Anxiety and insomnia may repress immune function

 

Women who suffer from anxiety symptoms may have fewer circulatory natural killer cells, while those reporting insomnia had fewer total natural killer cells, showing that these disorders could decrease immune response

Natural killer (NK) cells are the bodyguards of our immune system. As a first line of defense, they destroy invading pathogens, foreign bodies, and infected cells in early stages, thereby preventing them from spreading. NK cells can circulate within the blood stream (circulatory) or reside in tissue and organs. Having too few NK cells can lead to immune system dysfunction and increase susceptibility to disease.

Anxiety disorder and insomnia are two conditions that can disrupt the normal functioning of the immune system. Given these disorders are on the rise, researchers in Saudi Arabia have now examined the association between anxiety, insomnia, and NK cells in young, female students. They published their results in Frontiers in Immunology.

“We found that in students with insomnia symptoms, count and percentage of total NK cells and their sub-populations were declined,” said first author Dr Renad Alhamawi, an assistant professor of immunology and immunotherapy at Taibah University. “Students with general anxiety symptoms, on the other hand, had a lower percentage and number of circulatory NK cells and their sub-populations, compared to symptom-free students.”

Decimated defense

60 female students, aged between 17 and 23 years old, participated in the study. They filled out three questionnaires about sociodemographics as well as anxiety and insomnia symptoms. The symptoms of the latter two were self-reported. The surveys showed that around 53% of the participants reported sleeping disturbance suggestive of insomnia, and 75% reported anxiety symptoms, with around 17% and 13% reporting moderate and severe symptoms, respectively.

Participants also provided blood samples through which percentages of NK cells and their subtypes were determined. NK cells have two subtypes: CD16+CD56dim cells make up the majority of NK cells in the nervous system that connects the central nervous system to the rest of the body (peripheral NK cells). Cells belonging to this subtype also exhibit cytotoxicity, which means they can damage or kills cells that invade the body. The other subtype, CD16+CD56high cells, are less frequent and involved in the production of proteins that function as chemical messengers and in immunoregulation. Both subtypes are circulatory NK cells.

The results showed that students with anxiety symptoms had a lower percentage and number of circulatory NK cells and their sub-populations, compared to students who did not report symptoms. Severity of symptoms also played a role as students with moderate and severe anxiety symptoms had a significant lower percentage of circulatory NK cells compared to students without them. Among students with minimal or mild anxiety symptoms, only a statistically insignificant decline in NK cell percentage was observed. In students with insomnia symptoms, higher anxiety scores were negatively associated with the proportion of total peripheral NK cells.

Stressed immune systems

A reduction of these cells can lead to the impairment of the immune system, which may result in diseases, cancers, and mental disease, including depression. “Understanding how these psychological stressors influence the distribution and activity of immune cells, especially peripheral NK cells, may provide valuable insights into the mechanisms underlying inflammation and tumorigenesis,” Alhamawi explained.

The study is limited in some respects, the team pointed out. It only included young females – the group amongst whom anxiety and sleeping disorders have been rising disproportionally, limiting the generalizability of the results. The researchers said that future studies that include different age groups, sexes, and people from different regions, are necessary to gain a better overall view of the hidden effects of anxiety and insomnia on the proportion and function of these immune cells.

Previous studies have suggested healthy lifestyles with regular physical activity, stress reduction, and a healthy and balanced diet can boost the number and function of NK cells. However, the impact of anxiety and insomnia can disrupt the normal functioning of various body systems, including the immune system, thereby contributing to the development of chronic and inflammatory diseases. “Such impacts ultimately compromise overall health and quality of life,” concluded Alhamawi.

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Journal

Frontiers in Immunology

DOI

10.3389/fimmu.2025.1698155 

Some patients with depression could benefit from anti-inflammatory treatment

Naoise Mac Giollabhui, PhD, of the Department of Psychiatry at Mass General Brigham, is the lead author of a paper published in American Journal of Psychiatry, “Effect of anti-inflammatory treatment on depressive symptom severity and anhedonia in depressed individuals with elevated inflammation: Systematic review and meta-analysis of randomized controlled trials.” Richard Liu, PhD, of the Department of Psychiatry at Mass General Brigham, is the senior author.

Q: How would you summarize your study for a lay audience?

At any given moment in time, more than 400 million individuals worldwide are battling depression. The antidepressant treatments that we currently have don’t work for many and there is a real need for new, effective treatments.

Over the last 20 years, there has been increasing evidence that some depressed individuals have chronic, low-grade inflammation that might be driving their symptoms. This observation of a dysregulated immune system led to clinical trials in which depressed individuals were given a variety of anti-inflammatory treatments. The results of these clinical trials, however, were mixed.

We hypothesized that results may have been mixed because these trials did not target the subset of depressed individuals exhibiting immune dysfunction – if there is no inflammation to begin with, anti-inflammatory medication won’t be very helpful!

So, our study was designed to determine whether anti-inflammatory medications are effective when given to depressed individuals who are actively exhibiting chronic, low-grade inflammation.

Q: What question were you investigating?

We investigated whether anti-inflammatory medications are effective in reducing depressive symptom severity and anhedonia (decreased ability to feel pleasure) in a subset of depressed individuals with chronic, low-grade inflammation.

Q: What methods or approach did you use?

We conducted a systematic review and meta-analysis of all randomized controlled trials in which we could determine the effect of anti-inflammatory medication on depressive symptom severity and anhedonia in depressed individuals with elevated levels of inflammation.

Q: What did you find?

We identified up to 11 randomized controlled trials in which anti-inflammatory medications were administered in up to 321 depressed individuals with elevated levels of inflammation.

We found that anti-inflammatory medications significantly reduced both depressive symptom severity and anhedonia at the study endpoint. 

Q: What are the implications?

This suggests that there is a subtype of depression characterized by a dysregulated immune system that could be effectively treated using anti-inflammatory medications and lifestyle-based interventions.

Q: What are the next steps?

There’s a lot of work that needs to be done to develop immune biomarkers that more accurately identify who will benefit from anti-inflammatory treatment for depression and to develop treatment approaches that selectively target dysfunctional inflammatory physiology. At the moment, some of the more potent anti-inflammatory medications have serious side-effects that make them sub-optimal for use in a clinical setting. 

Be careful trusting TikTok for gout advice

 A new paper in Rheumatology Advances in Practice, published by Oxford University Press, indicates that Tik Tok videos about gout are commonly misleading, inconsistent, or inaccurate.

Gout is a painful inflammatory arthritis caused by high urate in the blood that crystallizes and deposits in the joints. An estimated forty-one million people worldwide suffer from gout, with physicians diagnosing about seven million new cases a year. There are persistent gaps in awareness and understanding about gout among patients and the public. Although rheumatology guidelines recommend long-term urate-lowering therapy for effective gout management, gout remains poorly controlled among patients.

Some 98% of people aged 12 years or older use social media, and those with health conditions (52%) are more likely to share health information on the platforms. TikTok, with 1.2 billion users, is particularly influential in shaping public beliefs, perceptions, and behaviors. A recent survey of 1,172 women between the ages of 18 and 29 years found that about 70% intentionally sought health information on TikTok, while 92% came across it unintentionally.

Researchers here searched the term “gout” on the TikTok discover page and collected the first two hundred videos, found on December 5, 2024. The investigation revealed that people with gout or close family members were the most prevalent video presenters (27%), followed by health professionals (24%), and members of the public (23%). The main purpose of videos was to provide health advice (38%), share personal gout stories (20%), and sell products (19%).

Approximately 45% of videos mentioned risk factors for gout, with diet and lifestyle being the most common (90%). About 79% of TikTok videos addressed gout management in their content, with a focus on dietary advice. Some videos reported foods to avoid, such as one featuring a patient hospitalized for gout who said that viewers “can reduce your incidences of gout if you cut back on your salt, your alcohol, and your red meat.” Supplements, herbal or home remedies were also commonly referenced types of gout management, with videos promoting products such as “pills made from pure herbs, with no hormones and no side effects.”

Only seven of the TikTok videos discussed medications as a gout management approach, primarily recommending pain relief options such as steroids and non-steroidal anti-inflammatory drugs like colchicine, ibuprofen, and naproxen. The researchers found that only two TikTok videos mentioned long-term urate-lowering therapy for effective gout management, even though this is the standard, clinically verified treatment for gout recommended by rheumatologists.

In general, the investigators found that the TikToks studied lacked accurate information about urate production and gout-related risk factors, potentially leading to misconceptions about gout. Discussions of risk factors in videos also regularly depicted it as a disease primarily resulting from dietary factors that influenced urate levels. While diet and alcohol are risk factors for the disease, genetics, kidney impairment, and weight play a significantly greater role. Content focused solely on lifestyle and dietary risk factors portrayed gout as a personal choice, rather than caused by underlying factors.

The researchers emphasize that videos here related to gout management primarily platformed advice and treatments not aligned with clinically recommended, evidence-based approaches. Seventy-nine percent of videos in this study mentioned gout management, but dietary advice was the most common (53%), which has limited long-term effectiveness. Herbal remedies and supplements were also widespread gout management strategies presented here, with videos selling products and using imagery of health professionals in their content.

"TikTok has great potential as a tool to raise awareness around health issues such as gout and promote information that aligns with clinical guidelines," said the paper's lead author, Samuela ‘Ofanoa. "In an increasingly digital world, there is a need for more health professionals and organisations to seize the opportunity that social media platforms present, and create content that can counter misinformation and improve understanding about gout in our communities."

The paper, “Gout, TikTok and misleading information: A content analysis,” is available (at midnight on December 10th) at https://academic.oup.com/rheumap/article-lookup/doi/10.1093/rap/rkaf126.

A chemical found in dark chocolate could slow the rate of biological aging

Research from King’s College London has found that the chemical theobromine, a common plant compound that comes from cocoa, could have anti-ageing properties.

The study, published today in Aging, compared levels of theobromine in people’s blood, with blood-based markers of biological ageing.

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Biological age markers indicate how old your body seems based on its health and function, as opposed to the years you have lived. These markers are based on patterns of small ‘bookmarks’ on our DNA, called methylation, that change over the course of our lives.

Across two European cohorts, which included 509 individuals from TwinsUK and 1,160 from KORA, the research found that those who had higher levels of theobromine circulating in their blood had a biological age that was lower than their actual age.

Professor Jordana Bell, senior author of the paper and a Professor in Epigenomics at King’s College London, said: “Our study finds links between a key component of dark chocolate and staying younger for longer. While we’re not saying that people should eat more dark chocolate, this research can help us understand how everyday foods may hold clues to healthier, longer lives.”

The team also tested whether other metabolites in cocoa and coffee showed a similar link. However, they found that the effect seemed to be specific to theobromine.

The researchers used two tests to assess the biological age of people in the study. One looked at chemical changes in DNA to estimate how quickly someone is aging. Another estimated the length of telomeres, the protective caps on the ends of your chromosomes. Shorter telomeres are associated with aging and age-related diseases.

Plant compounds in our diet may affect how our bodies age by changing the way our genes are switched on or off. Some of these compounds, called alkaloids, can interact with the cellular machinery that controls gene activity and helps shape health and longevity.

Theobromine, an alkaloid most commonly known as being poisonous to dogs, has been linked to health benefits in humans, such as a lower risk of heart disease. However, it has otherwise not been intensely investigated.

Dr Ramy Saad, lead researcher at King’s College London, who is also a researcher at University College London and a doctor in Clinical Genetics said: “This is a very exciting finding, and the next important questions are what is behind this association and how can we explore the interactions between dietary metabolites and our epigenome further? This approach could lead us to important discoveries towards ageing, and beyond, in common and rare diseases.”

The research team, including Professor Ana Rodriguez-Mateos who is a Professor of Human Nutrition at King’s College London, are exploring avenues for future work to dissect these results. One open question is whether the effect is unique to theobromine alone, or whether theobromine may interact with other compounds in dark chocolate, such as polyphenols, which are known to have beneficial effects on human health.

Dr Ricardo Costeira, a Postdoctoral Research Associate from King’s College London, said: “This study identifies another molecular mechanism through which naturally occurring compounds in cocoa may support health. While more research is needed, the findings from this study highlight the value of population-level analyses in aging and genetics.”

However, despite these promising findings the researchers are keen to stress that eating more dark chocolate isn’t automatically beneficial as it also contains sugar, fat and other compounds, and further research is needed to understand this association in more detail.

Tea linked to stronger bones in older women, while coffee may pose risks

 

A new study from Flinders University offers insight into how two of the world’s most popular beverages, coffee and tea, may influence bone health in older women.

The research, published in the journal Nutrients, followed nearly 10,000 women aged 65 and older over a decade to explore whether their daily habits of sipping coffee or tea were linked to changes in bone mineral density (BMD), a key indicator of osteoporosis risk.

Osteoporosis is a major global health concern, affecting one in three women over 50 and contributing to millions of fractures each year. With coffee and tea consumed daily by billions worldwide, understanding their impact on bone health is critical. Until now, evidence has been mixed, and few studies have tracked these relationships over such an extended period.

The Flinders University team analysed data from the Study of Osteoporotic Fractures, using repeated measures of both beverage intake and BMD at the hip and femoral neck, areas strongly associated with fracture risk.

Over ten years, participants reported their coffee and tea consumption, while researchers measured bone density using advanced imaging techniques.

The study found that tea drinkers had a slightly higher total hip BMD compared to non-tea drinkers.  While the difference was modest, it was statistically significant and could have meaningful implications at a population level.

“Even small improvements in bone density can translate into fewer fractures across large groups,” says Adjunct Associate Professor Enwu Liu from the College of Medicine and Public Health.

Coffee, on the other hand, told a more complex story. Overall, moderate coffee consumption, about two to three cups per day, did not appear to harm bone health. However, drinking more than five cups daily was linked to lower BMD, suggesting that excessive intake may be detrimental.

Interestingly, women with higher lifetime alcohol consumption experienced more negative effects from coffee, while tea seemed particularly beneficial for women with obesity.

Ryan Liu, co-author on the paper says that compounds called catechins, abundant in tea, may promote bone formation and slow bone breakdown.

“Coffee’s caffeine content, by contrast, has been shown in laboratory studies to interfere with calcium absorption and bone metabolism, though these effects are small and can be offset by adding milk,” says Ryan Liu from Flinders University.

Adjunct Associate Professor Enwu Liu adds that the findings suggest that enjoying a cup of tea each day could be a simple way to support bone health as we age.

“While moderate coffee drinking appears safe, very high consumption may not be ideal, especially for women who drink alcohol,” he says.

The authors caution that the observed differences, while statistically significant, are not large enough to warrant dramatic changes for individuals.

“Our results don’t mean you need to give up coffee or start drinking tea by the gallon,” says Associate Professor Liu.

“But they do suggest that moderate tea consumption could be one simple way to support bone health, and that very high coffee intake might not be ideal, especially for women who drink alcohol.

“While calcium and vitamin D remain cornerstones of bone health, what’s in your cup could play a role too. For older women, enjoying a daily cup of tea may be more than a comforting ritual, it could be a small step toward stronger bones,” he concludes.

The paper, ‘Longitudinal Association of Coffee and Tea Consumption with Bone Mineral Density in Older Women: A 10-Year Repeated-Measures Analysis in the Study of Osteoporotic Fractures’, by Ryan Yan Liu and Enwu Liu was published in Nutrients. DOI: 10.3390/nu17233660

Acknowledgements: The funding for the SOF study comes from the National Institute on Aging (NIA) and the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), supported by grants (AG05407, AR35582, AG05394, AR35584, and AR35583).

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Journal

Nutrients

DOI

10.3390/nu17233660 

Polyphenols and Healthy Aging: A Nutritional Pathway to Reduce Inflammation

As the global population ages, the prevalence of chronic low-grade inflammation—often termed “inflammaging”—has become a pressing public health issue. This silent inflammatory state not only accelerates biological aging but also contributes to the onset of metabolic, cardiovascular, and neurodegenerative diseases. Recent scientific attention has focused on the gut microbiome as a key regulator of this process, linking diet, microbial metabolism, and systemic immune responses. Among dietary components, polyphenols, naturally occurring compounds abundant in fruits, vegetables, tea, and cocoa, have emerged as promising modulators of both gut microbiota and inflammation.

 

New Evidence from the MaPLE Clinical Study

A team led by Simone Guglielmetti from the University of Milano-Bicocca and Giorgio Gargari from the University of Milan has provided new scientific evidence to deepen the understanding of the relationship between polyphenol-rich diets and healthy aging. In this randomized crossover clinical trial, 50 participants aged 60 and above followed either a polyphenol-rich diet (PR-diet) or a control diet for eight weeks. The PR-diet included polyphenol-dense foods such as berries, apples, green tea, and dark chocolate. Using advanced metagenomics and metabolomics analyses, researchers examined changes in gut microbial composition and metabolic pathways.

 

The results were remarkable. Participants with higher baseline inflammation showed significant reductions in pro-inflammatory markers—particularly interleukin-6 (IL-6) and C-reactive protein (CRP)—after consuming the PR-diet. At the same time, beneficial bacterial genera such as Blautia and Dorea became more abundant, and microbial diversity improved. Metabolomic profiles revealed increased levels of polyphenol-derived metabolites linked to anti-inflammatory and antioxidant activity, highlighting a biochemical bridge between diet, microbiota, and host immunity.

 

A Step Toward Personalized Nutrition and Healthy Longevity

According to the authors, these findings demonstrate that polyphenol-rich diets can serve as a simple, safe, and effective nutritional strategy to counteract inflammation and support healthy aging. More importantly, the results underscore the value of stratifying older adults by their inflammatory and microbial profiles to optimize dietary interventions. By integrating multi-omics approaches, the MaPLE study provides a model for understanding the complex interactions between diet, gut microbes, and host physiology.

 

Looking forward, future research will focus on identifying the most bioactive polyphenol compounds and exploring their synergistic roles within the gut–immune axis. As science continues to unravel how food components shape human health, this study reinforces a fundamental message: what we eat not only nourishes our bodies but also shapes the invisible microbial ecosystems that protect us from within.

Getting more. sleep may be the key to moving more

  Getting enough sleep and staying active are two of the most important things we can do for our health, but new research shows that most people struggle to achieve both, and that sleep may hold the key to moving more.

A study led by Flinders University analysed more than 28 million days of real-world health data from over 70,000 people across the globe and found that fewer than 13% consistently meet recommended sleep and physical activity targets.

The findings suggest that improving sleep quality could be an effective way to boost daily activity.

The research team examined data collected over three and a half years from consumer health devices that tracked nightly sleep and daily steps.

They discovered that most people fall short of the widely promoted benchmarks of seven to nine hours of sleep and at least 8,000 steps a day.

Alarmingly, nearly 17% of participants averaged less than seven hours of sleep and fewer than 5,000 steps—a combination linked to higher risks of chronic disease, weight gain and mental health challenges.

Lead author, Josh Fitton from Flinders University, says the results show that sleep quality and duration have a stronger influence on next-day physical activity than the reverse.

“We found that getting a good night’s sleep - especially high-quality sleep - sets you up for a more active day,” says Mr Fitton, a PhD candidate at FHMRI Sleep Health.

“People who slept well tended to move more the following day, but doing extra steps didn’t really improve sleep that night. This highlights the importance of sleep if we want to boost physical activity.”

Interestingly, the study revealed that the sweet spot for next-day activity was not the longest sleep duration.

“Our data showed that sleeping around six to seven hours per night was linked to the highest step counts the next day,” he says.

“But that doesn’t mean you should cut back on sleep because quality is just as important. People who slept more efficiently, meaning they spent less time tossing and turning, were consistently more active.”

The findings raise important questions about whether current health guidelines are realistic.

“Our findings call into question the real-world compatibility of prominent health recommendations and highlight how difficult it is for most people to have an active lifestyle and sleep well at the same time,” he says.

“Only a tiny fraction of people can achieve both recommended sleep and activity levels every day so we really need to think about how these guidelines work together and what we can do to support people to meet them in ways that fit real life.”

Senior author on the paper, Professor Danny Eckert, says for people balancing work, family and other demands, focusing on sleep may be the first step toward a healthier, more active life.

“Prioritising sleep could be the most effective way to boost your energy, motivation and capacity for movement,” says Professor Eckert.

“Simple changes like reducing screen time before bed, keeping a consistent bedtime, and creating a calm sleep environment can make a big difference.

“Our research shows that sleep is not just a passive state, it’s an active contributor to your ability to live a healthy, active life.”

The article, ‘Bidirectional associations between sleep and physical activity investigated using large-scale objective monitoring data’, s: https://www.nature.com/articles/s43856-025-01226-6

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Heavy energy drink intake may pose serious stroke ris

Downing several strong energy drinks every day may pose a serious stroke risk, doctors have warned in the journal BMJ Case Reports, after treating an otherwise fit and healthy man in his 50s with a daily 8-can habit and exceedingly high blood pressure.

 

The findings prompt the authors to call for tighter regulation of the sales and advertising of these drinks, particularly given their popularity among young people.

 

The man in question had a stroke in his thalamus—the part of the brain involved in sensory perception and movement. His symptoms included left-sided weakness, numbness, as well as difficulties with balance, walking, swallowing and speech—collectively known as ataxia.

 

On admission to hospital his blood pressure was 254/150 mm Hg, which is regarded as extremely high.

 

He was started on drugs to lower his blood pressure, and his systolic blood pressure—reflecting arterial pressure during the heart’s pump action—fell to 170 mm Hg.

 

But once back home, his blood pressure rose again and remained persistently high despite the ramping up of his drug treatment.

 

On further questioning, he revealed that he drank an average of 8 energy drinks every day, each of which contained 160 mg of caffeine, adding up to a daily intake of 1200-1300 mg of caffeine: the recommended maximum daily intake is 400 mg.

 

He was asked to give up this daily habit, after which his blood pressure returned to normal and blood pressure lowering drugs were no longer needed.

 

But he didn’t regain full feeling on his left side. Commenting on the experience, he said: “I obviously wasn’t aware of the dangers drinking energy drinks were causing to myself. (I) have been left with numbness (in my) left hand side hand and fingers, foot and toes even after 8 years.”

 

The report authors point out that the man’s lack of awareness about the potential cardiovascular risks associated with heavy energy drink consumption is probably not surprising as they aren’t generally thought of as a potential cardiovascular disease risk.

 

“The year 2018 saw major UK supermarkets implement a voluntary ban on sales of [these drinks] to under 16s in a drive to tackle obesity, diabetes, and tooth decay, but less explored are the possible increased risks of [energy drinks] for cardiovascular disease, including ischaemic [restricted blood supply or blood clot] and haemorrhagic [bleed in the brain] strokes, particularly in younger demographics otherwise expected to have lower stroke risk,” they emphasise.

 

Energy drinks contain more than 150 mg of caffeine per litre and typically have a very high glucose-based sugar content and varying quantities of other chemicals, they highlight.

 

“This declared amount is the ‘pure caffeine’, but other ingredients contain ‘hidden caffeine’— for example, guarana is thought to contain caffeine at twice the concentration of a coffee bean.

 

“The hypothesis is that the interaction of these other ingredients, including taurine, guarana, ginseng and glucuronolactone, potentiates the effects of caffeine heightening stroke [cardiovascular disease] risk through numerous mechanisms,” they explain.

 

“The average [energy drink] is said to contain around 80 mg of caffeine per 250 ml serving, compared with 30 mg in tea and 90 mg in coffee, but in some cases can contain up to 500 mg in a single serving,” they point out.

 

This report represents just one case, but the authors nevertheless conclude: “While the current evidence is not conclusive, given the accumulating literature, the high morbidity and mortality associated with stroke and [cardiovascular disease] and the well-documented adverse health effects of high-sugar drinks, we propose that increased regulation of [energy drink] sales and advertising campaigns (which are often targeted at younger ages) could be beneficial to the future cerebrovascular and cardiovascular health of our society.”

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Journal

BMJ Case Reports

DOI

10.1136/bcr-2025-267441 

Method of Research

Insufficient sleep associated with decreased life expectancy

 

Researchers find catching at least seven hours of sleep a night will improve how you feel and how long you live

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A good night’s sleep is more than a luxury: New research from Oregon Health & Science University suggests that insufficient sleep may shorten your life.

The study published today in the journal SLEEP Advances.

Researchers tapped a vast, nationwide database looking for survey trends associated with average life expectancy county by county. They compared county-level data about average life expectancy with comprehensive survey data collected by the Centers for Disease Control and Prevention between 2019 and 2025.

As a behavioral driver for life expectancy, sleep stood out more than diet, more than exercise, more than loneliness — indeed, more than any other factor except smoking.

“I didn’t expect it to be so strongly correlated to life expectancy,” said senior author Andrew McHill, Ph.D., associate professor in the OHSU School of Nursing, the OHSU School of Medicine and OHSU’s Oregon Institute of Occupational Health Sciences. “We’ve always thought sleep is important, but this research really drives that point home: People really should strive to get seven to nine hours of sleep if at all possible.”

The research was conducted primarily by graduate students in the Sleep, Chronobiology and Health Laboratory of the OHSU School of Nursing.

Scientists have broadly understood the importance of sufficient sleep for a variety of positive health outcomes. However, McHill and co-authors said they were surprised by the strength of the connection to life expectancy. The effect of insufficient sleep swamped the impact of diet and exercise as a predictor of life expectancy.

“It’s intuitive and makes a lot of sense, but it was still striking to see it materialize so strongly in all of these models,” McHill said. “I’m a sleep physiologist who understands the health benefits of sleep, but the strength of the association between sleep sufficiency and life expectancy was remarkable to me.”

Although previous research has shown broadly that lack of adequate sleep leads to higher mortality risk, the new research is the first to reveal year-to-year correlations between sleep and life expectancy for every U.S. state. For the purpose of modeling, the CDC defined sufficient sleep as at least seven hours a night, which is recommended by the American Academy of Sleep Medicine and the Sleep Research Society.

Researchers found clear correlations in each year and in most U.S. states between sleep and life expectancy.

The statistical analysis did not delve into reasons why inadequate sleep appears to shorten life expectancy, but McHill noted that sleep influences cardiovascular health, the immune system and brain function.

“This research shows that we need to prioritize sleep at least as much as we do to what we eat or how we exercise,” he said. “Sometimes, we think of sleep as something we can set aside and maybe put off until later or on the weekend.

“Getting a good night’s sleep will improve how you feel but also how long you live.”

No significant benefits daily multivitamin use for most older adults

 

Small, significant improvements in study participants with lower dietary quality and normal BP at baseline

New research from Mass General Brigham investigators suggests that long-term multivitamin supplementation could reduce hypertension risk and blood pressure (BP) in specific groups of older adults. A secondary analysis of data from the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) found no significant effects from those randomized to daily multivitamin use versus placebo on hypertension risk or blood pressure for the overall study population. However, analyses identified se. Results are published in the American Journal of Hypertension.

“Nutrition is one of the cornerstones for controlling blood pressure and hypertension. We found that a daily multivitamin might be useful for reducing the risk of hypertension in people with poorer nutritional intake,” said corresponding author Rikuta Hamaya, MD, PhD, MS, of the Division of Preventive Medicine in the Mass General Brigham Department of Medicine.

“Our findings suggest that a daily multivitamin may not be a one-size-fits-all solution for controlling blood pressure but could be beneficial for important subsets of older adults,” said corresponding and senior author Howard Sesso, ScD, MPH, of the Division of Preventive Medicine in the Mass General Brigham Department of Medicine.

COSMOS is a randomized, placebo-controlled clinical trial that investigated the effects of cocoa extract and multivitamin supplementation on health outcomes among older U.S. adults. In this study, the research team analyzed a subset of 8,905 older adults without hypertension at baseline, who took either Centrum Silver or placebo daily over a median window of 3.4 years. The researchers also evaluated blood pressure changes over two years in two groups of 529 and 994 participants, whose measurements were taken at a clinic or at home, respectively.

Overall, the investigators found no differences in self-reported incident hypertension between the multivitamin and placebo groups. Multivitamins lowered risk of hypertension in participants with comparatively lower diet quality, as measured by Alternative Healthy Eating Index (AHEI) and Alternate Mediterranean Diet (aMED) scores. In addition, participants with normal BP at baseline taking a daily multivitamin experienced small, significant reductions in BP measurements over two years.

The authors propose that further research is required to examine the effects of a daily multivitamin in younger and middle-aged adults, and across different populations based on nutritional status.

Alternative sweetener sorbitol linked to liver disease

 

Sweeteners such as aspartame, found in Equal packets, sucralose (Splenda), or sugar alcohols are often seen as healthier alternatives to food with refined sugar (glucose).

But that assumption is being challenged with new scientific research, including the recent finding that the sugar alcohol sorbitol is not as harmless a sugar substitute as once thought.

The study, published recently in Science Signaling, follows a line of research detailing the harmful effects of fructose on the liver and other systems from the lab of Gary Patti, at Washington University in St. Louis.

Patti, the Michael and Tana Powell Professor of Chemistry, in Art & Sciences, and of genetics and medicine, at WashU Medicine, previously has published research about how fructose processed in the liver can be hijacked to supercharge cancer cells. Previous research also has found that fructose is a key contributor to steatotic liver disease, affecting 30% of the adult population worldwide.

The most surprising finding from the current work is that because sorbitol is essentially “one transformation away from fructose,” it can induce similar effects, Patti said.

The research involved experiments with zebrafish demonstrating that sorbitol, often used in “low-calorie” candy and gum, and commonly found in stone fruits, can naturally be made by enzymes in the gut and eventually converted into fructose in the liver.

Patti’s team found there are many roads to fructose in the liver, and potential detours, depending on a person’s sorbitol and glucose consumption patterns, along with the bacterial populations colonizing their gut.

For starters, although most of the research on sorbitol metabolism has focused on its production due to glucose overload in pathological settings such as diabetes, sorbitol can be naturally produced in the gut from glucose after eating, Patti said.

The enzyme that produces sorbitol has a low affinity for glucose, so glucose levels must be high for it to take effect. That is why sorbitol production has primarily been associated with diabetes, where blood glucose levels can become elevated. But, even in healthy settings, glucose levels in the gut become high enough after feeding to drive sorbitol production within the intestine, according to the team’s zebrafish experiments.

“It can be produced in the body at significant levels,” said Patti. “But if you have the right bacteria, turns out, it doesn’t matter.”

Sorbitol-degrading Aeromonas bacterial strains convert the sugar alcohol into a harmless bacterial byproduct.

“However, if you don’t have the right bacteria, that’s when it becomes problematic. Because in those conditions, sorbitol doesn’t get degraded and as a result, it is passed on to the liver,” he said.

Once in the liver, it is converted to a derivative of fructose. It’s important to determine if alternative sweeteners are providing a healthy alternative to table sugar since people with diabetes and other metabolic disorders may be relying on them as “sugar free” products.

Gut bacteria do a good job of clearing sorbitol when it is present at modest levels, such as those found in fruit. But problems arise when sorbitol quantities become higher than what gut bacteria can degrade. This can occur when excessive amounts of glucose are consumed in the diet, which lead to high levels of glucose-derived sorbitol, or when dietary sorbitol itself is too high.

The more glucose and sorbitol consumed, then, even if someone has the friendly bacteria that clears it, those gut microbes may be overwhelmed with the task.

Avoiding both sugar and alternative sweeteners is increasingly complicated, as many foods are packed with multiple varieties of all the above. Patti was bemused to discover his own favorite protein bar was chock full of sorbitol.

The lab will need to do more research to understand the specific mechanisms for how bacteria clears sorbitol, but the basic idea that these sugar alcohols, called polyols, are harmlessly expelled, may not hold true.

“We do absolutely see that sorbitol given to animals ends up in tissues all over the body,” he said.

Bottom line: it’s becoming more apparent that “there is no free lunch” when trying to find sugar alternatives, with many roads leading to liver dysfunction.

Vitamin C from food boosts collagen levels in skin

 A breakthrough study from researchers at the University of Otago, Faculty of Medicine – Christchurch Ōtautahi, has found that collagen production and skin renewal directly respond to the amount of vitamin C we eat.  

The study, published in the international Journal of Investigative Dermatology, shows that skin vitamin C levels are closely tied to levels of the vitamin in the blood (plasma) and can be boosted by increasing fruit intake.  

Carried out on two dozen healthy adults in both Aotearoa New Zealand and Germany, the study shows that boosting plasma levels by consuming two vitamin C-rich SunGoldTM kiwifruit per day increases the amount of the vitamin in the skin, improving skin thickness (collagen production) and stimulating renewal and regeneration of the outer skin layer.  

Lead author, Professor Margreet Vissers from Mātai Hāora – Centre for Redox Biology and Medicine, within the Department of Pathology and Molecular Medicine, says the strength of the association between skin thickness and vitamin C intake is “compelling”. 

“We were surprised by the tight correlation between plasma vitamin C levels and those in the skin – this was much more marked than in any other organ we have investigated,” Professor Vissers says. 

“We are the first to demonstrate that vitamin C in the blood circulation penetrates all layers of the skin and is associated with improved skin function. I am very proud of my team and excited about what the data is telling us.” 

Professor Vissers says the study results suggest that beauty really does come from within, supporting your skin function from the inside-out by delivering vitamin C to the skin the way nature designed it – via the bloodstream.  

“We know that vitamin C is required for collagen production. This fact has inspired the addition of vitamin C to many skin cream formulations. However, vitamin C is highly water soluble and poorly absorbed through the outer skin barrier. Our study shows that the skin is extremely good at absorbing vitamin C from the blood circulation. Uptake into the outer epidermal skin layer also seems to be prioritised,” she says. 

Funded by New Zealand company Zespri International along with a University of Otago Research Grant, the study comprised two stages. The first stage established the association between plasma and skin vitamin C levels, using healthy skin tissue from patients undergoing elective surgical procedures at Te Whatu Ora Canterbury (with support from the Otago campus’s He Taonga Tapu - Canterbury Cancer Society Tissue Bank).  

The second stage involved a before-and-after, dietary vitamin C intervention study at two sites (in Christchurch and Germany), each with 12 healthy participants.  

“All were instructed to consume two Kiwi Gold kiwifruit daily - the equivalent of 250 micrograms of vitamin C - for eight weeks. We then collected skin samples before and after the intervention, with separate analyses allowing us to look at the skin basal layers in Christchurch and the outer dermal skin layer and skin function tests in Germany,” Professor Vissers explains.  

The German participants were recruited and tested by the SGS Institute Fresenius in Hamburg – their lab having the technical ability to collect the outer dermal skin layer (the blister “roof”). The Institute measured skin sample regeneration - including ultrasound tested measures of skin thickness, elasticity UV protection and renewal of epidermal cells - giving a complete picture of skin function. 

“The other really substantial finding showed a significant increase in the participants’ skin thickness levels, reflecting collagen production and an upsurge in the regeneration of their epidermal cells, in other words skin renewal,” Professor Vissers says. 

 She says SunGoldTM kiwifruit was chosen for the trial due to its proven high vitamin C levels, but it’s anticipated that other foods rich in vitamin C, particularly fresh fruit and vegetables such as citrus, berry fruit, capsicums and broccoli, would have similar beneficial effects.  

“We suggest that increasing your dietary vitamin C intake will result in effective vitamin C uptake into all compartments of the skin,” Professor Vissers says. 

“The important thing is to keep your plasma levels optimal, which we know can be easily achieved in a healthy person with a vitamin C intake of around 250mg per day. The body however does not store the vitamin, so we recommend 5+ a day, every day, with one of those five being a high vitamin C food, as a good habit to cultivate.” 

Foods rich in vitamin C include fruits like oranges, strawberries, kiwi, papaya, and cantaloupe, as well as vegetables such as bell peppers (especially red), broccoli, and Brussels sprouts. Other good sources are tomatoes, blackcurrants, and potatoes

Gas stoves and nitrogen dioxide exposure

 

Peer-Reviewed Publication

PNAS Nexus

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image: 

Indoor (gold) and outdoor (blue) average nitrogen dioxide exposures.

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Credit: Kashtan et al.

Twenty-two million Americans would no longer be breathing in unhealthy levels of nitrogen dioxide if they switched from gas and propane stoves to electric stoves. Robert Jackson and colleagues combined outdoor air quality data with estimates of indoor nitrogen dioxide emissions from stoves in more than fifteen cities. As outdoor air quality improves, stoves become an increasingly important source of exposure. According to the World Health Organization, health risks to the respiratory system increase at levels above 5.2 parts per billion by volume. Taking indoor and outdoor sources together, the authors found that average total residential long-term nitrogen dioxide exposure is approximately 10 parts per billion by volume for people with gas stoves and approximately 8 parts per billion by volume for those with electric stoves. For households in the 95th percentile of gas stove use, which corresponds to using multiple gas burners and a gas oven for multiple hours a day, stoves account for more than half of total nitrogen dioxide exposure. The authors estimate that approximately 22 million people whose outdoor nitrogen dioxide exposure falls below World Health Organization guidelines exceed those guidelines due to gas stove use. According to the authors, the study’s ZIP-code-level exposure maps could help identify regions to prioritize for indoor and outdoor air quality interventions, particularly in lower-income communities.