Corporal punishment can be simply defined as the "intentional infliction of physical pain by any means for the purpose of punishment, correction, discipline, instruction, or any other reason." This violence, particularly when inflicted by a parent, evokes a complex emotional experience. The researchers, led by Kreshnik Burani, MS, and working with Greg Hajcak, PhD, at Florida State University, wanted to understand the neural underpinnings of that experience and its downstream consequences.

The study appears in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier.

The researchers conducted a longitudinal study on 149 boys and girls ages 11 to 14 from the Tallahassee, FL, area. Participants performed a video game-like task and a monetary guessing game while undergoing continuously recorded electroencephalography, or EEG -- a noninvasive technique to measure brain-wave activity from the scalp. From the EEG data, the researchers determined two scores for each participant -- one reflecting their neural response to error and the other reflecting their neural response to reward.

Two years later, participants and their parents completed a series of questionnaires to screen for anxiety and depression and to assess parenting style. As expected, kids who had experienced corporal punishment were more likely to develop anxiety and depression.

"Our paper first replicates the well-known negative effect that corporal punishment has on a child's wellbeing: we found that corporal punishment is associated with increased anxiety and depressive symptoms in adolescence. However, our study goes further to demonstrate that corporal punishment might impact brain activity and neurodevelopment," said Burani.

That was reflected by larger neural response to error and a blunted response to reward in the adolescents who received physical punishments.

"Specifically," Burani added, "our paper links corporal punishment to increased neural sensitivity to making errors and decreased neural sensitivity to receiving rewards in adolescence. In previous and ongoing work with Dr. Hajcak, we see that increased neural response to errors is associated with anxiety and risk for anxiety, whereas decreased neural response to rewards is related to depression and risk for depression. Corporal punishment, therefore, might alter specific neurodevelopmental pathways that increase risk for anxiety and depression by making children hypersensitive to their own mistakes and less reactive to rewards and other positive events in their environment."

Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the findings, "Using EEG, this study provides new insights into the mechanisms that may underlie the adverse effects of corporal punishment on mental health in children as well as the neural systems that may be affected."

The work provides new clues as to the neural underpinnings of depression and anxiety and could help guide interventions for at-risk youth.

The study was led by a team of researchers: Dr. Irit Zohar, a researcher at TAU's Steinhardt Museum of Natural History and curator of the Beit Margolin Biological Collections at Oranim Academic College, and HU Professor Naama Goren-Inbar, director of the excavation site. The research team also included Dr. Marion Prevost at HU's Institute of Archaeology; Prof. Nira Alperson-Afil at BIU's Department for Israel Studies and Archaeology; Dr. Jens Najorka of the Natural History Museum in London; Dr. Guy Sisma-Ventura of the Israel Oceanographic and Limnological Research Institute; Prof. Thomas Tütken of the Johannes Gutenberg University in Mainz and Prof. Israel Hershkovitz at TAU's Faculty of Medicine.

Dr. Zohar and Dr. Prevost: "This study demonstrates the huge importance of fish in the life of prehistoric humans, for their diet and economic stability. Further, by studying the fish remains found at Gesher Benot Ya'aqob we were able to reconstruct, for the first time, the fish population of the ancient Hula Lake and to show that the lake held fish species that became extinct over time. These species included giant barbs (carp like fish) that reached up to 2 meters in length. The large quantity of fish remains found at the site proves their frequent consumption by early humans, who developed special cooking techniques. These new findings demonstrate not only the importance of freshwater habitats and the fish they contained for the sustenance of prehistoric man, but also illustrate prehistoric humans' ability to control fire in order to cook food, and their understanding the benefits of cooking fish before eating it."

In the study, the researchers focused on pharyngeal teeth (used to grind up hard food such as shells) belonging to fish from the carp family. These teeth were found in large quantities at different archaeological strata at the site. By studying the structure of the crystals that form the teeth enamel (whose size increases through exposure to heat), the researchers were able to prove that the fish caught at the ancient Hula Lake, adjacent to the site, were exposed to temperatures suitable for cooking, and were not simply burned by a spontaneous fire.

Until now, evidence of the use of fire for cooking had been limited to sites that came into use much later than the GBY site -- by some 600,000 years, and ones most are associated with the emergence of our own species, homo sapiens.

Prof. Goren-Inbar added: "The fact that the cooking of fish is evident over such a long and unbroken period of settlement at the site indicates a continuous tradition of cooking food. This is another in a series of discoveries relating to the high cognitive capabilities of the Acheulian hunter-gatherers who were active in the ancient Hula Valley region. These groups were deeply familiar with their environment and the various resources it offered them. Further, it shows they had extensive knowledge of the life cycles of different plant and animal species. Gaining the skill required to cook food marks a significant evolutionary advance, as it provided an additional means for making optimal use of available food resources. It is even possible that cooking was not limited to fish, but also included various types of animals and plants."

Prof. Hershkovitz and Dr. Zohar note that the transition from eating raw food to eating cooked food had dramatic implications for human development and behavior. Eating cooked food reduces the bodily energy required to break down and digest food, allowing other physical systems to develop. It also leads to changes in the structure of the human jaw and skull. This change freed humans from the daily, intensive work of searching for and digesting raw food, providing them free time in which to develop new social and behavioral systems. Some scientists view eating fish as a milestone in the quantum leap in human cognitive evolution, providing a central catalyst for the development of the human brain. They claim that eating fish is what made us human. Even today, it is widely known that the contents of fish flesh, such as omega-3 fatty acids, zinc, iodine and more, contribute greatly to brain development.

The research team believe that the location of freshwater areas, some of them in areas that have long since dried up and become arid deserts, determined the route of the migration of early man from Africa to the Levant and beyond. Not only did these habitats provide drinking water and attracted animals to the area but catching fish in shallow water is a relatively simple and safe task with a very high nutritional reward.

The team posits that exploiting fish in freshwater habitats was the first step on prehistoric humans' route out of Africa. Early man began to eat fish around 2 million years ago but cooking fish -- as found in this study -- represented a real revolution in the Acheulian diet and is an important foundation for understanding the relationship between man, the environment, climate, and migration when attempting to reconstruct the history of early humans.

It should be noted that evidence of the use of fire at the site -- the oldest such evidence in Eurasia -- was identified first by BIU's Prof. Nira Alperson-Afil. "The use of fire is a behavior that characterizes the entire continuum of settlement at the site," she explained. "This affected the spatial organization of the site and the activity conducted there, which revolved around fireplaces." Alperson-Afil's research of fire at the site was revolutionary for its time and showed that the use of fire began hundreds of thousands of years before previously thought.

HU's Goren-Inbar added that the archaeological site of GBY documents a continuum of repeated settlement by groups of hunter-gatherers on the shores of the ancient Hula Lake which lasting tens of thousands of years. "These groups made use of the rich array of resources provided by the ancient Hula Valley and left behind a long settlement continuum with over 20 settlement strata," Goren-Inbar explained. The excavations at the site have uncovered the material culture of these ancient hominins, including flint, basalt, and limestone tools, as well as their food sources, which were characterized by a rich diversity of plant species from the lake and its shores (including fruit, nuts, and seeds) and by many species of land mammals, both medium-sized and large.

Dr. Jens Najorka of the Natural History Museum in London explained: "In this study, we used geochemical methods to identify changes in the size of the tooth enamel crystals, as a result of exposure to different cooking temperatures. When they are burnt by fire, it is easy to identify the dramatic change in the size of the enamel crystals, but it is more difficult to identify the changes caused by cooking at temperatures between 200 and 500 degrees Celsius. The experiments I conducted with Dr. Zohar allowed us to identify the changes caused by cooking at low temperatures. We do not know exactly how the fish were cooked but given the lack of evidence of exposure to high temperatures, it is clear that they were not cooked directly in fire, and were not thrown into a fire as waste or as material for burning."

Dr. Guy Sisma-Ventura of the Israel Oceanographic and Limnological Research Institute and Prof. Thomas Tütken of the Johannes Gutenberg University Mainz were also part of the research group, providing analysis of the isotope composition of oxygen and carbon in the enamel of the fishes' teeth. "This study of isotopes is a real breakthrough, as it allowed us to reconstruct the hydrological conditions in this ancient lake throughout the seasons, and thus to determine that the fish were not a seasonal economic resource but were caught and eaten all year round. Thus, fish provided a constant source of nutrition that reduced the need for seasonal migration."

The new study, in the latest issue of the journal Obesity conducted by the University of Sydney's Charles Perkins Centre (CPC), was based on a national nutrition and physical activity survey undertaken by the Australian Bureau of Statistics (ABS), and further backs the 'Protein Leverage Hypothesis'.

First put forward in 2005 by professors Raubenheimer and Stephen Simpson, the Protein Leverage Hypothesis argues that people overeat fats and carbohydrates because of the body's strong appetite for protein, which the body actively favours over everything else. Because so much of modern diets consist of highly processed and refined foods -- which are low in protein -- people are driven to consume more energy-dense foods until they satisfy their protein demand.

Processed foods lack protein and drive craving

"As people consume more junk foods or highly processed and refined foods, they dilute their dietary protein and increase their risk of being overweight and obese, which we know increases the risk of chronic disease," said lead author Dr Amanda Grech, a Postdoctoral Research Fellow at the CPC and the university's School of Life and Environmental Sciences.

"It's increasingly clear that our bodies eat to satisfy a protein target," added Professor David Raubenheimer, the Leonard Ullmann Chair in Nutritional Ecology at the School of Life and Environmental Sciences. "But the problem is that the food in Western diets has increasingly less protein. So, you have to consume more of it to reach your protein target, which effectively elevates your daily energy intake.

"Humans, like many other species, have a stronger appetite for protein than for the main energy-providing nutrients of fats and carbohydrates. That means that if the protein in our diet is diluted with fats and carbohydrates, we will eat more energy to get the protein that our bodies crave."

Protein essential to good health

Proteins are the building blocks of life: every cell in the body contains them, and they are used to repair cells or make new ones; and it's estimated that over a million forms of protein are needed to allow a human body to function. Protein sources include meats, milk, fish, eggs, soy, legumes, beans, and some grains such as wheat germ and quinoa.

The University of Sydney scientists analysed data from a cross-sectional survey of nutrition and physical activity in 9,341 adults, known as the National Nutrition and Physical Activity Survey which was conducted from May 2011 to June 2012, with a mean age of 46.3 years. They found the population's mean energy intake was 8,671 kilojoules (kJ), with the mean percentage of energy from protein being just 18.4 percent, compared with 43.5 percent from carbohydrates and from 30.9 percent from fat, and just 2.2 percent from fibre and 4.3 percent from alcohol.

They then plotted energy intake versus the time of consumption and found that the pattern matched that predicted by the Protein Leverage Hypothesis. Those who consumed lower amounts of protein in their first meal of the day went on to increase their overall food intake in subsequent meals, whereas those who received the recommended amount of protein did not -- and, in fact, declined their food intake throughout the day.

'Protein hunger' found to drive overeating

They also found a statistically significant difference between groups by the third meal of the day: those with a higher proportion of energy from protein at the start of the day had much lower total energy intake for the day. Meanwhile, those who consumed foods low in protein at the start of the day proceeded to increase consumption, indicating they were seeking to compensate with a higher consumption of overall energy. This is despite the fact the first meal was the smallest for both groups, with the least amount of energy and food consumed, whereas the last meal was the largest.

Participants with a lower proportion of protein than recommended at the first meal consumed more discretionary foods -- energy-dense foods high in saturated fats, sugars, salt, or alcohol -- throughout the day, and less of the recommended five food groups (grains; vegetables/legumes; fruit; dairy and meats). Consequently, they had an overall poorer diet at each mealtime, with their percentage of protein energy decreasing even as their discretionary food intake rose -- an effect the scientists call 'protein dilution'.

Effect seen in other studies

Professor Raubenheimer and colleagues have seen this effect before in other studies for more than a decade, including randomised control trials.

"The problem with randomised controlled trials is that it treats diet as a disease, when it's not," said Dr Grech. "Laboratory studies may not be indicative of what people are actually eating and doing at a population level. So this study is important as it builds on work, showing that people do seek out protein. And it confirms that, at a population level, as the proportion of energy from protein increases in the diet, people eat less fats and carbohydrates."

While many factors contribute to excess weight gain -- including eating patterns, physical activity levels, and sleep routines -- the University of Sydney scientists argue the body's powerful demand for protein, and its lack in highly processed and refined foods, is a key driver of energy overconsumption and obesity in the Western world.

Explanation for obesity

"The results support an integrated ecological and mechanistic explanation for obesity, in which low-protein, highly processed foods lead to higher energy intake in response to a nutrient imbalance driven by a dominant appetite for protein," said Professor Raubenheimer. "It supports a central role for protein in the obesity epidemic, with significant implications for global health."

Seeking to understand how protein drives human nutrition has also sought taken Professor Raubenheimer to study the diets of people in some of the most remote places, from the Congo to the Himalayas. "The protein mechanism in appetite is a revolutionary insight," he said. "Obesity, diabetes, cardiovascular disease -- they're all driven by diet, and we have to use what we're learning to bring them under control."

Story Source:Materials provided by University of Sydney. Note: Content may be edited for style and length.

Professor Ben Marsland from the Central Clinical School's Department of Immunology, together with Swiss colleagues at the University Hospital of Lausanne (CHUV), showed that the fermentation of fibre in the gut by bacteria and subsequent production of short-chain fatty acids (SCFAs), in particular butyrate, protected against atopic dermatitis in mice.

The research was published today in Mucosal Immunology.

While it is well established that the gut microbiome shapes the immune system, the influence it has on the skin is less explored.

"Previous work from our group, and others, has focused on the local health benefits of SCFAs in the gut as well as at distal sites such as the lung and cardiovascular system," Professor Marsland said. "We wondered if this might also extend to the skin, which is an area that has not really been investigated.

"People speculate that diet can influence skin health, but there is not a great deal of science behind this."

The researchers fed mice a diet high in fermentable fibre or gave them purified SCFAs. "This treatment was profoundly protective against allergic skin inflammation," Professor Marsland said.

They labelled the butyrate with isotopes and tracked it in the body -- it took only minutes to reach the skin where it enhanced the metabolism of keratinocytes, priming them to mature and produce the key structural components required for a healthy skin barrier.

"The upshot of this was that the skin barrier was fortified against allergens -- we were using house dust mite allergens -- that would normally penetrate the skin barrier, activate the immune system and start an allergic reaction in these models," he said.

"It turns out the immune system was secondary to this skin barrier function."

Actively improving the skin barrier could have protective effects against environmental exposures that cause allergies and perhaps even other skin diseases which are underpinned by a damaged or weak skin barrier. SCFAs could be administered orally or directly on the skin as a cream, bypassing the gut, he said.

"The fact that short-chain fatty acids can be given topically and are well-tolerated opens up possibilities for the development of preventative strategies or disease-modifying interventions -- that represents the most significant translational potential of our research."

One possibility to explore is whether this could help children who are at risk of developing skin allergies that cascade towards food allergies and asthma, the so-called 'Atopic March'.

Professor Marsland and members of his Melbourne-based team conducted the project over five or six years together with scientists at the University Hospital of Lausanne where he previously worked before being recruited to Monash. The lead author was Swiss-based Aurélien Trompette.Story Source:Materials provided by Monash University. Note: Content may be edited for style and length.