Natural trans fats in dairy do not raise heart disease risk

 Trans fats found naturally in dairy foods such as milk, butter and cheese do not increase the risk of heart disease or type 2 diabetes, a new study has found.  

Researchers analysed evidence from 22 studies involving thousands of people across Europe, Canada and the United States and found that natural trans fats behave very differently in the body from the industrial kind. Unlike industrial trans fats, which are strongly linked to heart disease, those found in dairy appear to pose no risk.  

The first-of-its-kind research, published in the journal Nutrition Research, will also raise consumer’s awareness of this topic and provide clarity on trans fat labelling policies which may cause confusion.  

Professor Ian Givens, one of lead authors, and from the University of Reading, said: "People hear the words 'trans fats' and assume the worst, but the trans fats in your morning milk, yogurt, butter or cheese are not the same as the ones from industrial partially hydrogenated fats. This research should give people reassurance that dairy, eaten as part of a balanced diet, is not something to worry about for your heart."  

Two types of trans fat, two different stories  

Trans fats, a type of unsaturated fat, occur naturally in the milk of animals such as cows, sheep and goats, but can also be made artificially during the production of partially hydrogenated fats. The industrial  type, can be found in some processed and fried foods, are strongly linked to heart disease.  

To test whether dairy trans fats affect heart health, the researchers looked at two types of evidence. The first was ten dietary controlled trials in which people consumed dairy foods with naturally enhanced trans fats and compared with regular dairy foods. Scientists then measured the effect on blood lipid biomarkers, which are used to determine heart disease risk. Across all ten trials, covering trans fat intakes ranging from 1.3 to 13.2 grams per day, there were no meaningful differences in blood lipid levels between trans fat-enhanced dairy foods versus regular dairy foods. 

The second type of evidence came from twelve long-term cohort studies that tracked thousands of people over many years, in some cases more than two decades, and measured the levels of dairy trans fats in their blood. None of these studies found that higher levels of dairy trans fats were linked to a greater risk of heart disease, stroke or cardiovascular death.  

Likewise,  higher levels of dairy trans fats in their blood were  not linked with type 2 diabetes risk. 

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Journal

Nutrition Research

DOI

Depression may not only be a consequence, but also a cause of rheumatoid arthritis

According to researchers at Semmelweis University, not only inflammation, but also sleep disorders, depression, obesity, and smoking may sustain persistent rheumatic symptoms. In their publications in the journals Nature Reviews Rheumatology and The Lancet Rheumatology, they also proposed a model that can help identify and treat the true causes of symptoms in time.

Researchers at Semmelweis University analyzed how depression, smoking, obesity, sleep disorders, and other health problems are linked to difficult-to-treat rheumatoid arthritis.

Rheumatoid arthritis is a chronic autoimmune disease in which the immune system attacks the joints, causing pain, swelling, and stiffness. It affects tens of thousands of people in Hungary only. Most patients respond well to treatment, but 6–28 percent belong to the so-called “difficult-to-treat” group because they do not achieve lasting remission despite therapy.

According to the publications in Nature Reviews Rheumatology and The Lancet Rheumatology, these factors may not only coexist with the disease but may also help maintain it.

For example, pain and depression may reduce physical activity, increase body weight, worsen sleep and mood – all of which can feed back into pain and everyday functioning, creating a difficult-to-break “vicious cycle.” 

What does caffeine do to our sleep?

 Evening coffee has sparked controversy for years. Some people fall asleep without difficulty, while others toss and turn for half the night. However, a growing body of research suggests that the question of whether “coffee makes it harder to fall asleep” may be too simplistic. What appears to matter far more is what happens in the brain during sleep. 

Scientists studying the effects of caffeine on sleep are increasingly turning to EEG, or electroencephalography — a method used to record the brain’s electrical activity. Thanks to EEG, it is possible to observe not only sleep duration or moments of awakening, but also the biological quality of sleep itself. 

– EEG allows us to see not only whether a person is sleeping, but also how the brain is sleeping. Classical sleep assessment assesses sleep duration and its stages, whereas quantitative EEG analysis reveals more subtle changes, such as reduced slow-wave activity, which is an important marker of sleep depth and its restorative character, explains Prof. Donata Kurpas from the Department of Nursing, Wroclaw Medical University. 

Slow waves are one of the key components of deep sleep — the phase responsible for bodily regeneration, restoration of energy resources, and proper brain function. 

Caffeine may cause “shallow” sleep 

Research shows that the effects of caffeine do not always manifest as shorter sleep or difficulty falling asleep. Much more often, the changes concern the quality of nighttime rest. 

– Caffeine may shorten sleep or make it more difficult to fall asleep; however, even when sleep duration appears normal, it may reduce slow-wave activity and shift the EEG pattern toward a more ‘wakeful’ brain, says Prof. Kurpas. 

This means the body may spend eight hours in bed, but the brain may fail to fully regenerate. People are often unaware of this. 

– The subjective feeling of having slept well does not always correspond to what we observe in neurophysiological recordings. A person may fall asleep without major difficulty and not remember awakenings, while the brain may display fewer features of deep sleep, the expert adds. 

Why does coffee affect everyone differently? 

One of the most interesting conclusions emerging from research is the enormous individual variability in response to caffeine. Genetics, metabolic rate, age, stress levels, and chronic fatigue all play a role. 

For some individuals, even coffee consumed in the morning may be problematic. 

– It is not only about coffee consumed just before bedtime. For some people, the total amount of caffeine consumed during the day and whether the body has enough time to metabolize it before nightfall may also be important, Prof. Kurpas emphasizes. 

This is particularly important information for people engaged in intellectual work, athletes, and anyone who regularly uses caffeine to improve performance and concentration. 

Energy is borrowed from the body 

Caffeine improves alertness and reduces the sensation of fatigue, but experts point out that its effects may sometimes resemble “borrowing energy” at the expense of nighttime regeneration. 

– If caffeine helps a person function during the day while simultaneously worsening the quality of nighttime recovery, a vicious circle may develop: greater fatigue, greater need for stimulation, and poorer sleep, says Prof. Kurpas. 

For this reason, modern sleep research is increasingly moving away from simple questions about sleep duration and focusing instead on how the brain functions during nighttime rest. 

– Caffeine is neither ‘good’ nor ‘bad’. It is a biologically active substance whose effects depend on dose, time of day, age, lifestyle, sleep quality, stress burden, and individual sensitivity, the expert concludes.

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Plant-forward and low-insulinemic diets = reduced weight gain during menopause

 

, long-term study finds

Peer-Reviewed Publication

National University of Singapore, Yong Loo Lin School of Medicine

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A large long-term study of nearly 40,000 women has found that women who eat more plant-based, low-insulinemic foods may gain less weight and have a much lower risk of developing obesity during the years around menopause. A low-insulinemic diet refers to a diet that is less likely to cause repeated spikes in insulin, a hormone that helps regulate blood sugar and fat storage.

 

Menopause is a major life stage marked by hormonal and metabolic changes. During this period, many women are more likely to experience weight gain and face a higher risk of obesity, type 2 diabetes, and cardiovascular disease. While healthy eating is known to support weight management, there has been limited evidence on which specific diets may work best for women during this transition.

 

To address this gap, researchers from the NUS–Harvard Women’s Health Initiative (NUSHINE) conducted one of the first long-term studies to comprehensively compare 11 dietary patterns in women going through menopause. The study was co-led by Chair Professor Zhang Cuilin, Department of Obstetrics and Gynaecology, and Director of the Global Centre for Asian Women’s Health (GloW) at the NUS Yong Loo Lin School of Medicine (NUS Medicine), together with Harvard T.H. Chan School of Public Health’s Professor Frank B. Hu, Chair of the Department of Nutrition, and Dr Xia Tong, postdoctoral fellow , and other collaborators.

 

Published in JAMA Network Open, the study analysed data from 38,283 women enrolled in the Nurses’ Health Study II from 1989 to 2019, focusing on approximately 12 years around menopause. In the study, 90 per cent of the participants are Caucasian, with future studies focusing on more diverse populations, including Asians. Participants’ diets were assessed once every four years using validated food frequency questionnaires, and their body weight was tracked across six two-year intervals. This allowed the researchers to study how different eating habits were linked to weight changes during the menopausal transition. In total, the study compared 11 dietary patterns, along with ultra-processed food intake, within the same group of women.

 

Over the follow-up period, women gained an average of 0.80kg per year, while 5,214 developed obesity, based on over 340,000 combined years of follow-up across all participants. Among all the diets studied, the Planetary Health Diet Index, which focuses on plant-based foods such as nuts, legumes, whole grains, fruits, and vegetables, was most strongly linked to a lower risk of obesity. Women who followed this diet most closely had a 54 per cent lower risk of developing obesity compared with those who followed it the least.

 

Another dietary pattern, known as the reverse Empirical Dietary Index for Hyperinsulinemia, was linked to the greatest reduction in yearly weight gain. This diet is considered to have lower insulinemic potential, meaning it is less likely to place repeated high insulin demands on the body. Women who followed this pattern gained 0.28kg less per year than those whose diets had higher insulinemic potential. This pattern was marked by lower intakes of red and processed meats, French fries, potatoes, and sodium.

 

In contrast, diets higher in ultra-processed foods, red and processed meats, sodium, potatoes, and French fries were linked to greater weight gain and a higher risk of obesity. A diet high in red and processed meats, fries, and sodium was associated with nearly double the risk of obesity. Overall, the findings point to a practical message: eating more nuts, legumes, fruits, vegetables, and whole grains, while cutting back on red and processed meats, salty foods, and fried potatoes, may help women manage their weight more healthily during menopause.

 

“These findings send a hopeful and practical message to women navigating one of the most challenging metabolic transitions in their lives. Adopting a plant-forward, low-insulinemic diet does not require drastic changes — it can be as simple as eating more whole grains, nuts, legumes, and vegetables, and reducing reliance on processed and high-sodium foods. If incorporated into routine midlife care, this dietary guidance could meaningfully reduce the long-term burden of obesity and cardiometabolic disease in women,” said Prof Zhang.

 

“Our findings are especially timely as obesity and cardiometabolic diseases continue to rise among midlife women worldwide,” added Prof Hu. “Incorporating evidence-based dietary counselling into routine midlife healthcare may help women protect their long-term health and reduce the risk of obesity-related chronic diseases.”

 

Future studies should examine these associations in more diverse populations, including Asian women, and explore whether targeted dietary interventions during menopause can improve cardiometabolic health. The NUS–Harvard collaboration through NUSHINE is well-positioned to address these questions and generate evidence that could inform dietary guidelines and clinical practice for women in midlife.

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Journal

JAMA Network Open

DOI

10.1001/jamanetworkopen.2026.13102 

Tomato-soy juice lowers inflammation in adults with obesity

 Drinking tomato-soy juice  lowered pro-inflammatory proteins in healthy adults with obesity after four weeks, a new study found.

The findings hint at the juice’s promise as a functional food that may help curb the unchecked inflammation that characterizes a range of chronic conditions, researchers say.

The tomato-soy juice contained high levels of the plant-based compounds lycopene and soy isoflavones, both believed to have antioxidant and anti-inflammatory properties based on previous research. Compared to a control tomato juice lacking these compounds, the tomato-soy juice significantly lowered blood levels of three proteins that are markers of systemic inflammation.

“The idea is, can we use food-based interventions to modulate inflammation?” said lead author Jessica Cooperstone, associate professor of horticulture and crop science at The Ohio State University. “And can we test this in a rigorous way so that we can really see this is affecting inflammation, versus just saying something is anti-inflammatory?”

Based on these results and additional data, Cooperstone and colleagues have received National Institute of Diabetes and Digestive and Kidney Diseases funding for a pilot clinical trial testing whether consuming the same tomato-soy juice reduces inflammation in patients with pancreatitis.

The study was published recently in the journal Molecular Nutrition & Food Research.

Lycopene is a carotenoid that gives tomatoes and other vegetables their colors, and soy isoflavones are flavonoids that mimic the action of the hormone estrogen. Both are phytochemicals that help plants thrive.

Years ago, based on studies showing an association between diets high in either tomato products or soy and a lowered risk for prostate cancer, Ohio State researchers developed the tomato-soy juice made with tomatoes containing a high concentration of lycopene – also developed and grown at Ohio State – and enriched with soy isoflavone extract.

Later research at the university linked higher intake of the tomato-soy juice to reduced prostate-specific antigen levels in some men with prostate cancer, and studies elsewhere have suggested that tomatoes and soy, consumed separately or combined, can affect inflammatory and metabolic pathways related to obesity and other chronic illnesses.

“There’s been enough compelling evidence that compounds from tomatoes and soy might be modulating inflammation that we decided to test this in people,” Cooperstone said.

In the new study, 12 healthy adults with obesity consumed two 6-ounce cans of tomato-soy juice every day for four weeks. After a washout period, they consumed the low-carotenoid control tomato juice for four weeks.

“The hypothesis is that it’s the lycopene from the tomatoes and the isoflavones from the soy that’s inducing the effect, so we didn’t want to have a control that’s just water,” Cooperstone said.

Researchers took blood samples testing for cytokines – pro-inflammatory proteins produced by the immune system – before and after each four-week trial period. Only the tomato-soy juice resulted in significant reductions in three cytokines: Interleukin (IL)-5, IL-12p70 and granulocyte-macrophage colony-stimulating factor (GM-CSF), as well as showing a downward trend in tumor necrosis factor alpha (TNF-a) that was not statistically significant.

The team also analyzed participants’ urine before and after each trial period for changes in metabolites, the molecular products of biochemical reactions that break down nutrients to produce energy and perform other essential functions.

The findings showed that both the tomato-soy and control tomato juice led to some shared changes in the metabolite profiles, meaning some tomato-driven effects occurred in the absence of lycopene. Soy isoflavone metabolite shifts stood out among the changes induced by the tomato-soy juice. While further investigation is warranted, the changes provide additional evidence that this food-based intervention is affecting human biology.

“This is probably a function of the fact that there’s more to our intervention agents than just these two compounds,” Cooperstone said. “Ultimately, we want to have a better understanding of how the foods that we eat are relating to our health. And when we really want to be sure, we need to test them in clinical trials. And that’s what we’re doing here.”

She and colleagues have also found evidence in an animal model that the soy-tomato juice can reduce inflammation and the severity of chronic pancreatitis – data supporting the prediction in the current clinical trial that the intervention could improve outcomes for patients with pancreatitis.

“Care for patients with pancreatitis is palliative, focused on controlling pain and GI symptoms. Our hypothesis is that the tomato-soy juice may serve as an intervention to decrease inflammation and hopefully increase patients’ quality of life,” Cooperstone said.

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Daily glass of 100% fruit juice could help support mental wellbeing

People who drink a glass of 100% fruit juice or a smoothie each day as part of the UK’s 5-a-day healthy eating guidance see improvements in their mental wellbeing, according to new research from Newcastle University, UK.

In a new randomised controlled trial, adults with low intakes of fruit and vegetables were given support to increase their daily fruit and vegetable intake, with or without a glass of fruit juice or a smoothie, in order to meet the 5-a-day guideline.

After four weeks, both groups successfully boosted their fruit and vegetable intake but the group of people who added in fruit juice reported a reduction in depression scores.

The results, peer-reviewed and published in the British Journal of Nutrition and funded by the Fruit Juice Science Centre, add to growing evidence that simple, practical dietary changes can support mental health.

Dr Courtney Neal who completed the study while at Newcastle University and is now at the University of Liverpool said: “While most people know eating 5-a-day can be good for your health, many people struggle to.

“Our trial showed that when people with low fruit and vegetable intake were provided with targeted financial and educational support to address common barriers to eating 5-a-day, they were able to make meaningful changes to their diet. We found that simple, cost-effective solutions, like drinking a small glass of 100% fruit juice or a smoothie daily, could help people reach their 5-a-day, with potential benefits for mental wellbeing.”

Hitting the targets

Eating the recommended target of whole fruit and vegetables is linked to a lower risk of chronic disease and better long-term health. However, fewer than 1 in 5 (17%) UK adults and 1 in 10 teenagers currently meet the recommended 5-a-day.

In the 4-week trial, participants who all consumed two or fewer daily portions of fruit and vegetables at the start of the study, were given support to increase their intake to 5-a-day. Some were told to consume whole fruit and vegetables only, whilst others consumed whole fruit and vegetables and included one daily glass of fruit juice or smoothie in their diet. 

The impact of the dietary changes on participants’ mood was measured using validated questionnaires for anxiety and depression. The group consuming fruit juice and smoothies alongside whole fruit scored lower for markers of depression compared to the control group. The scores were 2.52 points lower on a 27-point scale, reflecting a modest but statistically significant difference.

Both intervention groups were estimated to have increased their fibre intake by 8-10g per day, according to dietary recalls they completed during the study, suggesting that drinking juice did not prevent participants from increasing their intake of other fibre-rich fruits and vegetables.

Despite ongoing concerns around sugar content, the study of 42 participants also found no adverse effects on metabolic health markers after the four-week period among participants consuming fruit juice and smoothies as part of the intervention.

Dr. Oliver Shannon, Lecturer in Nutrition and Ageing at Newcastle University and one of the senior authors of the study, said: “Given the ongoing cost of living pressures in the UK, the price of fresh produce is often a barrier for people trying to eat more fruit and vegetables. Our study shows that drinking a daily glass of fruit juice or a smoothie could be part of the solution and help people reach 5-a-day fruit and vegetable targets.

“The finding that fruit juice drinkers had reduced depression scores is promising and worthy of further exploration, particularly in individuals experiencing poor mental wellbeing. It backs up studies which report improved brain blood flow and cognitive function after people drink citrus juices. Simple dietary changes—like increasing fruit intake, including through a daily glass of juice—could play a role in supporting mental wellbeing.”

Reference:  Including fruit juice and smoothies within 5-a-day fruit and vegetable intake recommendations: A randomised controlled trial investigating impact on levels of intake, mood, and markers of health. Journal: British Journal of Nutrition. DOI: https://DOI.org/10.1017/S0007114526107569

Regular guava juice consumption may help lower women’s anemia risk

 

Iron supplements + guava juice combo more effective than supplements alone for boosting haemoglobin levels; Might be worth including it in dietary counselling for anemia prevention, say researchers

Peer-Reviewed Publication

BMJ Group

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Regular guava juice consumption may prove a readily accessible and affordable addition to helping lower the risk of anaemia in women in low and middle income countries, suggests a synthesis of the available evidence, published in the open access journal BMJ Nutrition Prevention & Health.

 

A combination of guava juice and iron supplements is more effective than the supplements alone for boosting haemoglobin levels, the pooled data indicate, prompting the researchers to suggest its inclusion in dietary counselling for anaemia prevention in countries with a high prevalence of the condition.

 

Iron deficiency anaemia is very common in teenage girls and pregnant women in low and middle income countries, putting them at heightened risk of ill health and death, note the researchers.

 

In many Asian regions, guava fruit is a rich, affordable source of vitamin C, which boosts uptake of dietary iron from plant sources, they add. The fruit contains up to 4 times as much vitamin C per 100 g as oranges, and also provides vitamin A, folate, dietary fibre, and modest amounts of iron, they point out.

 

While several small Indonesian studies have reported increases in haemoglobin after drinking the juice, the findings haven’t been synthesised to establish its overall effectiveness, they explain.

 

The researchers therefore scoured research databases for relevant clinical trials and quasi-experimental studies published in English from 2000 onwards.

 

They found 17 eligible studies, 15 of which were quasi-experimental trials, and 2 of which were randomised controlled trials. Six studies focused on teenage girls and 11 involved pregnant women. Most (9) evaluated the effects of guava juice plus iron supplementation.

 

The results of 12 quantitative studies involving 235 women and teenage girls were synthesised. The pooled average difference in haemoglobin levels was 1.71 g/dl, overall, indicating a significant improvement after guava juice consumption.

 

Further detailed analysis showed average differences after drinking the juice of 1.52 g/dl among teenage girls and 1.84 g/dl among pregnant women.

 

In the five studies directly comparing guava juice and iron supplementation combined and iron supplementation alone (102 participants in each group), the average difference was 1.29 g/dl greater with the guava juice combination.

“An increase of 1–2 g/dl may shift individuals from mild or moderate anaemia to non-anaemic categories, improving fatigue, cognitive function, and productivity outcomes,” suggest the researchers.

 

They highlight various limitations to their findings, including the fact that all the studies were carried out solely in Indonesia, and the wide variability in study design, intervention duration, guava variety, dose and participant characteristics.

 

The predominance of quasi-experimental designs also restricts causal inference, and the lack of long term follow up precludes assessment of the sustainability of any improvements in haemoglobin levels, they emphasise.

 

“Integrating guava juice into school nutrition programmes, antenatal care packages, or community health initiatives could represent a feasible approach to address mild-to-moderate anaemia, aligning with the United Nations’ Decade of Action on Nutrition (2016–2025), which emphasises dietary diversification and locally sourced nutrient-rich foods,” they point out.

 

“Given its nutritional richness, affordability, and cultural acceptance across Asia, guava juice offers a promising low-cost intervention. Strengthening local supply chains, standardising formulations and embedding such dietary approaches within public health nutrition programmes could collectively contribute to more sustainable anaemia control,” they add.

 

“This study builds on the established role of dietary sources high in vitamin C to enhance iron absorption and improve the effectiveness of iron supplementation,” comments Professor Sumantra Ray, chief scientist & executive director, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health.

 

“But quasi-experimental research, the wide variation in study design, small sample sizes, and limited length of follow-up mean that caution is required when interpreting the findings. Without further rigorous research, defining the best therapeutic dose and period of use, guava juice can’t be recommended as an alternative to conventional treatment in those at risk of iron deficiency anaemia,” he adds.

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Journal

BMJ Nutrition Prevention & Health

DOI

10.1136/bmjnph-2025-001466