Journalists and others should no longer reference or use the study findings in future reporting

BMJ Group has retracted research suggesting that small daily quantities of apple cider vinegar might help people who are overweight or obese to lose weight.

The small clinical trial was published in the open access journal BMJ Nutrition, Prevention & Health in March 2024 and its findings press released. The study findings generated widespread international attention at the time, and continue to be frequently referred to in media coverage.

The retraction was prompted by concerns raised about the quality of the work, including the approach to statistical analysis of the data; implausible statistical values; the reliability of the raw data; inadequate reporting of methods; and lack of prospective trial registration, which breaches BMJ Group’s editorial policy.

Initially, concerns were raised in critiques of the study, some of which were published as letters in the journal. But after review by BMJ Group’s content integrity team, the study was referred to statistical experts to evaluate its reliability.  This included attempts to replicate the results and examine the authenticity of the underlying data supplied by the authors.

It wasn’t possible for the statisticians to replicate the results and multiple analytical errors were identified. There were also irregularities in the data set, and their report, which is appended to the retraction notice, concluded that the data collected from each participant would require further independent scrutiny.

The authors said that the identified errors were honest mistakes, but they agree with the decision to retract the study.

Dr Helen Macdonald, Publication Ethics and Content Integrity Editor at BMJ Group, said: “Tempting though it is to alert readers to an ostensibly simple and apparently helpful weight loss aid, at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.”

She added: “This retraction reflects our strategic and proactive approach to investigating concerns raised about the content we publish. We act where necessary in the interests of openness and the importance of correcting the scientific record.

“While we deal with allegations as swiftly as possible, it’s very important that due process is followed. Investigations are often complex. This one involved detailed scrutiny of data and correspondence with researchers, institutions, and other experts, for example. Reaching a sound and fair and final decision can therefore take several months.”

Commenting on the decision to publish the study despite the lack of trial registration, Professor Martin Kohlmeier, editor in chief of BMJ Nutrition Prevention & Health, explained: “In hindsight, this was the wrong decision to make. But the authors come from a scientific environment that is underrepresented in nutritional research and the journal aims to prioritise high quality evidence, which usually comes from clinical trials.

“These are relatively unusual in nutritional research as they can be challenging to undertake because of the numbers of participants and time needed to obtain meaningful results.”

Notes for editors:
Retracted research: Apple cider vinegar for weight management in Lebanese adolescents and young adults with overweight and obesity: a randomised, double-blind, placebo-controlled study doi:10.1136/bmjnph-2023-000823

BMJ Nutrition Prevention & Health is co-owned with NNEdPro Global Institute for Food, Nutrition and Health

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These orders tend to be favoured by younger adults and those living with obesity
Limited impact of calorie labelling calls for extra strategies to promote healthier food choices

Taste and price, rather than calorie content, seem to be the key considerations for those ordering takeaways online, despite calorie labelling legislation designed to help consumers make healthier food choices, suggests an analysis of survey responses, published in the open access journal BMJ Nutrition Prevention & Health.

These orders tend to be favoured by younger people and those living with obesity, the responses indicate. And the limited impact of calorie labelling, despite relatively high awareness of the regulations, suggests that additional strategies are needed, say the researchers.

Takeaways are usually lower in nutritional content than home cooked meals. And their frequent consumption is linked to a less healthy diet, overall, and higher energy intake, note the researchers.

But it’s still not clear which factors might be driving these purchases and how interventions, such as calorie labelling, which was mandated in England in 2022 for food businesses with more than 250 employees, might help to promote healthier food choices, they add.

To find out, they drew on the responses of a consumer behaviour panel of 1040 adult takeaway consumers in England to a survey assessing their knowledge and awareness of calorie labelling legislation and the principal factors driving their food choices.

The survey covered: takeaway frequency; knowledge of recommended calorie content of a meal; awareness of calorie labelling; noticing calorie labels and their perceived impact; ranking of drivers of takeaway and home-cooked meal choices by healthiness, price, taste, preparation/delivery time, portion size, and low carbon footprint; and ranking of additional strategies—higher prices for less healthy items, smaller portions, exercise-based calorie labels, traffic light labels, and provision of healthier alternatives.

Around two thirds (68%) of respondents were women; over half were aged between 35 and 55. More than half were overweight (35%) or living with obesity (28%).

Around 1 in 4 (27%) respondents reported ordering a takeaway at least weekly. A further 41% had takeaways every 2 to 4 weeks, and around a third (32%) less than once a month.

Analysis of the responses showed that the under 35s were more than twice as likely to order them at least weekly as older age groups. Those who were living with obesity were also twice as likely to have weekly takeaways as those of healthy weight or who were underweight.

Respondents tended to overestimate the recommended calorie content of a meal. The average estimate was 747 kcal—about 25% higher than the recommended 600 kcal—which just 15% correctly identified. Women were twice as likely to identify the correct, or lower than recommended, calorie content of a meal as men.

Almost two thirds (63%) of respondents were aware of the calorie labelling legislation, although this was more likely among the highest socioeconomic group. But most (77%) didn’t notice any calorie information during their most recent online takeaway purchase.

Of those who did (235), nearly three quarters (71%) said it didn’t affect their food choices and almost two thirds (63%) reported no impact on their drink choices; 2–3% reported ordering higher calorie content food and drink.

Taste was the most important consideration for takeaways, followed by price, delivery time, and portion size. For home-cooked meals, taste and price were also the principal drivers, followed by portion size, preparation time, and convenience.

Healthiness was a more important consideration for home-cooked meals: more than half (56%) of the respondents scored this as (very) important compared with 22% for takeaways. Low carbon footprint was the least relevant driver for both meal types.

Women were 51% more likely than men to consider healthiness (very) important for a takeaway while those aged 65 or older were 4 times as likely to do so.                           

Around half of respondents agreed or strongly agreed that traffic light labels and healthy alternatives would encourage healthier choices, while around a third (30%) backed higher prices, exercise-based calorie labels, and smaller portions.

This is an observational study, and as such, can’t establish cause. And the researchers acknowledge that under 35s and men were underrepresented, while those reporting behaviour changes prompted by calorie labelling were too few to be representative.

“Our findings highlight the complexity of efforts to improve the healthiness of takeaway foods….Calorie labelling was widely unnoticed and influenced only a minority of choices,” they point out.

“More real-world evaluations are needed from different contexts and populations to understand motivations of takeaway consumption and the effectiveness of calorie labels in this setting, including in conjunction with other interventions,” they suggest.

“While calorie labelling may affect only a minority, it can be part of a broader strategy to address obesity and poor diets. However, its potential to improve diets without exacerbating existing health inequities remains uncertain,” they conclude.

12/08/2025

Notes for editors
Research: Calorie labelling and other drivers of takeaway food choices  Doi: 10.1136/bmjnph-2025-001268

Journal: BMJ Nutrition Prevention & Health

External funding: Medical Research Council; National Institute for Health and Care Research (NIHR) School for Public Health Research (SPHR)

Externally peer reviewed? Yes
Evidence type: Observational; survey data
Subjects: People

The post Taste and price, not calories, key drivers for online takeaway orders, survey suggests first appeared on BMJ Group.

Men and the overweight may be especially vulnerable to effects of restrictive eating

Following a low calorie diet is linked to a heightened risk of depressive symptoms, finds research published in the open access journal, BMJ Nutrition Prevention & Health.

Men and those who are overweight may be especially vulnerable to the effects of restrictive eating, the findings suggest.

A ‘healthy’ diet rich in minimally processed foods, fresh fruits and vegetables, whole grains, nuts, seeds, lean proteins and fish, is generally associated with a lower risk of depression, while an ‘unhealthy’ diet, dominated by ultra-processed foods, refined carbs, saturated fats, processed meats and sweets, is generally associated with a heightened risk, explain the researchers.

But people follow many different types of diet for health or medical reasons, including those that restrict calories or particular nutrients, and it’s not clear if these other dietary patterns might be associated with a risk of depressive symptoms, they add.

To explore this further, they drew on 28,525 adult respondents (14,329 women and 14,196 men) to the nationally representative US National Health and Nutrition Examination Survey (NHANES) for the years 2007–18, who had completed the Patient Health Questionnaire-9 (PHQ-9) for depressive symptom severity.

In all, 2508 people (just under 8%) reported depressive symptoms, and 7995 participants (29%) had a healthy weight; 9470 (33%) were overweight; and 11060 (38%) were obese.

Participants were asked if they were following any particular diet either to lose weight or for other health reasons, and if so, which of the 9 diet options set out in all 6 cycles of NHANES they were on.

Dietary patterns were categorised into 4 groups: (1) calorie-restrictive; (2) nutrient-restrictive (low in fat/cholesterol, sugar, salt, fibre, or carbs); (3) established dietary patterns (adapted for diabetes, for example); and (4) not on a diet.

Most participants (25,009, 87%) said they weren’t on any specific diet, while 2026 (8%) followed a calorie-restrictive diet, 859 (3%) a nutrient-restrictive diet, and 631 (2%) an established dietary pattern.

When stratified by sex, a greater proportion of men (12,772; 90%) than women (12,237; 85%) said they weren’t on a diet. Calorie restriction was most commonly reported by obese participants (1247;12%) and those who were overweight (594; 8%), while nutrient-restrictive and established dietary patterns were less commonly reported, with the highest proportion of established dietary pattern users among obese participants (359; 3%).

PHQ-9 scores were 0.29 points higher in those on calorie-restrictive diets than in those not on any specific diet.

The scores were higher among those who were overweight and following a calorie-restrictive diet: their PHQ-9 scores were 0.46 points higher, while a nutrient-restrictive diet was associated with a 0.61 point increase in PHQ-9 scores.

Calorie-restrictive diets were also associated with higher cognitive-affective symptom scores (measure of relationship between thoughts and feelings) while nutrient-restrictive diets were  associated with higher somatic symptom scores (excessive distress and anxiety about physical symptoms).

These scores also varied by sex: a nutrient-restrictive diet was associated with higher cognitive-affective symptom scores in men than in women not on a diet, while all 3 types of diet were associated with higher somatic symptom scores in men.

And people living with obesity following an established dietary pattern had higher cognitive-affective and somatic symptom scores than those of a healthy weight not on a diet.

This is an observational study, and as such no firm conclusions can be drawn about causality. Respondents may not have accurately classified their diets either, say the researchers.

The findings also contradict those of previously published studies suggesting that low calorie diets improve depressive symptoms. But the researchers explain: “This discrepancy may arise because prior studies were primarily randomised controlled trials (RCTs) where participants adhered to carefully designed diets ensuring balanced nutrient intake.

“In contrast, real-life calorie-restricted diets and obesity often result in nutritional deficiencies (particularly in protein, essential vitamins/minerals) and induce physiological stress, which can exacerbate depressive symptomatology including cognitive-affective symptoms.” Another possible explanation might be a failure to lose weight or weight cycling—losing weight and then putting it back on, they suggest.

By way of an explanation for the observed gender discrepancies, the researchers point out that glucose and the fatty acid omega-3 are critical for brain health.  “Diets low in carbohydrates (glucose) or fats (omega-3s) may theoretically worsen brain function and exacerbate cognitive-affective symptoms, especially in men with greater nutritional needs,” they suggest.

Professor Sumantra Ray, Chief Scientist and Executive Director of the NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health with BMJ Group, comments: “This study adds to the emerging evidence linking dietary patterns and mental health, raising important questions about whether restrictive diets which are low in nutrients considered beneficial for cognitive health, such as omega-3 fatty acids and vitamin B12, may precipitate depressive symptoms.

“But the effect sizes are small, with further statistical limitations limiting the generalisability of the findings. Further well designed studies that accurately capture dietary intake and minimise the impact of chance and confounding are needed to continue this important line of inquiry.”

04/06/2025

Research: Mental health consequences of dietary restriction: increased depressive symptoms in biological men and populations with elevated BMI  Doi: 10.1136/bmjnph-2025-001167

External funding: None declared

Externally peer reviewed? Yes
Evidence type: Observational
Subjects: People

The post Low calorie diets linked to heightened risk of depressive symptoms first appeared on BMJ Group.

Vitamin D most common ‘missing’ micronutrient; women at greater risk of ‘hidden hunger’

Micronutrient deficiency, whereby levels of vitamins and minerals essential for healthy bodily function are far too low, is common in people with type 2 diabetes, finds a pooled data analysis of the available evidence, published in the open access journal BMJ Nutrition Prevention & Health.

A lack of vitamin D is the most common ‘missing’ micronutrient, overall, the findings indicate, with women at greater risk than men of these deficiencies, dubbed ‘hidden hunger.’

Genetic predisposition, various environmental factors, sedentary lifestyle, an unhealthy diet and obesity are risk factors for the disease, explain the researchers. And previously published research suggests that micronutrients have a key role in the development of type 2 diabetes, by potentially affecting glucose metabolism and insulin signalling pathways.

In a bid to try and quantify the global prevalence of micronutrient deficiency in people with the condition, the researchers scoured research databases for relevant studies, with the aim of pooling the data.

Their analysis included 132 studies, involving 52,501 participants, and published in several languages between 1998 and 2023. With the exception of 3 studies, the rest were hospital based.

The pooled data analysis showed that the prevalence of micronutrient deficiency (vitamins, minerals, and electrolytes) among people with type 2 diabetes varied around the world, possibly because of diverse dietary habits, lifestyle choices, and cultural practices, suggest the researchers.

But, overall, the global prevalence was 45%—40% in those with complications of their disease.

A very low level of vitamin D was the most common micronutrient deficiency, affecting 60.5% of those with type 2 diabetes. But magnesium deficiency was also common, affecting 42%, while the prevalence of iron deficiency was 28%. The global prevalence of B12 deficiency was 29%, and higher, still, among patients taking metformin.

Further stratification of the pooled data showed that prevalence was higher in women with the condition than in men at nearly 49%, and highest among patients in the Americas (54%).

Most of the included studies were cross sectional, making it difficult to establish causality, nor was it clear whether the micronutrient deficiency preceded poor glycaemic control or was a consequence of it, caution the researchers.

And as there are no valid population based studies looking at micronutrient deficiency, it’s impossible to draw comparisons between patients with type 2 diabetes and the general population, they add.

“This systematic review exemplifies the double burden of malnutrition in action, whereby nutritional deficiencies and diet-related non-communicable diseases, such as type 2 diabetes, co-exist,” comments Shane McAuliffe, Visiting Senior Academic Associate, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns the journal.

“The treatment of type 2 diabetes often tends to focus on energy metabolism and macronutrients, but the identification of a higher prevalence of specific micronutrient deficiencies in those affected is a reminder that optimising overall nutrition should always be a priority.

“The findings should help to focus research and policy initiatives aimed at furthering our understanding of the causes and effects of these deficiencies and the potential for targeted and tailored interventions.”

29/01/2025

Notes for editors
Research: Burden of micronutrient deficiency among patients with type 2 diabetes: systematic review and meta-analysis  Doi: 10.1136/bmjnph-2024-000950
Journal: BMJ Nutrition Prevention & Health

External funding: Abbott Nutrition Research and Development

Link to Academy of Medical Sciences press release labelling system
http://press.psprings.co.uk/AMSlabels.pdf

Externally peer reviewed? Yes
Evidence type: Systematic review + meta analysis
Subjects: People

The post Lack of essential vitamins and minerals common in people with type 2 diabetes first appeared on BMJ Group.

But effects so small, it can’t be relied on alone to shed the pounds, warns author
Regular physical activity + healthy diet still key to slimming down and staying that way

Fizzy water might aid weight loss by boosting blood glucose uptake and metabolism—the rate at which the body uses and converts energy—but the effects are so small, drinking it can’t be relied on alone to shed the pounds, concludes a brief analysis published in the open access journal BMJ Nutrition Prevention & Health.

There are no quick fixes to slimming down and keeping off the weight, says the author: regular physical activity and a healthy balanced diet are still essential, added to which the long term effects of drinking large amounts of carbonated water aren’t known.

Because fizzy water is ‘filling,’ thereby helping to curb hunger pangs, and reportedly speeds up digestion and lowers blood glucose levels, it has been heralded as a potential slimming aid.

But it’s not clear exactly how carbonated water might reduce blood glucose or how this might contribute to weight management, points out the author, Dr Akira Takahashi, a physician in the dialysis centre at Tesseikai Neurosurgical Hospital in Shijonawate, Japan.

To try and find out, the author compared the process of drinking fizzy water with haemodialysis, whereby blood is filtered (dialysed) to remove waste and excess water when the kidneys no longer can, drawing on previously published research.

Haemodialysis turns blood alkaline, primarily producing carbon dioxide (CO₂). Similarly, the CO₂ of fizzy water is absorbed through the stomach lining and is rapidly converted to bicarbonate (HCO3) in red blood cells. This alkalinisation process speeds up glucose absorption and use by activating key enzymes in red blood cells, explains the author.

Clinical observations during haemodialysis show that blood glucose levels fall as blood passes through the dialyser, despite a higher glucose level in the dialysate solution to start with, he adds.

While these findings suggest that fizzy water may indirectly promote weight loss by enhancing the uptake and use of blood glucose, context is key, emphasises the author.

During a typical 4 hour haemodialysis session around 48000 ml of blood flows through the dialyser, resulting in around 9.5 g of glucose being used during the session, he explains.

“Given this minimal glucose reduction, the impact of CO₂ in carbonated water is not a standalone solution for weight loss. A balanced diet and regular physical activity remain crucial components of sustainable weight management,” he insists.

“Also, drinking carbonated water can have some effects on the digestive system, particularly for individuals with sensitive stomachs or pre-existing gastrointestinal conditions. The primary concerns include bloating, gas and, in some cases, exacerbation of certain symptoms associated with digestive disorders, such as irritable bowel syndrome or gastro-oesophageal reflux disease,” he points out.

“Moderation is key to avoiding discomfort while still enjoying the possible metabolic benefits of carbonated water,” he says.

Commenting on the analysis, Professor Sumantra Ray, Executive Director, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns the journal, said: “While there is a hypothetical link between carbonated water and glucose metabolism this has yet to be tested in well designed human intervention studies.

“And although this study adds to the evidence base, it doesn’t provide sufficient evidence on which to make recommendations for the preventive or therapeutic use of carbonated water. Additionally, any potential benefits must be weighed up against the potential harms of carbonated drinks which may contain sodium, glucose, or other additives.”

22/01/2025

Notes for editors
Brief report: Can carbonated water support weight loss? Doi: 10.1136/bmjnph-2024-001108
Journal: BMJ Nutrition, Prevention & Health

External funding: None declared

Link to Academy of Medical Sciences press release labelling system
http://press.psprings.co.uk/AMSlabels.pdf

Externally peer reviewed? Yes
Evidence type: Observational; analysis
Subjects: People

The post Fizzy water might aid weight loss by boosting glucose uptake and metabolism first appeared on BMJ Group.

Children living at 2000+ m above sea level 40% more at risk than those living 1000m below 
Children in rural areas seem to be the most vulnerable

Living at higher altitudes in India is linked to an increased risk of stunted growth, with children living in homes 2000 metres or more above sea level 40% more at risk than those living 1000 metres below, finds research published in the open access journal BMJ Nutrition Prevention & Health.

Children living in rural areas seem to be the most vulnerable, prompting the researchers to advocate prioritising nutritional programmes in hilly and mountainous regions of the country.

Despite various initiatives, childhood stunting, caused by chronic malnutrition, remains a major public health challenge in India, affecting over a third of 5-year olds, note the researchers.

While research from other countries indicates a link between residential altitude and stunting, it’s not clear if this might also be applicable in India, where a substantial number of people live more than 2500 metres above sea level.

To explore this further, the researchers drew on data from the 2015–16 National Family Health Survey (NFHS-4), a nationally representative household survey of India. Some 167,555 children under the age of 5 from across the country were included in the analysis.

GPS data were used to categorise altitude level while the World Health Organization (WHO) standard was used to define stunting.

Most (98%;164,874) of the children lived less than 1000 m above sea level; 1.4% (2346) lived between 1000 and 1999m above sea level; and 0.2% (335) lived at or above 2000m. Seven out of 10 lived in rural areas.

The overall prevalence of stunting among these children was 36%, with a higher prevalence among children aged 18–59 months (41%) than among those under 18 months of age (27%). 

Stunting was more common among children of third or higher birth order (44%) than it was among firstborns (30%). And stunting rates were even higher among those children who had been small or very small (45%) at birth.

Mother’s education emerged as an influential factor: stunting prevalence fell as maternal educational attainment rose. The proportion of children whose mothers had had no schooling was more than double that of children whose mothers had had a higher education: 48% vs 21%.

Other protective factors included elements of antenatal care, such as clinic visits, tetanus vaccination, and iron and folic acid supplements; proximity to health facilities; and not belonging to a particular caste or indigenous tribe. 

This is an observational study that captured a snapshot of the population at a specific point in time, making it difficult to confirm altitude as a cause of stunting, acknowledge the researchers.

But there are plausible explanations for their findings, they suggest. For example, chronic exposure to high altitude can reduce appetite, restrict oxygen delivery to tissues, and limit nutrient absorption. 

Food insecurity also tends to be greater at higher elevations where crop yields are lower and the climate is harsher. Similarly, healthcare provision, including implementing nutritional programmes, and healthcare access are also more challenging, they suggest.

“In summary, concerted efforts are needed across health and nutrition sectors to address stunting, tailored to focus on higher-risk children in vulnerable areas,” they conclude.

“A multipronged approach should combine reproductive health initiatives, women’s nutrition programmes, infant and young child feeding interventions, and food security measures. Continued research, monitoring, and evaluation will be key to guide evidence-based policies and targeted action to ensure every Indian child has the opportunity for healthy growth and development.”

Professor Sumantra Ray, Executive Director of the  NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health with BMJ, adds: 

“In recent decades public health interventions in India have effectively tackled previously prevalent nutritional problems, such as Iodine deficiency, which are associated with living at higher altitudes. 

“But this study highlights the complexities of malnutrition in hilly regions where wider determinants of malnutrition among the under 5s require further study to elucidate the relative contributions of heredity, environment, lifestyle, and socioeconomic factors.”

25/04/2024

Notes for editors
Research: Geographical altitude and stunting among children aged under 5 years in India Doi 10.1136/bmjnph-2024-000895
Journal: BMJ Nutrition Prevention & Health

External funding: None declared

Link to Academy of Medical Sciences press release labelling system
http://press.psprings.co.uk/AMSlabels.pdf

Externally peer reviewed? Yes
Evidence type: Observational; survey data
Subjects: People

The post Living at higher altitudes in India linked to increased risk of childhood stunting first appeared on BMJ Group.

Please note that this research paper has been retracted. Journalists and others should no longer reference or use the study findings in future reporting.

The retraction was prompted by concerns raised about the quality of the work, including the approach to statistical analysis of the data; implausible statistical values; the reliability of the raw data; inadequate reporting of methods; and lack of prospective trial registration, which breaches BMJ Group’s editorial policy.

Initially, concerns were raised in critiques of the study, some of which were published as letters in the journal. But after review by BMJ Group’s content integrity team, the study was referred to statistical experts to evaluate its reliability.  This included attempts to replicate the results and examine the authenticity of the underlying data supplied by the authors.

It wasn’t possible for the statisticians to replicate the results and multiple analytical errors were identified. There were also irregularities in the data set, and their report, which is appended to the retraction notice, concluded that the data collected from each participant would require further independent scrutiny.

The authors said that the identified errors were honest mistakes, but they agree with the decision to retract the study.

Dr Helen Macdonald, Publication Ethics and Content Integrity Editor at BMJ Group, said: “Tempting though it is to alert readers to an ostensibly simple and apparently helpful weight loss aid, at present the results of the study are unreliable, and journalists and others should no longer reference or use the results of this study in any future reporting.”

See BMJ Group retracts trial on apple cider vinegar and weight loss

The post Retracted: Apple cider vinegar aids weight management in obesity, small clinical trial suggests first appeared on BMJ Group.

Diet high in vegetables, legumes, nuts, and low in dairy and meat may be protective

A predominantly plant-based or vegetarian diet is linked to 39% lower odds of COVID-19 infection, finds research published in the open access journal BMJ Nutrition Prevention & Health.

The findings prompt the researchers to suggest that a diet high in vegetables, legumes, and nuts, and low in dairy products and meat may help to ward off the infection.

Several studies have suggested that diet may have an important role in the evolution of COVID-19 infection, as well as in the factors that heighten the risk of its associated complications.

The researchers therefore set out to evaluate the potential impact of dietary patterns on the incidence, severity, and duration of COVID-19 infection among 702 adult volunteers all of whom were recruited between March and July 2022.

Participants were surveyed on their usual eating patterns and food group frequency, as well as lifestyle and medical history, including vaccination against COVID-19. They were then divided into either omnivorous (424) or predominantly plant-based (278) dietary groups. 

The plant-based food group was further divided into flexitarians/semi-vegetarians who ate meat 3 or fewer times a week (87); and vegetarians and vegans (191).

Those who reported following predominantly plant-based or vegetarian diets routinely ate more vegetables, legumes, and nuts, and less/no dairy and meat.

There were no significant differences in sex, age, or vaccination uptake between the omnivores and plant-based groups. But a significantly higher number of people had been educated to postgraduate degree level in the latter. 

The omnivores also reported a higher rate of medical conditions and lower rates of physical activity. And the prevalence of overweight and obesity was significantly higher among the omnivores—all factors associated with higher COVID-19 infection risk and more severe symptoms/complications.

In all, 330 people (47%) said that they had had COVID-19 infection. Of these, 224 (32%) said they had mild symptoms and 106 (15%) moderate to severe symptoms. 

The omnivores had a significantly higher reported incidence of COVID-19 than the plant-based dietary groups: 52% vs 40%. And they were more likely to have had moderate to severe infection:18% vs just over 11%. 

There was no difference, however, in how long symptoms lasted.

After accounting for potentially influential factors, such as weight, pre-existing medical conditions, and physical activity levels, there was no overall difference in symptom severity between the omnivores and the plant-based dietary groups. 

But those following a predominantly plant-based or vegetarian/vegan diet were 39% less likely to become infected than the omnivores. 

It may be that predominantly plant-based diets provide more nutrients that boost the immune system and help to fight viral infections, they suggest, by way of an explanation for their findings.

“Plant-based dietary patterns are rich in antioxidants, phytosterols and polyphenols, which positively affect several cell types implicated in the immune function and exhibit direct antiviral properties,” they write.

This is an observational study, however, and as such, can’t establish causal factors. The researchers also acknowledge that the study relied on personal recall and subjective assessment, both of which are prone to error.

Nevertheless, they conclude: “In light of these findings and the findings of other studies, and because of the importance of identifying factors that can influence the incidence of COVID-19, we recommend the practice of following plant-based diets or vegetarian dietary patterns.”

“This research adds to the existing evidence, suggesting that diet may have a role in susceptibility to COVID-19 infection,” comments  Shane McAuliffe, Senior Visiting Academic Associate, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health with BMJ.

“But this remains an area of research that warrants more rigorous and high quality investigation before any firm conclusions can be drawn about whether particular dietary patterns increase the risk of COVID-19 infection,” he adds.

Notes for editors
Research: Vegetarian and plant- based diets associated with lower incidence of COVID-19 doi 10.1136/bmjnph-2023-000629
Journal: BMJ Nutrition Prevention & Health

Funding: None declared

Link to Academy of Medical Sciences labelling system
http://press.psprings.co.uk/AMSlabels.pdf 

Externally peer reviewed? Yes
Evidence type: Observational
Subjects: People

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Women seem to be 5 times as likely as men to put on a lot of weight in wake of quitting 

The diabetes drug dulaglutide (Trulicity) may significantly lower a woman’s risk of substantial weight gain after she has given up smoking, finds a secondary analysis of clinical trial data, published in the open access journal BMJ Nutrition Prevention & Health.

Women seem to be 5 times as likely as men to put on a lot of weight after they’ve stubbed out what they intend to be their last cigarette, the analysis suggests.

Women seem to have higher smoking relapse rates than men. And it’s been suggested that one of the possible explanations for this is that they may be more concerned about the risk of major weight gain in the wake of quitting, although there’s no solid evidence for this, note the researchers.

The results of a previously published clinical trial showed that compared with dummy treatment, the diabetes drug dulaglutide significantly reduced weight gain in those who had given up smoking. But it’s not clear if this weight loss is gender specific, say the researchers.

They therefore re-analysed the data from this trial to see if there were any gender differences in weight lost or gained in the 12 weeks after trying to quit smoking.

The trial included 255 adults, 155 of whom were women. The average age ranged from 42 to 44 and the number of cigarettes smoked daily averaged 20 for a period of between 19 and 22 years.

Trial participants were randomly assigned to receive either once weekly jabs of 1.5 mg/0.5 ml dulaglutide or 0.5 ml dummy treatment, plus the smoking cessation drug varenicline 2 mg/day and behavioural counselling for a period of 12 weeks.

Dulaglutide mimics the effects of the hormone GLP-1 which is naturally produced in the gut in response to food, helping to regulate the amount of glucose in the blood and weight gain. 

At the start of the trial, weight averaged just over 72 kilos among the women (BMI 26) and just over 92.5 kilos among the men (BMI 29).

After 12 weeks, dulaglutide had curbed weight gain risk in both sexes compared with dummy treatment.

Women on dulaglutide lost around 1-2 kilos compared with weight gain of around 2-2.5 kilos for women in the dummy treatment group.

Men taking dulaglutide shed just over half a kilo compared with weight gain of around 2 kilos among those in the dummy treatment group. 

Although weight change, overall, didn’t differ between the sexes, women were more likely to put on a lot of weight. And dulaglutide was associated with a significantly lower risk of substantial weight gain—defined as an increase of more than 6%—among the women.

Substantial weight gain was almost 5 times as common in women as it was in men in the dummy treatment group: 24% vs 5%. 

Similarly, substantial weight gain in women taking dulaglutide was significantly less common than it was among those on the dummy treatment: 1% (1 out of 83) vs 24% (17 out of 72). No such effects were seen among the men: 0% (0/44) vs 5% (3/56). 

But somewhat surprisingly, say the researchers, the positive effects of dulaglutide on weight had no impact on short term quit rates in either men or women, which were relatively high in both: 98 (63%) in women and 65 (65%) in men (65%). 

The risk of weight gain after stopping smoking may change over time or depend on other factors, such as the degree of nicotine dependence or age, caution the researchers.

But they conclude: “Our data suggest that an adjunct dulaglutide treatment could be particularly useful for patients facing a high risk of substantial weight gain after smoking cessation, such as women. 

“Another target group could be individuals of both genders who failed several cessation attempts due to weight gain.”

20/12/2023 

Notes for editors
Research: Gender differences in weight gain during attempted and successful smoking cessation on dulaglutide treatment: a predefined secondary analysis of a randomised trial doi: 10.1136/bmjnph-2023-000781

Journal: BMJ Nutrition Prevention & Health

Funding: Swiss National Foundation; G&J Bangerter-Rhyner, Goldschmidt-Jacobson and Hemmi Foundations, Swiss Academy of Medical Sciences

Link to Academy of Medical Sciences labelling system
http://press.psprings.co.uk/AMSlabels.pdf 

Externally peer reviewed? Yes
Evidence type: Randomised controlled trial (secondary analysis)
Subjects: People

The post Diabetes drug may significantly lower women’s risk of substantial weight gain after giving up smoking first appeared on BMJ Group.

And it’s associated with an increased risk of stroke before the age of 65 

Starting menstrual cycles at a young age—before the age of 13—is linked to a heightened risk of developing type 2 diabetes in mid-life, finds US research published online in the open access journal BMJ Nutrition Prevention & Health.

And it also seems to be associated with an increased risk of having a stroke before the age of 65 in those with the disease, particularly those who started having periods before the age of 10 or younger, the findings indicate.

Diabetes and its complications are on the rise among young and middle aged US adults, while the age at which women start having periods is falling worldwide, note the researchers. 

They therefore wanted to find out if there might be a link between these two phenomena in younger women, and drew on responses to the nationally representative National Health and Nutrition Examination Survey (NHANES) 1999–2018.

Some 17,377 women aged between 20 and 65 were included in the study, all of whom specified the age at which they had had their first menstrual cycle. This was categorised as 10 or younger, 11, 12, 13, 14 and 15 and older.

Of the total, 1773 (10%) reported a diagnosis of type 2 diabetes. And of these, 205 (11.5%) reported some type of cardiovascular disease.

Starting periods before the average age of 13 was associated with a heightened risk of type 2 diabetes, after accounting for a range of potentially influential factors, including age, race/ethnicity, education, motherhood, menopausal status and family history of diabetes, smoking, physical activity, alcohol consumption and weight (BMI). 

This ranged from 32% greater (10 or younger) through 14% greater (age 11) to 29% greater (age 12).

Among women with diabetes, earlier age at first menstrual cycle was associated with a heightened risk of stroke, although not cardiovascular disease in general, after accounting for the same set of potentially influential factors. 

Very early age at first menstrual cycle—10 or younger—was associated with a more than doubling in stroke risk among women below the age of 65 with diabetes, after similar adjustments for influential factors.

This risk fell in tandem with increasing age: 81% among those with their first menstrual bleed at the age of 11, to 32% at the age of 12, and to 15% at the age of 14.

This is an observational study, and as such, can’t establish causal factors. But, suggest the researchers: “Earlier age at [first menstrual cycle] may be one of early life indicators of the cardiometabolic disease trajectory in women.” 

They explain: “One potential pathway explanation may be that [such] women are exposed to oestrogen for longer periods of time, and early [menstruation] has been associated with higher oestrogen levels.”

They point out that while the observed associations between age at first menstrual cycle and stroke complications weakened slightly after accounting for weight, these still remained statistically significant. 

“Therefore, adiposity may also play a role in the observed association between early age at [first menstrual cycle] and stroke complications, as higher childhood adiposity is associated with earlier age at [menstruation] and with cardiometabolic diseases later in life,” they suggest.

“These findings add another dimension to the potentially less well understood determinants of cardiometabolic risk, particularly in women who have been relatively underrepresented in this area of research,” comments Professor Sumantra Ray, Executive Director of the NNEdPro Global Centre for Nutrition & Health, which co-owns BMJ Nutrition Prevention & Health.

“And they provide a clear steer on the need to design interventional studies looking at the prevention of cardiometabolic disease in ethnically diverse groups of women who start menstruating at a young age,” he adds.

06/12/2023

Notes for editors
Research: Age at menarche, type 2 diabetes and cardiovascular disease complications in US women aged under 65 years: NHANES 1999–2018 doi 10.1136/bmjnph-2023-000632
Journal: BMJ Nutrition Prevention & Health

Funding: National Institutes of Health

Link to Academy of Medical Sciences labelling system
http://press.psprings.co.uk/AMSlabels.pdf 

Externally peer reviewed? Yes
Evidence type: Observational; survey data
Subjects: Women

The post Young age at first menstrual cycle linked to heightened diabetes risk in mid-life first appeared on BMJ Group.