US Dietary Guidelines are a mixed bag, show industry influence, says physicians group

Physicians Committee for Responsible Medicine

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WASHINGTON, D.C. — The 2025-2030 Dietary Guidelines for Americans, released Jan. 7, score well for their streamlined approach, for limiting “bad” fat, for emphasizing fruits and vegetables, and for limiting alcohol, but need serious improvement in other areas, says the Physicians Committee for Responsible Medicine.

“The Guidelines are right to limit cholesterol-raising saturated (“bad”) fat,” says Neal Barnard, MD, FACC, president of the Physicians Committee for Responsible Medicine. “But they should spell out where it comes from: dairy products and meat, primarily. And here the Guidelines err in promoting meat and dairy products, which are principal drivers of cardiovascular disease, diabetes, and obesity.”  

“The Guidelines take a sledgehammer approach to processed foods, but plant-based and vitamin-fortified processed foods actually reduce the risk of birth defects, diabetes, heart disease, and cancer,” Dr. Barnard adds.

The health advocacy group, which has 17,000 doctor members, says there are several recommendations that the Guidelines got right and several that should be modified to keep Americans healthy.

The Guidelines are correct in:

Limiting saturated (“bad”) fat intake. Promoting plant-based foods, like fruits and vegetables.  Limiting alcohol. Streamlining advice and removing jargon, making recommendations easy to understand.

The Guidelines should be modified to:

Warn against animal protein, which is linked to heart disease and other chronic diseases. State that vegetarian and vegan diets provide all necessary nutrients, with a B12 supplement, and that plant-based processed foods are often fortified with essential nutrients and are a healthier option than animal products.    Warn against consuming dairy products, which are often high in saturated fat and linked to breast and prostate cancers. Eliminate confusion on saturated fat, specifying that it is in dairy products and meat and promotes heart disease and Alzheimer’s disease. Recognize that some highly processed foods are healthful. These include breakfast cereals and breads, which are fortified with folic acid, vitamin B12, and other nutrients that prevent birth defects and reduce risk of diabetes and cardiovascular disease. Recommend water as the beverage of choice instead of milk, recognizing milk’s link to prostate cancer, breast cancer, and lactose intolerance.

Meat and dairy products are the leading sources of saturated fat in the American diet. Research shows that consuming foods and beverages high in saturated fat raises LDL “bad” cholesterol levels, which increases heart disease risk. A new report in the Annals of Internal Medicine reaffirms that saturated fat raises cholesterol and increases the risk for heart disease. The American Heart Association Presidential Advisory reaffirms the strong evidence that saturated fat raises LDL cholesterol, which is a major driver of cardiovascular disease.

The new Guidelines’ increased protein recommendation is unnecessary and could be harmful if it results in eating more protein from animals.

“Americans already get enough protein,” says Dr. Barnard. “If the Guidelines are going to push for increased protein consumption, it should come from plants.”

Plant-based processed foods are associated with reduced risk of diabetes and cardiovascular disease and are often fortified with important nutrients, such as folic acid and vitamins D and B12, while animal products increase disease risk.

“The Guidelines have unjustly condemned highly processed foods and exonerated meat and dairy products,” says Dr. Barnard. “They should have done the reverse.”

A Harvard University study, for example, showed that animal-based products were associated with 44% increased risk of diabetes, while ultra-processed cereals were associated with 22% reduced risk.

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in education and research.

Researchers identify urban atmosphere as primary reservoir of microplastics

Chinese Academy of Sciences Headquarters

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MP and NP abundances in aerosols and estimated fluxes across atmospheric compartments in semiarid (XA) and humid subtropical (GZ) urban environments.

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Credit: Image by the Institute of Earth Environment, CAS

Over the past two decades, microplastics (MPs) and nanoplastics (NPs) have been recognized as emerging pollutants, detected across every environmental compartment of the Earth's system—the atmosphere, hydrosphere, lithosphere, and biosphere.

Their pervasive presence has drawn increasing attention from researchers focused on biogeochemical cycles and climate change. Significant gaps remain, however, in quantifying the stocks, sources, transformation, and fate of plastics, especially within the atmosphere, primarily due to analytical limitations in detecting and characterizing particles across micro- to nanoscale dimensions.

To address these challenges, a research team from the Institute of Earth Environment of the Chinese Academy of Sciences (IEECAS) developed a semi-automated microanalytical method to quantify atmospheric plastic particles and their cross-compartmental fluxes—airborne, dustfall, rain, snow, and dust resuspension—in two major Chinese megacities: Guangzhou and Xi'an.

By using a computer-controlled scanning electron microscopy system, which minimizes human bias compared to conventional manual inspections, the team detected plastic concentrations in total suspended particulates (TSP) and dustfall fluxes that are two–six orders of magnitude higher than those reported by visual identification techniques (e.g., manual SEM-EDX, μ-FTIR, or μ-Raman).

Additionally, estimated fluxes of MPs and NPs varied by two–five orders of magnitude across key atmospheric compartments, driven largely by roaddust resuspension and wet deposition. Furthermore, deposition samples contained more heterogeneously mixed plastic particles than aerosol and resuspension samples, indicating enhanced particle aggregation and removal during atmospheric transport.

This study marks the first detection of NPs as small as 200 nm in complex environmental matrices. It provides a quantitative assessment of atmospheric plastics, the least understood reservoir in the global plastic cycle, and delivers new insights into their environmental transformation, fate, and broader implications for climate dynamics, ecosystem integrity, and human health.

These findings were published in Science Advances on January 7. 

Plastic aggregate mixing states across atmospheric compartments in XA and GZ city.

Credit

Image by the Institute of Earth Environment, CAS

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Journal

Science Advances

DOI

10.1126/sciadv.adz7779 

Article Title

Abundance of microplastics and nanoplastics in urban atmosphere

Article Publication Date

7-Jan-2026

 

World’s oldest arrow poison – 60,000-year-old traces reveal early advanced hunting techniques

Stockholm University

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Both sides of one of the arrowheads analysed. The left-hand image shows the organic remains in which the arrowhead residues were identified. Photo: Marlize Lombard

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Credit: Marlize Lombard

Researchers have identified traces of plant poison from the South African plant gifbol on Stone Age arrowheads – the oldest known arrow poison in the world to date. The discovery, published in the scientific journal Science Advances, shows that 60,000 years ago, people in southern Africa had already developed advanced knowledge of toxic substances and how they could be used for hunting.

Researchers from South Africa and Sweden have found the oldest traces of arrow poison in the world to date. On 60,000-year-old quartz arrowheads from Umhlatuzana Rock Shelter in KwaZulu-Natal, South Africa, researchers have identified chemical residues of poison from the plant gifbol (Boophone disticha), a poisonous plant still used by traditional hunters in the region.

“This is the result of a long and close collaboration between researchers in South Africa and Sweden. Being able to identify the world's oldest arrow poison together has been a complex undertaking and is incredibly encouraging for continued research,” says Professor Sven Isaksson at the Archaeological Research Laboratory, Stockholm University, an expert in the analysis of organic residues in archaeological materials who carried out the chemical analyses.

Oldest evidence of arrow poison

“This is the oldest direct evidence that humans used arrow poison. It shows that our ancestors in southern Africa not only invented the bow and arrow much earlier than previously thought, but also understood how to use nature’s chemistry to increase hunting efficiency,” says Professor Marlize Lombard, a researcher at the Palaeo-Research Institute at the University of Johannesburg.

Chemical analyses revealed the presence of the alkaloids buphanidrine and epibuphanisine, substances found in the plant Boophone disticha – also known as gifbol (i.e. poisonous onion). The plant has long been known among local hunters for its highly toxic properties.

Similar substances were also found on 250-year-old arrowheads in Swedish collections, which were collected by travellers during the 18th century. The fact that the same plant poison was used in both historical and prehistoric times indicates a long continuity of knowledge and tradition.

“Finding traces of the same poison on both prehistoric and historical arrowheads was crucial,” says Professor Sven Isaksson. “By carefully studying the chemical structure of the substances and thus drawing conclusions about their properties, we were able to determine that these particular substances are stable enough to survive this long in the ground,” he continues. “It’s also fascinating that people had such a deep and long-standing understanding of the use of plants.”

Advanced planning abilities

Previously, indirect traces of poison have been used to interpret hunting practices, but the findings from Umhlatuzana Rock Shelter constitute the first direct evidence of hunting with poisoned arrows. The study shows that these early hunters not only had technical skills but also advanced planning abilities and an understanding of how poisons work over time – characteristics that reflect modern human cognition.

“Using arrow poison requires planning, patience and an understanding of cause and effect. It is a clear sign of advanced thinking in early humans,” says Professor Anders Högberg at the Department of Cultural Sciences, Linnaeus University.

 

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Journal

Science Advances

DOI

10.1126/sciadv.adz3281 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Direct Evidence for Poison Use on Microlithic Arrowheads in Southern Africa at 60 000 years ago

Article Publication Date

7-Jan-2026

Bristol scientists discover early sponges were soft

University of Bristol

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The diversity of sponges and their spicules. Sponges were the first reef builders and maintain a fundamental role in modern marine ecosystems.

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Credit: From Top left to bottom right: The barrel sponge (Xestospongia testudinaria)is by Albert Kok at Dutch Wikipedia - Transferred from nl.wikipedia to Commons., Public Domain, https://commons.wikimedia.org/w/index.php?curid=3017391. The demosponge spicules are by Ana Riesgo. The tube sponge (Pseudoceratina crassa) is by NURC/UNCW and NOAA/FGBNMS. - NOAA Photo Library: expl0628, Public Domain, https://commons.wikimedia.org/w/index.php?curid=17967456. The Branching tube sponge (Aiolochroia crassa) is by iNaturalist user: thibaudaronson - https://www.inaturalist.org/photos/12359922, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=89131968.

Sponges are among earth’s most ancient animals, but exactly when they evolved has long puzzled scientists. Genetic information from living sponges, as well as chemical signals from ancient rocks, suggest sponges evolved at least 650 million years ago. The research is published today [7 January] in Science Advances.

This evidence has proved highly controversial as it predates the fossil record of sponges by a minimum of  100 million years. Now an international team of scientists led by Dr M. Eleonora Rossi, from the University of Bristol’s School of Biological Sciences, have solved this conflict by examining the evolution of sponge skeletons. 

Living sponges have skeletons composed of millions of microscopic glass-like needles called spicules. These spicules also have an extremely good fossil record, dating back to around 543 million years ago in the late Ediacaran Period. Their absence from older rocks has led some scientists to question whether earlier estimates for the origin of sponges are accurate.

Dr Rossi and her team solved this mystery using a two-step approach. Firstly, they combined high-quality data from 133 protein-coding genes with fossil evidence to construct a new timescale for sponge evolution. They dated the origin of sponges to between 600-615 million years ago, closing the gap with the fossil record. Secondly, they investigated the evolution of sponge skeletons, revealing that spicules evolved independently in different sponge groups.

Dr Rossi, Honorary Research Associate, said: “Our results show that the first sponges were soft-bodied and lacked mineralised skeletons. That’s why we don’t see sponge spicules in rocks from around 600 million years ago — there simply weren’t any to preserve.”

Dr Ana Riesgo, a world-leading expert in sponge evolution from the Museum of Natural Sciences in Madrid (Spain) said: “We already had some clues that suggested sponge skeletons evolved independently. Modern sponge skeletons may look alike, but they’re built in very different ways. Some are made of calcite, the mineral that makes up chalk, others of silica, essentially glass, and when we examine their genomes we see that entirely different genes are involved.”

In order to reconstruct sponge skeleton evolution, the team used a statistical computer model. Dr Joseph Keating, also an author on the study, explained: “We used a Markov process, a type of predictive model that’s widely applied in fields like finance, AI, search engines, and weather forecasting. By modelling transitions between different skeletal types, including soft-bodied forms, we found that almost all models strongly reject the idea that the earliest sponges had mineralised skeletons. Only an unrealistic model treating all mineral types as equivalent suggests otherwise, and even then the results are ambiguous.”

The results of this study raise interesting questions about early sponge evolution. 

Professor Phil Donoghue, Professor of Palaeobiology at the University of Bristol said: “Given that nearly all living sponges have skeletons composed of mineralised spicules, we might naturally assume that spicules were important in early sponge evolution. Our results challenge this idea, suggesting that early sponge diversification was driven by something else entirely—and what that was is still a tantalising mystery.”

Professor Davide Pisani, Professor of Phylogenomics at the University of Bristol, concluded: “But this is not only about sponges. Sponges are the first lineage of reef building animals to evolve and might as well have been the very first animal lineage, although this is still debated. Understanding their evolution provide key insights on the origin of the very first reef systems. This is about how life and Earth co-evolved, and how the evolution of early animals changed our planet forever, ultimately enabling the emergence of the animal life forms we are familiar with, humans included”.

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Journal

Science Advances

DOI

10.1126/sciadv.adx1754 

Article Title

Independent origins of spicules reconcile paleontological and molecular evidence of sponge evolutionary history

Article Publication Date

7-Jan-2026