Healthy plant-based diet reduces diabetes risk by 24 per cent

At least 75 per cent of type 2 diabetes cases could be avoided by adopting a healthy lifestyle. A plant-based diet has been shown to play a key role in this. With limitations - as demonstrated in a study led by Tilman Kühn from MedUni Vienna's Center for Public Health: A more plant-based diet only develops its protective effects if not only the consumption of animal-based foods, but also industrially processed and highly sugary foods is reduced. For the first time, the scientists identified improvements in metabolism and liver and kidney function as reasons for the positive effects of a healthy plant-based diet, in addition to the associated lower likelihood of obesity. The study results were recently published in the journal Diabetes & Metabolism.

According to analyses by the research team, a healthy plant-based diet with plenty of fresh fruit and vegetables and wholemeal products reduces the risk of diabetes by 24 per cent, even in the presence of a genetic predisposition and other diabetes risk factors such as obesity, advanced age or a lack of physical activity. Unhealthy plant-based diets with a high proportion of sweets, refined grains and sugary drinks, on the other hand, are associated with an increased risk of type 2 diabetes.  

Key biomarkers identified
The research was carried out with 113,097 participants in the large-scale British cohort study (UK Biobank) over an observation period of twelve years. According to their findings, the reasons behind the anti-diabetic effect of a healthy plant-based diet go far beyond the well-known lower body fat percentage and waist circumference. "Our study is the first to identify biomarkers of central metabolic processes and organ functions as mediators of the health effects of a plant-based diet," says Tilman Kühn, Professor of Public Health Nutrition at MedUni Vienna and the University of Vienna, who led the study in close collaboration with researchers from Queen's University Belfast. The investigations confirmed that normal values for blood lipids (triglycerides), blood sugar (HbA1c), inflammatory parameters (CRP) and the insulin-like growth factor (IGF1) are associated with a low risk of diabetes.

Further benefits discovered
It has also been demonstrated how important the full function of the liver and kidneys is in diabetes prevention. Both organs play a major role in people who already have diabetes. "However, our research has now shown that a healthy plant-based diet can improve liver and kidney function and thus reduce the risk of diabetes," says Kühn, outlining a previously underestimated benefit of a conscious plant-based diet.

Twice daily electrical stimulation may boost mental processes in Alzheimer’s disease

Twice daily non-invasive electrical stimulation of the brain may boost mental processes (cognitive function) in people with Alzheimer’s disease, suggest the results of a small clinical trial published online in the open access journal General Psychiatry.

The technology, known as transcranial direct current stimulation, or tDCS for short, may help to fire up the brain’s plasticity, enabling ‘rewiring’ through the formation of new neural networks, the findings suggest. 

tDCS comes in the form of a device with two electrodes, placed over specific areas of a person’s head, which deliver a constant low intensity electrical current. It is starting to be used in many areas of medicine, including for the treatment of depression.

The researchers wanted to find out if tDCS might improve cognitive function in people with Alzheimer’s disease, and if so, whether this might be linked to their recovering some level of cortical plasticity–the brain’s capacity to form new neural networks. 

Some 140 patients with mild to moderate Alzheimer’s disease from four different hospitals were randomly allocated to receive either 2 daily sessions of active (constant low intensity 1-2 mA current) or sham tDCS, for 5 days of the week for a maximum period of 6 weeks.

The currents were applied to the prefrontal cortex, the region of the brain involved in higher order activities, such as planning, decision-making, working memory, moderating social behaviours, and controlling certain aspects of speech and language.

Participants were all aged over 65, had had their disease for more than 6 months, and had all scored below 26 on the Mini-Mental State Exam (MMSE). A score of 24 is regarded as abnormal and indicative of cognitive impairment. Both groups were comparable in terms of age, sex, and educational attainment.

The MMSE and the Alzheimer’s Disease Assessment Scale-Cognitive (ADAS-Cog) Test, which focuses on language and memory, were used to evaluate cognitive performance at the start of the trial, after 2 weeks, and again after 6 weeks.  

Readings of electrical signalling through the motor pathways of the nervous system, known as motor evoked potential or MEP, were used to indicate changes in neural plasticity.

In all, 133 patients completed the 2-week intervention and 124 completed the 6-week intervention. Reasons for withdrawal varied, but no one withdrew because of discomfort. 

The results showed that after 2 weeks there was no change in either group, but compared with baseline, 30 daily 20-minute sessions of tDCS significantly improved the cognitive function of those in the tCDS group, particularly their word recall, recall of test instructions, and word recognition. No such improvements were seen in the sham group.

The results also showed that in people with Alzheimer’s disease cortical plasticity is impaired, but that this improved after 6 weeks of tDCS.

In tandem with a decrease in MEP, word recall and word recognition got better among those in the tDCS group, but not among those in the sham group, suggesting that the improvement in cortical plasticity may reflect the degree of cognitive improvement, say the researchers.

But it’s still not clear how tDCS might exert its effects, they add, citing previous research,  indicating that the technology may alter ion activity, neurotransmitter release, and electrical activity in various areas of the brain.

The researchers acknowledge various limitations to their findings, including the small study size, the lack of MRI or electroencephalography scans to chart changes in brain structure, and the absence of cerebrospinal fluid and blood samples to monitor neurotransmitter changes.

But they nevertheless conclude: “The results of this study strongly indicate that tDCS treatment is a significant and promising intervention for improving cognitive function in [Alzheimer’s disease]. In addition, plasticity plays a vital role in cognitive change.” 

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JOURNAL

General Psychiatry

DOI

10.1136/gpsych-2023-101166 

Reliable research and evidence-based recommendations scarce for women who exercise according to menstrual cycle

 

 There is no shortage of advice for women on what to eat, how to train, or what supplements to take during their menstrual cycles, but a new review by an international team of scientists has found little evidence to support such recommendations.

In fact, they found sparse research on women and exercise at all, and even less on the effect of their periods on sports performance, physiology, or physical fitness.

The authors of the paper, from McMaster University, Manchester Metropolitan University and the Australian Catholic University in Melbourne, are calling for much more high quality, standardized research on women.

A key finding from the review was that hormonal levels vary substantially between women during their menstrual periods and between the cycles of individual women. Virtually no woman has a standard version of a menstrual cycle, which is typically 28 days long, with ovulation consistently occurring on day 14.

"The data suggests that from woman to woman, there are significant variations in estrogen and progesterone, the primary hormones that characterize the phases of the menstrual cycle," says co-lead author Alysha D'Souza, a graduate student in the Department of Kinesiology at McMaster University.

The findings are published in the most recent edition of the Journal of Applied Physiology.  

"Hormone levels can vary substantially. Not just between two women, but within one woman from one cycle to the next," says Mai Wageh, a PhD candidate in the Department of Kinesiology at McMaster and co-lead author of the article.

The findings prompted D'Souza and Wageh to dig deeper into physiological differences across the menstrual cycle, broadly categorized into follicular, ovulatory, and luteal phases. They found few or no differences when they looked at exercise results across the cycle phases and examined women’s use of fat versus carbohydrates, the potential for muscle growth, or blood-vessel function. 

The review relied on various methods, including a systematic review and meta-analysis, narrative interpretation and a previous umbrella review.

"Many women are following advice and planning exercises and practices based on some ostensible benefit of menstrual cycle phase-based exercise. We saw no evidence that such practice is science-based," said Stuart Phillips, a professor in the Department of Kinesiology at McMaster and senior author of the review.

"Women can feel better or worse, and some are even incapacitated during various phases of their cycle," said Wageh. "You need an individualized approach to training.  Track your cycle and your symptoms in each phase and adjust your exercise plan accordingly. There is no one-size-fits-all approach."

The next steps for this work will be to determine whether symptoms often associated with menstruation are cycle-related or due to other stressors, including lack of sleep, poor nutrition, or work and relationship-related issues.

High resolution photos and video related to this study can be found at:

https://photos.app.goo.gl/qrr27ua7qj4UBoc56

Fatty foods can impair the body’s response to everyday stress - study

Eating fatty foods during stressful periods can impair the body’s ‘recovery’ from the effects of stress, new research suggests. 

Different findings from a study, published recently in Frontiers in Nutrition and Nutrients, have shown that consuming foods high in fat before a mentally stressful episode can reduce brain oxygenation and cause poorer vascular function in adults.  

Rosalind Baynham, a PhD researcher at the University of Birmingham and first author explained: “We took a group of young healthy adults and gave them two butter croissants as breakfast. We then asked them to do mental maths, increasing in speed for eight minutes, alerting them when they got an answer wrong. They could also see themselves on a screen whilst they did the exercise. The experiment was designed to simulate everyday stress that we might have to deal with at work or at home. 

“When we get stressed, different things happen in the body, our heart rate and blood pressure go up, our blood vessels dilate and blood flow to the brain increases. We also know that the elasticity of our blood vessels – which is a measure of vascular function – declines following mental stress. We found that consuming fatty foods when mentally stressed reduced vascular function by 1.74% (as measured by Brachial Flow-mediated dilatation, FMD). Previous studies have shown that a 1% reduction in vascular function leads to a 13% increase in cardiovascular disease risk. Importantly we show that this impairment in vascular function persisted for even longer when our participants had eaten the croissants.” 

The scientists were also still able to detect reduced arterial elasticity in participants up to 90 minutes after the stressful event was over. 

The team also found that eating high-fat foods attenuated cerebral oxygenation in the pre-frontal cortex, with lower oxygen delivery (39% reduction in oxygenated haemoglobin) during stress compared to when participants consumed a low-fat meal.  Furthermore, fat consumption had a negative effect on mood both during and after the stress episode.  

Jet Veldhuijzen van Zanten, Professor of Biological Psychology at the University of Birmingham said: “We looked at healthy 18–30-year-olds for this study, and to see such a significant difference in how their bodies recover from stress when they eat fatty foods is staggering. For people who already have an increased risk of cardiovascular disease, the impacts could be even more serious. We all deal with stress all the time, but especially for those of us in high-stress jobs and at risk of cardiovascular disease, these findings should be taken seriously. This research can help us make decisions that reduce risks rather than make them worse.” 

The research also suggested that by consuming low-fat food and drinks people’s recovery from stress is less affected. After eating a low-fat meal, stress still had a negative effect on vascular function (1.18% decrease in FMD), but this decline returned to normal 90 minutes after the stressful event. 

Further research from the University of Birmingham team has shown that by consuming ‘healthier’ foods, particularly those rich in polyphenols, such as cocoa, berries, grapes, apples and other fruits and vegetables, this impairment in vascular function can be completely prevented.  

Dr Catarina Rendeiro, Assistant Professor in Nutritional Sciences at the University of Birmingham, said: “The impact of these foods during stressful periods cannot be understated. For example, reduced oxygenation to the brain could potentially impact mood and mental health, making people even more stressed. On the other hand, it could affect cognitive function and people’s ability to perform the very task they are stressing about, such as an interview, an exam or work meeting. This is something we would like to do more research into in the future. 

“Our studies show that food choices around stressful episodes can exacerbate or protect from the effects of stress on our cardiovascular system. The good news is that this means we can do something about this. We know that when people are stressed, they tend to gravitate towards higher-fat foods, either because it is the more convenient option if time is in short supply, or as a treat to deal with the stress. But by doing this, they are making their physical and psychological response to stress worse. By picking low-fat foods, they could be positioning themselves to cope with the stress more effectively.”  

Rosalind Baynham concluded: “The world is an incredibly stressful place right now, and even without outside factors such as war or a cost-of-living crisis, stress is something we all need to deal with. So, next time you are in a big meeting, or taking part in a job interview maybe try and resist the free biscuits and go for some berries instead. You might find you feel more relaxed and can cope with the stress just a little bit better.” 

Study i investigating health of expecting mothers: 90 per cent were lacking key vitamins needed for unborn infants

 

IMAGE: 

PREGNANT WOMEN MISSING KEY NUTRIENTS BY EATING MODERN DIETS

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CREDIT: UNIVERSITY OF SOUTHAMPTON

Pregnant women are not getting the essential nutrients they and their babies need from modern diets say scientists, who have warned that the situation will likely worsen as more people turn to plant-based foods.

A study looking at the health of expecting mothers from high-income countries, including the UK, New Zealand and Singapore, found that 90 per cent were lacking key vitamins necessary for healthy pregnancies and the wellbeing of unborn infants.

Scientists from the University of Southampton, working with experts worldwide, surveyed more than 1,700 women and found most were missing essential nutrients found in abundance in meat and dairy products.

These included vitamins B12, B6 and D, folic acid and riboflavin which are essential for the development of foetuses in the womb.

Lead author and Professor of Epidemiology Keith Godfrey, from the University of Southampton, said the prevalence of vitamin deficiencies among women attempting to become pregnant in wealthy countries is a serious concern.

He added: “The push to reduce our dependence on meat and dairy to achieve net-zero carbon emissions is likely to further deplete expecting mothers of vital nutrients, which could have lasting effects on unborn children.

“Our study shows that almost every woman trying to conceive had insufficient levels of one or more vitamin, and this figure is only going to get worse as the world moves towards plant-based diets.

“People think that nutrient deficiency only affects people in underdeveloped countries – but it is also affecting the majority of women living in high-income nations.”

The study, which was published in PLOS Medicine, assessed 1,729 women between the ages of 18 and 38 at conception and followed many during subsequent pregnancies.

It was undertaken by researchers from Southampton and its National Institute for Health and Care Research (NIHR) Biomedical Research Centre, the University of Auckland, National University of Singapore, and Agency for Science, Research and Technology, Singapore.

Results showed that nine out of ten women had marginal or low levels of folate, riboflavin, vitamins B12 and D around the time of conception, and that many developed vitamin B6 deficiency in late pregnancy.

Co-author Professor of Paediatric Endocrinology Wayne Cutfield, from the University of Auckland, said while folic acid is recommended for women planning conception and during pregnancy, expecting mothers should be given over-the-counter multivitamins to reduce nutrient deficiencies.

He added: “The wellbeing of a mother ahead of conceiving and during a pregnancy has a direct influence on the health of the infant, their lifelong physical development, and ability to learn.”

The PLOS Medicine trial was the first to show that supplements, available over the counter, can reduce vitamin insufficiencies during the preconception, pregnancy and lactational periods.

Associate Professor Shiao-Yng Chan at the National University of Singapore said: “If we continue to move towards diets with less meat and dairy products, reducing intakes of micronutrients essential for a child’s development, vitamin deficiencies will continue to grow unless women start taking more supplements or are supported with specific advice about nutrient-rich foods.”

Read more about the PLOS Medicine study at doi.org/10.1371/journal.pmed.1004260.

Diet has a major impact on risk of Alzheimer’s disease

 

 In a detailed study, Diet’s Role in Modifying Risk of Alzheimer’s Disease: History and Present Understanding published in the Journal of Alzheimer’s Disease, we can finally see which diets are helpful in reducing the risk of developing Alzheimer’s disease. The role of diet in modifying the risk of Alzheimer’s disease is discussed in detail. Diets that are more plant based, like the Mediterranean diet and traditional diets in China, Japan, and India, are shown to reduce risk, especially when compared to the Western diet.

Alzheimer’s disease rates rise in these countries as they make the nutrition transition to the Western diet. This study identifies dementia risk factors including higher consumption of saturated fats, meat, especially red meat such as hamburgers and barbeque as well as processed meats such as hot dogs, and ultra processed foods high in sugar and refined grains.

This review also lets us know why certain foods increase or reduce risk of Alzheimer’s disease. For example, meat raised risk of dementia the most by increasing risk factors such as inflammation, insulin resistance, oxidative stress, saturated fat, advanced glycation end products, and trimethylamine N-oxide. This study also outlines several foods that are protective against Alzheimer’s disease, such as green leafy vegetables, colorful fruits and vegetables, legumes (like beans), nuts, omega-3 fatty acids, and whole grains.

Ultra processed foods can increase the risk of obesity and diabetes, themselves risk factors for Alzheimer’s disease. Ultra processed foods often lack the very ingredients found in whole plant foods that keep dementia away, such as anti-inflammatory components and antioxidants.

Poverty is an important driver of Alzheimer’s disease in the US since ultra processed foods and meat are cheaper sources of energy than fruits, vegetables, whole grains, and other more nutritious foods, thus promoting obesity.

The paper also suggests that Alzheimer’s disease rates in the US are projected to increase by 50% from 2018 levels by 2038. This calculation is based on comparing trends of obesity in the US with Alzheimer’s disease trends. This comparison shows a 20-year lag between obesity rates and Alzheimer’s disease rates. This estimate is very close to the estimate published by the Alzheimer’s Association in 2018, an estimate of a 56% increase. Our estimate suggests that the rising trend of obesity, due to consumption of meat and ultra processed foods, is the force driving dementia. Although our personal risk of Alzheimer’s disease can be reduced with diet, it is expected that those who continue to eat the Western diet will continue to have a higher risk.

“Grant and Blake comprehensively review and synthesize the role of dietary factors in Alzheimer’s disease. Evidence from diverse perspectives support that a diet that emphasizes fruits, vegetables, legumes, nuts, whole grains, and…de-emphasizes meat, especially red meat, saturated fats, and ultra-processed foods is associated with lower risk of Alzheimer’s disease. Physical inactivity and obesity also contribute to higher risk. In addition, the dietary and lifestyle patterns associated with higher risk of Alzheimer’s disease are known to affect the constellation of mechanisms believed to increase risk, including inflammation, insulin resistance and oxidative stress, among others. Grant and Blake make a strong case that, while further research is needed to better understand the mechanisms, diet and lifestyle factors linked to diabetes, cardiovascular disease and some cancers are likely to influence risk of Alzheimer’s disease.”

Edward Giovannucci, MD, ScD, Professor of Nutrition and Epidemiology, Harvard University.

“Grant and Blake provide a comprehensive review on the dietary and other factors that affect the risk of Alzheimer's disease (AD). Apart from the particular type of diet they demonstrate that the consumption of red meat, insulin resistance, obesity, reactive oxygen species, and oxidative stress, phytochemicals and homocysteine amongst other factors interact with neuroinflammation and play a major role in the aetiology of AD. This treatise provides an excellent overview of modifiable risk factors for AD.”

Paul Marik, MD, Chairman and Co-Founder, FLCCC (Front Line COVID-19 Critical Care Alliance).

Excess thyroid hormone levels associated with higher risk of cognitive disorders among older adults

 

Thyrotoxicosis — excess thyroid hormone levels in the body — has been linked to an increased risk of cognitive disorders among older adults, according to a new study from Johns Hopkins Medicine. Exogenous thyrotoxicosis (caused by ingesting thyroid medication) and endogenous thyrotoxicosis (caused by thyroid disorders such as hyperthyroidism and Graves’ disease) were both associated with a higher likelihood of developing a cognitive disorder. The study was published online Oct. 23 by JAMA Internal Medicine.

“Some prior studies have suggested that thyrotoxicosis was associated with an increased risk of cognitive disorders,” says Roy Adams, Ph.D., M.S., first author of the study and assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. “But results have been mixed, and exogenous thyrotoxicosis was mostly excluded from those studies.”

According to GoodRx, thyroid hormone is among the most common prescriptions in the United States. A previous Johns Hopkins Medicine study found that up to 20% of people prescribed thyroid hormone may be overtreated, placing them at risk for exogenous thyrotoxicosis.

“Our goal was to investigate whether aggressive treatment practices, which can cause exogenous thyrotoxicosis, can also possibly cause cognitive harm,” says Adams. “Understanding the negative effects of overtreatment is critical to help guide clinicians in how they prescribe thyroid hormone therapy.”

The research team selected participants for the study from a Johns Hopkins Medicine electronic health record database. The team identified 65,931 qualified participants age 65 and older who received primary care within the Johns Hopkins Health System between Jan. 1, 2014, and May 6, 2023. The average age during the first recorded primary care visit was 71, and all patients had at least two visits that were 30 or more days apart.

Results showed that all-cause thyrotoxicosis — endogenous and exogenous thyrotoxicosis combined — was associated with a 39% increase in the risk of cognitive disorder diagnosis across age groups. Of patients who experienced thyrotoxicosis, 11% were diagnosed with a cognitive disorder by age 75 versus 6.4% of patients who did not experience thyrotoxicosis. By age 85, 34% of patients who had thyrotoxicosis were diagnosed with a cognitive disorder, compared with 26% of patients who did not have thyrotoxicosis. The excess risk associated with thyrotoxicosis persisted with an analysis using statistical models that examined possible sources of bias and alternative reasons for the associations.

The study also found that among those prescribed thyroid hormone, the level of exposure to thyroid hormone correlated with the degree of risk for a cognitive disorder. Patients with a more severe degree of excess thyroid hormone had a 65% increased risk of cognitive disorder, while those with a more moderate degree of excess thyroid hormone had a 23% increased risk.

“Our results suggest that an increased risk of cognitive disorders is among the potential negative consequences of thyroid hormone excess, a common consequence of thyroid hormone therapy,” says Jennifer Mammen, M.D., Ph.D., the study’s senior author and assistant professor of medicine at the Johns Hopkins University School of Medicine. “Clinicians considering thyroid hormone therapy in older adults should avoid overtreatment by using age-appropriate treatment strategies.”