‘Health Chatter’: Research Department of Behavioural Science and Health Blog
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    Learning to like vegetables: Starting early

    By Alison Fildes, on 10 June 2015

    Vegetables are commonly among children’s least liked foods, while sweet-tastes are preferred from the outset. These preferences are reflected in children’s diets with children in the UK and other European countries eating too few vegetables and too many sugary foods. Evidence suggests introducing vegetables early in life may have important implications for future health. It is possible to learn to like foods, such as vegetables, simply by trying them on multiple occasions. Older children (or adults) may need to try a food 14 times or more before they begin to like it but infants are particularly accepting of new tastes. This makes the weaning stage is a key period for learning to like a variety of different foods.

    As part of the European HabEat project we conducted an exploratory trial investigating the impact of advising parents to introduce of a variety of single vegetables at the very start of weaning. Pregnant women or mothers with infants less than 6 months old were recruited from healthcare settings in the UK, Greece and Portugal. Mothers and their infants were randomized (allocated by chance) to either an intervention group or a control group, ensuring there were equal numbers of breast-fed and formula-fed infants in each group. Intervention mothers were visited before they started weaning and were given advice on introducing five vegetables (one per day) as their baby’s first foods, repeated over 15 days. After the first 15 days, intervention mothers were told to continue to offer vegetables but also to start introducing other age-appropriate foods such as fruit. Mothers in the control group received standard care, which varied from country to country. For example, UK recommendations are to introduce fruits, vegetables and baby rice or cereal as first foods, but the information provided to mothers is inconsistent and access to advice may vary by region.

    Taste tests were conducted one month after the start of weaning. Intervention and control infants were fed unfamiliar vegetable (artichoke) and fruit (peach) purées and a researcher recorded how much of it they ate (g) and how much they appeared to enjoy these foods. When the results for the UK, Greece and Portugal were combined (n=139) the children who took part in the intervention, and ate a variety of vegetables for the first 15 days of weaning, had not eaten significantly more of the unfamiliar vegetable purée than the children from the control group. However in the UK, intervention children ate almost twice as much of the unfamiliar vegetable compared with control children whose parents were not advised to offer vegetables as first foods (32.8g vs. 16.5g). UK mothers and researchers also rated intervention infants’ as liking the vegetable more. Whereas in Portugal and Greece there was no significant effect of the intervention on infants’ intake of or liking for the vegetable. In all three countries, there was no difference between groups in the amount of fruit purée children ate or how much they seemed to like it.

    These results may be partly explained by variation in existing weaning practices across Europe. Common first foods given to UK infants include fruits and ‘baby rice’. Vegetables, particularly green or bitter tasting varieties, are offered less frequently. When they are introduced vegetable purées are often combined with fruits such as apple or pear, sweetening the food and potentially masking the vegetable flavour. In contrast vegetables are regularly offered as first foods in Portugal where vegetable soups are a common weaning food. These differences may be reflected in later dietary patterns as Portuguese school-children have some of the highest levels of vegetable intake in Europe.

    The findings of this study suggest that repeatedly offering a variety of vegetables to infants at the start of weaning may work to increase vegetable acceptance in countries where vegetables are not already given as first foods. However, we don’t know yet whether this effect will last throughout toddlerhood and into later childhood, so this will need to be explored in future studies.

    Reference: Fildes A., Lopes C., Moreira P., Moschonis G., Oliveira A., Mavrogianni C., Manios Y., Beeken R., Wardle J. & Cooke L. (2015). An exploratory trial of parental advice for increasing vegetable acceptance in infancy. British Journal of Nutrition. journals.cambridge.org/bjn/vegetabletrial

    ‘Health and happiness are more important than weight’: Why telling parents that their child is overweight may be ineffective at encouraging behaviour change

    By Susanne Meisel, on 24 March 2014

    Childhood obesity is becoming more common.  The latest available statistics show that about 1 in 5 of 4-5year old children (22%), and about 1 in 3 (33%) of 10-11year old children were overweight or obese in the UK .  This puts more and more children at risk of serious, chronic health conditions such as diabetes and heart disease which have traditionally only been observed in adults.  Overweight and very overweight children are also at risk of mental health problems such as depression; sometimes made worse because of weight-related teasing or bullying by their peers.  Preventing more children from becoming overweight, and helping those who already are overweight to prevent further weight gain, or to lose weight, is therefore important. 

    However, a huge number of factors contribute to the rising obesity rates in adults and children.  The solution is certainly not simple, and our researchers are working at finding out more about the many different factors that contribute to the current ‘obesity epidemic’. 

    Some people think that one factor that plays a part in childhood obesity is that some parents don’t know that their child is overweight and because they don’t know, they don’t do anything about it.  Therefore, it was thought that telling parents that their child is overweight could prompt some action to avoid further weight gain. However, studies so far have shown that telling parents about their child’s weight status has very little effect on behaviour change; although some parents are more likely to agree that their child is overweight after having been informed about it by researchers, many parents do not agree with the feedback or think that their child’s weight puts them at risk of health problems.  In other words, they seem to disregard the information for some reason.

    Researchers from our department wanted to better understand why telling parents about their child’s weight status had so little effect; and in fact often resulted in negative reactions. 

    They interviewed 52 parents, who received a letter from the National Child Measurement Programme (NCMP), which informed them that their child was overweight or very overweight.  The National Child Measurement Programme was established by the Department of Health in 2005 to monitor national trends in heights, weights and BMIs of children in Reception (aged 4-5 years) and Year 6 (10-11 years) in publicly funded primary schools in England.

    The researchers asked questions about parents’ thoughts on the feedback, and whether they agreed with it.

    It transpired that in all interviews, parents used a variety of markers, other than weight, to decide whether their child was a healthy weight or at risk of health problems caused by their weight.  The majority of parents felt that their child ate a healthy diet, was physically active, and was not teased or bullied, and therefore they were not concerned about their child’s weight.  Furthermore, many parents did not think their child ‘looked overweight’, often in comparison with the child’s peers. In this context parents also often referred to build (‘big bones’), or to ‘puppy fat’ which they expected their child to lose during puberty. Parents shared the view that ‘health and happiness is more important than weight.’

    This means that simply telling some parents that their child is overweight might not be an effective means of raising awareness about potential health problems, because they might not think that weight is a very accurate measure of their child’s health.  Taking a child’s lifestyle into account (diet, physical activity, and emotional health) might be a good way to improve the dialogue with parents about a child’s health. 

    Furthermore, because there seems to be an assumption that children will lose any extra weight during puberty, parents may think that overweight is an issue that will correct itself over time.  However, there is plenty of good research showing that overweight children are highly likely to turn into overweight adults; perhaps not least because of differences in appetite, as discussed in our previous blog.  Findings from this study showed us that more work needs to be done to communicate the link between child weight and adult weight better. 

    Lastly, because parents compare their own children to others, and weight has overall gone up in the population, they may consider their child ‘normal weight’ when it is, in fact, overweight.  Although there is also the argument that all measures of weight status are somewhat arbitrary and not without their faults, they do give a good indication about where things are headed, particularly for those at the upper end of the range.

    Although these findings are from only one study, and interviewed only a small number of parents and may therefore not hold true for a larger number of parents, they nonetheless bring up some points that might be worth thinking about in more detail. No doubt, weight is certainly not the only important marker for a child’s well-being, but given that many overweight children and adults suffer from related physical and mental difficulties, paying attention to a child’s weight is also not insignificant. Because ultimately, parents and health professionals want the same thing: keeping children happy and healthy.

    Article Reference:  Syrad H, Falconer C, Cooke L et al. Health and happiness is more important than weight: a qualitative investigation of the views of parents receiving written feedback on their child’s weight as part of the National Child Measurement Programme. J Hum Nutr Diet. 2014;n/a.  http://onlinelibrary.wiley.com/doi/10.1111/jhn.12217/abstract

     

    Why tackling appetite could hold the key to preventing childhood obesity

    By Susanne Meisel, on 19 February 2014

    A heartier appetite is linked to more rapid infant growth and to genetic predisposition to obesity, according to two studies recently published by our researchers in the journal JAMA Pediatrics.

    Although it is clear that some people seem to struggle much more than others to keep a healthy weight, so far it has been less obvious why this is the case.  Researchers from our department have now shown that differences in appetite, and especially lower satiety sensitivity (a reduced urge to eat in response to internal ‘fullness’ signals) and higher food responsiveness (an increased urge to eat in response to the sight or smell of nice food) may hold the key to unhealthy weight gain.

    In the first study, the researchers showed that infants with a heartier appetite grew more rapidly up to age 15 months, potentially putting them at increased risk of obesity.

    Our researchers used data from non-identical, same-sex twins born in the UK in 2007.  As we have previously discussed, twins are a good model to study differences between people because they are born at the same time, and usually grow up in a very similar environment.

    Twin pairs were selected that differed in measures of satiety responsiveness (172 pairs) and food responsiveness (121 pairs) at 3 months, and their growth up to age 15 months was compared. Within pairs, the infant who was more food responsive or less satiety responsive grew faster than their co-twin.

    The more food responsive twin was 654g heavier (1.4lbs) than their co-twin at six months and 991g heavier (2.1lbs) at 15 months. The less satiety responsive twin was 637g heavier (1.4lbs) than their co-twin at six months and 918g heavier (2lbs) at 15 months. 

    This is a considerable weight difference for children of this age, and represents a 10% weight difference. Over time as weight differences increase, these children are at a higher risk of obesity.  Therefore, it might be beneficial to watch out if a child seems to have difficulties filling up, or seems to be somewhat responsive to food cues in the environment.

    However, this first study could not tell whether children with low satiety responsiveness or high food responsiveness would continue to be heavier; nor did it tell about possible underlying genetics. 

    Therefore, the second study was set up to shed more light on how appetite, and especially low satiety responsiveness, acts as one of the mechanisms underlying genetic predisposition to obesity.  For this study, our researchers collaborated with a team from King’s College, London.

    The researchers accessed data from over 2,000 unrelated 10-year-old children born in the UK between 1994 and 1996.  First, the team created a combined genetic risk score (polygenic risk score) for each child.  To do this, they added up the number of higher risk versions of 28 obesity-related genes (each gene has 2 versions, as we all get one version from Mum and one version from Dad). A higher polygenic risk score meant that the child was at higher genetic risk of obesity.

    The researchers then looked at how the children’s genetic risk scores related not only to their satiety responsiveness, but also to their body fatness (measured using body mass index and waist circumference).  

    As expected, they found that children at a higher genetic risk of obesity had higher BMIs (which is a measure of weight status) and a larger waist circumference.  This finding was in line with what we already know about the genetic basis of obesity (see our other blogpost).  But key to our study was showing that they were also less sensitive to satiety. 

    This finding suggests that satiety responsiveness is one of the mechanisms through which ‘obesity genes’ influence body weight.  Therefore, it might indeed be beneficial to teach children with lower satiety sensitivity techniques that might improve their fullness signals when eating.  Advice to parents on encouraging children to eat more slowly, having a ‘no second helpings’ policy, and keeping tempting treats out of sight between meals could help. Knowing that there are genetic influences on appetite might help parents understand and accept that children differ, and that some need more support in learning the boundaries of appropriate eating.

    Likewise, for adults who feel they have difficulty controlling their weight, it might be beneficial to understand that differences in appetite might be one contributing reason.  Techniques that help adults to ‘feel’ the fullness, such as ‘mindful eating’ and portion control may be useful aides in ‘outsmarting’ any biological tendencies to eat too much.

    Article references: JAMA Pediatrics

    van Jaarsveld CM, Boniface D, Llewellyn CH, Wardle J. Appetite and Growth: A Longitudinal Sibling Analysis. JAMA Pediatr. 2014;():. doi:10.1001/jamapediatrics.2013.4951.

     

    Llewellyn CH, Trzaskowski M, van Jaarsveld CM, Plomin R, Wardle J. Satiety Mechanisms in Genetic Risk of Obesity. JAMA Pediatr. 2014;():. doi:10.1001/jamapediatrics.2013.4944.

     

    Do you want your kids eating their greens? Then, you better start, too…

    By Susanne Meisel, on 23 February 2012

    You don’t need to be Jamie Oliver to figure out what is going on with children’s diets – but his efforts certainly helped to pull the candyfloss from our eyes:  children in England are eating plenty of snacks high in fat, salt and sugar, but only one quarter eats their recommended minimum 5 portions of fruit and vegetables a day.  This can be problematic, because not only could it lead to nutritional deficiencies, but also to disproportionate weight gain.

    Unfortunately, it is not the case that children simply ‘outgrow’ their ‘puppy-fat’; the vast majority of overweight children grow into overweight teenagers and potentially obese adults.  This is because people naturally put on about 2 pounds per year as they age (unless they do something about it, of course) – and the higher the ‘starting weight’ is, the higher the chances are that people shift up across the weight spectrum as they get older. Furthermore, people who become overweight or obese early in life are often more severely affected by illnesses linked with an unhealthy weight, such as diabetes, heart disease and some cancers.

    This is why it is important to figure out what it is that makes children eat their greens (and all those other healthy fruit and veggies, even if cooking like Jamie isn’t your thing).  It has long been known that many different factors such as inherited taste preferences, family eating habits or the amount of time spent watching TV are important when looking at reasons why children eat (or don’t eat) certain foods; but rarely has research looked at factors related to healthy and unhealthy eating habits at the same time in the same group of families.

    In this study, the researchers were interested in the actual foods children in England eat (as opposed to specific nutrients, such as vitamins). The researchers had records of what children and their parents ate from several hundred families, along with information on factors which may influence what they eat.  They decided to look in particular at factors which affected how much fruit, vegetables, unhealthy snacks and sugary drinks children consume; focusing on preschool-aged children – as they are not yet strongly influenced by their peers, and are more dependent on eating what their caregivers provide for them.

    Perhaps unsurprisingly, the researchers found that when children liked the taste of fruit and veggies it predicted how much of these they ate.  However, what is more important, they also found that parents’ consumption of either fruit, vegetables, unhealthy snacks or sweetened drinks was a very important indicator of how much children ate of these foods.  This might be not only because caregivers may feed children what they themselves eat, but also because children tend to copy adults’ behaviour – so if mum eats healthily, children will be more likely to want to eat healthily too.  Of course, that is also true for unhealthy eating habits – which is why not having junk foods in the home in the first instance can help.  Because it was mainly mothers who filled out the questionnaires, these results focused only on mothers.

    Furthermore, praising children for eating fruit and veggies was a good indicator of how much children ate, and monitoring the unhealthy snacks children eat was linked with them eating less of these and more fruit and vegetables.  The amount of time children spent watching TV was also an indicator of children eating unhealthy snacks and having sweetened drinks, but it had no impact on their consumption of fruit and vegetables.

    The research provides a little more evidence on how eating habits are transmitted within a family.  It highlights that different strategies need to be used in order to increase the amount of healthy foods vs. decreasing amounts of unhealthy foods children eat.

    So, ultimately, if you want your children to eat their greens, you might not have any choice but to take a bite too and start singing their praises, and if you really want to cut down on their junk intake then get rid of it from within your home and turn off the telly – and at last Jamie will be happy.

     

    http://www.nature.com/ejcn/journal/vaop/ncurrent/full/ejcn2011224a.html

    Tell me about your family and I can tell you about your weight?

    By Susanne Meisel, on 4 October 2011

    Mentioning genetics in the context of weight is like treading into a minefield; those who are brave enough to approach the topic need to don their hard hats and be prepared to take hits by followers in the ‘eat-less-and-move-more’ camp. Accusations of laziness, lack of willpower, making excuses and just looking for an easy way out are common responses to the genetic argument of obesity.

    However, to ignore genetics when talking about obesity is somewhat confusing when considering how keen people are to attribute skinniness to ‘good genes’, ‘fast metabolism’, and ‘being naturally active’. Nobody seems to notice that skinniness and fatness are two sides of the same coin.

    As so often in life, the truth lies somewhere in between. While behaviour is certainly not to be ignored when searching for the root cause of the obesity epidemic, neither should the heritability of body weight. Two recent studies from our research group add evidence to the idea that the predisposition to thinness, as well as to overweight, is transmitted across generations. Researchers used data from the Health Survey for England, which included a large sample of families with children aged 2-15 years to see whether thin children were more likely to have thin parents. Of the thousands of families included in the first study, it was shown that thin children were almost twice as likely to have 2 thin parents.  Furthermore, as parents’ weight decreased, children likewise got progressively lighter.

    But, what about the reverse side of the coin – parental weight of children who were overweight? Here, exactly the same pattern was found, but it was even more apparent. Children, who had 2 obese or severely obese parents, were approximately 12 times more likely to be overweight and again the likelihood of obesity gradually decreased with decreased parental body weight. In both studies, findings were unrelated to other factors such as age, sex, social status or ethnicity. Interestingly, the mothers’ weight seemed to be more predictive of a child’s than the father’s, but only among those children that were overweight. For thin children, mothers’ and fathers’ genes appeared to contribute equally to being thin.

    Two things are important here. Firstly, weight is governed in part by genetic factors; but, and this is the second important conclusion to take away, there are environmental factors involved that influence a child’s weight – otherwise all children would have had parents that fully resembled their weight status. Influences seem to come especially from the mother’s side, which may be, because the foetus receives nutrients from the maternal diet in the womb and after birth when the infant is breast-fed. In addition, maternal environmental influences may be stronger because the mother is usually in charge of food preparation.

    Unfortunately, dietary records of participants were not available, so it was not possible to investigate how diets between underweight and overweight children and their parents differed.

    Genes do not always act in the same way; their activity is influenced by the environment. This flexibility allowed our species to adapt well to changing environmental conditions, which made it possible to survive and evolve.  Variation is the key. And this is why it is easier for some than for others to (not) have their cake and eat it, too.

     

    References:

    Whitaker KL, Jarvis MJ, Boniface D, Wardle J. Inter-generational transmission of thinness. Archives of Pediatrics and Adolescent Medicine. http://archpedi.ama-assn.org/cgi/content/full/165/10/900

    Whitaker KL, Jarvis, MJ, Beeken RJ, Boniface D, Wardle J. Comparing maternal and paternal intergenerational transmission of obesity risk in a large population-based sample. American Journal of Clinical Nutrition. 91, 2010, 1560-1567. http://asn-cdn-remembers.s3.amazonaws.com/f8ee4cfad55bd34900cff3371b9a146d.pdf