USC study links ultra-processed food intake to prediabetes in young adults

Researchers tracked 85 young adults over a four-year period, finding that increases in ultra-processed food consumption were linked with elevated blood sugar and early signs of diabetes risk.

Keck School of Medicine of USC

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More than half of calories consumed in the United States come from ultra-processed foods (UPFs), items like fast food and packaged snacks that are often high in sodium, sugar and unhealthy fats. In adults, research has clearly linked these foods to type 2 diabetes and other conditions, but few studies have explored their effects among youth.

Now, researchers from the Keck School of Medicine of USC have completed one of the first studies to examine the link between UPF consumption and how the body processes glucose, which is known to predict diabetes risk. By tracking changes over time, they gained insights into how dietary choices may influence key biological processes.

The researchers studied a group of 85 young adults over a four-year period. They found that an increase in UPF intake was associated with a higher risk for prediabetes, or early-stage high blood sugar that can lead to diabetes. Eating more UPFs was also linked to insulin resistance, where the body becomes less effective at using insulin to control blood sugar. The study, funded in part by the National Institutes of Health, was just published in the journal Nutrition and Metabolism.

"Our findings show that even modest increases in ultra-processed food intake can disrupt glucose regulation in young adults at risk for obesity. These results point to diet as a modifiable driver of early metabolic disease, and an urgent target for prevention strategies among young people,” said Vaia Lida Chatzi, MD, PhD, a professor of population and public health sciences and pediatrics and director of the Southern California Superfund Research and Training Program for PFAS Assessment, Remediation and Prevention (ShARP) Center at the Keck School of Medicine, who is the study’s senior author.

Early adulthood is a formative stage where people have reached physical maturity and are building habits that can persist for years. Trading packaged or restaurant meals for whole and raw foods like fruits, vegetables, and whole grains can reduce the likelihood of developing type 2 diabetes later in life.

"Young adulthood is a critical window for shaping long-term health,” Chatzi said. “By focusing on young adults, we have an opportunity to intervene early, before prediabetes and other risk factors become lifelong conditions.”

Signs of prediabetes

The research included 85 young adults from the Metabolic and Asthma Incidence Research (Meta-AIR) study, part of the broader Southern California Children's Health Study. Participants, aged 17-22, provided data at a baseline visit between 2014 and 2018 and a follow-up visit approximately four years later.

At each visit, participants reported everything they had eaten on one recent weekday and one recent weekend day. Researchers classified foods into two categories: UPFs (such as candy, soda, cereal, packaged spreads, flavored yogurts, and many restaurant foods) and foods that were not ultra-processed. They then calculated what percentage of each participant’s daily caloric intake came from UPFs.

The researchers also collected blood samples from participants before and after they consumed a sugary drink to test how effectively their body responded to blood sugar with insulin. They then conducted a statistical analysis to compare dietary changes with signs of prediabetes, adjusting for differences in age, sex, ethnicity and physical activity levels.

From baseline to follow-up, a 10% increase in UPF consumption was associated with a 64% higher risk for prediabetes and a 56% higher risk for problems with glucose regulation. Participants who reported eating more UPFs at their initial visit were also more likely to have elevated insulin levels at follow-up—an early sign of insulin resistance, where the body must produce more insulin to keep blood sugar in a healthy range.

Limiting ultra-processed foods

The study shows that the risks of UPFs extend to young adults, a group often overlooked in previous research.

“These findings indicate that ultra-processed food consumption increases the risk for pre-diabetes and type 2 diabetes among young adults—and that limiting consumption of those foods can help prevent disease,” said the study’s first author, Yiping Li, a doctoral student in quantitative biomedical sciences at Dartmouth College who previously worked as a researcher at the Keck School of Medicine.

Future studies with larger groups and more detailed diet tracking can help clarify which foods pose the greatest risk for young adults, the researchers said. They also plan to continue investigating the biological mechanisms behind these links, including how specific nutrients in UPFs may influence insulin and blood sugar regulation.

About this research

In addition to Li and Chatzi, the study’s other authors are Elizabeth Costello, Sarah Rock, Zhanghua Chen, Frank Gilliland, Michael I. Goren, Jesse A. Goodrich and David V. Conti from the Department of Population and Public Health Sciences, Keck School of Medicine of USC, University of Southern California; William B. Patterson from the University of Colorado School of Medicine; Tanya L. Alderete from the Bloomberg School of Public Health, Johns Hopkins University; and Nikos Stratakis from the Barcelona Institute for Global Health (ISGlobal).

This work was primarily supported by the National Institute of Environmental Health Sciences (NIEHS) of the National Institutes of Health [P42ES036506, P30ES007048]. Funding for the Meta-AIR study came from the Southern California Children’s Environmental Health Center grants funded by NIEHS [5P01ES022845-03, P30ES007048, 5P01ES011627]; the U.S. Environmental Protection Agency [RD83544101]; and the Hastings Foundation. Additional funding came from NIEHS [R01ES036253, R01ES029944, R01ES030364, U01HG013288, T32ES013678, U01HG013288, R01ES035035 and R01ES035056]; the European Union [The Advancing Tools for Human Early Lifecourse Exposome Research and Translation (ATHLETE) project: 874583]; the National Institute on Minority Health and Health Disparities [P50MD017344]; and the Horizon Europe Research and Innovation Program [Marie Skłodowska-Curie Actions Postdoctoral Fellowships: 101059245].The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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Journal

Nutrition & Metabolism

DOI

10.1186/s12986-025-01036-6 

Article Title

Ultra-processed food intake is associated with altered glucose homeostasis in young adults with a history of overweight or obesity: a longitudinal study

Article Publication Date

10-Nov-2025

 

Continents peel from below, triggering oceanic volcanoes

University of Southampton

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image: 

A piece of the lowermost continental mantle (the crystalline roots of the continents). This represents the material that the research proposes is removed and swept sideways into the oceanic mantle

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Credit: Prof Tom Gernon, University of Southampton

Earth scientists have discovered how continents are slowly peeled from beneath, fuelling volcanic activity in an unexpected place: the oceans.

The research, led by the University of Southampton, shows how slivers of continents are slowly stripped from below and swept into the oceanic mantle – the hot, mostly solid layer beneath the ocean floor that slowly flows. Here, the continental material fuels volcanic activity for tens of millions of years.

The discovery solves a long-standing geological mystery: why many ocean islands far from plate tectonic boundaries contain materials that look distinctly continental, despite being found in the middle of oceans.

The study, published in Nature Geoscience, was led by the University of Southampton, and involved the GFZ Helmholtz Centre for Geosciences in Potsdam, Germany, the University of Potsdam, Queen’s University Canada, and Swansea University.

Ancient chemical trails in the mantle

Many ocean islands, such as Christmas Island in the northeast Indian Ocean, contain unusually high levels of certain so-called ‘enriched’ elements that are normally found in continents – possibly because deep Earth processes have folded in older, recycled material, much like a churning cake mixer.

It was thought these elements came from sediments that get recycled when ocean plates dive into the mantle, or by columns of hot rock, known as mantle plumes, which rise from deep within the Earth.

But these explanations fall short, as some volcanic regions show little sign of crustal recycling, while others appear too cool and shallow to be driven by mantle plumes.  

“We’ve known for decades that parts of the mantle beneath the oceans look strangely contaminated, as if pieces of ancient continents somehow ended up in there,” said Thomas Gernon, Professor of Earth Science at the University of Southampton, and lead author of the study. “But we haven’t been able to adequately explain how all that continental material got there.”

The continents are peeling from below

The study proposes a novel answer: continents don’t just rift apart at the surface – they also peel away from below, and over much greater distances than previously thought possible.

The scientists developed simulations to mimic the behaviour of continents and mantle as they are stretched by tectonic forces.

Their work builds on their previous research showing that when continents break apart, deep tectonic forces trigger a wave of instabilities – a ‘mantle wave’ – that sweeps along the continents’ base, disturbing their roots at depths of 150 to 200 km.

This sweeping movement unfolds at an incredibly slow pace, just a millionth the speed of a snail, gradually stripping material from the deep roots of continents.

These peeled fragments are then swept sideways – sometimes over more than 1,000 km – into the oceanic mantle, where they feed volcanic eruptions in the ocean over tens of millions of years.

Study co-author Professor Sascha Brune, of GFZ in Potsdam, said: “We found that the mantle is still feeling the effects of continental breakup long after the continents themselves have separated. The system doesn’t switch off when a new ocean basin forms – the mantle keeps moving, reorganising, and transporting enriched material far from where it originated.”

Evidence from the Indian Ocean

The team analysed geochemical data from areas of the Earth including the Indian Ocean Seamount Province, a chain of volcanic features formed after the supercontinent Gondwana broke apart over 100 million years ago.

Through simulations and chemical analysis, they discovered that soon after Gondwana broke apart, a burst of unusually enriched magma rose to the surface.

Over tens of millions of years, that chemical signal faded as the flow of material from beneath the continent waned. This happened without a mantle plume coming from deep in the Earth, which geologists had long assumed must be responsible.

Professor Gernon explained: “We’re not ruling out mantle plumes, but this discovery points to a completely new mechanism that also shapes the composition of the Earth’s mantle. Mantle waves can carry blobs of continental material far into the oceanic mantle, leaving behind a chemical signature that endures long after the continents have broken apart.”

The study builds on the team’s recent discovery that mantle waves can also stir dramatic changes deep within continents. Their earlier work showed that these slow, rolling movements in the Earth’s mantle can help trigger diamond eruptions and even reshape landscapes thousands of kilometres from the edges of tectonic plates.

ENDS

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01843-9 

Article Publication Date

11-Nov-2025

Where does continental material on islands come from?

Continents are scraped from below. The material feeds volcanoes in the ocean.

GFZ Helmholtz-Zentrum für Geoforschung

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image: 

A microscopic image of a fragment of the lowermost continental mantle — the crystalline roots of the continents. This is the type of material that the authors propose is stripped away and laterally transported into the oceanic mantle. Photo: Prof Tom Gernon (University of Southampton).

view more 

Credit: Prof Tom Gernon (University of Southampton).

Many oceanic islands far from active plate tectonic boundaries contain materials that clearly originate from continents, even though they are located in the middle of an oceanic plate. Where do the continental remnants come from? Are they sediments that are recycled when oceanic plates subduct into the mantle? Or do they originate from the depths of the Earth's mantle and are carried upward by hot currents, known as mantle plumes? Both explanations are being discussed, but they fall short. This is because some volcanic regions show little evidence of crustal recycling, while others are too cool to be driven by mantle plumes.

Researchers at the University of Southampton and the GFZ Helmholtz Centre for Geosciences have now proposed a new explanation. Geochemical analyses and modelling have revealed the following picture: When continents break apart, a wave of instability is created at a depth of more than a hundred kilometres. This “mantle wave” scrapes material from the underside of the continents along the base, which is then transported sideways into the Earth's mantle beneath the oceans.

There, these remnants of continental roots feed volcanic eruptions in the ocean crust over millions of years. Sometimes the material travels more than a thousand kilometres from the continental interiors before it forms oceanic islands.

Professor Sascha Brune from GFZ in Potsdam and co-author of the study, says: “We have found that the mantle continues to ‘feel’ the effects of continental rifting long after the continents have separated. The system does not shut down when a new ocean basin forms—the mantle continues to move, reorganize, and transport enriched material far away from its place of origin.”

The team analyzed geochemical data from various regions of the Earth, including the Seamount Province in the Indian Ocean, a chain of volcanic formations that formed after the breakup of the supercontinent Gondwana over 100 million years ago.

Through simulations and chemical analyses, the team discovered that shortly after Gondwana broke apart, unusually enriched material with a continental fingerprint appeared beneath the new-born ocean and generated melts that can now be found at oceanic islands and submerged seamounts. Over millions of years, this chemical signal faded as the flow of material from the interior of the continent slowed.

This happened without there having been a mantle plume. Thomas Gernon, Professor of Earth Science at the University of Southampton and lead author of the study, says: "We are not ruling out mantle plumes, but our discovery points to a completely new mechanism that also influences the composition of the Earth's mantle. Mantle waves can transport continental material far into the oceanic mantle, leaving behind a chemical signature that persists long after the continents have broken apart."

The study builds on the team's recent discovery that “mantle waves” can also cause dramatic changes deep within continents. Their previous work showed that these slow, rolling motions in the Earth's mantle can help trigger diamond eruptions and even reshape landscapes thousands of kilometres away from the edges of tectonic plates.

The study, published in Nature Geoscience, was led by the University of Southampton and conducted in collaboration with the GFZ Helmholtz Centre for Geosciences in Potsdam, the University of Potsdam, Queen's University Canada, and Swansea University.

Original study: Thomas Gernon et al.: Enriched mantle generated through persistent convective erosion of continental roots; in: Nature Geoscience https://doi.org/10.1038/s41561-025-01843-9

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01843-9 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Enriched mantle generated through persistent convective erosion of continental roots

Article Publication Date

11-Nov-2025

GOOD NEWS

Houthis Announce End of Red Sea Shipping Attacks

Aftermath of the Houthi attack on the tanker Sounion, September 2024 (EUNAVFOR)

Published Nov 11, 2025 11:51 AM by The Maritime Executive


In a significant change in direction, the rebel Houthi leadership in Yemen have declared that they will bring to an end their declared campaign against maritime interests connected to Israel.

Since the US-Houthi ceasefire mediated by Oman in May, Houthi attacks on shipping were in theory limited to attacks on vessels with links to Israel. But the Houthis in the past have frequently been inaccurate in their targeting, meaning that most Western-linked shipping lines opted to avoid the Red Sea, for fear of being targeted by mistake. But now that the Houthis have declared they will for the moment cease all attacks, this general threat has been lifted, and normal traffic flows through the Red Sea and Suez Canal can be expected to resume (after a period of watchful waiting). Safe access to the Red Sea will provide a much-needed financial boost for the Suez Canal Authority, but will hurt the balance sheets of ocean carriers, which have benefited from Cape of Good Hope diversions.

The Houthi change of heart was announced in a released copy of a letter sent by the newly-appointed Houthi Chief of Staff Major General Yousef Hassan Al Madani, whose predecessor Major General Mohammed Al Ghamari was killed in an airstrike - along with the Prime Minister and most of the cabinet - on August 28. Al Ghamari has generally been credited with being the architect of the anti-shipping campaign and the missile attacks on Israel.

The Houthi letter announced that not only would they cease their attacks on Israeli-linked shipping, they are also planning to lift their 'blockade' on Israeli ports - which was largely implemented by firing ballistic missiles at random targets in Israel. Hence a general all-clear is now in place, save that the Houthis have pledged to remain loyal to the Hamas cause, so a collapse of the agreements reached over Gaza could presage a resumption of Houthi hostilities.

It is not clear why the Houthis have chosen to declare a ceasefire at this point, save that it has been clear that in recent weeks the Houthi inner circle's leadership has felt under significant pressure, chastened by the effects of Israeli and US air raids both on their missile and drone infrastructure but particularly by the casualties inflicted on their senior leaders. The Houthis could have responded by talking up the threat posed by external enemies, to cement internal loyalties. But instead, they have pursued the course of peace - which promises economic rewards from the Saudis and others, such as the back-payment of government salaries owed to those working in Houthi-controlled areas.

The Houthis may also have been worried that with reconciliations afoot in the region - such as that between President Ahmed Al Sharaa of Syria and Yemeni National Resistance Leader Tareq Saleh, seen together recently at COP30 in Brazil - they may have become isolated politically had they carried on with their anti-shipping, anti-everyone campaign. There will be no acknowledgements or credit claimed, but the persuasive, mediating hand of Oman is evident in the Houthi change of heart.