The University of Reading

Eating a poor quality diet might lead to brain changes that are associated with depression and anxiety. This is according to a first-of-its-kind study into the brain chemistry and structure, and diet quality of 30 volunteers. Eating a poor quality diet might lead to brain changes that are associated with depression and anxiety. This is according to a first-of-its-kind study into the brain chemistry and structure, and diet quality of 30 volunteers. Brain scans show changes in neurotransmitters and grey matter volume in people who have a poor diet, versus those who adhere to a Mediterranean style diet, which is considered very healthy. The researchers also found that these changes are associated with rumination, a part of the diagnostic criteria for conditions affecting mental health, such as depression and anxiety. This research was carried out by the University of Reading, Roehampton University, FrieslandCampina (Netherlands), and Kings College London, and is published in Nutritional Neuroscience. When someone eats a poor quality diet, there is reduced gamma aminobutyric acid (GABA) and elevated glutamate -- both neurotransmitters, along with reduced grey matter volume -- in the frontal area of their brain. This could explain the association between what we eat, and how we feel. Dr Piril Hepsomali, University of Reading, said: "We can eat ourselves well! Ultimately, we see that people who have an unhealthy diet -- high in sugar and saturated fat -- have imbalanced excitatory and inhibitory neurotransmission, as well as reduced volume of grey matter in the frontal part of the brain. This part of the brain is involved in mental health issues such as depression and anxiety." The exact reason that diet affects the brain in this way is still under investigation. It's possible that obesity and dietary patterns that are high in saturated fats cause changes in glutamate and GABA metabolism and neurotransmission, as has been shown in animal studies. Distinct alterations of the gut microbiome, due to dietary patterns that are high in saturated fats, is thought to have an impact on cell machinery that drives both GABA and glutamate production. A high saturated fat, high sugar, diet has also been shown to reduce the number of parvalbumin interneurons, which perform the role of delivering GABA to where it is needed. Unhealthy diets also have an impact on glucose, making blood glucose and insulin higher. This increases glutamate in the brain and plasma, thus reducing GABA production and release. Having a diet high in fat and cholesterol can cause changes in cell membranes that alter the release of neurotransmitters, too. These changes in brain chemistry might lead to changes in the brain grey matter volume, as observed in this study. Dr Hepsomali continued: "I would like to note that GABA and glutamate are intimately involved in appetite and food intake, too. Reduced GABA and/or increased glutamate might also be a driving factor in making unhealthy food choices. So, there may be a circular relationship between eating well, having a healthier brain and better mental wellbeing, and making better food choices to eat well."

A new study calls into question Bergmann's rule, an 1800s-era scientific principle stating that animals in high-latitude, cooler climates tend to be larger than close relatives living in warmer climates. When you throw dinosaurs into the mix, sometimes you find that a rule simply isn't. A new study led by scientists at the University of Alaska Fairbanks and the University of Reading calls into question Bergmann's rule, an 1800s-era scientific principle stating that animals in high-latitude, cooler climates tend to be larger than close relatives living in warmer climates. The fossil record shows otherwise. "Our study shows that the evolution of diverse body sizes in dinosaurs and mammals cannot be reduced to simply being a function of latitude or temperature," said Lauren Wilson, a UAF graduate student and a lead author of a paper published today in the journal Nature Communications. "We found that Bergmann's rule is only applicable to a subset of homeothermic animals (those that maintain stable body temperatures), and only when you consider temperature, ignoring all other climatic variables. This suggests that Bergmann's 'rule' is really the exception rather than the rule." The study started as a simple question Wilson discussed with her undergraduate advisor: Does Bergmann's rule apply to dinosaurs? After evaluating hundreds of data points gleaned from the fossil record, the answer seemed a solid "no." The dataset included the northernmost dinosaurs known to scientists, those in Alaska's Prince Creek Formation. They experienced freezing temperatures and snowfall. Despite this, the researchers found no notable increase in body size for any of the Arctic dinosaurs. Next the researchers tried the same evaluation with modern mammals and birds, the descendants of prehistoric mammals and dinosaurs. The results were largely the same: Latitude was not a predictor of body size in modern bird and mammal species. There was a small relationship between the body size of modern birds and temperature, but the same was not the case for prehistoric birds. The researchers say the study is a good example of how scientists can and should use the fossil record to test current-day scientific rules and hypotheses. "The fossil record provides a window into completely different ecosystems and climate conditions, allowing us to assess the applicability of these ecological rules in a whole new way," said Jacob Gardner, a postdoctoral researcher at the University of Reading and the other lead author of the paper. Scientific rules should apply to fossil organisms in the same way they do modern organisms, said Pat Druckenmiller, director of the University of Alaska Museum of the North and one of the co-authors of the paper. "You can't understand modern ecosystems if you ignore their evolutionary roots," he said. "You have to look to the past to understand how things became what they are today."

Models suggest summer rainfall in southern Europe could decline by up to 48% by the year 2100 if emissions of greenhouse gases continue to rise rapidly. Rapid climate action could mean devastating dry periods in the Mediterranean become less frequent by the end of the century, a new study shows. Advanced computer modelling suggests summer rainfall in southern Europe could decline by up to 48% by the year 2100 if emissions of greenhouse gases continue to rise rapidly, but much of this projected decline could be avoided by reaching net-zero emissions as soon as possible. The study, led by scientists at the University of Reading, published today (Monday 25 March) in Geophysical Research Letters, provides additional evidence to motivate accelerated climate action and prevent drastic rainfall decline, more droughts and more forest fires. Dr Andrea Dittus, the study's lead author, said: "The climate has already warmed so much that some rainfall decline is inevitable, but our findings show that further summer drying projected for Europe could be avoided. Halting rising global temperatures by reducing fossil fuel emissions to net-zero will mean the Mediterranean does not continue to get drier. "We have no time to waste in cutting emissions. If we don't act rapidly, many countries in the Mediterranean will suffer from a significant lack of rain, with potential major knock-on effects for the UK and elsewhere." Slowing global warming In July 2023, Dr Dittus was awarded £580,000 by the UKRI Natural Environment Research Council to investigate what a net zero world would look like. Many previous studies have investigated the impact on Earth at different levels of global warming, but studying net zero climates is a relatively recent focus of research that follows commitments by world leaders -- such as in the 2015 Paris Agreement -- to limit global warming. The new study focuses specifically on the impact of stabilising temperatures in Europe. The researchers highlight that the speed of global warming is a critical factor in preventing drought and extreme dry periods. When temperatures rise quickly due to unchecked emissions, it causes more extreme shifts in rainfall. But if warming happens more gradually because of strong climate action, the impacts are less severe. This means that the steps taken by countries to cut pollution in the coming years could hugely influence Europe's future summers. While focused on Europe, the scientists say similar benefits of rapid climate action are likely for other regions across the world. However, the researchers caution that avoiding the most serious impacts depends on achieving major emissions reductions starting right away. The more optimistic scenarios are only possible if the world transitions away from fossil fuels as soon as possible.