Sugar amplifies damage done to gut health by antibiotics

 

Eating sweets while taking antibiotics may worsen the harm done by the drugs to the normal community of bacteria in the gut, a new study found.

The work centers on the intestinal microbiome, which harbors bacterial species that co-evolved with humans to live in the digestive tract, help digest food, and support the immune system. Antibiotics, among the most prescribed drugs globally, are known to eliminate helpful bacteria alongside harmful species, in some cases letting harmful ones dominate. 

The microbiome is more capable of resisting the buildup of harmful pathogens when natural species diversity is in place, but antibiotics reduce diversity in ways that make the gut more vulnerable to disease, the study authors said.

Led by researchers from NYU Langone Health, City of Hope, and Memorial Sloan Kettering, the study precisely tracked every food item in 9,419 meals eaten by 173 hospitalized cancer patients and then measured their gut microbiome changes. The team found an additional 21% reduction in alpha diversity, a measure of the variety of helpful bacterial species present, for every 100 grams of sugar consumed in the 48 hours before treatment.  

Publishing online Sept. 30 in the journal Nature, the work also showed how the combination of a sugary diet and antibiotic treatment caused blooms in patients of the bacterial species Enterococcus faecium, which has been linked to hard-to-treat infections. Experiments in mice confirmed this pattern, wherein exposure to the antibiotic biapenem and dietary sucrose drove a 16.3-fold increase in the Enterococcus population in the gut by day 3 of the study, and 33.4-fold higher burden by day 6.

“As we are learning how collateral damage of antibiotics to the microbiome are linked with long-term health problems, it’s important to identify factors that limit these unintended health risks,” said the study’s co-senior author Jonas Schluter, PhD, assistant professor in the Department of Microbiology at NYU Langone. “Our study, which used more than 9,000 recorded meals, suggests that modifying diet during and after antibiotics, specifically by reducing sweets intake, could help with that.”

The research team studied patients with blood cancers because they receive antibiotics frequently and precisely tracking food intake is feasible during hospitalization. The researchers recorded patient diets at every meal and collected microbiome samples daily, making the study among the largest and highest-resolution of its kind to date.

"The microbiome is emerging as an important factor in cancer care", said co-senior study author Marcel van den Brink, MD, PhD, chief physician executive at City of Hope. "For patients undergoing intensive treatments such as bone marrow transplantation, the healthy diversity of the gut microbiome can have important implications for outcomes. Studies like this help us better understand how everyday factors, including diet, may affect a delicate balance that influences how patients respond to treatment, recover and experience side effects."

Patients with blood cancers who undergo stem cell transplantation are typically hospitalized for several weeks, during which they receive both chemotherapy and antibiotics. During this time, they show drastic changes in nutrition as well as severe damage to their microbiomes. In these patients, harmful bacterial species like Enterococcus faecium often thrive because the rest of the gut ecosystem has been “destroyed.”

“Especially in blood cancer patients, microbiome injury is associated with worse outcomes, including higher overall mortality and infections,” said Jonathan Peled, co-senior author on the study and associate director of the Center for Hematological Malignancies at Memorial Sloan Kettering Cancer Center. “An important next step will be to design clinical trials to test whether short-term dietary changes can improve clinical outcomes in patients.”

“The new work identifies dietary sugars as an amplifier of antibiotic-induced microbiome disruption, probably because the potentially harmful bacteria that survive the antibiotics are benefiting from the dietary sugars that they can use to expand,” said study second author William Jogia, a PhD student in Dr. Schluter’s lab in the Institute for Systems Genetics. “While the findings suggest that reducing simple sugars may limit microbiome injury, whether sugar directly supports Enterococcus, weakens competing bacteria, or acts through another mechanism in patients remains to be seen.”

High-intensity walking can reverse frailty more effectively than casual-speed walking

 Interventions to reduce frailty and promote healthy aging are critical to improving quality of life and reducing disability in older adults. Walking is the most common form of exercise among older adults; however, the optimal walking intensity for prefrail and frail adults remains unclear. We conducted a cluster-randomized, assessor- and participant-blinded trial to determine whether high-intensity walking (HIW) improves frailty more than casual-speed walking (CSW). Fourteen retirement communities were randomized to either HIW or CSW using a modified minimal sufficient balance randomization scheme. We recruited 165 prefrail and frail adults aged ≥60 years, of whom 105 were included in the analytic cohort. Participants were able to ambulate at least 10 feet with moderate assistance or less.  This cluster-randomized trial demonstrates that high-intensity walking can reverse frailty more effectively than casual-speed walking due to increased physiologic stimuli during more intensive activity.

Full study

Digital menstrual tracking risks creating more harm than benefit

 

Digital menstrual tracking risks creating more harm than benefit and requires greater scrutiny, warn experts in The BMJ today. 

Widely promoted to women and girls on social media and by tech firms, menstrual tracking apps and other “femtech” tools claim to scientifically analyse personal data to improve health, wellbeing, and performance based on a user's menstrual cycle. 

But Katharine Lee and colleagues argue that neither menstrual tracking nor "cycle syncing" - adjusting diet and exercise according to menstrual cycle phases - have been convincingly shown to improve health or other performance measures. 

And they say the slick marketing of digital menstrual cycle tracking apps and the scientifically suspect practice of cycle syncing “require critical interrogation and resistance.”

For example, decades of sports science research shows no overall effect of menstrual cycle phase on performance, injury risk, or health, and any effects found have been trivial and highly individualised. Research on phased based dietary interventions to reduce menstrual cycle symptoms or improve performance is also generally inconclusive, highly individualised, or speculative.

Even if menstrual phase corresponded with fluctuations in health, performance, or vulnerability to injury in individuals, simple digital tracking technologies cannot reliably predict such variation, they explain.

Aside from their weak evidence base, digital cycle tracking technologies also come with serious risks, they write, including wasted time and labour, unwanted surveillance, risks to health data privacy, and may distract from or even threaten efforts to advance women’s health.

“These apps have the potential for widespread impact on the wellbeing of women and girls. Yet, the evidence that these digital tools can actually help in the management of menstrual conditions, boost health, and provide insights into exercise and nutritional needs is lacking,” they warn.

Suggestions to address the risks of digital tracking include strengthening protections for consumer and employee data, improving user awareness of how data are used, and advising clinicians to recommend apps to patients only when they meet stringent standards.

Others have emphasised the need to regulate misleading marketing and resist the commercial co-option of feminist activist rhetoric.

Tailoring health communications approaches to the social media environments where users encounter cycle syncing content may offer an opportunity to build the public’s trust in more credible sources and counteract misleading narratives about hormones and health, they note.

Meanwhile, health practitioners, regulators, and the general public must be aware of and work to address the risks of these consumer technologies on women’s health, they conclude.

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Journal

The BMJ

DOI

10.1136/bmj-2026-100858 

Blueberries daily for older, sedentary adults: less depression

A new pilot study has found that older, sedentary adults who consumed blueberries daily showed a greater, more consistent reduction in depressive symptoms, paired with minor changes in markers of gut microbial enzymes.

While there were no statistically significant differences in changes in depressive symptoms between the test and placebo groups, the preliminary data warrant additional research to investigate the link between blueberries, the gut microbiome, and mood in older adults.

“Fiber and anthocyanins in blueberries have potential to modify the gut microbiome and metabolites that are relevant to depression in older adults,” said lead author Courtney L. Millar, PhD, assistant scientist II at Hebrew SeniorLife’s Hinda and Arthur Marcus Institute for Aging Research and assistant professor of medicine at Beth Israel Deaconess Medical Center and Harvard Medical School. “Our objective was to preliminarily determine the effect of blueberry consumption on the gut microbiome, metabolites, and depressive symptoms.”

Study design

Sedentary adults 65 years and older with mild depressive symptoms were enrolled in a randomized, double-blind, parallel-arm, placebo-controlled pilot study. Participants consumed 48 grams per day of blueberry powder (approximately two cups of fresh berries) or a matched placebo powder for three months. Metagenomic sequencing measured the abundance of gut microbiota species and genes, liquid chromatography/mass spectrometry evaluated gut-derived fecal short-chain fatty acids, and validated questionnaires evaluated depressive symptoms before and after the intervention.

Study participants

Eighteen participants, predominantly female and white, completed the intervention (placebo group, n = 8; mean age: 75 ± 6; blueberry group, n = 10; mean age: 71 ± 4).

Measures of gut microbe species abundance, MetaCyc pathways, and short-chain fatty acid metabolites did not change. There were statistically significant differences in the gene abundance of several enzyme commissions of the gut microbiome within the blueberry group — including EC 3.6.3.31 Polyamine Transporting ATPase, which is involved in the production of the neurotransmitter, gamma-aminobutyric acid (GABA).

The study, “A pilot study of daily blueberry intake modulates the gut microbiota enzyme commissions in older, sedentary adults with mild depressive symptoms,” was published in the Journal of Nutrition, Health and Aging.

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Pre-exercise caffeine enhances repeated performance for at least 3.5 hours

 Caffeine is one of the most widely used performance-enhancing supplements in sport. Despite its established ergogenic effects, the duration for which these benefits persist and how physiological responses change over that period remain unclear.

In the study, 12 healthy young adults consumed either caffeine (5.5 mg per kilogram of body mass) or a placebo 60 min before exercise. Participants then completed repeated cycling sprint tests over 3.5 h. Physiological measurements included plasma caffeine and noradrenaline concentrations, cardiovascular and respiratory responses, cerebral blood flow, and ratings of perceptual responses. Caffeine enhanced both mean and peak sprint power output, with noticeable performance benefits for at least 3.5 hours after ingestion. In addition, caffeine increased plasma noradrenaline concentrations after sprint exercise and decreased ratings of perceived exertion and leg muscle pain. Furthermore, caffeine altered cardiovascular and respiratory responses and reduced middle cerebral artery blood velocity, a common index of cerebral blood flow.

These findings show that a single pre-exercise caffeine dose can maintain its performance-enhancing effects for several hours during prolonged intermittent exercise. They provide new insight into how long caffeine's performance-enhancing effects persist during prolonged intermittent exercise and may help athletes better take advantage of caffeine's effects during prolonged competitions.

Reducing ultra-processed food (UPF) intake & being active can cut risk of type 2 diabetes

 

, regardless of genetic make-up

Your genes are not your destiny, say study’s authors

Reports and Proceedings

European Association for the Study of Diabetes

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Eating a diet low in ultra-processed foods (UPFs) and exercising can cut the risk of type 2 diabetes, even in those with a strong genetic disposition to the condition, new research being presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2) suggests.

The analysis of data on tens of thousands of people in the UK found that those who had a diet low in processed food and did regular moderate to vigorous physical activity were up to 70% less likely to develop the condition.

In those with a strong genetic predisposition, the diet-exercise combination halved the risk of type 2 diabetes.

“Type 2 diabetes is caused by a combination of a person’s genetic susceptibility and their lifestyle,” says Wenxin Xu, of City University of Hong Kong, Hong Kong, China, who led the research.

“In terms of lifestyle, eating more ultra-processed food is associated with a higher risk, whereas physical activity is protective.

“However, whether a lower UPF intake reduces genetic susceptibility hasn’t been clear. Nor have we known whether exercising helps offset the impact of UPFs.

“It is important to find this out because, unlike genetic susceptibility, diet and physical activity can be modified – they are things people can change.”

To find out more, Ms Xu and colleagues at the City University of Hong Kong (Hong Kong and Dongguan) examined data on 56,964 adults in the UK Biobank study (average age 69.5 years, 42.3% male).

Detailed questionnaires provided information on UPF intake at baseline, as defined by the Nova system1. The amount of moderate-to-vigorous physical activity (MVPA) was calculated from activity trackers worn on the wrist for a week. MVPA is exercise that increases heart rate and breathing rate. Examples include brisk walking, cycling, hiking and walking the dog. Sports, housework and gardening jobs that require sustained physical effort are also included. Genetic susceptibility to type 2 diabetes was estimated from genetic data.

During an average follow-up period of 7.8 years, 926 of the participants developed type 2 diabetes.

As expected, eating more UPFs was associated with a higher risk of the condition and, MVPA, a lower risk. Type 2 diabetes risk increased in line with UPF intake. Every 10% (by weight) of an individual’s diet that was made up of UPFs increased their risk of type 2 diabetes by 7%. Meanwhile, the participants who met the World Health Organization (WHO) recommendation of at least 150 minutes of MVPA a week were 39% less likely to develop type 2 diabetes than those who exercised less.

Further analysis indicated that a lower UPF intake and MVPA both partially offset genetic susceptibility to type 2 diabetes.

In those whose genes put them at high risk of type 2 diabetes, a low UPF intake (approximately 11% or less of total food intake by weight came from ultra-processed foods) was associated with a 35% lower likelihood of the condition. Meeting the MVPA recommendations was associated with a 33% lower risk of type 2 diabetes.

The researchers also found that exercise seems to reduce the impact of UPFs, even in those with a strong genetic predisposition to type 2 diabetes. In participants with high UPF intake (approximately 33% or more of total food intake by weight came from ultra-processed foods), meeting WHO recommendations for MVPA was assåΩociated with 31% lower risk of type 2 diabetes risk in those with a high genetic risk, 57% in those with an intermediate genetic risk and 58% in those at low genetic risk.

The combination of lower UPF intake and MVPA was associated with even greater protection against the condition. It was linked to a 49% reduction of risk of type 2 diabetes in those whose genes made them highly susceptible to type 2 diabetes, a 70% reduction in those with an intermediate genetic susceptibility and a 59% reduction in those with a low genetic susceptibility.

This highlights the importance of considering lifestyle changes together, rather than in isolation, say the authors. They acknowledge that the findings are observational and so cannot prove cause and effect. However, they are in line with existing advice to eat a healthier diet and stay physically active to prevent or delay the onset of type 2 diabetes.

Ms Xu adds: “Our study indicates that our genes are not our destiny.

"Even among people with a high genetic susceptibility to type 2 diabetes, lower intake of ultra-processed foods and regular moderate-to-vigorous physical activity were associated with a substantially lower risk of developing the condition.

“While we cannot say that type 2 diabetes can always be avoided, our results suggest that healthy lifestyle choices may help reduce the risk whatever your genetic background.”å

Appendectomy for appendicitis associated with 58% lower colorectal cancer risk

 

 than antibiotics alone

In a matched study of more than 30,000 patients, colorectal cancer was later diagnosed in 0.7% of those who had surgery for acute appendicitis compared with 1.7% of those treated with antibiotics alone

Reports and Proceedings

American College of Surgeons

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Key Takeaways 

• In a matched cohort of more than 30,000 appendicitis patients, appendectomy was associated with a 58% lower relative risk of a later colorectal cancer diagnosis (0.7% vs. 1.7%). 

• Age, family history, genetic predisposition, and other established colorectal cancer risk factors may ultimately help inform patient selection and follow-up. 

• Exact mechanisms behind the association are unknown, but could be tied to earlier detection of an underlying cancer, removal of a source of inflammation, and the appendix’s potential role in the intestinal microbiome and immune system. 

• The findings will be presented at the American College of Surgeons Clinical Congress 2026 in Washington, Sept. 26-29. 

WASHINGTON (September 25, 2026) — Patients who underwent an appendectomy for acute appendicitis had a significantly lower subsequent risk of colorectal cancer than similar patients treated with antibiotics alone, according to new research. 

The research will be presented at the American College of Surgeons (ACS) Clinical Congress 2026 in Washington, Sept. 26-29, where thousands of surgeons will convene to advance surgical quality, patient safety, and access to care. 

Appendicitis is inflammation of the appendix, a small, narrow organ located near the junction of the small and large intestines. The removal of the appendix, or appendectomy, is one of the most common surgeries in the United States. In select patients, appendicitis can also be managed with antibiotics rather than surgery. 

“The management of acute appendicitis has changed significantly over the last decade, and antibiotic therapy is now an accepted option,” said senior author Valentine Nfonsam, MD, MS, FACS, FASCRS, professor and executive vice chair of the department of surgery at Morehouse School of Medicine. “However, most of the discussion has focused on short-term outcomes: avoiding surgery, recurrence, complications, and quality of life. We wanted to ask a different question: Are there potential long-term oncologic implications of leaving the appendix in place after appendicitis?” 

Researchers performed a retrospective cohort study using the TriNetX Global Collaborative Network, which included data from 168 health care organizations. The investigators identified patients diagnosed with acute appendicitis who were treated with either an appendectomy or antibiotics alone. 

After matching the groups by characteristics, each treatment group included 15,774 patients. Once patients with a colorectal cancer diagnosis before the study’s outcome period were excluded, there were 15,616 appendectomy patients and 15,295 patients treated with antibiotics. 

Using retrospective data, the researchers found that colorectal cancer was diagnosed in 110 patients who underwent appendectomy, or 0.7%, compared with 254 patients treated with antibiotics alone, or 1.7%. Appendectomy was associated with a 58% lower relative risk of a subsequent colorectal cancer diagnosis. 

“These results should not be interpreted to mean that everyone with appendicitis needs an appendectomy to prevent cancer,” Dr. Nfonsam said. “Antibiotic management remains an important option. But when we discuss nonoperative management, we should also think beyond the immediate episode of appendicitis and consider potential long-term oncologic risk and appropriate monitoring.” 

“Useless” Organ or Small but Mighty?  

The appendix was once widely viewed as a useless organ, simply a leftover from evolution. Emerging research, however, suggests that it may play a role in the intestinal immune system and the gut microbiome, the community of bacteria and other microorganisms living in the digestive tract. 

According to Dr. Nfonsam, the appendix contains a substantial amount of lymphoid tissue that is thought to contribute to immune system functioning. Changes in inflammation and the microbial environment have been linked to processes involved in colorectal cancer, so the appendix’s biological functions represent one possible area for further investigation. 

The authors say that an inflamed appendix could be a symptom of a larger problem in the digestive system, such as colorectal cancer. Removing the appendix gives surgeons a chance to examine the health of the digestive system directly and eliminates a source of inflammation. 

“The appendix is more than a vestigial organ,” said Dr. Nfonsam. “It is rich in lymphoid tissue and participates in the intestinal microbiome and immune system in that area. Whether persistent inflammation or changes in the local microbial environment contribute to the development of cancer is biologically plausible, but our study cannot answer that question.” 

In some patients, appendicitis may be an early sign of an undiagnosed colorectal cancer rather than a cause of a future cancer. For example, an occult right-sided colorectal tumor may obstruct drainage from the appendix and initially present as acute appendicitis. 

Appendectomy also allows the removed appendix to undergo pathologic examination. Findings from that examination may prompt additional diagnostic testing. Patients treated with antibiotics alone do not have the same immediate opportunity for tissue analysis. 

“Treatment should not be one size fits all,” Dr. Nfonsam said. “Age, genetic predisposition, family history, and other colorectal cancer risk factors may all be relevant as we study how to select patients and plan follow-up.”