Science Sphere

🩸 A landmark study found traces of toxic metals, including lead and arsenic, in tampons — but newer FDA testing suggests the amounts released during use are too low to cause harm.

Researchers from UC Berkeley and Columbia University a**lysed 30 tampons from 14 brands sold in the United States, United Kingdom and European Union.

They tested for 16 metals and detected measurable amounts of every one of them in at least some samples.

These included lead, arsenic, cadmium, mercury, nickel and chromium.

Lead averaged about 120 nanograms per gram of tampon material, while arsenic averaged about 2.6 nanograms per gram.

Metal levels differed between products.

Non-organic tampons contained more lead on average, while organic tampons contained more arsenic.

No category — organic, non-organic, store brand or name brand — consistently had the lowest levels of all metals.

Researchers suggested the metals could enter cotton through soil, water or air during cultivation, or through manufacturing processes.

But the original study measured metals inside the tampon material.

It did not test how much actually leaches out during use or enters the bloodstream.

That distinction matters.

In 2026, FDA scientists tested 11 tampon products under exaggerated conditions designed to estimate metal release during use.

They detected trace metals, but their toxicological risk assessment concluded that the amounts likely to be released were too low to pose a health concern.

So the discovery of metals in tampons does not mean tampon use causes metal poisoning.

Still, the original study prompted regulators to investigate the issue more closely and pushed for better testing and transparency around menstrual-product ingredients.

📃 RESEARCH PAPER
📌 Shearston et al., “Tampons as a source of exposure to metal(loid)s”, Environment International

🦠 Nearly one in eight new cancer cases worldwide may be caused by infections, according to a major global a**lysis.

Researchers from the International Agency for Research on Cancer estimated how many cancers diagnosed in 2024 were attributable to 12 infectious agents already classified as definite human carcinogens.

Altogether, infections were linked to about 2.3 million new cancer cases — roughly 12% of all cancers diagnosed globally that year.

Five pathogens accounted for almost all of this burden.

Helicobacter pylori, the stomach bacterium that can cause ulcers, was linked to about 760,000 cases, mostly stomach cancers.

Human papillomavirus, or HPV, accounted for around 750,000 cases, including most cervical cancers and some a**l, pe**le, vulvar, vaginal and throat cancers.

Hepatitis B was linked to about 2% of all new cancers worldwide, largely liver cancer.

Epstein-Barr virus accounted for roughly 1%, while hepatitis C was responsible for less than 1%.

The burden was not distributed equally.

More than three-quarters of infection-related cancers occurred in low- and middle-income countries, while eastern Asia alone accounted for about 42% of the global total.

The encouraging part is that many of these cancers are potentially preventable.

Vaccines already exist for HPV and hepatitis B, while testing and treatment can reduce risks from H. pylori and hepatitis C.

But this does not mean everyone infected with these pathogens will develop cancer.

Most infected people never do, and cancer usually develops through a combination of infection, genetics, immune responses and other risk factors.

Still, the study shows that preventing and treating a small number of common infections could prevent a substantial number of cancers worldwide.

📃 RESEARCH PAPER
📌 Rumgay et al., “Global burden of cancer attributable to infections in 2024: a worldwide incidence a**lysis”, The Lancet Oncology (2026)

🧠 A single dose of an L*D-based drug has now succeeded in two Phase 3 trials for generalized anxiety disorder.

The drug, called DT120, is an orally dissolving pharmaceutical form of lysergide, better known as L*D.

Unlike conventional anxiety medications that are usually taken every day, DT120 is being developed as a single supervised treatment with effects lasting for weeks.

In the latest Phase 3 Panorama trial, 245 adults with generalized anxiety disorder received either 100 micrograms of DT120, a lower 50-microgram dose or placebo.

After 12 weeks, anxiety scores in the 100-microgram group had fallen by 9.8 points on the Hamilton Anxiety Rating Scale.

The placebo group improved by 4.7 points, giving DT120 a 5.1-point advantage.

Benefits appeared as early as the second day after treatment and remained significant throughout the 12-week study.

A separate Phase 3 trial called Voyage produced similar results, with DT120 showing a 5.4-point advantage over placebo after 12 weeks.

Participants were closely monitored after dosing because L*D temporarily causes major changes in perception, thinking and emotion.

In Panorama, the average time before participants met criteria to leave the clinic was about 6.2 hours, and 94% were cleared within eight hours.

The treatment was generally well tolerated, with no new safety signals reported.

But L*D has not been approved for anxiety yet.

The Phase 3 findings are currently topline company results and have not yet been published as full peer-reviewed papers.

Definium Therapeutics plans to submit a New Drug Application to the FDA in the first half of 2027.

If regulators approve it, DT120 could become one of the first psychedelic-based medicines available for generalized anxiety disorder.

📃 PHASE 3 CLINICAL TRIALS
📌 Definium Therapeutics, Panorama and Voyage Phase 3 trials of DT120 ODT for generalized anxiety disorder (2026)

🚲 Cycling as a regular form of transport was linked to a lower risk of dementia and Alzheimer’s disease in a large UK study.

Researchers a**lysed data from 479,723 adults in the UK Biobank, with an average age of about 57.

None had dementia at the start of the study, and participants were followed for a median of 13.1 years.

Researchers grouped people according to how they usually travelled: non-active transport such as cars or public transport, walking, mixed walking, or cycling and mixed cycling.

During follow-up, 8,845 participants developed dementia, including 3,956 cases of Alzheimer’s disease.

Compared with people using non-active transport, those who cycled or combined cycling with other forms of travel had a 19% lower risk of developing dementia.

Their risk of Alzheimer’s disease was 22% lower.

Cycling and mixed cycling were also associated with a 40% lower risk of younger-onset dementia, diagnosed before age 65, and a 17% lower risk of later-onset dementia.

Brain scans added another interesting clue.

People in the cycling groups tended to have larger hippocampal volumes. The hippocampus is a brain region crucial for learning and memory and is strongly affected in Alzheimer’s disease.

But this does not prove that cycling itself prevents dementia.

The study was observational, so people who cycle may differ from non-cyclists in health, fitness, income, lifestyle or other ways that researchers cannot fully account for.

Travel habits were also self-reported, and people with subtle early cognitive problems may have been less likely to cycle even before receiving a diagnosis.

Still, after adjustment for many lifestyle and health factors, cycling remained associated with lower dementia risk.

The findings add to growing evidence that building regular physical activity into everyday life may help support long-term brain health.

📃 RESEARCH PAPER
📌 Hou et al., “Active Travel Mode and Incident Dementia and Brain Structure”, JAMA Network Open (2025)

🌙 Women who were natural “night owls” had more body fat, more abdominal fat and less favorable metabolic markers than earlier chronotypes in a New Zealand study.

Researchers studied 287 healthy women aged 18 to 45 of European and Pacific New Zealand ancestry.

Participants were classified as morning, intermediate or evening chronotypes based on their natural sleep and wake preferences.

The researchers also measured body composition using DXA scans, recorded food intake for five days and a**lysed fasting blood samples.

About 34% of the women were evening types.

Compared with morning and intermediate types, night owls had a higher average BMI, higher total body-fat percentage and a greater ratio of abdominal to hip-and-thigh fat.

They also showed less favorable blood-fat profiles and poorer markers of glucose regulation.

Interestingly, the difference was not simply that night owls ate vastly more food overall.

Meal timing appeared important.

Evening types ate less energy, protein, carbohydrate and fat earlier in the day, but consumed more of these nutrients after 8 p.m.

Among night owls, greater evening intake was significantly associated with higher body-fat percentage and more abdominal fat.

Researchers suggest that repeatedly eating late, when the body’s circadian system is preparing for sleep and fasting, could contribute to poorer metabolic health.

But this study does not prove that staying up late causes weight gain.

It was cross-sectional, meaning sleep patterns, diet and body composition were measured around the same period rather than tracking weight changes over time.

The study also included only women aged 18 to 45.

Still, the findings suggest that for natural night owls, when they eat may matter alongside how much they eat.

📃 RESEARCH PAPER
📌 van der Merwe et al., “Chronotype and associations with dietary intake, meal timing, body composition, and metabolic biomarkers”, Frontiers in Nutrition (2026)

🌵 Mescaline, the psychedelic compound found in pe**te and San Pedro cacti, appears to disrupt the brain’s normal sensory filtering system, according to a new rat study.

Researchers at Northeastern University gave mescaline to awake rats and tracked their brain activity using functional MRI.

The strongest changes appeared in the cerebellum, a region traditionally linked to movement and balance but also involved in attention and sensory processing.

Mescaline reduced activity within several parts of the cerebellum.

At the same time, it increased communication between the cerebellum and regions involved in memory, sensory relay and body awareness, including the hippocampus, thalamus and somatosensory cortex.

The hippocampal change was especially striking.

Brain regions that showed almost no functional connection with the cerebellar nuclei under normal conditions became strongly connected after mescaline.

Researchers also tested how the animals responded to smell and sound.

Mescaline nearly eliminated the normal brain response to a rewarding almond scent.

It also altered prepulse inhibition, a process the brain uses to filter repeated sounds, but the effect depended on sound frequency.

Rather than simply switching sensory filtering off, researchers think mescaline may change which incoming signals are amplified and which are suppressed.

This could help explain why psychedelics can dramatically alter perception and bodily awareness.

But this study was conducted in rats.

Scientists cannot know whether rats experience hallucinations like humans, and the same brain changes have not yet been demonstrated in people taking mescaline.

Still, the findings provide a new clue to how one of humanity’s oldest psychedelics may reshape sensory processing in the brain.

📃 RESEARCH PAPER
📌 Cavallaro et al., “Mescaline Alters Cerebellar Function, Global Connectivity, and Frequency-Selective Acoustic Gating: A BOLD fMRI Study in Awake Rats”, Neuroscience Bulletin (2026)

🫃 Your stomach rumbles may reveal how well your brain senses what is happening inside your gut, according to a new study.

Researchers at University College London developed a test called “Rumble Recognition” to measure gastrointestinal interoception — our ability to detect and interpret signals from the digestive system.

They recruited 45 healthy adults.

After fasting for three hours, participants had a digital stethoscope placed on their abdomen to record normal bowel sounds, scientifically called borborygmi.

They then listened to two 15-second recordings.

One was a live feed of their gut sounds at that moment, while the other had been recorded a few minutes earlier.

Participants had to identify which sound was happening live and rate how confident they were.

The task was repeated while fasting, after drinking sparkling water, and after consuming a high-protein meal-replacement shake.

Overall accuracy was only around 56 to 60% — slightly above the 50% expected by chance.

But there were striking differences between individuals.

Roughly one in five participants performed significantly above chance while fasting, rising to around one in four after sparkling water or the meal replacement.

Some people were also better at judging when their own answers were likely to be correct.

Researchers say this inexpensive, non-invasive test could help scientists study differences in gut awareness linked to hunger, eating disorders, irritable bowel syndrome, anxiety and depression.

But stomach noises themselves are not a diagnostic test for these conditions.

The study involved only healthy adults and measured awareness of gut signals, not whether specific sounds reveal a particular disease.

Still, the work offers a new way to study how closely the brain listens to the digestive system.

📃 RESEARCH PAPER
📌 Savage et al., “Rumble Recognition: a gastrointestinal sound discrimination task to measure gastrointestinal interoception”, Scientific Reports (2026)

🍬 Cutting back on sugary foods during antibiotic treatment may help protect the gut microbiome from disruption, according to a new study.

Researchers tracked 9,419 meals eaten by 173 people hospitalized for hematopoietic stem-cell transplantation, a group that often receives powerful broad-spectrum antibiotics.

Among 158 patients with repeated stool samples, higher intake of sweets and added sugars during antibiotic exposure was linked to lower gut-bacterial diversity.

For every additional 100 grams of sugary foods consumed after broad-spectrum antibiotics, the model predicted about a 24% further drop in microbial diversity.

Sugar intake was also linked to greater expansion of Enterococcus faecium, a bacterium that can become problematic when it dominates the gut, particularly in medically vulnerable patients.

The team then tested the relationship in mice.

Adding sucrose to the diet after antibiotic treatment caused Enterococcus levels to rise around 16-fold more by day 3 and 33-fold more by day 6 compared with antibiotics alone.

Importantly, sugar by itself did not cause the same bacterial bloom.

Researchers also found that the effect was not limited to sucrose: glucose, fructose and even a fruit smoothie could worsen Enterococcus expansion after antibiotics in some experiments.

But this does not mean everyone taking antibiotics must completely avoid sugar.

The human part of the study involved seriously ill transplant patients, and it was observational, so it cannot prove that sugar caused the microbiome changes.

The mouse experiments provide stronger evidence for a biological effect, but human dietary trials are still needed.

Still, the findings suggest that reducing simple sugars around antibiotic treatment could be one practical way to lessen microbiome disruption.

📃 RESEARCH PAPER
📌 Dai et al., “Sugar-rich foods exacerbate antibiotic-induced microbiome disruption”, Nature (2026)

🍄 A single dose of psilocybin produced a much greater reduction in treatment-resistant depression than placebo in the first publicly funded UK randomized trial of its kind.

Researchers at King’s College London and South London and Maudsley NHS Foundation Trust enrolled 60 adults whose depression had not responded adequately to at least two previous treatments.

Half received a single 25-milligram dose of psilocybin, while the other half received a true placebo.

Both groups also received psychological preparation, support during dosing and follow-up integration.

Three weeks later, depression scores had fallen substantially more in the psilocybin group.

About 43% of people who received psilocybin met the trial’s threshold for a clinical response, compared with just 3% in the placebo group.

By six weeks, 50% of the psilocybin group met the response threshold, while the placebo group remained at 3%.

Remission showed a similar pattern.

Around 40% of participants who received psilocybin were in remission at three weeks, compared with 3% on placebo, and that difference was maintained at six weeks.

Most side effects were mild and temporary.

Four serious adverse events occurred — three in the psilocybin group and one in the placebo group — but none were judged to have been caused by psilocybin.

There is an important limitation.

Because psilocybin produces obvious psychedelic effects, every participant in the psilocybin group correctly guessed what they had received, and 70% of placebo participants also guessed correctly.

Expectations may therefore have contributed to some of the difference.

Still, the results strengthen evidence that a single medically supervised psilocybin session may provide rapid relief for some people with treatment-resistant depression.

📃 RESEARCH PAPER
📌 Rucker et al., “Psilocybin-assisted therapy for treatment-resistant major depressive disorder in a public healthcare setting: a randomized controlled trial”, Nature Medicine (2026)

🦠 Scientists have engineered a probiotic gut bacterium to act like a tiny drug factory inside pancreatic tumors.

Researchers at the University of Chicago modified Bifidobacterium longum, a bacterium naturally found in the human gut, to produce a redesigned immune molecule called SumIL-2.

IL-2 can activate cancer-fighting T cells, but conventional IL-2 therapy can also cause serious side effects and stimulate immune cells that suppress antitumor responses.

SumIL-2 was designed to favor cancer-fighting T cells while limiting those unwanted effects.

The bacteria were then injected into mice with pancreatic ductal adenocarcinoma.

Because Bifidobacterium thrives in low-oxygen environments, it preferentially accumulated inside the oxygen-poor regions of tumors while being cleared from healthier tissues.

Once there, the engineered bacteria released SumIL-2 directly into the tumor.

The treatment slowed pancreatic tumor growth and increased the activity of CD8+ T cells, which can directly kill cancer cells.

Researchers also found that the therapy worked even better when combined with standard treatments.

Pairing the bacteria with the chemotherapy drug gemcitabine produced greater tumor suppression and improved survival compared with either treatment alone.

Combining it with radiation and anti-PD-L1 immunotherapy also produced stronger tumor control.

But this has not been tested in people.

The experiments involved small groups of mice, and researchers still need to establish long-term safety, durability and whether the bacteria can be delivered in a practical way to patients.

Still, the study demonstrates an unusual strategy: using engineered probiotic bacteria to carry powerful immune therapy directly into one of the hardest cancers to treat.

📃 RESEARCH PAPER
📌 Lee et al., “Engineered probiotic Bifidobacterium for tumor-targeted pancreatic cancer therapy”, Science Advances (2026)