of healthy life (14). In addition, SFA reduction can have other important benefits as well; lower cardiovascular disease rates resulting from reduced SFA intake could help save a lot of money to our overburdened and financially stressed social healthcare systems, as suggested by two studies in Finland and the U.S. (15,16).
The EU has also decided to act upon SFA reduction. On initiative of the European Commission, the EU and its Member States are now moving towards a framework for the reduction of saturated fat consumption. The main feature of this initiative is to reduce saturated fat by 5% over 4 years in food categories like school and ready meals, dairy and meat products, fats, oils and margarines (17). It should be stressed here that SFA reduction is just one part of the European Commission's holistic approach to improve diet and lifestyles by reformulating foods, and the logical step forward after the Salt Reduction Framework initiative.
To conclude, SFA reduction is in line with the recommendations of all major scientific bodies and authorities, and, although disputed by some scientists, it is supported by the most of the literature and strengthened by the successful examples of Finland and Iceland. So, now that we can navigate the fat labyrinth, we can do our share and start reducing foods that are high in SFAs and substitute them with foods rich in poly and mono-unsaturated fatty acids…for our heart's sake. (PM)
*saturated fats are fatty acids (triglycerides) that have no double bonds between the carbon atoms that make up the fatty acid chain (i.e. all positions around the carbon atoms are "saturated" with hydrogen atoms). Unsaturated fatty acids on the other hand have one (mono-) or more than one (poly-) double bonds between carbons in the fatty acid chain.
Image: Copyright © Jack Corbett. CartoonStock.com
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. The Nutrition team is comprised of Sandra Caldeira, Raymond Gemen, Petros Maragkoudakis & Jan Wollgast.
The views expressed here do not necessarily reflect the opinion of the European Commission.
© European Union, 2012. Reproduction of articles (excluding photographs) is authorised, except for commercial purposes, provided that the source is mentioned.