1. Study suggests calorie counts on menus make a difference

    November 5, 2017 by Ashley

    From the University of Technology Sydney press release:

    One the most comprehensive pieces of research into the impact of displaying calories on menus reveals it not only influences consumers to make lower calorie choices but also encourages retailers to provide lower calorie options.

    The research confirms the move that has been made in Australia towards, and supports a push in the United States, for greater disclosure of calorie or kilojoule information on menus at fast-food outlets and restaurant chains.

    The researchers, Dr Natalina Zlatevska from University of Technology Sydney, Dr Nico Neumann from Melbourne Business School, and Professor Chris Dubelaar from Deakin University, collated 186 studies on the effect on consumers of displaying calories on menus, as well as 41 studies on the effect on retailers.

    The results of the meta-analysis, to be published in the international Journal of Retailing, show that displaying calorie information encouraged a reduction of 27 calories (112 kilojoules) per meal for consumers and 15 calories (62 kilojoules) per menu item by food retailers.

    Lead researcher Natalina Zlatevska, from the Marketing Discipline Group at UTS Business School, says while the calorie reduction isn’t much if you only eat out once a year, for those who eat out regularly it can make a real difference.

    The impact was also greater for women, with a 60 calorie (251 kilojoule) reduction per meal, and for those who are overweight, with a reduction of 83 calories (347 kilojoules) per meal.

    “With more and more food dollars spent on meals purchased outside the home, anything we can do to educate consumers, and make them a bit more aware of their choices is a good start,” Zlatevska says.

    Obesity increases the risk of many chronic and lethal diseases including type 2 diabetes and heart disease, and is a leading cause of premature death in the US, UK and Australia.

    Zlatevska says the finding that retailers adjust the choices they offer when required to display calorie information is significant.

    “In the same way that corporate or financial disclosure changes behaviour, here we see the disclosure effect changing the food environment,” she says.

    “We know that retailers are adjusting so there is the possibility of a combined effect. That is where I think bigger change will probably happen. All these incremental changes add up, it is cumulative.”

    In the US providing calorie information on menus has proved controversial, with constant delays and “push back” from food industry groups fearing the cost of implementing the laws.

    First mandated in the 2010 Affordable Care Act, labelling laws are due to be implemented in the US in May 2018, but already there are suggestions they will again be postponed or watered-down.

    In Australia, displaying kilojoule information on menus is mandatory in NSW, SA, ACT and Queensland for food outlets and restaurant chains with more than 20 stores in a state or 50 nationwide, with Victoria to follow suit next year.


  2. Study suggests marketing food as a “meal” rather than “snack” may help prevent overeating

    November 1, 2017 by Ashley

    From the University of Surrey press release:

    Marketing food as a ‘snack’ leads to increased consumption and continued overeating, a new study in the journal Appetite reports.

    In the first ever study of its kind, Professor Jane Ogden and her researchers from the University of Surrey examined the impact of labelling food products as ‘snacks’ or ‘meals’.

    During this innovative investigation, eighty participants were asked to eat a pasta pot which was either labelled as a ‘snack’ or a ‘meal.’ Each pot was presented as a ‘snack’ (eaten standing up from a plastic pot with a plastic fork) or a ‘meal’ (seated at a table from a ceramic plate and metal fork). Once consumed, participants were invited to take part in an additional taste test of different foods (animal biscuits, hula hoops, M&M’s and mini cheddars.)

    Researchers found that those who had eaten pasta labelled as a ‘snack’ ate more at the taste test then when it had been labelled as a ‘meal.’ It was also found that those who ate the ‘snack’ standing up consumed more (50 per cent more total mass, sweet mass and total calories and 100 per cent more M&M’s) than those who had eaten the pasta sitting down at a table. This unique set of results demonstrate that when a food is labelled as a snack rather than a meal consumption is higher, particularly when standing rather than sitting.

    Researchers have attributed this to a combination of factors and believe that when eating a snack we are more easily distracted and may not be conscious of consumption. They also argue that memories for snacks and meals may be encoded differently in our subconscious and that we are unable to recall what we have eaten as a ‘snack.’

    Jane Ogden, Professor in Health Psychology at the University of Surrey, said: “With our lives getting busier increasing numbers of people are eating on the go and consuming foods that are labelled as ‘snacks’ to sustain them. What we have found is that those who are consuming snacks are more likely to over eat as they may not realise or even remember what they have eaten.

    “To overcome this we should call our food a meal and eat it as meal, helping make us more aware of what we are eating so that we don’t overeat later on.”

    Obesity is a growing problem in the United Kingdom with levels reported to have trebled in the last 30 years with 24.9 per cent of people now deemed obese, the highest levels in Europe. It is estimated that £16 billion a year is spent on the direct medical costs of diabetes and conditions related to being overweight or obese.


  3. Study suggests junk food almost twice as distracting as healthy food

    October 29, 2017 by Ashley

    From the Johns Hopkins University press release:

    Even when people are hard at work, pictures of cookies, pizza and ice cream can distract them — and these junk food images are almost twice as distracting as health food pictures, concludes a new Johns Hopkins University study, which also found that after a few bites of candy, people found junk food no more interesting than kale.

    The study, which underscores people’s implicit bias for fatty, sugary foods, and confirms the old adage that you shouldn’t grocery shop hungry, is newly published online by the journal Psychonomic Bulletin and Review.

    “We wanted to see if pictures of food, particularly high-fat, high-calorie food, would be a distraction for people engaged in a complicated task, said co-author Howard Egeth, a professor in the Department of Psychological and Brain Sciences. “So we showed them carrots and apples, and it slowed them down. We showed them bicycles and thumb tacks, and it slowed them down. But when we showed them chocolate cake and hot dogs, these things slowed them down about twice as much.”

    First, Egeth and lead author Corbin A. Cunningham, Distinguished Science of Learning Fellow in the Department of Psychological and Brain Sciences, created a complicated computer task, in which food was irrelevant, and asked a group of participants to find the answers as quickly as possible. As the participants worked diligently, pictures flashed in the periphery of the screen — visible for only 125 milliseconds, which is too quick for people to fully realize what they just saw. The pictures were a mix of images of high-fat, high-calorie foods, healthy foods, or items that weren’t food.

    All of the pictures distracted people from the task, but Cunningham and Egeth found things like doughnuts, potato chips, cheese and candy were about twice as distracting. The healthy food pictures — like carrots, apples and salads — were no more distracting to people than non-foods like bicycles, lava lamps and footballs.

    Next, the researchers recreated the experiment, but had a new group of participants eat two fun-sized candy bars before starting the computer work.

    The researchers were surprised to find that after eating the chocolate, people weren’t distracted by the high-fat, high-calorie food images any more than by healthy foods or other pictures.

    The researchers wonder now if less chocolate or even other snacks would have the same effect.

    “I assume it was because it was a delicious, high-fat, chocolatey snack,” Egeth said. “But what if we gave them an apple? What if we gave them a zero-calorie soda? What if we told the subjects they’d get money if they performed the task quickly, which would be a real incentive not to get distracted. Could junk food pictures override even that?”

    Cunningham said the results strikingly demonstrate that even when food is entirely irrelevant, and even when people think they’re working hard and concentrating, food has the power to sneak in and grab our attention — at least until we eat a little of it.

    “What your grandmother might have told you about not going to the grocery store hungry seems to be true,” Cunningham said. “You would probably make choices that you shouldn’t or ordinarily wouldn’t.”


  4. Study looks at possible links between sleep and hunger

    October 22, 2017 by Ashley

    From the Scripps Research Institute press release:

    A new study from scientists on the Florida campus of The Scripps Research Institute (TSRI) offers important insights into possible links between sleep and hunger — and the benefits of studying the two in tandem. A related paper from the same lab is providing researchers an accessible tool for pursuing further investigations involving multiple fruit fly behaviors.

    While many humans enjoy a daily caffeine fix, scientists have found that caffeine repels Drosophila melanogaster — a species of fruit fly often used as a model for studying human conditions and genetics. Scientists believe that plants produce the caffeine molecule as a defense mechanism to prevent organisms such as fruit flies from eating them. Regardless of the cause of the fly’s aversion, caffeine does seem to negatively impact their sleep, much like it does in humans.

    Caffeine is known to stave off sleep in humans through pharmacological effects on the adenosine receptor. Nonetheless, many studies in mammals have shown genetic differences in responses to caffeine. Interestingly, caffeine apparently can prevent sleep in fruit flies despite the fact that it doesn’t act through their adenosine receptor.

    Erin Keebaugh, Ph.D., a postdoctoral researcher in Associate Professor William Ja’s Laboratory at TSRI, suspected that the systems responsible for caffeine’s impact on fly (and maybe human) sleep patterns are more complex than a single caffeine and receptor interaction.

    In her study, published in the journal Sleep on October 3, 2017, her team gave groups of flies varying levels of dietary caffeine. They then measured how much the flies slept in the following 24 hours while on those diets. They also studied whether varying levels of caffeine impacted the insects’ feeding behavior by measuring how much they ate over the same 24-hour period.

    Interestingly, the team found that sleep loss couldn’t be explained by caffeine intake alone. Instead, they believe that the sleep loss was mediated by changes in the animal’s feeding behavior. “There could still be a pharmacological effect, but there’s definitely dietary inputs to that,” said Keebaugh.

    The study reinforced the idea that the processes of sleep and eating need to be studied together, explained the scientists, especially as a growing number of researchers investigate the relationship between sleep and metabolic disorders. Further studies into this relationship could lead to the development of therapies that treat disorders such as obesity and diabetes.

    A Closer Look at Fly Behavior

    To that end, another member of the Ja Laboratory, Graduate Student Keith Murphy, has developed a new open-source, customizable technique for jointly studying multiple fly behaviors. Many studies designed to understand the interactions between multiple fly behaviors require researchers to measure each behavior separately; for example, one study measures how much the flies eat while a second study measures how much they sleep, and then the data are combined and compared. With Murphy’s device, the Activity Recording CAFE (ARC), researchers could measure both behaviors simultaneously, giving the researchers a cleaner, simpler strategy to investigate previously convoluted questions.

    Using the ARC protocol, as described in a paper recently published in Nature Protocols, anyone with access to a 3D printer can print the chamber and set it up in two hours or less to collect fly data. The chamber is hooked up to a computer that continuously tracks both the amount of food that a fly consumes and its position in the chamber, which can tell a researcher whether or not it’s sleeping.

    Though the protocol is specifically designed for studying sleep and feeding behaviors, Murphy emphasized that the ARC could be customized to study a variety of behaviors in flies. Researchers could program the machine vision program on the computer to apply optogenetic controls tied to certain behaviors, deliver vibrations or cause the fly’s food to move to assess memory, motivation and other behaviors.

    “We’re hoping that this paper creates a community around the tool and people come up with new uses,” said Murphy. “If others get on board, this thing could change what a small lab can do.”

    In addition to Keebaugh, other authors of the study in Sleep were Jin Hong Park, Chenchen Su, Ryuichi Yamada and William Ja of TSRI. The research was supported by the National Institutes of Health (grant R01AG045036).


  5. Study suggests eye-catching labels may stigmatize many healthy foods

    October 20, 2017 by Ashley

    From the University of Delaware press release:

    When customers walk down aisles of grocery stores, they are inundated with labels such as organic, fair-trade and cage free, just to name a few. Labels such as these may be eye-catching but are often free of any scientific basis and stigmatize many healthy foods, a new University of Delaware-led study found.

    The paper published recently in the journal Applied Economics Perspectives and Policy examined the good, the bad and the ugly of food labeling to see how labels identifying the process in which food was produced positively and negatively influenced consumer behavior.

    By reviewing over 90 academic studies on consumer response to process labels, the researchers found that while these labels satisfy consumer demand for quality assurances and can create value for both consumers and producers, misinterpretation is common and can stigmatize food produced by conventional processes even when there is no scientific evidence those foods cause harm.

    For the poor, in particular, there is danger in misunderstanding which food items are safe, said Kent Messer, the study’s lead author and the Unidel Howard Cosgrove Career Development Chair for the Environment.

    “That has me worried about the poor and those who are food insecure,” said Messer, who is also director of the Center for Experimental and Applied Economics in the College of Agriculture and Natural Resources. “Because now you’re trying to make everything a high-end food choice and frankly, we just want to have healthy food choices, we don’t need to have extra labels that scare away people,”

    Process labels, by definition, focus on the production of a food, but largely ignore important outcomes of the process such as taste or healthiness. According to Messer and his study co-authors, policy changes could help consumers better understand their choices. They argue governments should not impose bans on process labels but rather encourage labels that help document how the processes affect important quality traits, such as calorie count.

    “Relying on process labels alone, on the other hand, is a laissez faire approach that inevitably surrenders the educational component of labeling to mass media, the colorful array of opinion providers, and even food retailers, who may not always be honest brokers of information,” the researchers wrote.

    The Good

    With regards to the positive impact process labels have on consumers, Messer said that consumers are able to more freely align their purchasing decisions with their values and preferences.

    If, for example, a consumer wants to buy fair trade coffee, they are able to do so with greater ease.

    “The good part is that process labels can help bridge the trust between the producer and the consumer because it gives the consumer more insight into the market,” said Messer. “New products can be introduced this way, niche markets can be created, and consumers, in many cases, are willing to pay more for these products. It’s good for industry, consumers are getting what they want, and new players get to find ways of getting a higher price.”

    The Bad

    The bad part is that consumers are already in the midst of a marketplace filled with information that can be overwhelming because of the sheer amount of product choices and information available.

    In addition, when most consumers go to buy food, they are often crunched for time.

    “Human choice tends to be worse when you put time constraints on it,” said Messer. “Maybe you’ve got a child in the aisle with you and now you’re adding this new label and there’s lots of misinterpretation of what it means. The natural label is a classic one which means very little, yet consumers assume it means more than it does. They think it means ‘No GMO’ but it doesn’t. They think it means it is ‘organic’ but it isn’t. This label is not helping them align their values to their food, and they’re paying a price premium but not getting what they wanted to buy.”

    Messer said that another problem are “halo effects,” overly optimistic misinterpretation of what a label means.

    “If you show consumers a chocolate bar that is labeled as ‘fair trade’, some will tell you that it has lower calories,” Messer said. “But the label is not about calories. Consumers do this frequently with the ‘organic’ label as they think it is healthy for the consumer. Organic practices may be healthier for the farm workers or the environment, but for the actual consumer, there’s very little evidence behind that. You’re getting lots of mixed, wrong messages out there.”

    The Ugly

    Like halo effects, the ugly side of food processing labels comes into play when labels sound like they have a positive impact but really have a negative one.

    A label such as “low food miles” might sound nice but could actually be causing more harm than good.

    “Sometimes, where food is grown doesn’t mean that it’s actually the best for climate change,” said Messer.

    Hot house tomatoes grown in Canada, for example, might have low food miles for Canadian consumers but it’s probably far better environmentally — because of all the energy expended in creating tomatoes in an energy intensive hot house in Canada — to grow the tomatoes in Florida and then ship them to Canada.

    “If you just count miles and not true energy use, you can get people paying more money for something that’s actually going the opposite of what they wanted which is to get a lower carbon footprint,” said Messer.

    He added that the ugly side of food labeling is that a lot of fear is being introduced into the marketplace that isn’t based on science.

    “When you start labeling everything as ‘free of this’ such as ‘gluten free water,’ you can end up listing stuff that could never have been present in the food in the first place,” Messer said. “These ‘free of’ labels can cause unnecessary fear and cast the conventionally produced food in a harsh, negative light.”

    Since the vast majority of the food market is still conventionally produced and is the lower cost product, there is a danger in taking that safe food and calling it unsafe because of a few new entrants into the food market.

    Messer also said that there is evidence that food companies are getting worried about investing in science and technology because they don’t know how the consumer is going to respond or how marketers are going to attack their food product because it’s new and different and therefore, can be labeled as bad or dangerous.

    “We’ve got a lot of mouths to feed in our country and around the world,” Messer said. “We are currently able to feed so many because of advances in agricultural science and technology. If we’re afraid of that now, we have a long-term impact on the poor that could be quite negative in our country and around the world. That’s when I start thinking these process labels could really be ugly.”


  6. Study looks at how both nature and nurture may be influencing eating behavior in young children

    October 16, 2017 by Ashley

    From the University of Illinois College of Agricultural, Consumer and Environmental Sciences press release:

    For most preschool-age children, picky eating is just a normal part of growing up. But for others, behaviors such as insisting on only eating their favorite food item — think chicken nuggets at every meal — or refusing to try something new might lead to the risk of being over- or underweight, gastrointestinal distress, or other eating disorders later in childhood.

    Parents and other caregivers often deem children as being “picky eaters” for a variety of reasons, but there is not a hard-fast definition in place for research. Nutrition and family studies researchers at the University of Illinois have collaborated for the last 10 years to understand the characteristics of picky eaters and to identify possible correlations of the behavior.

    In a new study, the researchers wanted to see if chemosensory genes might have a possible relationship to picky eating behavior in young children. They found that certain genes related to taste perception may be behind some of these picky eating habits.

    “For most children, picky eating is a normal part of development,” says Natasha Cole, a doctoral student in the Division of Nutritional Sciences at U of I and lead author of the study. “But for some children, the behavior is more worrisome.” Cole, also part of the Illinois Transdisciplinary Obesity Prevention Program at U of I, hopes the research can help identify the determinants of picky eating behavior in early childhood.

    Leading up to the taste perception genes study, the U of I researchers identified common characteristics of picky eaters, ages 2 to 4 years, and divided these “types” of picky eaters into distinct groups. Further research from the team looked at how parenting styles may affect picky eating behavior and whether children exhibit picky eating behavior both at home and in childcare — homecare or center-based — situations.

    “This has kind of been an evolution of the research, seeing an interaction rather than just seeing the child as on its own, which, when we first started trying to define a picky eater, we were just looking at the child,” explains Soo-Yeun Lee, a professor in the Department of Food Science and Human Nutrition at U of I. “As we were moving into different parts of the research we realized, it’s not just the child, it’s the caregiver and the environment, as well.”

    Now, they are looking at the influence of “nature and nurture” on a child’s picky eating behavior.

    “Natasha is actually taking a deeper look at the child and genetic predisposition,” Lee says. “She is looking at sensory taste genes and also at some of the behavioral genes that have been highlighted in the literature. She has been looking at the whole field of picky eating research, and classifying it based on ‘nature vs. nurture.’ Nature is the genetic disposition and nurture is the environment and the caregivers.”

    The idea, Lee explains, is based on an orchid/dandelion hypothesis. “There are some genes — the behavioral genes — that make the child more prone and more sensitive to being more behaviorally problematic when external influences are present that may not work out their way. That’s the orchid concept. This may be a sensitive child who may not be as resilient with negative feedback or negative mealtime strategies given by parents, versus a dandelion child who is very robust and resistant to whatever, nurture or not, is given to them.

    “There is that fine line, and it’s not just the nurture, the environment, that’s influencing that, but it’s the child’s susceptibility to the environmental cues as well,” she adds.

    For the study, the researchers collected information about breastfeeding history and picky eating behaviors, such as limited food variety, food refusals, and struggles for control, for 153 preschoolers, as reported by their caregivers. Saliva samples were also taken for DNA extraction and genotyping.

    The researchers looked at genetic variation in single nucleotide polymorphisms (SNPs, pronounced “snips”) from five candidate genes related to taste perception. Of the five, they found that two had an association with picky eating behaviors in the preschoolers. One (TAS2R38) was associated with limited dietary variety, and the other (CA6) with struggles for control during mealtime.

    Interestingly, both the TAS2R38 and CA6 genes are possibly related to bitter taste perception. So it is not surprising that the children who are genetically “bitter-sensitive” may be more likely to be picky eaters (i.e. turning down Brussel sprouts or broccoli). Other chemosensory factors, such as odor, color, and texture, may affect eating behaviors as well. Further studies are needed to see how children’s food preferences are affected by the look or smell of their food.

    Along with continuing to look at genetic associations with picky eating, Cole is also interested in understanding how picky eating behaviors start even in children before 2 years of age. Most picky eating research has focused on children over 2 years, but eating habits begin to form before then. She and the research team recently published another study that reviews the research literature on picky eating in children younger than 2 years. The study discusses picky eating associations from an ecological model, starting with the child, and moving out to the child’s environment.

    “By two years, children know how to eat and have pretty set habits,” Cole says. “There is a huge gap in the research when children transition from a milk-based diet to foods that the rest of the family eats.”

    Cole adds that the research involving children under 2 years shows that 22 percent of those children are perceived as picky eaters by their parents or caregivers. Surprisingly, she also found that each additional month of the child’s age was associated with an increase in food-related fussiness. “So a child could go from rarely being a picky eater to being a frequent picky eater in less than a year,” she says.

    Collecting and integrating this comprehensive information from “Cell to Society” is critical to better understand nature-nurture interactions, as many questions in this area remain unsolved, explains Margarita Teran-Garcia, an assistant professor in nutritional sciences, human development and family studies, and the Carle Illinois College of Medicine at the U of I, and co-author of the paper.


  7. Brain cells that control appetite identified for first time

    October 5, 2017 by Ashley

    From the University of Warwick press release:

    Dieting could be revolutionised, thanks to the ground-breaking discovery by the University of Warwick of the key brain cells which control our appetite.

    Professor Nicholas Dale in the School of Life Sciences has identified for the first time that tanycytes — cells found in part of the brain that controls energy levels — detect nutrients in food and tell the brain directly about the food we have eaten.

    According to the new research, tanycytes in the brain respond to amino acids found in foods, via the same receptors that sense the flavour of amino acids (“umami” taste), which are found in the taste buds of the tongue.

    Two amino acids that react most with tanycytes — and therefore are likely to make you feel fuller — are arginine and lysine.

    These amino acids are found in high concentration in foods such as pork shoulder, beef sirloin steak, chicken, mackerel, plums, apricots, avocadoes, lentils and almonds — so eating those foods will activate the tanycytes and make you feel less hungry quicker.

    The researchers made their discovery by adding concentrated amounts of arginine and lysine into brain cells, which were made fluorescent so that any microscopic reactions would be visible. They observed that within thirty seconds, the tanycytes detected and responded to the amino acids, releasing information to the part of the brain that controls appetite and body weight.

    They found that signals from amino acids are directly detected by the umami taste receptors by removing or blocking these receptors and observing that the amino acids no longer reacted with tanycytes.

    Nicholas Dale, who is Ted Pridgeon Professor of Neuroscience at the University of Warwick, commented:

    “Amino acid levels in blood and brain following a meal are a very important signal that imparts the sensation of feeling full. Finding that tanycytes, located at the centre of the brain region that controls body weight, directly sense amino acids has very significant implications for coming up with new ways to help people to control their body weight within healthy bounds.”

    This major discovery opens up new possibilities for creating more effective diets — and even future treatments to suppress one’s appetite by directly activating the brain’s tanycytes, bypassing food and the digestive system.

    Nearly two thirds of the UK population is overweight or obese. This excess weight elevates the risk of premature death and a range of illnesses, such as cancer, diabetes, cardiovascular disease and stroke, which greatly reduce quality of life. A new understanding of how appetite functions could curb the growing obesity crisis.

    The research, ‘Amino Acid Sensing in Hypothalamic Tanycytes via Umami Taste Receptors’, will be published in Molecular Metabolism.

    It is funded by the Biotechnology and Biological Sciences Research Council.


  8. Study maps the neurons that drive salt cravings

    October 3, 2017 by Ashley

    From the Beth Israel Deaconess Medical Center press release:

    While the average American’s high-salt diet has been linked to high blood pressure and cardiovascular disease, the truth is we couldn’t live without this once scarce mineral. Salt helps the body balance its water content and plays a critical role in regulating blood pressure and cellular function throughout the body. As salt is lost through excretion and other metabolic processes, hormones are released in response to sodium deficiency. But exactly how these hormones work on the brain to trigger salt-seeking and salt-consuming behavior has remained a mystery.

    Now, a team of scientists in the Division of Endocrinology, Diabetes and Metabolism at Beth Israel Deaconess Medical Center (BIDMC), have shed new light on the process. In research published today in the journal Neuron, a team of scientists working in the lab of Bradford Lowell, MD, PhD, identified the sub-population of neurons that respond to the body’s sodium deficiency and mapped the brain circuitry underlying the drive to consume salt.

    “We identified a specific circuit in the brain that detects sodium deficiency and drives an appetite specific for sodium to correct the deficiency,” said co-first author Jon M. Resch, PhD, a post-doctoral fellow in Lowell’s lab. “In addition, this work establishes that sodium ingestion is tightly regulated by the brain, and dysfunction in these neurons could lead to over- or under consumption of sodium, which could lead to stress on the cardiovascular system over time.”

    The team focused on a subset of neurons — known as NTSHSD2 — discovered a decade ago by co-corresponding author, Joel Geerling, MD, PhD, formerly of BIDMC and now assistant professor in the Department of Neurology at Carver College of Medicine at the University of Iowa. In a series of experiments in sodium-deficient mice, the researchers demonstrate that sodium deficiency activates these neurons. They also showed that the presence of the hormone aldosterone, which the body releases during sodium deficiency, increases the neurons’ response.

    “These neurons appear to be highly influenced by these hormones and less so by inputs from other neurons — though further study is warranted,” said Resch. “This is a unique and very unexpected feature of these NTSHSD2 neurons.”

    The researchers also revealed that NTSHSD2 neurons — located in a part of the brain called the nucleus of the solitary tract — are not solely responsible for driving the sodium appetite. In experiments using mice not deficient in sodium, artificial activation of NTSHSD2 neurons triggered sodium consumption only when there was also concurrent signaling by angiotensin II, a hormone also released by the body during sodium deficiency. From this, Resch and colleagues concluded that another set of neurons sensitive to angiotensin II likely plays a role in driving sodium appetite.

    These neurons have yet to be identified.

    The findings demonstrated that only a synergistic relationship between the two distinct sub-populations of neurons that respond to aldosterone and angiotensin II can cause the rapid and robust onset of the sodium appetite seen in the experimentally deficient mice. Resch notes the sodium-appetite circuity he and colleagues have revealed provides a physiological framework for a hypothesis put forth in the early 1980s.

    “Several questions remain with regard to how sodium appetite works, but a major one is where ATII is acting in the brain and how the signal works in concert with NTSHSD2 neurons that respond to aldosterone,” he said. “We have already begun work to help us close these gaps in our knowledge.”


  9. Study suggests link between BMI and how we assess food

    October 2, 2017 by Ashley

    From the Scuola Internazionale Superiore di Studi Avanzati press release:

    A new study demonstrated that people of normal weight tend to associate natural foods such as apples with their sensory characteristics. On the other hand, processed foods such as pizzas are generally associated with their function or the context in which they are eaten.

    “It can be considered an instance of ‘embodiment‘ in which our brain interacts with our body.” This is the comment made by Raffaella Rumiati, neuroscientist at the International School for Advanced Studies — SISSA in Trieste, on the results of research carried out by her group which reveals that the way we process different foods changes in accordance with our body mass index. With two behavioural and electroencephalographic experiments, the study demonstrated that people of normal weight tend to associate natural foods such as apples with their sensory characteristics such as sweetness or softness.

    On the other hand, processed foods such as pizzas are generally associated with their function or the context in which they are eaten such as parties or picnics.

    “The results are in line with the theory according to which sensory characteristics and the functions of items are processed differently by the brain,” comments Giulio Pergola, the work’s primary author. “They represent an important step forward in our understanding of the mechanisms at the basis of the assessments we make of food.” But that’s not all.

    Recently published in the Biological Psychology journal, the research also highlighted the ways in which underweight people pay greater attention to natural foods and overweight people to processed foods. Even when subjected to the same stimuli, these two groups show different electroencephalography signals. These results show once again the importance of cognitive neuroscience also in the understanding of extremely topical clinical fields such as dietary disorders.

     


  10. Study suggests you are what you think you eat

    September 20, 2017 by Ashley

    From the British Psychological Society (BPS) press release:

    Despite eating the same breakfast, made from the same ingredients, people consumed more calories throughout the day when they believed that one of the breakfasts was less substantial than the other.

    The research, funded by the Rural and Environment Science and Analytical Services at the Rowett Institute, is the key finding of research led by Steven Brown from Sheffield Hallam University which is being presented today at the annual conference of the British Psychological Society’s Division of Health Psychology.

    Previous studies have investigated the link between how filling we expect liquids (e.g. drinks) or semi-solids (e.g. smoothies/soups) to be and people’s subsequent feelings of hunger up to three hours later.

    These initial expectations have also been shown to be an important determinant of how much people eat at a meal provided a short time later. The current research shows that a similar effect can be seen when using solid foods (i.e. an omelette) and that the influence of those expectations is still present after a longer period of time (four hours later and the total day’s calorific intake).

    A total of 26 participants took part. Over two visits, participants believed they were eating either a two or four egg omelette for breakfast. However, both of the omelettes actually contained three eggs.

    When the participants believed that the omelette was smaller they reported themselves to be significantly hungrier after two hours, they consumed significantly more of a pasta lunch and, in total, consumed significantly more calories throughout the day than when the same participants believed that they were eating a larger omelette.

    Steven Brown said, “Previous studies have shown that a person’s expectations can have an impact on their subsequent feelings of hunger and fullness and, to a degree, their later calorie consumption. Our work builds on this with the introduction of solid food and measured people’s subsequent consumption four hours later, a period of time more indicative of the gap between breakfast and lunch.

    “We were also able to measure participants’ consumption throughout the rest of the day and found that total intake was lower when participants believed that they had eaten a larger breakfast.

    “As part of the study, we were able to take blood samples from participants throughout their visits. Having analysed levels of ghrelin, a known hunger hormone, our data also suggest that changes in reported hunger and the differences in later consumption are not due to a differences in participants’ physical response to the food.

    Therefore, memory for prior consumption, as opposed to physiological factors, may be a better target for investigating why expectations for a meal have an effect on subsequent feelings of hunger and calorie intake.”