Tag Archives: #food

Eating For Hunger Or Pleasure Involves Regulating Different Brain Circuits (Food / Neuroscience)

Many times we eat, not because we are hungry, but because of social pressures or because the food is so appetizing, that, even though we are full, we just want another bite.

Overeating, whether it is guided by hunger or pleasure, typically leads to obesity, which affects about 42% of the adults in the U.S., according to the Centers for Disease Control and Prevention. Looking to contribute to the development of effective treatments for obesity, an international team led by researchers at Baylor College of Medicine investigated in an animal model how the brain regulates feeding triggered by hunger or other factors.

Led by Dr. Yong Xu, professor of pediatrics – nutrition and molecular and cellular biology at Baylor, the team discovered that although the brain regulates both types of feeding behavior through serotonin-producing neurons in the midbrain, each type of feeding is wired by its own independent circuit that does not influence the other type of feeding. The researchers also identified two serotonin receptors and two ion channels that can affect the feeding behaviors, opening the possibility that modulating their activities might help regulate overeating. The study appears in the journal Molecular Psychiatry.

Mapping the roads that control feeding behavior in the brain

Xu and his colleagues identified two distinct brain circuits formed by serotonin-producing neurons in the midbrain. One of the circuits extends to the hypothalamus, while the other projects into another region of the midbrain. These circuits play very distinct roles in regulating feeding.

“We discovered that the circuit that projects to the hypothalamus primarily regulates hunger-driven feeding, but does not influence the non-hunger driven feeding behavior,” Xu said. “The other circuit that projects into the midbrain regulates primarily the non-hunger driven feeding, but not the feeding behavior triggered by hunger. This indicates that, at the circuit level, the brain wires the two types of feeding behavior differently.”

The other significant contribution of this work refers to the identification of potential molecular targets associated with the circuits that could be used to treat overeating.

“One potential target is serotonin receptors, which are molecules that mediate the functions of the neurotransmitter serotonin produced by the neurons,” Xu explained. “We found that two receptors, serotonin 2C receptor and serotonin 1B receptor, are involved in both types of feeding behavior. Our data suggests that combining compounds directed at both receptors might produce a synergistic benefit by suppressing feeding.”

In addition, the team identified ion channels associated with the circuits that also might offer an opportunity to regulate the feeding behaviors. “One is the GABA A receptor, a chloride channel, found to be important in regulating serotonin circuits during hunger-driven feeding, but not during non-hunger driven feeding,” Xu said.

The other is a potassium channel that influences feeding triggered by hunger-independent cues, but not hunger-driven feeding. “There is a clear segregation of these two ion channels,” Xu said. “They have distinct functions in feeding behavior, which suggests they also could be target candidates to regulate overeating.”

The findings have encouraged the researchers to conduct future studies to identify more molecules that could modulate the activity of the ion channels to produce anti-overeating effects in animal models. “We also want to explore how external factors related to nutrition might affect ion channel functions at the molecular level,” Xu said.

The following authors also contributed to this work: Yanlin He, Xing Cai, Hailan Liu, Kristine M. Conde, Pingwen Xu, Yongxiang Li, Chunmei Wang, Meng Yu, Yang He, Hesong Liu, Chen Liang, Tingting Yang, Yongjie Yang, Kaifan Yu, Julia Wang, Rong Zheng, Feng Liu, Zheng Sun, Lora Heisler, Qi Wu, Qingchun Tong, Canjun Zhu and Gang Shu. The authors are affiliated with one or more of the following institutions: Baylor College of Medicine, South China Agricultural University, University of Texas Health at San Antonio, University of Aberdeen and University of Texas Health Science Center at Houston.

The investigators were supported by grants from the NIH (R01DK114279, R01DK109934, R21NS108091, R01ES027544, R01DK111436, R00DK107008, R01DK109194, R56DK109194, P01DK113954, R01DK115761, R01DK117281, R01DK125480, R01DK120858, K01DK119471 and P20GM135002).

Further support was provided by USDA/CRIS (51000-064-01 S), American Diabetes Association (1-17-PDF-138, 7-13-JF-61 and 1-15-BS-184), American Heart Association awards (16POST27260254), the Pew Charitable Trust awards (0026188), Baylor Collaborative Faculty Research Investment Program grants, the Faculty Start-up grants from USDA/ARS, the Biotechnology and Biological Sciences Research Council (BB/K001418/1 and BB/NO17838/1), the Medical Research Council (MC/PC/15077), a Pew Scholarship of Biomedical Sciences and a Kavli Scholarship.

Reference: He, Y., Cai, X., Liu, H. et al. 5-HT recruits distinct neurocircuits to inhibit hunger-driven and non-hunger-driven feeding. Mol Psychiatry (2021). https://doi.org/10.1038/s41380-021-01220-z

Provided by BCM

What Should I Eat To Avoid Heart Disease? (Food)

Plant-based foods should dominate heart healthy diets, according to a paper published today in Cardiovascular Research, a journal of the European Society of Cardiology (ESC). This comprehensive review of research on food and heart disease provides updated evidence on how much, and how often, each item can be safely consumed.

“There is no indication that any food is poison in terms of cardiovascular risk. It’s a matter of quantity and frequency of consumption,” said study author Professor Gabriele Riccardi of the University of Naples Federico II, Italy. “A mistake we made in the past was to consider one dietary component the enemy and the only thing we had to change. Instead, we need to look at diets as a whole and if we reduce the amount of one food, it is important to choose a healthy replacement.”

Overall, there is consistent evidence that for healthy adults, low consumption of salt and foods of animal origin, and increased intake of plant-based foods – including whole grains, fruits, vegetables, legumes and nuts – are linked with reduced risk of atherosclerosis. The same applies to replacing butter and other animal fats with non-tropical vegetable fats such as olive oil.

New evidence differentiates processed and red meat – both associated with increased risk of cardiovascular disease – from poultry, which shows no relationship at moderate intakes (up to three servings of 100 g per week). Red meat (i.e. beef, pork, lamb) should be limited to two servings of 100 g per week, and processed meat (i.e. bacon, sausages, salami) limited to occasional use.

Legumes (up to four servings of 180 g per week) are the recommended protein replacement for red meat. Moderate fish consumption (two to four servings of 150 g per week) is also supported by the latest evidence for prevention of heart disease, although there might be sustainability concerns. Poultry may be a suitable protein alternative to red meat, but in moderate amounts.

As for fruits and vegetables, given their strong association with a lower risk of atherosclerosis, daily consumption should be increased to as much as 400 g for each. Regarding nuts, a handful (around 30 g) per day is recommended.

For the healthy population, recent evidence does not support a requirement to use low-fat, instead of full-fat, dairy products to prevent heart disease. Rather, both full-fat and low-fat dairy products, in moderate amounts and in the context of a balanced diet, are not associated with increased risk.

“Small quantities of cheese (three servings of 50 g per week) and regular yogurt consumption (200 g per day) are even linked with a protective effect due to the fact that they are fermented,” said Professor Riccardi. “We now understand that gut bacteria play a major role in influencing cardiovascular risk. Fermented dairy products contain good bacteria which promote health.”

With respect to cereals, novel advice is given according to the glycaemic index (GI), where high GI foods raise blood sugar more quickly than low GI foods. High GI foods (i.e. white bread, white rice) are associated with an elevated atherosclerosis risk; therefore, consumption should be limited to two servings per week and they should otherwise be replaced with whole grain foods (i.e. bread, rice, oat, barley) and low GI foods (i.e. pasta, parboiled rice, corn tortilla).

As for beverages, coffee and tea (up to three cups daily) are associated with reduced cardiovascular risk. Soft drinks, including low-calorie options, are linked with higher risk and should be replaced with water except on limited occasions. Moderate alcohol consumption (wine: up to two glasses per day in men and one glass in women; or one can of beer) is associated with a lower risk of heart disease compared to higher amounts or abstinence. But Professor Riccardi said: “Considering the overall impact of alcohol on health, this evidence should be interpreted as the maximal allowed intake rather than a recommended amount.”

Regarding chocolate, the available evidence allows up to 10 g of dark chocolate per day. The authors state that “for this amount of consumption the beneficial effects exceed the risk of weight gain and its related harmful consequences on cardiovascular health”.

Professor Riccardi noted that eating should be enjoyable to motivate healthy people to make long-term changes. He said: “We need to rediscover culinary traditions such as the Mediterranean diet which has delicious recipes using beans, whole grains, nuts, fruits and vegetables.”

The authors concluded: “A strategy based exclusively on guidelines and nutritional education will not be sufficient to change the lifestyle of the population; policy options to be considered should necessarily include initiatives to facilitate production, marketing, availability and affordability of foods that are not only healthy but also gastronomically appealing.”

Reference: Gabriele Riccardi, Annalisa Giosuè, Ilaria Calabrese, Olga Vaccaro, Dietary recommendations for prevention of atherosclerosis, Cardiovascular Research, 2021;, cvab173, https://doi.org/10.1093/cvr/cvab173

Provided by European Society of Cardiology

What Happens In the Brain Of Flies and Maybe, People when They Choose Their Food? (Neuroscience)

Flies have discriminating taste. Like a gourmet perusing a menu, they spend much of their time seeking sweet nutritious calories and avoiding bitter, potentially toxic food. But what happens in their brains when they make these food choices?

Yale researchers discovered an interesting way to find out. They tricked them.

In a study that could also help illuminate how people make food choices, the researchers gave hungry fruit flies the choice between sweet, nutritious food laced with bitter quinine and a less sweet, but not bitter, food containing fewer calories. Then, using neuroimaging, they tracked neural activity in their brains as they made these tough choices.

So which won? Calories or better taste?

“It depends on how hungry they are,” said Michael Nitabach, professor of cellular and molecular physiology, genetics, and neuroscience at Yale School of Medicine and senior author of the study. “The hungrier they are, the more likely they will tolerate bitter taste to obtain more calories.”

But the real answer to how flies make these decisions is a little more complex, according to the study published July 5 in the journal Nature Communications.

According to the research team, led by Preeti Sareen, associate research scientist at Yale, flies relay sensory information to a portion of their brain called the fan-shaped body, where signals are integrated, triggering what amounts to the insect version of an executive decision. The researchers found that patterns of neuronal activity in the fan-shaped body change adaptively when novel food choices are introduced, which dictates the fly’s decision over what food to eat.

But researchers went a step further. And things got even stranger. They found they could change a fly’s choice by manipulating neurons in areas of the brain that feed into the fan-shaped body. For example, when they caused a decrease in activity in the neurons involved in metabolism, the found that it made hungry flies choose the lower calorie food.

“It is one big feedback loop, not just top-down decision making,” Nitabach said.

And this is where there are connections to food choices of humans, he said. Neural activity in both a fly’s brain and a human’s brain are regulated by the secretion of neuropeptides and the neurotransmitter dopamine, which in humans helps regulate sensations of reward. Changes in this network may alter how the brain responds to different types of food. In other words, neurochemistry may sometimes dictate food choices we think we are making consciously.

“The study provides a template to understand how it is that things like hunger and internal emotional states influence our behavior,” Nitabach said.

Sareen and Li Yan McCurdy, a graduate student at Yale School of Medicine, are co-authors of the paper.

Reference: Sareen, P.F., McCurdy, L.Y. & Nitabach, M.N. A neuronal ensemble encoding adaptive choice during sensory conflict in Drosophila. Nat Commun 12, 4131 (2021). https://doi.org/10.1038/s41467-021-24423-y

Provided by Yale University

Plant-based Diet Protects From Hypertension, Preeclampsia (Food)

A plant-based diet appears to afford significant protection to rats bred to become hypertensive on a high-salt diet, scientists report. When the rats become pregnant, the whole grain diet also protects the mothers and their offspring from deadly preeclampsia.

Although we have all heard to avoid the salt shaker, an estimated 30-50% of us have a significant increase in blood pressure in response to high-salt intake, percentages that are even higher and more impactful in Blacks.

The two new studies provide more evidence that the gut microbiota, which contains trillions of microorganisms that help us digest food and plays a key role in regulating the response of our immune system, is also a player in the unhealthy response to salt, investigators at the Medical College of Georgia and Medical College of Wisconsin report in the journals ACTA PHYSIOLOGICA and Pregnancy Hypertension: An International Journal of Women’s Cardiovascular Health.

The findings provide more evidence of the “potential power” of nutritional intervention to improve the gut microbiota, and consequently our long-term health, says Dr. David L. Mattson, chair of the MCG Department of Physiology, Georgia Research Alliance Eminent Scholar in Hypertension and senior author on the two studies.

They result from the unexpected observation that the protection works even in a well-established model of salt-sensitive hypertension: The Dahl salt sensitive rat.

As their name indicates, these rodents are bred to develop hypertension and progressive kidney disease on a high-salt diet. In 2001, the Medical College of Wisconsin shared their colony of Dahl SS rats, who were fed a milk-based protein diet, with Charles Rivers Laboratories. Once the rats arrived as Charles River Laboratories, headquartered in Wilmington, Massachusetts, they were switched to a grain-based diet. Both diets are relatively low in sodium, although the protein, or casein-based, diet actually has a little less salt.

It was soon noted that when high-salt content was added to their diet, the relocated rodents developed significantly less high blood pressure and related kidney damage than the rat colonies that remained in Wisconsin.

“People ordered them and used them with the idea that they were going to study hypertension and they developed next to none,” Mattson says. More than a decade of research documented these differences, Mattson and his colleagues at MCG and MCW write, and now has shown them that developing salt-sensitive hypertension isn’t just about sodium consumption.

“The animal protein amplified the effects of the salt,” says Mattson, a longtime hypertension researcher, who along with Dr. Justine M. Abais-Battad, physiologist, and postdoc Dr. John Henry Dasinger, came to MCG from Wisconsin two summers ago.

“Since the gut microbiota has been implicated in chronic diseases like hypertension, we hypothesized that dietary alterations shift the microbiota to mediate the development of salt-sensitive hypertension and renal disease,” they write in the journal ACTA PHYSIOLOGICA.

The gut microbiome is designed to metabolize what we eat, break it down and put it in a form that gives us nutrition, first author Abais-Battad says, and reciprocally it reflects what we eat.

When they looked at the microbiomes in the rats: “Sure enough, they were different,” she says.

They sequenced the genetic material of both rat colonies and found they were “virtually identical,” but their response to a high-salt diet was anything but, Mattson says.

As they anticipated at this juncture, the Wisconsin rats developed renal damage and inflammation — both indicators of high blood pressure — but on the same high-salt diet, the Charles River rats experienced significantly less of these unhealthy results. The distinct differences they saw in their microbiota, reflected the difference in disease incidence and severity.

When they gave the protected rats some of the distinctive gut microbiota from the Wisconsin rats, via fecal transplant, the rats experienced increases in blood pressure, kidney damage and in the number of immune cells moving into the kidneys, organs which play a huge role in blood pressure regulation by regulating fluid balance, in part by determining how much sodium is retained. It also changed the composition of their microbiota.

But when they shared the microbiota of the protected rats with the Wisconsin rats, it didn’t have much impact, potentially because the new microorganisms couldn’t flourish in the face of the animal-based protein diet, the scientists say.

Preeclampsia is a potentially lethal problem during pregnancy where the mother’s blood pressure, which typically was normal before, soars and organs like the kidneys and liver show signs of damage. There is evidence that even on a low-salt diet, Dahl salt sensitive rats are inclined to develop preeclampsia.

To look at the impact of diet in this scenario, the Dahl SS rats were kept on their respective plant- or animal-based protein diet, which again are each relatively low salt, and both groups had three separate pregnancies and deliveries.

Rats on the whole wheat based-chow were protected from preeclampsia while about half of the rats on the animal-based casein diet developed this significant complication of pregnancy, says Dasinger, first author on the preeclampsia study. They experienced a significant increase in the protein spilled into their urine, an indicator of kidney trouble, which worsened with each pregnancy; increased inflammation, a driver of high blood pressure; increased pressure inside the renal artery; and showed significant signs of kidney destruction when the organs were studied on follow up. They died of problems like stroke, kidney disease and other cardiovascular problems.

“This means that if mom is careful with what she eats during pregnancy, it will help during the pregnancy, but also with her long-term health and could provide protective effects for her children,” Dasinger says. The scientists note this reinforces the message that physicians and scientists alike have been sending mothers-to-be for decades.

They plan to look more directly at the impact of diet on offspring and whether protection is passed to the babies through breast milk, Dasinger says. Since they know that the function of immune cells is affected by diet, they also want to look further at the function of the immune cells that show up and already have some evidence that T cells, drivers of the immune response, are a factor in the development of preeclampsia.

The work Abais-Battad, Dasinger and Mattson already have done shows that a key difference the different diets yield is the protein-based diet results in production of more proinflammatory molecules, where the plant-based diet actually seems to suppress these factors.

They also are further exploring the impact of diet of the renin-angiotensin system, which helps regulate blood pressure. They also want to better dissect the blood pressure-raising bacteria and the factors they produce.

High blood pressure is the largest modifiable risk factor for development of cardiovascular disease, and, according to the newest guidelines from groups like the American Heart Association, which say a systolic, or top number of 120+ is elevated and top numbers of 130-139 is stage one hypertension, nearly half of us are hypertensive. Diet — including a high-salt diet — is one of the top modifiable risk factors for high blood pressure and cardiovascular disease, the scientists say. Hypertensive humans and animals alike have been found to have an unbalanced, less diverse gut microbiota than those with normal blood pressure.

The research was supported by the National Heart, Lung and Blood Institute, the American Heart Association and the Georgia Research Alliance.

Read the studies here and here.

Featured image: (from left) Drs. John Henry Dasinger, Justine M. Abais-Battad and David L. Mattson. © Michael Holahan, Augusta University

Provided by Medical University of Georgia at Augusta University

How a Vietnamese Raw Pork Snack Could Help Us Keep Food Fresh, Naturally (Food)

Fermented meat snack is helping researchers develop a safe, all-natural food preservative

A traditional Vietnamese meat snack could hold the key to developing a safe and natural food preservative, addressing the twin global problems of food waste and food-borne illnesses.

Key Points

  • Bacteria-killing compound discovered in Nem Chua, a fermented pork snack
  • Toxic to bacteria but safe for humans, it’s a natural alternative to artificial food preservatives
  • New study reveals ideal growth conditions to potentially make the bacteria-killer at industrial scales

The fermented pork snack, Nem Chua, is eaten raw but does not cause food poisoning when prepared correctly.

This is because friendly bacteria that thrive in the fermented meat make a special compound that destroys more dangerous bacteria.

Now researchers at RMIT University in Melbourne, Australia, have shown how this natural bacteria-killing compound could be used to keep food fresh for longer.

Food waste is a global issue that costs around $US680 billion annually in industrialised countries, consumes nearly a quarter of the water used in agriculture and produces 8% of global greenhouse emissions.

Food-borne diseases like Listeria or Salmonella affect millions each year and can be life threatening for pregnant women, older people and those who are immunocompromised.

Listeria bacteria (green) dying after exposure to Plantacyclin B21AG. The bumps visible on many of the cells are the cell contents beginning to leak out. © Dr Elvina Parlindungan

Co-lead researcher Professor Oliver Jones said changes in consumer habits have led to a greater demand for natural alternatives to artificial food preservatives.

“Scientists have known about these bacteria-killing compounds for many years but the challenge is to produce them in large enough quantities to be used by the food industry,” said Jones, Associate Dean of Biosciences and Food Technology at RMIT.

“The Nem Chua compound is colourless, odourless, tasteless and very resilient.

“Through this new research, we’ve identified the right growth conditions that would enable us to make it in large amounts, potentially at industrial scales.

“With further development, we hope this could be an effective, safe and all-natural solution for both food waste and food-borne disease.”

Bacteria-killing weapon

A team of RMIT researchers was inspired to investigate Nem Chua for its potential antibacterial properties after travelling to Vietnam and observing people eating the raw meat snack without getting sick, despite the hot and humid climate.

The team, led by Professor Andrew Smith (now at Griffith University) and Dr Bee May, discovered a new type of bacteria-killing compound in Nem Chua.

Plantacyclin B21AG is one of a group of compounds known as bacteriocins, which are produced by bacteria to destroy rival bacterial strains.

Bacteriocins form holes in the membranes of target bacteria. This causes the contents of the cell to leak out – effectively killing the bacteria.

The problem is most bacteriocins only work against one or two types of bacteria and they are not very stable in different environmental conditions.

Only one – Nisin, which came to market in the 1960s – is currently licensed for use as a food preservative, in a market estimated to be worth more than $US513 million in 2020, but this compound is temperature and pH sensitive limiting its use.

Tough and effective

The Nem Chua-derived compound is more robust than Nisin and is effective against a wide range of bacteria even after exposure to a range of environments typical in food processing.

It can survive being heated to 90°C for 20 minutes and remains stable across high and low pH levels.

Left: Listeria bacteria, alive and with intact cell membranes. Right: The same bacteria after exposure to Plantacyclin B21AG, dead and with the cell membranes destroyed. © Dr Elvina Parlindungan

The compound can also destroy a range of disease-causing organisms commonly found in food including potentially life-threating Listeria, which can survive refrigeration and even freezing.

Co-lead researcher Dr Elvina Parlindungan, who completed the new study as part of her PhD research at RMIT, is now a postdoctoral fellow at APC Microbiome, part of University College Cork in Ireland.

“Using bacteriocins as food preservatives effectively means we are turning bacteria’s own toxic weapons against them – harnessing nature’s smart solutions to tackle our big challenges,” Parlindungan said.

“In the future, these compounds might also be useful as an antibiotic in human medicine.”

Researchers at RMIT’s School of Science have begun experimenting with methods to further purify the compound and are planning to incorporate it into test food products.

The team is keen to collaborate with potential industry partners to further develop the technology.

This work was supported by a PhD scholarship from the Indonesian Endowment Fund for Education (LPDP), part of the Ministry of Finance of the Republic of Indonesia, awarded to Parlindungan.

Factors that influence growth and bacteriocin production in Lactiplantibacillus plantarum B21,’ with co-author Dr Chaitali Dekiwadia (RMIT Microscopy and Microanalysis Facility), is published in Process Biochemistry (DOI:10.1016/j.procbio.2021.05.009).

Featured image: Vietnamese fermented pork snack, Nem Chua. © RMIT University

Reference: Elvina Parlindungan, Chaitali Dekiwadia, Oliver A.H. Jones, Factors that influence growth and bacteriocin production in Lactiplantibacillus plantarum B21, Process Biochemistry, Volume 107, 2021, Pages 18-26, ISSN 1359-5113, https://doi.org/10.1016/j.procbio.2021.05.009. (https://www.sciencedirect.com/science/article/pii/S1359511321001525)

Provided by RMIT University

Can Regulating A Novel Brain Circuit Help Control Obesity? (Neuroscience)

Like a good story, feeding has a beginning, a middle and an end. It begins with appetite prompting the search for food, continues with eating the food and it ends when satiation hits and the consumption of food is stopped. At Baylor College of Medicine, Dr. Qi WuDr. Yong Han and their colleagues have uncovered new aspects of the last part of this story that relate to the little-known neural circuits and neurotransmitters involved in ending food consumption.

The team discovered a novel circuit that connects a unique subset of dopamine-producing neurons with downstream neurons in the hindbrain (lower brainstem) and potently suppresses food intake by triggering satiation in mice. They also found that the FDA-approved drug methylphenidate (MPH) mediates its noticeable weight loss effect by activating this particular circuit, opening the possibility that regulating this circuit might help people control weight. The study appears in the journal Sciences Advances.

“Many people struggle with weight control, eating more than what the body needs, which adds extra pounds that can lead to obesity and higher risk of serious conditions such as heart disease, stroke and type 2 diabetes,” said Han, a postdoctoral associate in pediatrics-nutrition in the Wu lab and the first author of this study. “Our lab is interested in improving our understanding of what goes on in the brain during feeding with the hope that our findings might one day help people better control their weight.”

New insights into brain regulation of the satiation response

“The current study is about a circuit in the brain that helps to precisely regulate the size of the food portion that is consumed,” said Wu, assistant professor in pediatrics-nutrition and the corresponding author of the study. “It is not about how eating begins but about how it ends. It’s about the satiation response, which is as important as appetite.”

Using several advanced techniques to study neural function, including cell-specific circuitry mapping, optogenetics and real-time recordings of brain activity, the researchers discovered a novel neural circuit that connects a unique group of dopamine-producing neurons called DA-VTA with downstream target neurons known as DRD1-LPBN and regulates food consumption in mice.

The team examined the activities of the two sets of neurons while the mice were eating. They observed that the activity of these DA-VTA neurons increased immediately before the animals stopped eating. When the researchers genetically inhibited these neurons, the animals prolonged their feeding, drastically increasing the portion size. This suggests that inhibiting the circuit prevented the satiation response. They also found that enhancing the activity of the DRD1-LPBN neurons, which receive signals from the DA-VTA neurons, robustly generated the response of meal termination.

The researchers also found that the novel circuit mediated the weight loss effect that is associated with taking the drug MPH, which is approved for mitigation of attention deficit hyperactivity disorder.

“Other brain circuits have been proposed to regulate feeding, but the one we discovered is the first to be fully described to regulate portion size via dopamine signaling,” Han said. “Our new study shows that a circuit connecting neurons that produce dopamine, a chemical messenger previously known for the regulation of motivation and pleasure, has a new role in the control of feeding through dynamically regulating the satiety response.”

“Our finding that MPH suppresses feeding and reduces body weight in laboratory mice by strengthening the dopamine-supported novel circuit we discovered, suggests a potential off-label application of a class of MPH and derivatives in tackling obesity,” Wu said. “This also has implications for the future development of circuitry-based precision medicine that can deliver weight-reducing results with higher safety and effectiveness.”.

Guobin Xia, Yanlin He, Yang He, Monica Farias and Yong Xu, all at Baylor College of Medicine, also contributed to this work.

This project was supported by funding from a Shared Instrumentation grant from the NIH (S10 599 OD016167), the NIH Digestive Diseases Center PHS grant P30 DK056338, NIH grants (R01DK109194, R56DK109194), the Pew Charitable Trust award (0026188), American Diabetes Association awards (#7-13-JF-61), Baylor Collaborative Faculty Research Investment Program grants and USDA/CRIS grants (3092-5-001-059). Further support was provided by the Faculty Start-up grants from USDA/ARS NIH grants (R01DK093587, R01DK101379, and R01DK117281), USDA/CRIS grants (3092-5-001-059), American Heart Association awards (17GRNT32960003), American Diabetes Association (1-17-PDF-138), the NIH Centers of Biomedical Research Excellence (COBRE) grant P20 GM135002, a Pew Scholarship of Biomedical Sciences and a Kavli Scholarship.

Reference: Yong Han, Guobin Xia, Yanlin He et al., “A hindbrain dopaminergic neural circuit prevents weight gain by reinforcing food satiation”, Science Advances  26 May 2021: Vol. 7, no. 22, eabf8719 DOI: 10.1126/sciadv.abf8719

Provided by Baylor College of Medicine

Eating More Fruit and Vegetables Linked to Less Stress (Food)

Eating a diet rich in fruit and vegetables is associated with less stress, according to new research from Edith Cowan University (ECU).

The study examined the link between fruit and vegetable intake and stress levels of more than 8,600 Australians aged between 25 and 91 participating in the Australian Diabetes, Obesity and Lifestyle (AusDiab) Study from Baker Heart and Diabetes Institute.

The findings revealed people who ate at least 470 grams of fruit and vegetables daily had 10 per cent lower stress levels than those who consumed less than 230 grams. The World Health Organization (WHO) recommends eating at least 400 grams of fruit and vegetables per day.

Lead researcher, PhD candidate Simone Radavelli-Bagatini from ECU’s Institute for Nutrition Research, said the study strengthens the link between diets rich in fruit and vegetables and mental wellbeing.

“We found that people who have higher fruit and veggie intakes are less stressed than those with lower intakes, which suggests diet plays a key role in mental wellbeing,” said Ms Radavelli-Bagatini.

A growing issue

Mental health conditions are an increasing problem in Australia and around the world. Around one in two Australians will experience a mental health issue in their lifetime. Globally, approximately 1 in 10 people live with a mental health disorder.

According to Ms Radavelli-Bagatini, some stress is considered normal, but long-term exposure can significantly impact mental health.

“Long-term and unmanaged stress can lead to a range of health problems including heart disease, diabetes, depression and anxiety so we need to find ways to prevent and possibly alleviate mental health problems in the future,” said Ms Radavelli-Bagatini.

The benefits of a healthy diet are well known, but only 1 in 2 Australians eat the recommended two serves of fruit per day and fewer than 1 in 10 eat the recommended five serves of vegetables each day.

“Previous studies have shown the link between fruit and vegetable consumption and stress in younger adults, but this is the first time we’re seeing similar results across adults of all ages,” said Ms Radavelli-Bagatini.

“The study’s findings emphasise that it’s important for people to have a diet rich in fruit and vegetables to potentially minimise stress.”

Food and mood

While the mechanisms behind how fruit and vegetable consumption influences stress are still unclear, Ms Radavelli-Bagatini said key nutrients could be a factor.

“Vegetables and fruits contain important nutrients such as vitamins, minerals, flavonoids and carotenoids that can reduce inflammation and oxidative stress, and therefore improve mental wellbeing,” she said.

“Inflammation and oxidative stress in the body are recognised factors that can lead to increased stress, anxiety and lower mood.”

“These findings encourage more research into diet and specifically what fruits and vegetables provide the most benefits for mental health.”

The research is part of ECU’s recently launched Institute for Nutrition Research, which aims to investigate how nutrition can help prevent and treat chronic health conditions.

‘Fruit and vegetable intake is inversely associated with perceived stress across the adult lifespan’ was published in Clinical Nutrition.

Provided by Edith Cowan University

Compound Found in Some Vegetables May Reduce Diabetes-related Kidney Damage (Food)

Phenethyl isothiocyanate, derived from watercress and other cruciferous vegetables, shows benefits in rats

New research conducted in rats suggests a compound that gives some cruciferous vegetables their pungent taste could help to reverse kidney problems associated with diabetes.

It is estimated that about one-quarter of people with diabetes will eventually develop diabetic nephropathy, a gradual loss of kidney function eventually requiring dialysis. The condition is a leading cause of chronic kidney disease in the U.S. and is also associated with a high risk of heart disease. There is currently no cure.

For the new study, researchers assessed the effects of phenethyl isothiocyanate (PEITC) in rats with diabetic nephropathy. PEITC is found in several types of vegetables but is most concentrated in watercress.

“Our study provides, for the first time, evidence that PEITC might be effective as a naturally occurring agent to reverse serious kidney damage in people with diabetes,” said lead study author Mohamed El-Sherbiny, PhD, a postdoctoral fellow at AlMaarefa University in Riyadh, Saudi Arabia. “Our study introduces mechanistic evidence of how PEITC might manage kidney injury associated with diabetes by targeting multiple interconnected pathways involved in diabetic nephropathy, including inflammation, glycation and oxidative status.”

El-Sherbiny will present the research at the American Association for Anatomy annual meeting during the Experimental Biology (EB) 2021 meeting, held virtually April 27-30.

Previous studies have suggested sulforaphane, a related compound in cruciferous vegetables, also helps reduce diabetes-associated kidney damage. The new study bolsters the evidence that eating more vegetables containing these compounds could help people with diabetes to stave off kidney problems.

“PEITC seems to manage one of the most serious and painful diabetic complications. Luckily, PEITC is naturally present in many dietary sources, importantly watercress, broccoli, turnips and radish,” said El-Sherbiny.

Since the research was conducted in animal models, further studies will be needed to confirm the findings and understand how the results could translate to new treatments or dietary recommendations for people with diabetes.

El-Sherbiny will present this research from 3:45-4 p.m. Thursday, April 29 (abstract). Contact the media team for more information or to obtain a free press pass to access the virtual meeting.

Featured image: A schematic illustrating how PEITC treatment affected induced nephropathy in rats by modulating glycative stress, oxidative stress and inflammatory pathways. © Image courtesy of Mohamed El-Sherbiny, AlMaarefa University.

Provided by Experimental Biology

Vegetarian Diets Reduce Risk of Death from Heart Disease (Food)

Vegetarian diets reduce the risk of death from ischemic heart disease, according to a meta-analysis published in the American Journal of Preventive Cardiology. Researchers reviewed eight observational studies that compared vegetarian and nonvegetarian diets with mortality. Vegetarian diets, including vegan eating patterns, were associated with a 30% reduced risk of death from ischemic heart disease when compared to nonvegetarian diets. Vegetarian diets benefit risk factors for heart disease, including weight, cholesterol, and blood pressure levels. Vegetarian diets avoid animal products, which are often high in saturated fat, iron, and hormones. The authors recommend clinicians consider vegetarian diets as a cost-effective intervention for high-risk groups to reduce mortality from heart disease.


Jabri A, Kumar A, Verghese E, et al. Meta-analysis of Effect of Vegetarian Diet on Ischemic Heart Disease and All-cause Mortality. Am J Prev Cardiol. Published online April 9, 2021. doi: 10.1016/j.ajpc.2021.100182 

Provided by Physicians Committee for Responsible Medicine