Adolescents who sleep longer perform better at cognitive tasks

 

Adolescents who sleep for longer – and from an earlier bedtime – than their peers tend to have improved brain function and perform better at cognitive tests, researchers from the UK and China have shown.

But the study of adolescents in the US also showed that even those with better sleeping habits were not reaching the amount of sleep recommended for their age group.

Sleep plays an important role in helping our bodies function. It is thought that while we are asleep, toxins that have built up in our brains are cleared out, and brain connections are consolidated and pruned, enhancing memory, learning, and problem-solving skills. Sleep has also been shown to boost our immune systems and improve our mental health.

During adolescence, our sleep patterns change. We tend to start going to bed later and sleeping less, which affects our body clocks. All of this coincides with a period of important development in our brain function and cognitive development. The American Academy of Sleep Medicine says that the ideal amount of sleep during this period is between eight- and 10-hours’ sleep.

Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge said: “Regularly getting a good night’s sleep is important in helping us function properly, but while we know a lot about sleep in adulthood and later life, we know surprisingly little about sleep in adolescence, even though this is a crucial time in our development. How long do young people sleep for, for example, and what impact does this have on their brain function and cognitive performance?”

Studies looking at how much sleep adolescents get usually rely on self-reporting, which can be inaccurate. To get around this, a team led by researchers at Fudan University, Shanghai, and the University of Cambridge turned to data from the Adolescent Brain Cognitive Development (ABCD) Study, the largest long-term study of brain development and child health in the United States.

As part of the ABCD Study, more than 3,200 adolescents aged 11-12 years old had been given FitBits, allowing the researchers to look at objective data on their sleep patterns and to compare it against brain scans and results from cognitive tests. The team double-checked their results against two additional groups of 13-14 years old, totalling around 1,190 participants. The results are published today in Cell Reports.

The team found that the adolescents could be divided broadly into one of three groups:

Group One, accounting for around 39% of participants, slept an average (mean) of 7 hours 10 mins. They tended to go to bed and fall asleep the latest and wake up the earliest.

Group Two, accounting for 24% of participants, slept an average of 7 hours 21 mins. They had average levels across all sleep characteristics.

Group Three, accounting for 37% of participants, slept an average of 7 hours 25 mins. They tended to go to bed and fall asleep the earliest and had lower heart rates during sleep.

Although the researchers found no significant differences in school achievement between the groups, when it came to cognitive tests looking at aspects such as vocabulary, reading, problem solving and focus, Group Three performed better than Group Two, which in turn performed better than Group One.

Group Three also had the largest brain volume and best brain functions, with Group One the smallest volume and poorest brain functions.

Professor Sahakian said: “Even though the differences in the amount of sleep that each group got was relatively small, at just over a quarter-of-an-hour between the best and worst sleepers, we could still see differences in brain structure and activity and in how well they did at tasks. This drives home to us just how important it is to have a good night’s sleep at this important time in life.”

First author Dr Qing Ma from Fudan University said: “Although our study can’t answer conclusively whether young people have better brain function and perform better at tests because they sleep better, there are a number of studies that would support this idea. For example, research has shown the benefits of sleep on memory, especially on memory consolidation, which is important for learning.”

The researchers also assessed the participants’ heart rates, finding that Group Three had the lowest heart rates across the sleep states and Group One the highest. Lower heart rates are usually a sign of better health, whereas higher rates often accompany poor sleep quality like restless sleep, frequent awakenings and excessive daytime sleepiness.

Because the ABCD Study is a longitudinal study – that is, one that follows its participants over time – the team was able to show that the differences in sleep patterns, brain structure and function, and cognitive performance, tended be present two years before and two years after the snapshot that they looked at.

Senior author Dr Wei Cheng from Fudan University added: “Given the importance of sleep, we now need to look at why some children go to bed later and sleep less than others. Is it because of playing videogames or smartphones, for example, or is just that their body clocks do not tell them it’s time to sleep until later?”

The research was supported by the National Key R&D Program of China, National Natural Science Foundation of China, National Postdoctoral Foundation of China and Shanghai Postdoctoral Excellence Program. The ABCD Study is supported by the National Institutes of Health.

Reference

Ma, Q et al. Neural correlates of device-based sleep characteristics in adolescents. Cell Reports; 22 Apr 2025; DOI: 10.1016/j.celrep.2025.115565

Walnut consumption curbs inflammation and colon cancer risk

 

There are new findings out about the benefits of eating walnuts. Results from a UConn School of Medicine clinical trial on the cover of the April edition of the journal Cancer Prevention Research show walnuts improve systemic inflammation while also reducing colon cancer risk.

Why walnuts?
Ellagitannins, plant-derived polyphenol compounds found in walnuts, are shown to be metabolized exclusively by the gut microbiome into a wide range of anti-inflammatory molecules called urolithins. These urolithins are associated with very potent anti-inflammatory properties and may even inhibit cancer.

“Ellagitannins in the walnut are importantly providing the anti-inflammatory and anti-cancer properties that we’re seeing in patients in our clinical trial research, particularly the gut’s conversion of ellagitannins to a potent anti-inflammatory agent, urolithin A,” reports Daniel W. Rosenberg, Ph.D. and his multidisciplinary team of researchers at the UConn School of Medicine.

Rosenberg serves as the HealthNet Chair in Cancer Biology and is an Investigator in the Center for Molecular Oncology. He has studied walnut properties for more than a decade and has researched the connection between walnut consumption and its anti-inflammatory properties.

The UConn research team’s clinical trial findings show that high levels of urolithin A formation by the gut microbiome from walnut consumption has a positive impact on reducing inflammatory markers across blood, urine, and fecal samples, and may even positively affect the immune cells within colon polyps.

For the clinical trial, patients between the ages of 40 to 65 years and at an elevated risk for colon cancer, were referred for the study from the Division of Gastroenterology at UConn Health, the University of Connecticut’s academic medical center. Each of the 39 enrolled study participants were screened by the clinical research team at UConn John Dempsey Hospital and asked to complete an NIH Food Frequency Questionnaire for analysis by Ock Chun Ph.D., a nutritional epidemiologist in the College of Agriculture, Health and Natural Resources at UConn Storrs. Patients were asked to avoid all ellagitannin-containing foods and beverages for a week to set their urolithin levels at or close to zero before they began consuming ellagitannin-rich walnuts as part of their closely monitored diet. At the end of the three-week study, all participants received a high-definition colonoscopy performed by Drs. John Birk and Haleh Vaziri.

Among the key findings, the researchers found that elevated urolithin A levels in the urine of patients correlated with the serum levels of peptide YY, an interesting protein that has been associated with inhibition of colorectal cancer. Reduced levels of several inflammation markers present in the blood were also found, especially in obese patients that had the greatest capacity to form urolithins by their gut microbiome.

Rosenberg also used high-dimensional spatial imaging technology that allowed UConn researchers to develop a detailed view of the direct cellular interactions present inside colon polyps that were removed during colonoscopy at the end of the walnut study. This cutting-edge advanced imaging technology revealed that patients with high levels of urolithin A formation following walnut consumption was directly associated with reduced levels of several important proteins that are often present in polyps, showing for the first time how walnut ingestion may directly enhance colon health.

The research team also discovered that the protein vimentin, often associated with more advanced forms of colon cancer, was greatly reduced inside polyp tissues obtained from patients who had also formed the highest levels of urolithin A by their gut microbiome.

These important new research findings build upon the earlier work of Dr. Masako Nakanishi, an assistant professor in the Rosenberg Lab, who showed in several earlier publications that walnuts had beneficial and anti-cancer effects in the colons of cancer-prone mice, key findings that prompted the current clinical trial.

“Urolithin A has a very positive influence on inflammation and maybe even cancer prevention,” says Rosenberg. “Our study proves that dietary supplementation with walnuts can boost the general population’s urolithin levels in those people with the right microbiome, while significantly reducing several inflammatory markers, especially in obese patients.”

Rosenberg concludes, “Our study provides strong rationale for dietary inclusion of walnut ellagitannins for cancer prevention. Nutrients from walnuts can contribute to reduced cancer risk. There are many potential benefits one can get from eating walnuts, with so little downside risk, that just grabbing a handful every day is really something that you can easily do for your long-term health benefit.”

This research is supported by generous awards from the American Institute for Cancer Research, the California Walnut Commission, and the National Cancer Institute.

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Journal

Cancer Prevention Research

Omnivorous? Vegan? Makes no difference to muscle building after weight training,

 

 A new study asked three questions about muscle protein synthesis in response to a nine-day diet and weight training regimen: First, does the source of protein — plant or animal-based — make any difference to muscle gain? Second, does it matter if total daily protein intake is evenly distributed throughout the day? And third, does a moderate but sufficient daily protein intake influence any of these variables? The answer to all three questions is “no,” the researchers found.

Their findings are reported in the journal Medicine and Science in Sports and Exercise.

“The longstanding belief or the current dogma was that animal-based protein sources were better, particularly for the muscle-building response,”  said Nicholas Burd, a professor of health and kinesiology at the University of Illinois Urbana-Champaign who led the new study with former graduate student Andrew Askow. This belief was rooted in science: Previous studies that took muscle biopsies after a single feeding found that an animal-based meal provided more of a stimulus for muscle protein synthesis than a vegan meal, Burd said. “And so, our general hypothesis based on these previous studies was that the animal-based eating pattern would be more effective at supporting the muscle-building response.”

But measurements taken after a single meal might not reflect the effects of consuming a balanced vegan diet over time, Burd said.

One previous clinical trial had looked at muscle responses in vegans and omnivores who ate a laboratory diet and engaged in weight training for 10 weeks. That study found no significant differences in muscle protein synthesis over time. However, volunteers in that study consumed 1.6-1.8 grams of protein per kilogram of body weight per day, which is much higher than what is needed to maximize muscle protein synthesis and build bigger muscles with weight lifting, Burd said. It also gave those on the vegan diet the bulk of their plant protein in supplements, which is not a realistic recreation of how vegans normally eat, he said.

Burd and his colleagues wanted to know whether the habitual consumption of a varied vegan or meat-based diet of whole foods — rather than ingestion of just a single meal or getting one’s protein from limited sources — would influence the rate of muscle protein synthesis over time. They also wanted to test the hypothesis that a moderate protein intake — in the range of 1.1-1.2 grams of protein per kilogram of body weight per day — should be distributed evenly throughout the day to maximize muscle growth.

A previous study from Burd’s lab found that protein intakes higher than 1.1 g/kg per day make no difference to the rate of muscle protein synthesis when weight training. This amount of protein also is more in line with a typical American diet, and testing what people normally eat is important, he said.

For the new study, the team recruited 40 healthy, physically active 20-40-year-old adults. The participants underwent a seven-day “habituation diet” to standardize their nutritional status prior to the clinical trial. Then they were randomly assigned to either a vegan or omnivorous diet. The research team provided all meals, some of which were eaten in the lab while most were consumed at home. Roughly 70% of the protein for the omnivorous meals was obtained from animal sources: beef, pork, chicken, dairy, eggs. The vegan diet balanced the amino acid content of the meals, ensuring that participants consumed complete proteins.  

The vegan and omnivorous groups were each divided again into those who ate roughly the same amount of protein at each of three meals and those whose protein intake varied across five meals throughout the day, with a larger proportion of protein consumed toward the end of the day.

All participants engaged in a series of muscle-strengthening activities in the lab every three days. They also wore accelerometers to keep track of their activity levels when not in the lab.

Each day, participants drank “heavy” water, which was labeled with deuterium, a stable isotope of hydrogen. The deuterium atoms “exchanged with hydrogen atoms within amino acids to make them heavy and served as tracers” that allowed the team to trace their incorporation into muscle tissue, Burd said. Biopsies of tissue from a leg muscle were taken at the beginning and end of the trial.

Burd was initially surprised to see that there were no differences in rates of muscle protein synthesis between those eating vegan or omnivorous diets. He also was surprised to see that protein distribution across the day had no effect on the rate of muscle building given results from past studies of acute responses to dietary interventions and weight training.

“It was thought that it was better to get a steady-state delivery of nutrients throughout the day,” he said. “I also thought that if you’re getting a lower quality protein — in terms of its digestibility and amino acid content — that perhaps distribution would make a difference. And surprisingly, we showed it doesn’t matter.”

Now, Burd says, if anyone asks him what’s the best type of food they should eat for muscle building, he’ll tell them: “It’s the kind you put in your mouth after exercise. As long as you’re getting sufficient high-quality protein from your food, then it really doesn’t make a difference.”

The Beef Checkoff program, overseen by the National Cattlemen’s Beef Board, supported this research.

Transcendental Meditation reduces post-traumatic stress disorder (PTSD) symptom

  

Caption

All fifteen studies in the most recent paper showed that in every case TM worked more rapidly than the control procedure. The four charts shown in this figure used repeated measures, illustrating that TM (dotted lines) worked more rapidly than the control groups (solid lines). For military personnel, (Nidich et al., 2018), TM worked more rapidly than Health Education (HE), or Prolonged Exposure therapy (PE), a first-line therapy used by the U.S.A. Veterans Administration. For traumatized South African college students who had lived during war and racial discrimination (Bandy et al., 2019), TM worked more rapidly than controls who received only their usual college curriculum, NT = No Treatment. For clinical nurses during COVID (Bonamer et al., 2024) TM worked more rapidly than Wait List Controls (WLC) who agreed to wait until after the experiment to learn TM. For survivors of domestic violence (battered women, Leach and Lorenzon, 2023) TM worked faster than Support Group therapy. PTSD patients in every population noticed obvious reductions in PTSD symptoms, within one month of practicing TM. Those who practiced it according to the recommended twice a day schedule got the best results.

Credit

Maharishi International University

Just published is the third new study showing that TM is highly effective in reducing stress in a wide array of populations. This meta-analysis included 15 studies with over 1,200 participants from military and civilian backgrounds. Using rigorous meta-analytic methods, the study found a large effect size of 1.01 for TM compared to control groups. An effect size over 0.80 is considered a large effect that the person, their family, and their medical staff would likely notice and discuss.

Effective across multiple ethnicities and trauma types

TM was consistently effective for people of different ethnicities in the U.S., Japan, the Democratic Republic of Congo, Ukraine, South Africa, Israel, and Australia. It was effective for war veterans, female survivors of domestic violence, war refugees, earthquake-tsunami victims, healthcare workers during the COVID pandemic, college students living with racial violence, male and female prison inmates, and nurses traumatized during the COVID-19 pandemic. In every study, TM reduced PTSD symptoms by 10 or more points on the standard PTSD Checklist (PCL), a threshold considered clinically meaningful. You can view the paper and download a free PDF at Medicina 2025; 61(4):659.

The new study validates previous research.

A previous paper, published this past December, compared 61 studies that used some form of meditation for treating PTSD. The average reduction in PTSD symptoms from pretest to posttest was moderate (effect size = 0.67). Separate tests found TM treatment had a large effect (effect size = 1.13), which was significantly greater than different forms of mindfulness and other forms of meditation, Medicina 2024; 60(12):2050.

These findings are consistent with a third recent study involving effects on stress-related gene expression, EEG measures of cognitive function, and persistent levels of cortisol by Wenuganen, Walton and colleagues. Biomolecules 2025. This study provides evidence for stress-related molecular mechanisms that may underlie reductions in PTSD, cardiometabolic diseases, and aging-related declines.

Faster PTSD Reduction in TM Than in Control Groups

All fifteen studies in the most recent paper showed that in every case TM worked more rapidly than the control procedure. The four charts shown in this figure used repeated measures, illustrating that TM (dotted lines) worked more rapidly than the control groups (solid lines). For military personnel, (Nidich et al., 2018), TM worked more rapidly than Health Education (HE), or Prolonged Exposure therapy (PE), a first-line therapy used by the U.S.A. Veterans Administration. For traumatized South African college students who had lived during war and racial discrimination (Bandy et al., 2019), TM worked more rapidly than controls who received only their usual college curriculum, NT = No Treatment. For clinical nurses during COVID (Bonamer et al., 2024) TM worked more rapidly than Wait List Controls (WLC) who agreed to wait until after the experiment to learn TM. For survivors of domestic violence (battered women, Leach and Lorenzon, 2023) TM worked faster than Support Group therapy. PTSD patients in every population noticed obvious reductions in PTSD symptoms, within one month of practicing TM. Those who practiced it according to the recommended twice a day schedule got the best results.

“I’ve served in war zones and seen how PTSD ravages lives long after the battle ends,” said Colonel (Ret.) Brian Rees, M.D., co-author and former U.S. Army Medical Corps officer. “This research shows TM offers a safe, scalable, and profoundly effective solution—often with results in just a few weeks.”

Another co-author, Dr. Vernon Barnes said: "I have 13 years of experience teaching TM in an army hospital to over 300 active-duty soldiers with PTSD and traumatic brain injury issues. These soldiers have combat-related PTSD laid on top of years of pre-existing trauma starting in childhood. That is a reason their PTSD is so intense. That population needs evidence-based, behavioral-health therapy, and then TM as an adjunctive therapy to promote healing and cement the gains. The experience of providers I have worked with is that patients who get TM after therapy recover faster and more completely than those who do not." Dr. Barnes is Faculty Emeritus of Georgia Prevention Institute, Department of Medicine, Augusta University, Augusta, GA.

Lead author Dr. David Orme-Johnson, Distinguished Emeritus Professor of Psychology of Maharishi International University, taught TM to 2,000 survivors of the Armenian earthquake of 1989-1990. He said: “Everyone in the country either had a relative or friend die in the earthquake or had participated in digging bodies out of the rubble. I saw people burst into tears of relief during their very first meditation. One man I taught was so traumatized from war and then the earthquake that he did not speak. I did not know he was mute because his brother brought him in and spoke for him.  I taught him TM the usual way, which involves speaking, and when the brother came in and asked how he did, and I said fine, he was astonished. When he told me his brother had been mute, I was the astonished one. TM became so popular in Yerevan that people from every level of society, from the top physicists and artists to the cleaning ladies, sought us out to learn. Our group of ten TM teachers taught 15,000 people in six months, for free, I might add.”

The authors note the unique value of TM as a non-trauma-focused, non-pharmacological option. Unlike treatments that require re-experiencing traumatic events, TM offers a gentler approach that helps settle the nervous system without directly confronting traumatic memories. The authors conclude: “We recommend that large-scale, phase III trials be conducted to further establish TM’s role alongside or in place of existing treatments for PTSD”.

This study, Systematic Review and Meta-Analysis of Transcendental Meditation for Post-Traumatic Stress Disorder, was co-authored by David W. Orme-Johnson, Ph.D., Vernon A. Barnes, Ph.D., Brian Rees, M.D., and Jean Tobin.

 

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Journal

Medicina

DOI

10.3390/medicina61040659 

More Americans are using psilocybin—especially those with mental health conditions

 Use of psilocybin, the hallucinogenic chemical found in what is known as  “magic mushrooms,” has increased significantly nationwide since 2019, according to a new study led by researchers at the University of Colorado Anschutz Medical Campus and Rocky Mountain Poison and Drug Safety.

The study was published today in the Annals of Internal Medicine.

The researchers found that psilocybin use increased across all age groups, with the largest rise in young adults and older adults.

“We found that since 2019, the number of people using psilocybin has gone up sharply,” said Karilynn Rockhill, PhD, co-lead author of the study and researcher at the Colorado School of Public Health. “This seems to line up with when some U.S. states began to decriminalize or legalize it.”

Some of the most significant findings include:

• Lifetime use among adults rose from 10% in 2019 (about 25 million people) to 12.1% in 2023 (over 31 million people).
• Past-year use increased by 44% among young adults (ages 18–29) and 188% among adults over 30.
• People with mental health conditions or chronic pain were more likely to report using psilocybin.
• Psilocybin-related poison center calls rose dramatically. 201% in adults, 317% in teens and 723% in children between 2019 and 2023.
• In 2023, more adults used psilocybin than drugs like cocaine, LSD, methamphetamine or illegal opioids.

“What really surprised us was how quickly these numbers changed and how many people using psilocybin had conditions like depression, anxiety or chronic pain,” said Rockhill. “New laws or growing interest in its potential mental health benefits may be prompting people to seek psilocybin as a form of self-treatment.”

Psilocybin has been studied as a possible treatment for conditions like PTSD, depression and substance use disorders, though it is not yet approved by the US Food and Drug Administration (FDA).

“Public views on psilocybin are shifting. However, that means we also need to make sure people understand the risks, know how to use it safely if they choose to and that health care systems are prepared,” said Joshua Black, PhD, co-lead author and senior scientist at Rocky Mountain Poison and Drug Safety, a division of Denver Health.

The study also revealed a gap in how well current medical coding systems track psilocybin-related problems in emergency departments. While poison center calls have gone way up, very few cases are recorded in hospital ambulatory data.

“If hospitals and public health systems aren’t seeing the full picture, they can’t respond appropriately,” said Black. “Improved tracking tools and education are critical as more states consider regulating or legalizing psilocybin.”

The study utilized data from five major national surveys from 2014-2023. Data was used from the National Survey on Drug Use and Health (NSDUH), the Survey of Non-Medical Use of Prescription Drugs (NMURx), Monitoring the Future (MTF), the National Poison Data System (NPDS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS).

This was a collaborative project with the Substance Abuse and Mental Health Administration (SAMHSA), but the views expressed here are those of the authors and may not represent the positions of SAMHSA.

High-fat, high-sugar diets impact cognitive function

 

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New research from the University of Sydney links fatty, sugary diets to impaired brain function. The findings build on a growing body of evidence showing the negative impact of high-fat, high-sugar (HFHS) diets on cognitive ability, adding to their well-known physical effects.  

Published on Friday in the International Journal of Obesity, the research is the first to test in humans the relationship between HFHS diets, particularly those high in refined sugar and saturated fat, and first-person spatial navigation. Spatial navigation is the ability to learn and remember a path from one location to another, a process that can approximate the health of the brain’s hippocampus.  

Dr Dominic Tran from the Faculty of Science’s School of Psychology led the research, which found HFHS diets have a detrimental effect on some aspects of cognitive function. It is likely those effects centre on the hippocampus, the brain structure important for spatial navigation and memory formation, rather than acting across the entire brain.   

“The good news is we think this is an easily reversible situation,” Dr Tran said. “Dietary changes can improve the health of the hippocampus, and therefore our ability to navigate our environment, such as when we’re exploring a new city or learning a new route home.” 

The research team recruited 55 university students aged between 18 and 38. Each participant completed questionnaires capturing their intake of sugary and fatty foods. They also had their working memory tested in a number recall exercise, and their body mass index (BMI) recorded.  

The experiment itself required participants to navigate a virtual reality maze and locate a treasure chest six times. The maze was surrounded by landmarks that participants could use to remember their route. Their starting point and the location of the treasure chest remained constant in each trial.  

If participants found the treasure in less than four minutes, they continued to the next trial. If they failed to find the treasure in this time, they were teleported to its location and given 10 seconds to familiarise themselves with that location before the next trial.  

A seventh trial removed the treasure chest from the virtual maze but asked participants to find and mark its former location based purely on memory. Those with lower levels of fat and sugar in their diets were able to pinpoint the location with a higher degree of accuracy than those who consumed these foods multiple times a week.  

“After controlling for working memory and BMI, measured separately to the experiment, participants’ sugar and fat intake was a reliable predictor of performance in that final, seventh, test,” Dr Tran said.  

Dr Tran said the results highlight the importance of making good dietary choices to maintain healthy brain function. 

“We’ve long known eating too much refined sugar and saturated fat brings the risk of obesity, metabolic and cardiovascular disease, and certain cancers. We also know these unhealthy eating habits hasten the onset of age-related cognitive decline in middle age and older adults. 

“This research gives us evidence that diet is important for brain health in early adulthood, a period when cognitive function is usually intact,” Dr Tran said. 

Dr Tran said the sample group used in this research was not representative of the wider population, but the findings still apply more broadly. 

“It’s likely our participants were a little healthier than the general population and we think, if our sample better represented the public, the impact of diet on spatial navigation would likely be even more pronounced.” 

Dr Tran is a recipient of an Australian Research Council Discovery Early Career Research Award (DECRA).  

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Journal

International Journal of Obesity

DOI

10.1038/s41366-025-01776-8 

Even vegans who get enough total protein may fall short for some essential amino acids

 

In New Zealand study, 3 in 4 vegans ate sufficient protein, but half didn’t meet daily lysine and leucine requirements

Peer-Reviewed Publication

PLOS

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image: 

Variation in vegan dietary patterns and their influence on total protein intake and protein quality using a story of three vegans. Mandy demonstrates the most balanced approach of achieving both high total protein intake and protein quality. Jerry, on the other hand, meets his protein intake but his diet falls short on protein quality. Sandy represents a common pattern observed in our cohort, and her existing diet fails in meeting both protein quantity and protein quality. In summary, our findings show a high protein intake alone does not always guarantee adequate protein quality.

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Credit: Soh et al., CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

In a new study of people with long-term vegan diets, most ate an adequate amount of total daily protein, but a significant proportion did not meet required levels of the amino acids lysine and leucine. Bi Xue Patricia Soh and colleagues at Massey University, New Zealand, present these findings in the open-access journal PLOS One on April 16, 2025.

Proteins are made up of various molecular “building blocks” known as amino acids. While the human body can synthesize most of the amino acids we need to live, we completely rely on the food we eat to provide the nine “indispensable amino acids” we cannot make ourselves. Typically, plant-based foods have more varied levels of indispensable amino acids that the body can use, as compared to animal-sourced foods, so they are of particular concern in vegan diets.

However, most prior research on protein in vegan diets has not considered specific amino acids nor the digestibility of different foods, which accounts for the fact that not all of what we eat, including amino acids, is fully utilized by the body.

To help deepen understanding of amino acid intake in vegan diets, Soh and colleagues analyzed detailed, four-day food diaries kept by 193 long-term vegans living in New Zealand. They used information from the United States Department of Agriculture and the New Zealand FoodFiles database to calculate participants’ intake of different amino acids from the different foods they ate.

The analysis showed that about three quarters of participants met daily total protein requirements. Accounting for body weight, intake of all indispensable amino acids also met requirements.

However, when considering digestibility, only about half of the participants met daily requirements for lysine and leucine levels, making them the most limiting indispensable amino acids in the study. Among the food types consumed by participants, legumes and pulses were the biggest contributors to overall protein and lysine intake.

These findings underscore that meeting total daily protein requirements does not necessarily mean meeting indispensable amino acid requirements. On the basis of their findings, the researchers call for future research to explore how intake of leucine and lysine could be boosted for vegans in a nutritionally balanced manner.

The authors add: “Vegan diets are the most restrictive form of plant-based eating, relying entirely on plant sources for all nutrients. Achieving high protein quality on a vegan diet requires more than just consuming enough protein – it also depends on the right balance and variety of plant foods to supply all the amino acids in the quantities that our body needs. Prolonged deficiencies in these essential nutrients can negatively affect overall protein balance, muscle maintenance and other physiological functions, especially in more vulnerable populations.”

“In our study, lysine and leucine were the most commonly under-consumed amino acids in our vegan cohort and fall below the daily requirements needed by our body. This is because many plant foods generally contain lower quantities of these amino acids that can be absorbed and utilized by the body. However, the inclusion of legumes, nuts and seeds emerged as valuable plant sources – not only to support overall protein intake but also to specifically increase lysine and leucine quantities in a vegan diet.”

 

Brisk walking pace + time spent at this speed may lower risk of heart rhythm abnormalities

 

A brisk walking pace, and the amount of time spent at this speed, may lower the risk of heart rhythm abnormalities, such as atrial fibrillation, tachycardia (rapid heartbeat), and bradycardia (very slow heartbeat), finds research published online in the journal Heart.

The findings were independent of known cardiovascular risk factors, but strongest in women, the under 60s, those who weren’t obese, and those with pre-existing long term conditions.

Heart rhythm abnormalities (arrhythmias) are common, note the authors, with atrial fibrillation alone doubling in prevalence over the past 3 decades to reach nearly 60 million cases worldwide in 2019.

As these abnormalities are associated with heightened risks of cardiovascular disease, sudden cardiac death, and disability, pinpointing modifiable risk factors is essential to stave off the toll taken on health, they add.

While walking pace is associated with lower risks of cardiovascular disease and death, few studies have looked at its potential impact on heart rhythm abnormalities.

The researchers therefore looked at the impact of different walking speeds while exploring the potential role of metabolic factors and inflammation, as well as risk factors, such as age, sex, obesity, smoking, alcohol intake, and pre-existing long term conditions. 

They drew on 420,925 UK Biobank participants for whom walking speed data was available from questionnaire responses. The amount of time spent walking at different paces—derived from activity tracker readings—was available for 81,956 of them.

A slow pace was defined as walking at less than 3 miles an hour; steady/average pace as 3–4 miles/hour; and a brisk pace as more than 4 miles/hour.

The average age of the participants was 55; more than half (55%) were women, and most (97%) were White. 

Overall, 27,877 participants (just over 6.5%) reported a slow walking pace; 221,664 (53%) an average walking pace; and 171,384 (41%) a brisk walking pace. 

During an average tracking period of 13 years, 36,574 (9%) participants developed heart rhythm abnormalities: 23,526 atrial fibrillation; 19,093 other cardiac arrhythmias; 5678 an abnormally slow heart rate; and 2168 ventricular arrhythmias (abnormal rhythms originating in the lower chambers of the heart). 

Participants reporting a faster walking pace were more likely to be men, and tended to live in less deprived areas, and have healthier lifestyles. They also had smaller waists, weighed less, had better grip strength, and lower levels of metabolic risk factors, including blood fats and fasting glucose, as well as lower levels of inflammatory activity, and fewer long term conditions.

After accounting for potentially influential background demographic and lifestyle factors, an average or brisk walking pace was associated with significantly lower (35% and 43%, respectively) risks of all heart rhythm abnormalities compared with a slow walking pace.

And these walking speeds were associated with lower risks of atrial fibrillation (38% and 46%, respectively); and other cardiac arrhythmias (21% and 39%, respectively) compared with those who reported walking at a slow pace.

Some 4117 of the 81,956 participants with activity tracker data developed arrhythmias. Those who spent more time walking at a brisk pace were generally younger, more likely to be White and male, and live in less deprived areas. They generally had healthier lifestyles, and were healthier, overall. 

While the amount of time spent walking at a slow pace wasn’t associated with the risk of developing heart rhythm abnormalities, more time spent walking at an average or brisk pace was associated with a 27% lower risk.

Overall, around 36% of the association between walking pace and all heart rhythm abnormalities was influenced by metabolic and inflammatory factors. 

The observed associations were independent of known cardiovascular risk factors, but were strongest in women, the under 60s, those who weren’t obese, those who had high blood pressure, and those with 2 or more long term conditions.

This is an observational study, and as such, no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that part of the study relied on self report while the study participants didn’t reflect a broad spectrum of ages and ethnic backgrounds.

But they write: “This study is the first to explore the pathways underpinning the association between walking pace and arrhythmias, and to provide evidence that metabolic and inflammatory factors may have a role: walking faster decreased the risk of obesity and inflammation, which, in turn, reduced the risk of arrhythmia.” 

And they explain: “This finding is biologically plausible because cumulative epidemiological studies have shown that walking pace is inversely associated with metabolic factors, such as obesity, HbA1c [fasting glucose], diabetes, and [high blood pressure] which, in turn, are associated with the risk of arrhythmias.”

Symptoms of ice cold feet + heaviness in legs strongly linked to varicose veins

 

Hypersensitivity to the cold, especially ice cold feet, as well as a feeling of heaviness in the legs, are linked to the presence of varicose veins, finds a large study published in the open access journal Open Heart. 

Cold hypersensitivity is often underestimated as a subjective symptom, say the researchers.

Varicose veins are usually caused by impaired functioning of the deep or superficial veins, and the perforator veins (short veins that link the superficial and deep venous systems in the legs). 

The prevalence of varicose veins ranges from 2% to 30% in adults, with women at higher risk. And symptoms include sensations of heaviness, aching, throbbing, and itching; restlessness in the legs; fluid retention and swelling; muscle cramps; and leg ulcers in severe cases. 

Previously published research indicates that heightened sensitivity to cold may be associated with varicose veins, note the researchers. To explore this further, they mined data covering the period January 2008 to December 2020 inclusive from the Taiwan Biobank, the largest genetic and population-based database in Taiwan. 

In all, 8782 participants aged between 30 and 70 with moderate and severe varicose veins were included in the analysis. They were quizzed about their hypersensitivity to cold in their feet and the extent to which they felt heaviness in their legs.

And information on potentially influential factors was collected on sex, diet (vegetarian), age, cigarette smoking, alcohol intake, regular exercise, weight (BMI), education level, job type (predominantly standing or sedentary), and presence of diabetes and high blood pressure.

In all, 676 participants said they had moderate to severe varicose veins. 

Of the total number of participants, 5888 said they weren’t hypersensitive to the cold, just under 6% (340) of whom had varicose veins. 

Of the remainder, 1535 participants said they were moderately hypersensitive to the cold, just over 9% (144) of whom had varicose veins; and 1359 said they were extremely hypersensitive to the cold, just over 14% (192) of whom had varicose veins.

Statistical analysis showed that moderate to severe cold hypersensitivity was associated with a 49%-89% heightened likelihood of varicose veins compared with no hypersensitivity.

Similarly, 4 times as many people with varicose veins had heavy legs as those without the condition. 

Job type was also an influential factor: jobs involving prolonged standing were associated with a 45%  higher likelihood of varicose veins.

The association between cold hypersensitivity and heavy legs was significant. 

In the absence of cold hypersensitivity, the likelihood of varicose veins and heaviness in the legs was 7 times greater than in those who didn’t report leg heaviness. 

Among those who did report this symptom, the likelihood of varicose veins was 90% higher for those with moderate cold hypersensitivity, and more than 3 times as high among those reporting extreme hypersensitivity to the cold.

And compared with those reporting neither cold hypersensitivity nor heaviness in the legs, moderate and severe cold hypersensitivities were associated with an 80% and more than doubling in the likelihood of varicose veins, respectively. 

This is an observational study, and as such can’t establish causal factors. It also relied on subjectively assessed self report rather than clinical assessment, added to which no information was available on any forms of treatment for varicose veins.

But the researchers point out: “Healthcare providers frequently underestimate the gravity and implications of varicose veins, leading to their neglect, and there is usually a gap in understanding the comprehensive spectrum of linked symptoms.” 

They add: “In clinical practice, the sensation of coldness is usually relegated to a secondary position among the many varicose vein symptoms. This relegation is attributed to its subjectivity and the consequent ease with which it can be overlooked. 

“However, our study showed the presence of a moderate-to-severe degree of hypersensitivity to cold in the lower extremities, which has hitherto been underestimated as a subjective symptom associated with varicose veins. 

“Of note is the significance of the concurrent symptoms of heaviness and cold feet. When these symptoms coexist, the likelihood of confirming the presence of varicose veins is notably amplified compared with individuals without such symptoms.”