An erratic sleep schedule harming your mental health

 

Depression and anxiety may be the price you pay for going to bed and waking up at inconsistent times

People with irregular sleep-wake schedules may experience more severe symptoms of anxiety, depression, and even loneliness, according to a large study led by UC San Francisco and UC San Diego.  

Although prior sleep research has largely focused on sleep duration and sleep quality, this study examined sleep regularity — how consistently people followed the same sleep-wake patterns each day — using months of data from wearables. 

The study was published in Scientific Reports on Nov. 12.  

“Regular sleep and wake time help keep circadian rhythms aligned,” said senior author Ashley Mason, PhD, of the UCSF Department of Psychiatry and Behavioral Sciences. “Irregular sleep-wake timing may weaken circadian alignment, which is associated with depression and other mental health disorders.” 

Irregular sleep schedules can also disrupt the timing of light exposure, meals, exercise, and social activity, all of which help regulate the circadian rhythm, noted Mason, who is also affiliated with the UCSF Osher Center for Integrative Health.  

In this study, researchers analyzed data from approximately 23,000 participants who were enrolled in TemPredict, a study launched in 2020 to investigate whether data from wearables could help identify COVID-19 before people recognized symptoms.  

Participants contributed an average of 154 days of sleep data, which allowed researchers to examine sleep regularity over time. They also created a “typical week” snapshot to compare their findings with previous, much shorter studies on sleep regularity. They discovered that associations between sleep and mental health were stronger with the longer-term data. 

The participants’ average age was 46 and just under half were women. They wore a smart ring that uses sensors to detect movement and measure vital signs. The smart ring used this data to estimate when they fell asleep and woke up. Researchers were then able to calculate each participant’s Sleep Regularity Index (SRI), ranging from 0 to 100, with higher scores indicating more consistent sleep patterns. 

Worsening depression, anxiety tied to progressive sleep irregularity 

Participants’ depression, anxiety, and loneliness were assessed by a monthly self-reported survey. Overall, less regularly timed sleep correlated with greater depression and anxiety. 

In the long-term analysis, participants with few symptoms of depression or none at all had an average SRI of 84, compared with 83 for those with mild depressive symptoms, 81 for moderate symptoms, and 75 for severe symptoms.   

Participants with normal levels of anxiety had an average SRI of 84, compared to 79 for those with severe anxiety. Participants with elevated loneliness also had less regular sleep-wake schedules.  

“Someone with an SRI of 84 might go to bed and wake up roughly an hour earlier or later than the previous day, on average,” said first author Severine Soltani, PhD, formerly of the Bioinformatics and Systems Biology graduate program at UC San Diego. “For someone with an SRI of 75, that shift in sleep schedule might be closer to an hour and a half.” 

Mason said the association between poor sleep and poor mental health could be codirectional: Irregular sleep could also be explained as a symptom of poor mental health. “Other longitudinal research provides some reason to think that irregular sleep may come first and contribute to later poor health, rather than being solely a consequence of it.” 

The authors say future research should test whether helping people establish more regular sleep schedules can improve mental health. 

  

A green Mediterranean diet produced a 14% reduction in the fat in the pancreas

 Fat that builds up in the pancreas is one of the lesser-known risk factors for diabetes and metabolic syndrome, but it turns out it can be targeted directly through what's on the plate.

A new international study led by Ben-Gurion University of the Negev, published in The American Journal of Clinical Nutrition (https://doi.org/10.1016/j.ajcnut.2026.101513), shows how a precise dietary change can draw fat out of the pancreas, the organ that regulates blood sugar and insulin secretion. The study was carried out during the DIRECT-PLUS trial and followed about 300 participants who underwent advanced abdominal MRI scans over 18 months. A green Mediterranean (Green-MED) diet produced a 14% reduction in the fat stored inside the pancreas, compared with just 0.8% in the group following standard dietary guidelines. Specifically, a direct association was observed between the amount consumed and the magnitude of pancreatic fat reduction: participants who consumed more than 3 servings of Mankai per week or more than 5.5 servings of walnuts per week had significantly greater reductions in pancreatic fat than those with lower intakes.

Unlike liver fat or abdominal (visceral) fat, pancreatic fat has no agreed clinical threshold yet, but its buildup causes local lipotoxicity. One of the study's key advances was using MRI to separate the clearance of pancreatic fat from the preservation of functional pancreatic volume. This distinction matters clinically: obesity enlarges the pancreas through fat infiltration, while diabetes and aging shrink it through beta-cell death. The study found that the green diet, together with regular exercise, cleared the toxic fat without shrinking the functional tissue, which points to preservation of the organ's healthy structure. Clearing fat from the pancreas also improved glycemic measures and insulin resistance, even after statistically adjusting for the drop in intra-abdominal fat and for weight loss. This shows that pancreatic fat affects blood-sugar control directly and in its own right, not just as a byproduct of losing weight or trimming the waistline.

The study also sheds new light on the role of the aquatic plant Mankai and points to a clear anatomical mechanism. Earlier research showed that Mankai helps balance blood sugar after meals, and this study adds another mechanism behind that effect. Refined carbohydrates worked the other way. Eating bread, cereal and pasta slowed and blocked the clearance of fat from the organ.

High-fat diet may increase colon cancer risk

 

Researchers at Arizona State University, USA, find that a high-fat diet leaves lasting changes in intestinal stem cells, potentially increasing the risk of tumor development.

About one in 25 people develop colon cancer during their lifetime, and obesity increases the risk by 30–50%. Colon cancer can arise when intestinal stem cells, which normally produce new cells to maintain a healthy intestine, begin to grow uncontrollably. A new study published today in Stem Cell Reports reveals how a high-fat diet can alter these stem cells and promote tumor development.

Led by Miyeko Mana, the researchers fed mice a Western-style high-fat diet for approximately six months. Compared with mice on a low-fat diet, these mice gained more weight and developed more intestinal stem cells, which also grew faster. Mice genetically predisposed to intestinal cancer developed more and larger tumors when fed the high-fat diet.

The researchers also identified changes in the DNA of intestinal stem cells that may help explain their increased growth and survival. Although stem cell behavior returned to normal after mice switched to a low-fat diet, some DNA changes persisted. After four weeks, approximately 18% of these changes remained.

When mice returned to a high-fat diet, their intestinal stem cells responded more quickly and strongly than those of mice exposed to the diet for the first time. Mice genetically predisposed to intestinal cancer also developed more and larger tumors after repeated exposure to a high-fat diet than after a single period of exposure.

The findings suggest that a high-fat diet can leave lasting changes in intestinal stem cells, making them more responsive to future high-fat exposure and, together with genetic mutations, increasing the likelihood of tumor development. The study also suggests that maintaining a healthy, low-fat diet may help regulate intestinal stem cell growth and reduce colon cancer risk.

Urolithin A is found to increase blood flow to the brain during memory tasks

 A dietary supplement called urolithin A increased blood flow to the brain during mental activity in middle-aged adults with obesity, according to a University of Oklahoma study published in JAMA Network Open. The findings could help researchers better understand the relationship between the supplement, blood vessel function and brain health.

Obesity is associated with changes in blood vessel function that can affect circulation throughout the body, including the brain. Researchers wanted to determine whether urolithin A could improve blood vessel function in adults with obesity. To find out, they conducted a randomized clinical trial involving 50 adults aged 40 to 64. Participants received either 1,000 milligrams of urolithin A daily or a placebo for four weeks.

Researchers found that participants who took urolithin A experienced a greater increase in blood flow to the brain while performing a challenging memory task than those who received the placebo. The change was particularly apparent in the left dorsolateral prefrontal cortex, a region of the brain involved in working memory. However, the supplement did not significantly improve the function of blood vessels in the arm, and participants did not perform significantly better on memory tests. This is the first human study to report an effect of urolithin A on cerebrovascular function, the researchers said.

“The brain needs an adequate supply of blood to meet the demands of mental activity,” said the study’s first author, Ana Clara da Costa Pinaffi Langley, Ph.D., an assistant professor in the Department of Nutritional Sciences at the OU College of Allied Health on the OU Harold Hamm Health Campus. “We found that urolithin A increased blood flow to the brain during a memory task, suggesting the supplement may help the brain meet its increased need for oxygen and nutrients when it is working harder. We plan to conduct more research to understand what this finding means for brain health.”

Urolithin A is a substance produced when certain gut bacteria break down compounds found in foods such as strawberries, pomegranates and walnuts. The amount that people naturally produce varies, but existing research suggests that a person’s ability to produce urolithin A decreases with age and as body mass index goes up, Langley said. Urolithin A is also available as a dietary supplement.

The supplement was well-tolerated during the study. However, the researchers noted that the trial was relatively small and conducted at a single site, and that longer studies involving more participants are needed to understand the effects of urolithin A.

“These findings offer an interesting starting point for understanding how urolithin A affects the brain,” said study co-author Andriy Yabluchanskiy, M.D., Ph.D., an associate professor in the Department of Neurosurgery at the OU College of Medicine. “Although we saw increased blood flow to the brain during mental activity, participants did not demonstrate measurable improvements in memory or attention. Future studies will need to determine whether taking the supplement for a longer period leads to meaningful improvements in cognitive function or other health benefits.”

Langley added that the ultimate goal of the research is to extend healthspan. “The idea is to mitigate cognitive decline,” she said. “We want to expand the time that people are living healthier lives.”

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About the project

The study, “Urolithin A and Endothelial and Cerebrovascular Function in Middle-Aged Adults With Obesity, can be found here

Alzheimer’s risk 53 per cent higher for those with type 2 diabetes

 

A Curtin University-led review has revealed type 2 diabetes significantly raises risk of developing Alzheimer’s disease.

 

Researchers conducted a systematic review and meta-analysis of 40 studies and found if 1000 people living with type 2 diabetes were followed for a year, an estimated average of 4.7 would develop Alzheimer’s.

 

In a separate analysis, type 2 diabetes was associated with a 53 per cent higher adjusted relative risk of Alzheimer’s disease, compared with people living without type 2 diabetes.

 

Study author Dr Emmanuel Adewuyi, an NHMRC Investigator Fellow at the Curtin School of Population Health, said the review was important as it quantifies the relative risk and incidence if Alzheimer’s in people living with type 2 diabetes.

“While many earlier reviews combined different types of diabetes or dementia, this review focused specifically on type 2 diabetes and Alzheimer’s disease and estimated how often new cases occurred," Dr Adewuyi said.

"Relative risk tells us how two groups compare, while incidence tells us how often new cases occur: putting those numbers together gives us a clearer picture of the burden of Alzheimer’s disease among people living with type 2 diabetes.”

"Incidence and risk of Alzheimer’s disease in individuals with type 2 diabetes: a systematic review and meta-analysis," was published in Alzheimer's Research & Therapy.

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Coffee appears to change how your gut functions

 

It may be a slightly awkward topic, but many of us know the feeling: that cup of coffee that gets things moving.

Research now suggests that regular coffee consumption affects how our digestive system functions.

A research team from the University of Copenhagen asked a group of Danish participants to swallow a small electronic capsule. As it travelled through the digestive tract, the capsule measured, among other things, transit time through the gastrointestinal system, temperature, pH levels and intestinal contractions.

The participants were categorised into frequent coffee drinkers, defined as consuming between one and five cups a day on more than three of the eight study days, and those who drank coffee less often.

The results first and foremost confirmed that coffee affects the composition of gut bacteria, as previous studies have suggested. Frequent coffee drinkers had a greater diversity of microorganisms in their gut than those who drank coffee less often.

"But perhaps more importantly, frequent coffee consumption appears to affect the physiology of the gut itself, in other words how the gut functions," says first author Francesca Bucci, a PhD student at the Department of Nutrition, Exercise and Sports at the University of Copenhagen.

It is already well established that moderate coffee consumption is associated with a reduced risk of cardiovascular disease, diabetes, depression and several types of cancer. However, much less is known about how habitual coffee consumption relates to physiological conditions within the gut.

Stimulates contractions in the gut

The researchers found that frequent coffee drinkers had a significantly lower pH in the small intestine than those who drank coffee less often. They also observed that higher coffee consumption was associated with more contractions in the colon.

So are these physiological differences beneficial or not?

"Contractions in the gut can support healthy digestion, help prevent constipation and keep the intestinal muscles in good condition," says Francesca Bucci.

The researchers cannot yet determine whether the lower pH is beneficial or harmful to health. However, the pH level in the small intestine plays an important role in the activity of digestive enzymes and in how food is broken down.

The researchers also stress that the study cannot establish whether the differences are caused solely by coffee consumption. Nevertheless, senior author Henrik Munch Roager believes there is good reason to think coffee plays a key role.

"For example, we already know from other studies that coffee can influence a range of processes in the digestive system, including acid secretion in the stomach. So there are good reasons to believe that what we are seeing is not merely coincidence. Anecdotally, many people also report that coffee affects their digestion," says Henrik Munch Roager, Associate Professor and Research Group Leader at the Department of Nutrition, Exercise and Sports.

Peanuts May Help Lower Type 2 Diabetes Risk

 

 A recent study from the University of Barcelona and the German Institute of Human Nutrition Potsdam-Rehbruecke has found that eating peanuts was associated with favorable changes in blood lipids linked to a lower risk of type 2 diabetes (T2D). The changes largely involved a class of lipids called sphingolipids, which contained very long-chain saturated fatty acids (VLCSFA). Unlike some other saturated fats, higher levels of VLCSFAs in the blood have been associated with lower T2D risk, better heart health and longevity in emerging research. The findings were recently published online in the international, peer-reviewed journal The American Journal of Clinical Nutrition.