Science
As global plastic production grows, so does the concentration of microplastics in our brains

Finding microplastics in human body parts is not new: Scientists have uncovered the minuscule waste products in human blood, lungs, brains, hearts and testicles.
But a new study, published Monday in the journal Nature Medicine, shows a lockstep relationship between the amount of plastic found in tissues harvested from human cadavers and the amount being produced by the plastic industry.
As global plastic production has ramped up in the last 20 years, so too has the concentration of these shredded, fossil fuel-derived polymers in human tissue samples.
The findings are “pretty striking,” said Phil Landrigan, director of the Program for Global Public Health and the Common Good at Boston College, who was not affiliated with the research.
The study also showed a concerning correlation between patients who had received a dementia diagnosis before they died and the amount of plastic particles found in their brains — adding to a growing body of research indicating that the presence of these particles in the human body can potentially cause harm.
The study was published by a team of researchers at the University of New Mexico, Oklahoma State University, Duke University and Universidad del Valle, in Colombia.
The team acquired brain, liver and kidney tissue samples from patients who had undergone autopsies between 2016 and 2024 at the University of New Mexico.
To determine both the concentration and kinds of plastic in the samples, the team visually inspected the samples and applied pyrolysis-gas chromatography–mass spectrometry — a technique that allowed them to analyze the tissue’s chemical composition.
They found that the concentrations of particles in kidney and liver samples were comparable, with an average of 433 micrograms of microplastic per gram of tissue in the liver samples and 404 micrograms per gram of the kidney samples.
But the levels seen in the brain samples — all taken from the frontal lobe — dwarfed those numbers, and showed a jump over time. In the samples they harvested from people who died in 2016, they found average concentrations of 3,345 micrograms/gram. In the 2024 cohort, the average was 4,917.
“I never would have imagined it was this high,” said Matthew Campen, professor of pharmaceutical sciences at the University of New Mexico. “I certainly don’t feel comfortable with this much plastic in my brain, and I don’t need to wait around 30 more years to find out what happens if the concentrations quadruple.”
The concentrations of microplastics the researchers found were independent of the biological age of the deceased person — it didn’t matter if the person was young or old when they died. What mattered was the year they died — the more recent the death, the more accumulated plastic in the body.
Intrigued by this increase in plastic concentration over time, the researchers obtained more brain tissue samples. This time, they examined brains from people who died between 1997 and 2013. They made sure the cadavers were similarly aged to the ones they had already examined — but could not control for geography. The second cohort all came from people who had died on the East Coast.
Again, the researchers found “significantly increasing trends for total plastics” over time in this second group of samples.
Polyethylene — a plastic polymer used to make things such as plastic bags, milk jugs, shampoo bottles, etc. — was the most common microplastic found in the brain. It comprised 75% of the plastic shards observed in the brain tissue samples. But the researchers also detected polypropylene (the plastic used to make yogurt cups and rigid takeout food containers), polyvinylchloride (which is used in most water pipes), and styrene-butadiene rubber (found in some pneumatic tires, shoe soles, brake pads and electrical insulation).
The concentration of all of these plastics increased from 2016 to 2024, irrespective of the biological age of the cadaver.
They also noted that brain tissue harvested from patients who’d been diagnosed with dementia had higher concentrations of microplastics than those who hadn’t. Although it was a concerning observation, they noted that their sample size was small, and that hallmarks of dementia include brain tissue atrophy, impaired blood-brain barrier integrity, and poor brain clearance mechanisms — which could themselves lead to microplastic buildup.
Therefore, they could make no claims to causation — just correlation.
Landrigan said the work reinforces our knowledge “that we’re all exposed, that these things actually get into our bodies, into people of all ages” and that it “appears to be getting worse with time.”
He said it adds to the urgency of a Global Plastics Treaty — to cap plastic production — and which reached an impasse at the last round of negotiations in South Korea, in 2024. He said negotiators plan to reconvene later this year.
According to Landrigan, it’s unclear how the United States, under President Trump, would approach the treaty. If Trump follows the advice of the fossil fuel proponents in his administration, it’s likely the U.S. will vote the deal down — or not even show up.
But if the Robert F. Kennedy Jr. element gets a seat at the table, the U.S. is a wild card, Landrigan said. Kennedy was openly critical of the Biden administration for not doing enough to stanch the flow of microplastics into the environment, and he penned a detailed plan that would ban most hazardous chemicals, reform the recycling infrastructure and curtail the production of plastics.
Landrigan said he has known Kennedy for decades, and would happily sit down with him to present this research and the growing number of studies showing the harms these particles — and the chemicals they carry — cause in the human body.
“I’m a pediatrician with the American Academy of Pediatrics, and we’ve always taken the position that the academy will do what it has to do to protect children’s health. We will always stand up for children. So, if there’s an opening there for conversation with Bobby, why not?” he said.

Science
Top N.I.H. Official Abruptly Resigns as Trump Orders Deep Cuts

The No. 2 official at the National Institutes of Health abruptly resigned and retired from government service on Tuesday, in another sign that the Trump administration is reshaping the nation’s public health and biomedical research institutions.
The official, Dr. Lawrence A. Tabak, a dentist and researcher, was long considered a steadying force and had weathered past presidential transitions. In a letter that Dr. Tabak sent to colleagues on Tuesday, he did not give a reason for his decision. One person familiar with the decision said Dr. Tabak had been confronted with a reassignment that he viewed as unacceptable.
“It has been an enormous privilege to work with each of you (and your predecessors) to support and further the critical NIH mission,” Dr. Tabak wrote.
Dr. Tabak resigned at a turbulent time for the institutes, the nation’s premier biomedical research industry, composed of 27 separate institutes and centers that study and develop treatments for diseases like cancer and heart conditions as well as infectious diseases like AIDS and Covid. The N.I.H. spends roughly $48 billion a year on medical research, much of it in grants to medical centers, universities and hospitals across the country.
President Trump’s decision to slash billions of dollars in N.I.H. grant funding has sparked a bitter court battle. And the Senate on Wednesday voted to advance the nomination of Robert F. Kennedy Jr., a vaccine skeptic and the president’s pick for secretary of the Department of Health and Human Services, which oversees the N.I.H.
Mr. Kennedy has said he would cut 600 N.I.H. jobs.
The N.I.H. said it would soon have a statement about Dr. Tabak’s decision.
Dr. Tabak was not well-known to the public. But his decision to leave is surprising, and destabilizing for an agency that is on the political hot seat. He was viewed as someone who could work across party lines; he had survived the presidential turnovers of both parties and had indicated he expected to stay on after Mr. Trump was elected in November.
Ordinarily, Dr. Tabak would have ascended to the job of acting N.I.H. director during the transition from one administration to the next. But the Trump administration installed another researcher, Matthew Memoli of the National Institute of Allergy and Infectious Diseases, as acting director. Dr. Memoli criticized Covid vaccine mandates, as did Mr. Kennedy.
As acting director of the N.I.H. last year, Dr. Tabak pushed back against Republicans’ assertions that a lab leak stemming from U.S. taxpayer-funded research might have caused the coronavirus pandemic. He told lawmakers that viruses being studied at a laboratory in Wuhan, China, bore no resemblance to the one that set off the world’s worst public health crisis in a century.
Ellen Barry contributed reporting.
Science
California’s Scary Product Warning Labels Might Be Working, Study Says

The warnings, on thousands of products sold in California, are stark.
“Use of the following products,” one label says, “will expose you to chemicals known to the State of California to cause cancer, birth defects or other reproductive harm.”
Now, new research shows the warnings may be working.
A study published Wednesday in the journal Environmental Science & Technology found that California’s right-to-know law, which requires companies to warn people about harmful chemicals in their products, has swayed many companies to stop using those chemicals altogether.
As it turns out, companies don’t want to sell a product that carries a big cancer warning label, said Dr. Megan Schwarzman, a physician and environmental-health scientist at the University of California, Berkeley School of Public Health and an author of the study.
Combine that with the threat of lawsuits and reputational costs, as well as companies just wanting to do the right thing for health, and “it becomes a great motivator for change,” she said.
California maintains a list of about 900 chemicals known to cause cancer and other health effects. Under the 1986 right-to-know law, also known as Prop 65, products that could expose people to harmful amounts of those chemicals must carry warning labels.
Critics had long mocked the measure, saying the warnings were so ubiquitous — affixed to cookware, faux leather jackets, even baked goods — that they had become largely meaningless in the eyes of shoppers. But the latest study found that companies, more than consumers, may be most influenced by the warnings.
To assess the law’s effect, researchers carried out interviews at 32 global manufacturers and retailers that sell clothing, personal-care, cleaning, and a range of home products. Almost 80 percent of interviewees said Prop 65 had prompted them to reformulate their products.
Companies can avoid the warning labels if they reduce the level of any Prop 65 chemicals below a “safe harbor” threshold.
A similar share of companies said they looked to Prop 65 to determine which chemicals to avoid. And 63 percent said the law had prompted them to also reformulate products they sold outside California.
The American Chemistry Council, which represents chemical manufacturers, did not immediately respond to a request for comment on the study.
No other state has a law quite like Prop. 65, requiring warnings on such a wide range of products about cancer or reproductive harm. New York enacted a more limited law in 2020 that requires manufacturers to disclose certain chemicals in children’s products and that bans the use of certain chemicals by 2023. Other states have laws geared toward disclosure of ingredients on labels.
California, meanwhile, is pushing ahead. A 2018 change to Prop 65 has meant products are starting to carry even more specific labels. Some food and beverage cans, for example, may carry labels that warn that they “have linings containing bisphenol A (BPA), a chemical known to the State of California to cause harm to the female reproductive system.”
The latest research is part of a larger effort to analyze Prop 65’s effect on people’s exposure to toxic chemicals. In a study published last year, researchers at the Silent Spring Institute and UC Berkeley found that in the years after certain chemicals were listed under the law, levels of those chemicals in people’s bodies decreased both in California and nationwide.
That research came with a caveat, however. In some examples where levels of a listed chemical decreased, a close substitute to that chemical, potentially with similar harmful effects, increased. Prop 65 has no mechanism to check the safety of alternative chemicals.
It suggested that stronger policies were needed at both the federal and state levels to study and regulate the thousands of chemicals on the market, Dr. Schwarzman said. “This is so much bigger than the individual consumer and what we choose off-the-shelf,” she said.
Science
NIH cuts put medical research at risk, scientists say, raising concerns at UC and elsewhere

Each year, the National Institutes of Health gives billions of dollars to the University of California to pay for research into cancer, Alzheimer’s, Parkinson’s, heart disease, diabetes and other diseases it has been at the forefront of studying for decades.
But a drastic cut to NIH funding under the Trump administration set to take place Monday has caused alarm among UC leaders and many medical researchers, who said the move would “jeopardize America’s research preeminence.”
Speaking to The Times since the cuts were announced Friday night, UC medical researchers expressed concerns about the future of their labs and lifesaving endeavors — as have others at universities and academic medical centers nationwide.
The NIH said late Friday that it would slash by more than half so-called “indirect funding” — overhead for research supplies, building maintenance, utilities, support staff and other costs — that institutions receive as part of medical research grants.
Beginning Monday, NIH-sponsored indirect funding will be capped at 15% of grants, down from 57% that many UCLA research projects receive and the 64% given at UC San Francisco, which has the highest rate in the UC system.
In its X post on the change Friday, the NIH shared a graphic that compared the indirect funding rates for Harvard, Yale and Johns Hopkins with their multibillion-dollar endowments. The highest among them, Harvard, was 69%.
The NIH’s move would save roughly $4 billion a year in tax dollars, the post stated. The agency said that more than a quarter of its $35 billion in research funding last year went to overhead. As a comparison, it cited private foundations, including the Chan Zuckerberg Initiative and the Gates Foundation, saying their overhead costs are 15% or lower.
“The United States should have the best medical research in the world,” the NIH said in guidance posted to its website. “It is accordingly vital to ensure that as many funds as possible go towards direct scientific research costs rather than administrative overhead.”
University researchers said the money, despite being labeled “indirect funding,” is essential to their work and pays to keep lifesaving science going — from ensuring the proper storage of biological samples to keeping alive animals for medical trials. They also contend that private foundations do not have to follow the same rules in how they categorize spending, saying it is unfair to compare overheads between the two.
Republicans argue that the costs are superfluous, part of bloated spending of taxpayer funds that President Trump has appointed Elon Musk to pare down.
Scientists point out that universities have already been paying a greater share for research costs. Data from the National Center for Science and Engineering Statistics show that, since 1980, the federal slice of research support at universities has gone down 12% while university payments have gone up 11%.
Cuts could ‘imperil’ UC medical research
The NIH is the largest funder of UC research, providing $2.6 billion in the last academic year — 62% of the university’s federal awards of more than $4.2 billion.
In a statement, UC said that the “new administration guidance would imperil this vital support and jeopardize America’s research preeminence.”
“These time-honored university partnerships have led to some of the most powerful and impactful research discoveries in human history,” the statement said. “Life-saving treatments for cancer, diabetes, heart attacks, and strokes, including in children, and new technologies and industries that translate into hundreds of thousands of well-paying jobs are all at risk. America is first in research, but its dominance is not assured.”
On Saturday, UC officials were still analyzing the effect of the NIH move, and were in contact with UC lawyers, researchers and administrators on how to respond.
In an email to his science faculty after the NIH announcement, a UCLA dean said: “As with many announcements over the last several weeks, this no doubt causes significant anxiety. Please know that the leadership at UCLA and across the UC is working to understand the implications.”
White House defends move
The White House defended its action, saying in an email blast to media outlets Saturday that “the NIH did not announce any cuts to actual research.” It cited Vinay Prasad, a professor of epidemiology and biostatistics and medicine at UC San Francisco, who praised the NIH move on his blog.
The cut “might even mean more science. Less money spent on the administration is more money to give out to actual scientists,” wrote Prasad. “I am shocked to see researchers crying about how much money the university gets — it means more grants can be given per cycle.”
Several other UC researchers, many who had just applied for grant renewals after a recent application pause or were in the midst of assembling grant proposals, said they were stunned.
“All my research will be shut down if this goes through. There is no other way to say it. It will be done,” said Beate Ritz, a professor and vice chair of the epidemiology department at UCLA who has received at least $1 million a year for more than a decade from the NIH to research environmental pollution, Parkinson’s and Alzheimer’s. “It’s not my salary. I get paid by the state to teach. But it is the cost of much of everything else.”
What is being cut
Indirect costs cover items outside of salaries, travel, supplies and other direct expenses. The indirect costs are negotiated between the university and the federal government — typically every three or four years for UC campuses — which is why the change surprised scientists.
Gina Poe, a neurobiology professor in UCLA’s David Geffen School of Medicine, said she feared that her decades of research into memory, sleep and post-traumatic stress syndrome were threatened.
Poe explained how her grant works. She receives $250,000 a year from the NIH to pay five undergraduate and graduate research assistants, among other expenditures, including rats and mice. This does not include her indirect funding.
With UCLA’s indirect cost rate of 57%, at first glance, it appears Poe would receive an additional $142,500 in such funding. But she said the math is more complicated and she gets much less.
The federal government, Poe said, deducts certain costs from the grant before it calculates indirect funding levels. Major equipment costs, tuition awards to students and more are not included. In the end, her NIH indirect funding totals an additional $114,000, which mostly goes to UCLA and to the university’s life sciences division to cover facilities costs and other expenditures.
Among the budget items indirect funding pays for: workers who care for rats and mice, feeding them and cleaning their cages. It also pays for medicine and veterinarian visits.
Under the new NIH formula, Poe’s indirect funding allowance would be minimal.
“The only way left for me to make up that money is to move my work to a private company, for UCLA to raise tuition to cover extra costs or to apply to private foundations where the competition is going to increase significantly for funding,” Poe said.
Vivek Shetty, a UCLA professor of oral and maxillofacial surgery and biomedical engineering and former Academic Senate chair, expressed concerns that U.S. research power could be diminished.
“America’s global leadership in science and technology wasn’t built on genius alone. It relied heavily on infrastructure and systems that allowed universities to transform ideas into innovations. Cripple that infrastructure, and the next medical or AI advancement will happen elsewhere — taking with it not just jobs and prestige, but also the economic vitality and societal progress that innovation brings,” Shetty said.
The funding change has hit a particular nerve at universities since Trump’s inauguration. Many administrators have felt under the microscope from a president who has spoken out against what he describes as “Marxist” universities overrun with leftists.
Last month, UC officials raised concerns after a temporary NIH pause on research grant reviews. Trump’s executive orders have also targeted diversity, equity and inclusion programs — including in federal grants and programming. On Wednesday he signed an executive order designed to ban transgender athletes from participating in women’s or girls’ sporting events.
Times Staff Writer Corinne Purtill contributed to this story.
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