The study was conducted by Professor Frank Hu and colleagues at the Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA, and aimed to identify the metabolite profiles related to different plant-based diets and investigate possible associations between those profiles and the risk of developing T2D.

A metabolite is a substance used or produced by the chemical processes in a living organism and includes the vast number of compounds found in different foods as well as the complex variety of molecules created as those compounds are broken down and transformed for use by the body. Differences in the chemical makeup of foods means that an individual’s diet should be reflected in their metabolite profile. Recent technological advances in the field of high-throughput metabolomics profiling have ushered in a new era of nutritional research. Metabolomics is defined as the comprehensive analysis and identification of all the different metabolites present within a biological sample.

Over 90% of diabetes cases are the type 2 form, and the condition poses a major threat to health around the world. Global prevalence of the disease in adults has more than tripled in less than two decades, with cases increasing from around 150 million in 2000 to over 450 million in 2019 and projected to rise to around 700 million in 2045.

The global health burden of T2D is further increased by the numerous complications arising from the disease, both macrovascular, such as cardiovascular disease, and microvascular, which damage the kidneys, the eyes, and the nervous system. The diabetes epidemic is primarily caused by unhealthy diets, having overweight or obesity, genetic predisposition, and other lifestyle factors such as a lack of exercise. Plant-based diets, especially healthy ones rich in high quality foods such as whole grains, fruits, and vegetables, have been associated with a lower risk of developing T2D but the underlying mechanisms involved are not fully understood.

The team conducted an analysis of blood plasma samples and dietary intake of 10,684 participants from three prospective cohorts (Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study). Participants were predominantly white, middle-aged (mean age 54 years), and with a mean body mass index (BMI) of 25.6kg/m².

Study participants completed food frequency questionnaires (FFQs) which were scored according to their adherence to three plant-based diets: an overall Plant-based Diet Index (PDI), a healthy Plant-based Diet Index (hPDI), and an Unhealthy Plant-Based Diet Index (uPDI). Diet indices were based on that individual’s intake of 18 food groups: healthy plant foods (whole grains, fruits, vegetables, nuts, legumes, vegetable oils, and tea/coffee); unhealthy plant foods (refined grains, fruit juices, potatoes, sugar-sweetened beverages, and sweets/desserts); and animal foods (animal fats, dairy, eggs, fish/seafood, meat, and miscellaneous animal-based foods). The team distinguished between healthy and unhealthy plant foods according to their association with T2D, cardiovascular disease, certain cancers, and other conditions, including obesity and high blood pressure.

The researchers tested blood samples taken back in late 1980s and 1990s in the early phase of the three studies mentioned above to create metabolite profile scores for the participants, and any cases of incident T2D during the follow-up period of the study were recorded. Analyses of these data together with the diet index scores enabled the team to find any correlations between metabolite profile, diet index, and T2D risk.

The study found that compared with participants who did not develop T2D, those who were diagnosed with the disease during follow-up had a lower intake of healthy plant-based foods, as well as lower scores for PDI and hPDI. In addition, they had a higher average BMI, and were more likely to have high blood pressure and cholesterol levels, use blood pressure and cholesterol drugs, have a family history of diabetes, and be less physically active.

The metabolomics data revealed that plant-based diets were associated with unique multi-metabolite profiles, and that these patterns differed significantly between the healthy and unhealthy plant-based diets. In addition, metabolite profile scores for both the overall plant-based diet and the healthy plant-based diet were inversely associated with incident T2D in a generally healthy population, independent of BMI, and other diabetes risk factors, while no association was observed for the unhealthy plant-based diet. As a result, higher metabolite profile scores for PDI and hPDI indicated both closer adherence to those diets and having a lower risk of developing T2D.

Further analysis revealed that after adjusting for levels of trigonelline, hippurate, isoleucine, a small set of triacyglycerols (TAGs), and several other intermediate metabolites, the association between plant-based diets and T2D largely disappeared, suggesting that they might play a key role in linking those diets to incident diabetes. Trigonelline, for example, is found in coffee and has demonstrated beneficial effects on insulin resistance in animal studies, while higher levels of hippurate are associated with better glycaemic control, enhanced insulin secretion and lower risk of T2D. The team suggest that these metabolites could be investigated further and may provide mechanistic explanations of how plant-based diets can have a beneficial effect on T2D risk.

Professor Hu explains: “While it is difficult to tease out the contributions of individual foods because they were analysed together as a pattern, individual metabolites from consumption of polyphenol-rich plant foods like fruits, vegetables, coffee, and legumes are all closely linked to healthy plant-based diet and lower risk of diabetes.”

The authors conclude: “Our findings support the beneficial role of healthy plant-based diets in diabetes prevention and provide new insights for future investigation…our findings regarding the intermediate metabolites are at the moment intriguing but further studies are needed to confirm their causal role in the associations of plant-based diets and the risk of developing type 2 diabetes.”

Since they only collected blood samples at one point in time, the authors also believe that long-term repeated metabolomics data are needed to understand how dietary changes relate to changes in metabolome, thereby influencing T2D risk.

“With the high-resolution microscopy techniques developed by us and others worldwide, we gain fascinating insights into the dynamic ultrastructure of the heart,” says the study’s lead author Dr Eva Rog-Zielinska. She heads the 4D Imaging Section at the Institute of Experimental Cardiovascular Medicine (IEKM) of the University Heart Centre at the University Medical Centre Freiburg. “We can use this insight to analyse the three-dimensional structure of heart cells with unprecedented precision. Our images are made up of cubes — so-called voxels — with an edge length of one nanometre or less. For illustration: one nanometre is the distance a fingernail grows in one second,” Rog-Zielinska explains.

Watching the heart beat in super slow motion

A challenge is to link ultra-high resolution mapping of the heart to a moving target. “Thanks to recent advances in imaging, we now have a much better understanding of how muscle and connective tissue cells behave in the beating heart,” says co-author Prof Peter Kohl, Director of the IEKM, who is also the spokesperson of the German Collaborative Research Centre 1425 dedicated to exploring cardiac scarring.

Electron microscopy itself, but crucially also newly developed methods for the preparation and post-processing of corresponding samples, play a central role in the generation of molecular insight. “It is particularly exciting that we can record muscle cells like individual frames in a film — thanks to millisecond-precise high-pressure freezing. This allows us to watch the heart’s molecular structures beating in super slow motion, as it were,” says Kohl.

Experiments, simulations and artificial intelligence intertwine

The microscopic images are evaluated at IEKM with the help of artificial intelligence, assisted by computer simulations to depict heart function and pathological changes as realistically as possible. “Newly gained insight allows us to gain a completely new understanding of cardiac activity and, based on this, to develop new therapeutic concepts. We are looking forward to a very exciting time in heart research,” says Kohl.

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

Climate scientists count the Atlantic Meridional Overturning Circulation (or AMOC) among the biggest tipping points on the way to a planetary climate disaster. The Atlantic Ocean current acts like a conveyor belt carrying warm tropical surface water north and cooler, heavier deeper water south.

“We’ve been taught to picture it like a conveyor belt — even in middle school and high school now, it’s taught this way — that shuts down when freshwater comes in from ice melt,” says Feng He, an associate scientist at UW-Madison’s Center for Climatic Research.

However, building upon previous work, He says researchers are revising their understanding of the relationship between AMOC and freshwater from melting polar ice.

In the past, a stalled AMOC has accompanied abrupt climate events like the Bølling-Allerød warming, a 14,500-year-old, sharp global temperature hike. He successfully reproduced that event using a climate model he conducted in 2009 while a UW-Madison graduate student.

“That was a success, reproducing the abrupt warming about 14,700 years ago that is seen in the paleoclimate record,” says He, now. “But our accuracy didn’t continue past that abrupt change period.”

Instead, while Earth’s temperatures cooled after this abrupt warming before rising again to plateau at new highs for the last 10,000 years, the 2009 model couldn’t keep pace. The simulated warming over the northern regions of the planet didn’t match the increase in temperatures seen in geological archives of climate, like ice cores.

In a study published this week in the journal Nature Climate Change, He and Oregon State University paleoclimatologist Peter Clark describe a new model simulation that matches the warmth of the last 10,000 years. And they did it by doing away with the trigger most scientists believe stalls or shuts down the AMOC.

Warming temperatures on Earth’s surface cause sea ice in the Arctic Ocean and the Greenland Ice Sheet to melt, releasing fresh water into the ocean. Scientists widely believed that the freshwater influx disrupts the density differences in the North Atlantic that make the AMOC’s north-bound water sink and turn back south.

“The problem,” says He, “is with the geological climate data.”

Though the climate record shows an abundance of freshwater that came from the final melting of the ice sheets over North America and Europe, the AMOC barely changed. So, He removed the assumption of a freshwater deluge from his model.

“Without the freshwater coming in making the AMOC slow down in the model, we get a simulation with much better, lasting agreement with the temperature data from the climate record,” He says. “The important result is that the AMOC appears to be less sensitive to freshwater forcing than has long been thought, according to both the data and model.”

This is particularly important to climate models that evaluate how the AMOC will respond to future increases of freshwater from ice melt.

“It’s built into many models,” He says. “Future global warming from increasing carbon dioxide in the atmosphere melts sea ice, and the freshwater from the melting ice is believed to cause the AMOC to weaken.”

The widespread consequences of a drastic weakening of the AMOC include rapid sea-level rise on the eastern coast of North America, cooling over Europe that could disrupt agriculture, a parched Amazon rainforest and disruption of Asian monsoons. The new modeling study anticipates a much smaller reduction in AMOC strength, but that doesn’t rule out abrupt change.

“We suggest until this challenge is solved, any simulated AMOC changes from freshwater forcing should be viewed with caution,” He says. “We can’t be certain why the AMOC shut down in the past. but we are certain it did change. And it can change again.”

A team from the Artie McFerrin Department of Chemical Engineering at Texas A&M University consisting of Dr. Abdoulaye Djire, assistant professor, and graduate student Denis Johnson, has furthered a method to produce ammonia through electrochemical processes, helping to reduce carbon emissions. This research aims to replace the Haber-Bosch thermochemical process with an electrochemical process that is more sustainable and safer for the environment.

The researchers recently published their findings in Nature Scientific Reports.

Since the early 1900s, the Haber-Bosch process has been used to produce ammonia. This process works by reacting atmospheric nitrogen with hydrogen gas. A downside of the Haber-Bosch process is that it requires high pressure and high temperature, leaving a large energy footprint. The method also requires hydrogen feedstock, which is derived from nonrenewable resources. It is not sustainable and has negative implications on the environment, expediting the need for new and environmentally friendly processes.

The researchers have proposed using the electrochemical nitrogen reduction reaction (NRR) to produce ammonia from atmospheric nitrogen and water. The benefits of using an electrochemical method include using water to provide protons and the ability to produce ammonia at ambient temperature and pressure. This process would potentially require lower amounts of energy and would be less costly and more environmentally friendly than the Haber-Bosch process.

The NRR works by using an electrocatalyst. For this process to succeed, nitrogen must bond to the surface and break apart to produce ammonia. In this study, the researchers used MXene, a titanium nitride, as the electrocatalyst. What differentiates this catalyst from others is that nitrogen is already in its structure, allowing for more efficient ammonia formulation.

“It’s easier for ammonia to form because the protons can attach to the nitrogen in the structure, form the ammonia and then the ammonia will leave out of the structure,” said Johnson. “A hole is made in the structure that can pull the nitrogen gas in and separate the triple bond.”

The researchers found that using titanium nitride induces a Mars-van Krevelen mechanism, a popular mechanism for hydrocarbon oxidation. This mechanism follows a lower energy pathway that would allow for higher ammonia production rates and selectivity because of the nitrogen from the titanium nitride catalyst.

Without modifications to the materials, the researchers reached a selectivity of 20%, which is the ratio of the desired product formed compared to the undesired product formed. Their method could potentially reach a higher selectivity percentage with modifications, forging a new pathway to ammonia production through electrochemical processes.

“The Department of Energy has set a goal of a selectivity of 60%, which is a challenging number to reach,” said Johnson. “We were able to reach 20% using our material, showcasing a method that we might be able to take advantage of moving forward. If we upgrade our material, can we reach 60% soon? That is the question we will continue to work to answer.”

This research could potentially reduce the carbon footprint and global energy usage on a larger scale.

“In the future, this could be a major scientific reform,” said Djire. “About 2% of the world’s total energy is used for ammonia production. Reducing that huge number would drastically reduce our carbon footprint and energy consumption.”

This study was funded by the Startup Research Fund. Other contributors to the publication are Eric Kelley from the chemical engineering department at Texas A&M, Brock Hunter from Auburn University, and Jevaun Christie and Cullan King from Prairie View A&M University.

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Materials provided by Texas A&M University. Original written by Michelle Revels. Note: Content may be edited for style and length.