Mediterranean and low fat diets lower risk of death and heart attack in patients at risk of cardiovascular disease

Mediterranean and low fat dietary programmes reduce the likelihood of death and heart attack in patients at heightened risk of cardiovascular disease, finds the first comparative review based on randomised trials of seven popular dietary programmes published by The BMJ today.

Dietary programmes are diets with or without exercise and other health behaviour (eg. smoking cessation) support.

Mediterranean dietary programmes are also likely to reduce stroke risk, but other dietary programmes showed little or no benefit over minimal intervention (eg. usual diet or brief dietary advice from a health professional).

Current guidelines recommend various dietary programmes for patients at increased cardiovascular risk, but they have typically relied on low certainty evidence from non-randomised studies.

Several analyses of randomised controlled trials have suggested that some diets and dietary programmes can reduce major cardiovascular events, such as heart attacks (myocardial infarction) and strokes, but any beneficial impact on death is still uncertain.

To address this, researchers trawled databases for randomised trials looking at the impact of dietary programmes for preventing death and major cardiovascular events in patients at increased risk of cardiovascular disease.

Forty eligible trials were identified involving 35,548 participants who were followed for an average of three years across seven named dietary programmes (low fat, 18 trials; Mediterranean, 12; very low fat, 6; modified fat, 4; combined low fat and low sodium, 3; Ornish, 3; Pritikin, 1). Some trials compared two different diets (eg. mediterranean vs low fat).

The researchers assessed the methodological quality of each trial and judged 13 to be at low overall risk of bias and 27 at high risk.

Based on moderate certainty evidence, Mediterranean dietary programmes were better than minimal intervention at preventing all cause mortality (17 fewer deaths per 1000 over five years), non-fatal heart attack (17 fewer per 1000) and stroke (7 fewer per 1000) for patients at intermediate risk of cardiovascular disease.

Low fat programmes were also superior to minimal intervention with moderate certainty for prevention of all cause mortality (9 fewer deaths per 1000) and non-fatal heart attack (7 fewer per 1000).

When compared with one another, there were no convincing differences between Mediterranean and low fat programmes for mortality or non-fatal heart attack.

The absolute effects for both dietary programmes were more pronounced for patients at high risk of cardiovascular disease (36 fewer all-cause deaths per 1000 and 39 fewer cardiovascular deaths per 1000 among those that followed the Mediterranean dietary programme over 5 years).

The five other dietary programmes generally had little or no benefit compared with minimal intervention typically based on low to moderate certainty evidence.

The researchers acknowledge several limitations, such as being unable to measure adherence to dietary programmes and the possibility that some of the benefits may have been due to other elements within the programmes like drug treatment and support to stop smoking.

Nevertheless, this was a comprehensive review based on a thorough literature search, rigorous assessment of study bias, and adherence to recognised GRADE methods to assess the certainty of estimates.

As such, they conclude that Mediterranean and low fat dietary programmes “probably reduce the risk of mortality and non-fatal myocardial infarction in people at increased cardiovascular risk.”

Mediterranean dietary programmes are also likely to reduce the risk of stroke, while other named dietary programmes were generally not superior to minimal intervention, they add.

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JOURNAL

The BMJ

DOI

10.1136/bmj-2022-072003 

Exercise may reduce negative effects of unhealthy sleep duration on longevity

 

 Sleeping too little or too long is linked with a shorter life, but scientists have found that physical activity counteracts some of these negative effects. The research in more than 90,000 adults is published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).1

 

“The study showed that increased physical activity levels weakened the mortality risks associated with short or long sleep duration,” said study author Dr. Jihui Zhang of The Affiliated Brain Hospital of Guangzhou Medical University, China.

 

Both sufficient exercise and healthy sleep contribute to prolonged life expectancy. However, it has been unclear how physical activity may interact with sleep duration to promote health. The main limitation of previous studies was the use of self-reported physical activity and sleep, which is subjective and may be inaccurate. In contrast, an accelerometer device records movement, thereby providing objective and more reliable estimates of activity and sleep duration.

 

This was the first study to examine the joint effects of physical activity and sleep duration on mortality risk using accelerometry. The study included 92,221 adults aged 40 to 73 years in the UK Biobank cohort who wore an accelerometer wristband for one week between 2013 and 2015.

 

Sleep duration per night was classified as short (less than six hours), normal (six to eight hours) or long (more than eight hours). Total volume of physical activity was divided into tertiles (low, intermediate, high). Moderate to vigorous physical activity was classified as meeting World Health Organization (WHO) guidelines or not.2 Mortality data were collected from death registries. The primary outcome was all-cause death. The secondary endpoints were death due to cardiovascular disease and death due to cancer.

 

The average age of participants was 62 years and 56% were women. During a median follow up of seven years, 3,080 participants died – 1,074 from cardiovascular disease and 1,871 from cancer.

 

The researchers examined how physical activity influenced sleep’s impact on mortality – first looking at the volume of activity and second at moderate to vigorous physical activity. The analyses were adjusted for factors that could influence the relationship including age, sex, ethnicity, deprivation, education level, season of sleep measurement, body mass index, diet, smoking, alcohol intake and shift work.

 

Regarding the volume of activity, in those with low amounts, short and long sleep were associated with 16% and 37% raised risks of all-cause death, respectively. In participants with intermediate amounts of exercise, only short sleep was detrimental, with a 41% raised likelihood of all-cause death. In those with a high amount of exercise, sleep duration was not linked with risk of death. For cardiovascular death, short sleepers with a low volume of exercise had a 69% elevated risk, which disappeared when exercise increased to moderate or high volumes. For cancer death, long sleepers with low amounts of exercise had a 21% raised risk which disappeared with moderate or high volumes of exercise.

 

Similar results were found for moderate to vigorous physical activity. In participants not meeting the WHO recommendations, short and long sleep were associated with 31% and 20% raised risks of all-cause death, respectively. These risks disappeared in those meeting the WHO advice. For cardiovascular death, short sleepers who failed to meet the advice on intensity of exercise had a 52% elevated risk, which disappeared in those achieving the recommendations. For cancer death, long sleepers not meeting the advice had a 21% raised risk which disappeared in those following the WHO guidance.

 

Dr. Zhang said: “Our findings suggest that health promotion efforts targeting both physical activity and sleep duration may be more effective in preventing or delaying premature death in middle-aged

and older adults than focusing on one behaviour alone. In an ideal scenario, people would always get healthy amounts of both sleep and physical activity. However, our study indicates that getting sufficient exercise may partially offset the detrimental impact of missing a good night’s sleep.”

Icing promotes muscle regeneration after mild injury

 

IMAGE: LEFT: METHOD OF INDUCING MILD MUSCLE INJURY. WHILE UNDER ANAESTHETIC, THE PROTRACTOR MUSCLE IN THE ANIMAL’S HIND LEG IS EXPOSED AND THEN CLAMPED BY FORCEPS WITH A 250G WEIGHT ATTACHED.RIGHT: THE MUSCLE INJURIES INDUCED USING THIS METHOD AFFECT AROUND 4% OF TOTAL MYOFIBERS. C SHOWS THAT THIS METHOD ENABLES MILD INJURY TO BE CONSISTENTLY INDUCED. view more 

CREDIT: AUTHOR: ITSUKI NAGATA EDITED BY MASATO KAWASHIMA AND TAKAMITSU ARAKAWA

Applying ice to a muscle injury is a widespread first-aid treatment, but exactly what effect does this have on the muscle regeneration and does it really help? Cumulative research by a multi-institutional Japanese research collaboration reveals that ‘to ice or not to ice’ may depend on the degree of muscle injury.

In their latest research, the group consisting of Associate Professor ARAKAWA Takamitsu and Master’s student NAGATA Itsuki (from Kobe University’s Graduate School of Health Sciences), and Assistant Professor KAWASHIMA Masato (Kawasaki University of Medical Welfare) et al. have shown that applying ice to muscle damage in a small percentage of muscle fibers in rats promotes muscle regeneration. This is believed to be the first study in the world to show benefits of icing on muscle repair. In conjunction with their previous study on serious muscle injuries (‘Icing muscle injuries may delay recovery’), it is hoped that these results can be used as a basis for more accurate guidelines on whether or not to ice such injuries.

These research findings were first reported in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology on March 6, 2023.

Main Points

• The experiments showed that applying ice after a mild muscle injury promotes muscle regeneration.
• This is believed to be the first time in the world that a study has shown a positive effect of icing on muscle regeneration.
• The researchers showed that the extent of the injury may have a greater impact on the effectiveness of icing than the method or timing employed.
• The findings of this ongoing research will lead to the spread of more accurate information on the effects of icing throughout hospitals, and in the realms of sports and physical education.

Research Background
‘RICE treatment’ is a common approach for treating the acute phase of sports injuries. This acronym stands for Rest, Ice, Compression and Elevation and it is also often used in physical education in schools and even clinical settings. There are a variety of subsequent steps that can be taken to treat the injury afterwards, yet opinions vary as to whether or not icing should be applied. However, there is a lack of evidence on the benefits of icing.

The current research team has conducted many experiments to investigate the effectiveness of icing, which led them to publish their previous findings (‘Icing muscle injuries may delay recovery’ ). However, no previous animal experiments have indicated that icing promotes muscle regeneration.

In this study, the researchers focused on altering the severity of the muscle injury in the experiments. The reasoning behind this was that the majority of sports-related muscle injuries are limited; in other words less than 10% of the overall number of muscle fibers (myofibers) are damaged and necrotized. However, all animal experiments up until now had looked at more serious injuries where over 20% of the myofibers were damaged.

Thus, the team devised an animal model for mild muscle injuries, and experimented with applying ice after injury using a similar method as before.

Research Findings
After the animal was anaesthetized, the muscle was exposed and clamped between forceps to induce injury. In their previous experiments, the researchers attached a 500g weight to the forceps, which induced an injury that affected 20% of the total number of fibers in the muscle. In the present study, they tried attaching a 250g weight to the forceps and demonstrated that this could be used to consistently injure 4% of the fibers (Figure 1). This is similar to the degree of injury that often occurs after sports activities such as vigorous exercise or long-distance marathon running.

Icing was carried out by placing polyethylene bags of ice on surface of the skin over three 30-minute sessions per day, with each session being 1.5 hours apart. This was continued until two days after injury for a total of 9 icing sessions (i.e. immediately after injury = 3 sessions, 1 day after injury = 3 sessions, 2 days after injury = 3 sessions). The icing method was the same as in the previously reported study (‘Icing muscle injuries may delay recovery’).

Observations of muscles that were regenerating in the icing group and no-icing group 2 weeks after injury revealed significant differences in the size of regenerating fibers in cross-sections (Figure 2). In other words, this demonstrated the possibility that skeletal muscle regeneration is promoted by icing.

Macrophages are immune cells that orchestrate the reparative process of injured muscle. Pro-inflammatory macrophages accumulate in the damaged site soon after injury occurs, however they express an inducible nitric oxide synthase (iNOS), which has a disadvantageous side-effect of expanding the injury’s size. The results of this team’s experiments revealed that icing after mild muscle injury reduces the accumulation of iNOS-expressing pro-inflammatory macrophages (Figure 3). By causing this phenomenon, icing prevents the expansion of muscle injury size (Figure 3).

In other words, icing attenuates the recruitment of pro-inflammatory macrophages in the injury site. This was also reported in their previous study (‘Icing muscle injuries may delay recovery’), demonstrating that this is an effect caused by icing regardless of whether the muscle injury is serious or mild. In the previous study, icing was found to delay the regeneration of muscle after a serious injury that destroyed many fibers because the pro-inflammatory macrophages were unable to sufficiently phagocytose (*5) the injured muscle. In contrast to this, the current study shows that icing has a positive effect when the muscle injury is mild because it prevents the secondary expansion of the muscle injury caused by the pro-inflammatory macrophages. It suggests that this particular effect of icing is connected to the promotion of muscle regeneration.

Further Research
Icing has been used in the treatment of muscle injuries for a long time, however the positive effects of icing had yet to be elucidated until now. This study has shown that icing can promote muscle regeneration when used to treat commonly-occurring mild muscle injuries.

However, this does not mean that icing is effective for all types or degree of muscle injury. The researchers aim to further elucidate and raise awareness of this. For example, the group’s previous study showed that icing actually inhibited regeneration in cases of serious muscle injury. In addition, the term ‘muscle injury’ also includes extremely minute injuries that have yet to be observed through the team’s animal experiments, so it is still unclear as to what effect icing has on the repair from such microtraumas.

The researchers’ next challenge is to determine the extent of muscle injury up to which icing is appropriate. By building upon their previous investigations, they aim to contribute towards guidelines that will enable people in sports and clinical rehabilitation to make accurate judgements about whether or not to ice an injury.

Glossary
※1　Macrophage: A population of white blood cells. There are two known types of macrophage: pro-inflammatory and anti-inflammatory.
※2　Pro-inflammatory macrophage: A type of macrophages that immediately migrate into the site of a tissue injury. They phagocytose the damaged tissue and trigger inflammation.
※3　Inflammation: A pathological reaction that occurs when tissue is damaged. Symptoms include rubefaction (reddening of the skin), feverishness, swelling and pain.
※4 Inducible nitric oxide synthase (iNOS): An enzyme involved in the synthesis of nitric oxide. Macrophages can damage muscle cells when they express iNOS.
※5 phagocytose (noun = phagocytosis) : A behavior of macrophages that surrounds and removes damaged tissue.

A higher dose of magnesium each day keeps dementia at bay

 

IMAGE: DR ERIN WALSH. CREDIT: JAMIE KIDSTON/ANU view more 

CREDIT: CREDIT: JAMIE KIDSTON/ANU

More magnesium in our daily diet leads to better brain health as we age, according to scientists from the Neuroimaging and Brain Lab at The Australian National University (ANU).  

The researchers say increased intake of magnesium-rich foods such as spinach and nuts could also help reduce the risk of dementia, which is the second leading cause of death in Australia and the seventh biggest killer globally.  

The study of more than 6,000 cognitively healthy participants in the United Kingdom aged 40 to 73 found people who consume more than 550 milligrams of magnesium each day have a brain age that is approximately one year younger by the time they reach 55 compared with someone with a normal magnesium intake of about 350 milligrams a day.   

“Our study shows a 41 per cent increase in magnesium intake could lead to less age-related brain shrinkage, which is associated with better cognitive function and lower risk or delayed onset of dementia in later life,” lead author and PhD researcher Khawlah Alateeq, from the ANU National Centre for Epidemiology and Population Health, said.  

“This research highlights the potential benefits of a diet high in magnesium and the role it plays in promoting good brain health.”  

It’s believed the number of people worldwide who will be diagnosed with dementia is expected to more than double from 57.4 million in 2019 to 152.8 million in 2050, placing a greater strain on health and social services and the global economy.  

“Since there is no cure for dementia and the development of pharmacological treatments have been unsuccessful for the past 30 years, it’s been suggested that greater attention should be directed towards prevention,” study co-author Dr Erin Walsh, who is also from ANU, said. 

“Our research could inform the development of public health interventions aimed at promoting healthy brain ageing through dietary strategies.” 

The researchers say a higher intake of magnesium in our diets from a younger age may safeguard against neurodegenerative diseases and cognitive decline by the time we reach our 40s.  

“The study shows higher dietary magnesium intake may contribute to neuroprotection earlier in the ageing process and preventative effects may begin in our 40s or even earlier,” Ms Alateeq said. 

“This means people of all ages should be paying closer attention to their magnesium intake. 

“We also found the neuroprotective effects of more dietary magnesium appears to benefit women more than men and more so in post-menopausal than pre-menopausal women, although this may be due to the anti-inflammatory effect of magnesium.” 

Participants completed an online questionnaire five times over a period of 16 months. The responses provided were used to calculate the daily magnesium intake of participants and were based on 200 different foods with varying portion sizes. The ANU team focused on magnesium-rich foods such as leafy green vegetables, legumes, nuts, seeds and wholegrains to provide an average estimation of magnesium intake from the participants’ diets.  

The research is published in the European Journal of Nutrition. 

Being fit partially offsets negative impact of high blood pressure

 

: High fitness levels may reduce the risk of death from cardiovascular disease in men with high blood pressure, according to a 29-year study published today in the European Journal of Preventive Cardiology, a journal of the ESC.1

 

“This was the first study to evaluate the joint effects of fitness and blood pressure on the risk of dying from cardiovascular disease,” said study author Professor Jari Laukkanen of the University of Eastern Finland, Kuopio, Finland. “The results suggest that being fit helps protect against some of the negative effects of high blood pressure.”

 

Nearly 1.3 billion adults aged 30 to 79 years worldwide have high blood pressure (hypertension).2 Hypertension is a major risk factor for heart attack and stroke and a leading cause of premature death globally. Previous studies have shown that high cardiorespiratory fitness is linked with greater longevity. This study examined the interplay between blood pressure, fitness and risk of death from cardiovascular disease.

 

The study included 2,280 men aged 42 to 61 years living in eastern Finland and enrolled in the Kuopio Ischaemic Heart Disease Risk Factor Study. Baseline measurements were conducted between 1984 and 1989. These included blood pressure and cardiorespiratory fitness, which was assessed as maximal oxygen uptake while riding a stationary bicycle. Blood pressure was classified as normal or high, and fitness was classified as low, medium or high.

 

The average age at baseline was 53 years. Participants were followed up until 2018. During a median follow up of 29 years, there were 644 deaths due to cardiovascular disease. The risk of death from cardiovascular disease was analysed after adjusting for age, body mass index, cholesterol levels, smoking status, type 2 diabetes, coronary heart disease, use of antihypertensive medication, alcohol consumption, physical activity, socioeconomic status, and high sensitivity C-reactive protein (a marker of inflammation).

 

Considering blood pressure alone, compared to normal values, high blood pressure was associated with a 39% increased risk of cardiovascular mortality (hazard ratio [HR] 1.39; 95% confidence interval [CI] 1.17–1.63). Considering fitness alone, compared with high levels, low fitness was associated with a 74% elevated likelihood of cardiovascular death (HR 1.74; 95% CI 1.35–2.23).

 

To evaluate the joint associations of blood pressure and fitness with risk of cardiovascular death, participants were categorised into four groups: 1) normal blood pressure and high fitness (this was the reference group for comparison); 2) normal blood pressure and low fitness; 3) high blood pressure and high fitness; 4) high blood pressure and low fitness.

 

Men with high blood pressure and low fitness had a more than doubled risk of cardiovascular death compared to those with normal blood pressure and high fitness (HR 2.35; 95% CI 1.81–3.04). When men with high blood pressure had high fitness levels, their elevated risk of cardiovascular risk persisted but was weaker: it was 55% higher than those with normal blood pressure and high fitness (HR 1.55; 95% CI 1.16–2.07).

 

Professor Laukkanen said: “Both high blood pressure and low fitness levels were each associated with an increased risk of cardiovascular death. High fitness levels attenuated, but did not eliminate, the increased risk of cardiovascular mortality in men with elevated blood pressure.”

 

The paper states: The inability of cardiorespiratory fitness to completely eliminate the risk of cardiovascular mortality in those with high blood pressure could partly be due to the strong, independent and causal relationship between blood pressure and cardiovascular disease.

 

Professor Laukkanen concluded: “Getting blood pressure under control should remain a goal in those with elevated levels. Our study indicates that men with high blood pressure should also aim to improve their fitness levels with regular physical activity. In addition to habitual exercise, avoiding excess body weight may enhance fitness.”

 

ESC guidelines recommend that adults of all ages to strive for at least 150 to 300 minutes a week of moderate-intensity or 75 to 150 minutes a week of vigorous-intensity aerobic physical activity, or an equivalent combination, to reduce all-cause death, cardiovascular death, and illness.3

 

ENDS

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JOURNAL

European Journal of Preventive Cardiology

DOI

10.1093/eurjpc/zwad034 

Road noise makes your blood pressure rise – literally

 

If you live near a busy road you might feel like the constant sound of roaring engines, honking horns and wailing sirens makes your blood pressure rise. Now a new study published today in JACC: Advances confirms it can do exactly that.

Previous studies have shown a connection between noisy road traffic and increased risk of hypertension. However, strong evidence was lacking, and it was unclear whether noise or air pollution played a bigger role. The new research shows that it is exposure to road traffic noise itself that can elevate hypertension risk.

“We were a little surprised that the association between road traffic noise and hypertension was robust even after adjustment for air pollution,” said Jing Huang, assistant professor in the Department of Occupational and Environmental Health Sciences in the School of Public Health at Peking University in Beijing, China, and lead author of the study.

Previous studies of the issue were cross-sectional, meaning they showed that traffic noise and hypertension were linked, but failed to show a causal relationship. For the new paper, researchers conducted a prospective study using UK Biobank data that looked at health outcomes over time.

Researchers analyzed data from more than 240,000 people (aged 40 to 69 years) who started out without hypertension. They estimated road traffic noise based on residential address and the Common Noise Assessment Method, a European modeling tool.

Using follow-up data over a median 8.1 years, they looked at how many people developed hypertension. Not only did they find that people living near road traffic noise were more likely to develop hypertension, they also found that risk increased in tandem with the noise “dose.”

These associations held true even when researchers adjusted for exposure to fine particles and nitrogen dioxide. However, people who had high exposure to both traffic noise and air pollution had the highest hypertension risk, showing that air pollution plays a role as well.

“Road traffic noise and traffic-related air pollution coexist around us,” Huang said. “It is essential to explore the independent effects of road traffic noise, rather than the total environment.”

The findings can support public health measures because they confirm that exposure to road traffic noise is harmful to our blood pressure, she said. Policymaking may alleviate the adverse impacts of road traffic noise as a societal effort, such as setting stricter noise guideline and enforcement, improving road conditions and urban design, and investing advanced technology on quieter vehicles.

“To date, this is the first large-sized prospective study directly addressing the effect of road traffic noise on the incidence of newly-diagnosed hypertension,” said Jiandong Zhang, cardiovascular disease fellow in the division of cardiology at the University of North Carolina at Chapel Hill, and author of the accompanying editorial comment. “The data demonstrated in this article provides a higher quality of evidence to justify the potential to modify road traffic noise and air pollution from both individual and societal levels in improving cardiovascular health.”

As a follow-up, Huang said field studies are underway to better understand the pathophysiological mechanisms through which road noise affects hypertension.

People who have low bone density may have an increased risk of developing dementia

 People who have low bone density may have an increased risk of developing dementia compared to people who have higher bone density, according to a study published in the March 22, 2023, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study does not prove that low bone density causes dementia. It only shows an association.

“Low bone density and dementia are two conditions that commonly affect older people simultaneously, especially as bone loss often increases due to physical inactivity and poor nutrition during dementia,” said study author Mohammad Arfan Ikram, MD, PhD, of the Erasmus University Medical Center in Rotterdam, Netherlands. “However, little is known about bone loss that occurs in the period leading up to dementia. Our study found that bone loss indeed already occurs before dementia and thus is linked to a higher risk of dementia.”

The study involved 3,651 people in the Netherlands with an average age of 72 who did not have dementia at the start of the study.

Over an average of 11 years, 688 people or 19% developed dementia.

Researchers looked at X-rays to identify bone density. Participants were interviewed every four to five years and completed physical tests such as bone scans and tests for dementia.

Of the 1,211 people with the lowest total body bone density, 90 people developed dementia within 10 years, compared to 57 of the 1,211 people with the highest bone density.

After adjusting for factors such as age, sex, education, other illnesses and medication use, and a family history of dementia, researchers found that within 10 years, people with the lowest total body bone density were 42% more likely to develop dementia than people in the highest group.

“Previous research has found factors like diet and exercise may impact bones differently as well as the risk of dementia,” Ikram added. “Our research has found a link between bone loss and dementia, but further studies are needed to better understand this connection between bone density and memory loss. It’s possible that bone loss may occur already in the earliest phases of dementia, years before any clinical symptoms manifest themselves. If that were the case, bone loss could be an indicator of risk for dementia and people with bone loss could be targeted for screening and improved care.”

A limitation of the study is that participants were primarily of European origin and age 70 or older at the start of the study, so these findings may vary in different races, ethnicities, and younger age groups.

Mediterranean diet cuts women’s cardiovascular disease and death risk by nearly 25%

 

Sticking closely to a Mediterranean diet cuts a woman’s risks of cardiovascular disease and death by nearly 25%, finds a pooled data analysis of the available evidence—the first of its kind—published online in the journal Heart.

The findings prompt the researchers to call for more sex specific research to guide clinical practice in heart health.

Cardiovascular disease accounts for more than a third of all deaths in women around the world. While a healthy diet is a key plank of prevention, most relevant clinical trials have included relatively few women or haven’t reported the results by sex, say the researchers.

And current guidelines on how best to lower cardiovascular disease risk don’t differentiate by sex.

To build on the evidence base to inform sex specific guidance and clinical practice, the researchers trawled research databases for studies looking at the potential impact of eating a Mediterranean diet on women’s cardiovascular health and their risk of death.

The Mediterranean diet is rich in wholegrains, vegetables, fruit, legumes, nuts, and extra virgin olive oil; moderate in fish/shellfish; low to moderate in wine; and low in red/processed meats, dairy products, animal fat, and processed foods.

From an initial haul of 190 relevant studies, the researchers included 16 published between 2003 and 2021 in their pooled data analysis.

The studies, which were mostly carried out in the US and Europe, involved more than 700,000 women aged 18 and above whose cardiovascular health was monitored for an average of 12.5 years.

The results of the analysis showed that sticking closely to a Mediterranean diet was associated with a 24% lower risk of cardiovascular disease, and a 23% lower risk of death from any cause in women. 

The risk of coronary heart disease was 25% lower, while that of stroke was also lower, although not statistically significant, in those who most closely followed this diet compared with those who did so the least.

Excluding each of the studies one at a time from the analysis didn’t materially affect the findings,  “further supporting a strong inverse relationship for incident [cardiovascular disease] and total mortality with higher Mediterranean diet adherence in women,” write the researchers.

They nevertheless acknowledge various limitations to their findings, including that all the studies analysed were observational and relied on self-reported food frequency questionnaires. And adjustments for potentially influential factors varied across the included studies. 

But the Mediterranean diet’s antioxidant and gut microbiome effects on inflammation and cardiovascular risk factors are among the possible explanations for the observed associations, say the researchers. 

And the diet’s various components, such as polyphenols, nitrates, omega-3 fatty acids, increased fibre intake and reduced glycaemic load, may all separately contribute to a better cardiovascular risk profile, they suggest. 

“However, mechanisms explaining the sex specific effect of the Mediterranean diet on [cardiovascular disease] and death remain unclear,” they note, adding that the findings reinforce the need for more sex specific research in cardiology.

“Female specific cardiovascular risk factors, including premature menopause, pre-eclampsia and gestational diabetes, or female predominant risk factors, such as systemic lupus, can all independently increase [cardiovascular disease] risk,” they write.

“It is possible that preventative measures, such as a Mediterranean diet, that targets inflammation and [cardiovascular disease] risk factors, impose differing effects in women compared with men,” they add.

High blood caffeine level might curb amount of body fat and type 2 diabetes risk

 

A high blood caffeine level might curb the amount of body fat a person carries and their risk of type 2 diabetes, suggests research published in the open access journal BMJ Medicine.

In light of their findings, the potential role of calorie free caffeinated drinks for lowering the risks of obesity and type 2 diabetes is probably now worth exploring, say the researchers.

Previously published research indicates that drinking 3-5 daily cups of coffee, a rich source of caffeine, is associated with a lower risk of type 2 diabetes and cardiovascular disease, note the researchers. An average cup of coffee contains around 70–150 mg caffeine.

But most of the published research to date has concerned observational studies, which can’t reliably establish causal effects, because of the other potentially influential factors involved, point out the researchers.

What’s more, it’s difficult to disentangle any specific effects of caffeine from the other compounds included in caffeinated drinks and foods, they add.

To try and overcome these issues, the researchers used Mendelian randomisation to find out what effect higher blood caffeine levels have on body fat and the long term risks of type 2 diabetes and major cardiovascular diseases—coronary artery disease, stroke, heart failure, and irregular heart rhythm (atrial fibrillation).

Mendelian randomisation is a technique that uses genetic variants as proxies for a particular risk factor—in this case blood levels of caffeine—to obtain genetic evidence in support of a particular outcome—in this study, weight (BMI) and type 2 diabetes risk.

The researchers looked at the role of two common genetic variants of the CYP1A2 and AHR genes in nearly 10,000 people of predominantly European ancestry, who were taking part in 6 long term studies. The CYP1A2 and AHR genes are associated with the speed of caffeine metabolism in the body.

People who carry genetic variants associated with slower caffeine metabolism drink, on average, less coffee, yet have higher levels of caffeine in their blood than people who metabolise it quickly to reach or retain the levels required for its stimulant effects. 

The results of the analysis showed that higher genetically predicted blood caffeine levels were associated with lower weight (BMI) and body fat. 

Higher genetically predicted blood caffeine levels were also associated with a lower risk of type 2 diabetes.  

The researchers then used Mendelian randomisation to further explore the extent to which any effect of caffeine on type 2 diabetes risk might principally be driven by the concurrent weight loss.

The results showed that weight loss drove nearly half (43%) of the effect of caffeine on type 2 diabetes risk.

No strong associations emerged between genetically predicted blood caffeine levels and the risk of any of the studied cardiovascular disease outcomes.

The researchers acknowledge various limitations to their findings, including the use of only two genetic variants, and the inclusion of only people of European ancestry.

But caffeine is known to boost metabolism, increase fat burning, and reduce appetite, they explain. And a daily intake of 100 mg has been estimated to increase energy expenditure by around 100 calories a day, which could consequently lower the risk of developing obesity.

“Our mendelian randomisation finding suggests that caffeine might, at least in part, explain the inverse association between coffee consumption and risk of type 2 diabetes,” write the researchers.

“Randomised controlled trials are warranted to assess whether non-caloric caffeine containing beverages might play a role in reducing the risk of obesity and type 2 diabetes,” they conclude.

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Too little sleep could make vaccination less effective

How strongly a vaccine protects you may depend on getting enough sleep in the days before and after inoculation, finds a new meta-analysis examining the relationship between sleep duration and the body’s response to vaccination.

Sleeping fewer than six hours per night around the time of vaccination was associated with a robust decrease in antibody response, according to the multi-institution study published March 13 in Current Biology. Adults are typically recommended to get between seven and nine hours of sleep per night.

The meta-analysis included data on the association between sleep duration and antibody responses for the influenza and hepatitis vaccines. While comparable data on COVID-19 vaccination were not available, researchers said their study highlighted the need to identify simple behavioral interventions, such as sufficient sleep, that could improve the response to COVID-19 vaccination amid the ongoing pandemic.

The weakened antibody response in those with shortened sleep was so profound, it was similar to the decline in COVID-19 antibodies two months following vaccination with the Pfizer-BioNTech or Moderna shots.

“We have previously found that cognitive behavioral therapy, as well as mindfulness, robustly improve insomnia and also normalize various aspects of immunity, although it is not yet known whether insomnia treatment can augment vaccination responses,” said Michael Irwin, MD, a study co-author and director of the Cousins Center for Psychoneuroimmunology at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at UCLA.

The researchers also examined the data by sex, since women typically have a stronger vaccination response than men. There was a robust association between sleep duration and antibody response in men, but they said more data are needed for women because the studies did not control for variations in sex hormone levels, which are known to affect immune function.

Large-scale studies are also needed to determine when people should get sufficient sleep to promote an optimal vaccine response around the time of inoculation, the researchers said.

FDA Authorizes First Over-the-Counter At-Home Test to Detect Both Influenza and COVID-19 Viruses

 Today, the U.S. Food and Drug Administration issued an emergency use authorization (EUA) for the first over-the-counter (OTC) at-home diagnostic test that can differentiate and detect influenza A and B, commonly known as the flu, and SARS-CoV-2, the virus that causes COVID-19. The Lucira COVID-19 & Flu Home Test is a single-use at-home test kit that provides results from self-collected nasal swab samples in roughly 30 minutes. 

“Today’s authorization of the first OTC test that can detect Influenza A and B, along with SARS-CoV-2, is a major milestone in bringing greater consumer access to diagnostic tests that can be performed entirely at home,” said Jeff Shuren, M.D., J.D., director of the FDA’s Center for Devices and Radiological Health. 

The Lucira COVID-19 & Flu Home Test is a single use test for individuals with signs and symptoms consistent with a respiratory tract infection, including COVID-19. The test can be purchased without a prescription and performed completely at-home using nasal swab samples self-collected by individuals ages 14 years or older or collected by an adult for individuals 2 years of age or older. 

The test works by swirling the sample swab in a vial that is placed in the test unit. In 30 minutes or less, the test unit will display the results that show whether a person is positive or negative for each of the following: Influenza A, Influenza B and COVID-19. Individuals should report all results obtained to their healthcare provider for public health reporting and to receive appropriate medical care. 

In individuals with symptoms, the Lucira COVID-19 & Flu Home Test correctly identified 99.3% of negative and 90% of positive Influenza A samples, 100% of negative and 88.3% of positive COVID-19 samples and 99.9% of negative Influenza B samples. Since there are currently not enough cases of Influenza B circulating to include in a clinical study, validation confirmed that the test can identify the virus in contrived specimens, and the EUA requires Lucira to continue to collect samples to study the test’s ability to detect Influenza B in real-world settings.   

]Dim lights before bedtime to reduce risk of gestational diabetes

• Gestational diabetes mellitus is a common pregnancy complication with significant health risks for both mother and offspring
• Gestational diabetes is rising fast and is now 7.8% of all births in U.S.
• Mother with gestational diabetes has increased risk of diabetes, heart disease and dementia; offspring more likely to have obesity and hypertensio

CHICAGO --- Pregnant persons should dim the lights in their home and turn off or at least dim their screens (computer monitors and smartphones) a few hours before bedtime to reduce the risk of gestational diabetes mellitus, a new Northwestern Medicine study shows.

Women who developed gestational diabetes mellitus in the multi-site study had greater light exposure in the three hours before sleep onset. They did not differ in their light exposure during daytime or sleep or in their activity levels compared to those who did not develop it. 

“Our study suggests that light exposure before bedtime may be an under-recognized yet easily modifiable risk factor of gestational diabetes,” said lead study author Dr. Minjee Kim, assistant professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine neurologist. 

Growing evidence suggests exposure to light at night before bedtime may be linked to impaired glucose regulation in non-pregnant adults. However, little is known about the effect of evening light exposure during pregnancy on the risk of developing gestational diabetes, a common pregnancy complication with significant health implications for both mother and offspring. 

This is believed to be one of the first multi-site studies to examine light exposure before sleep on the risk of developing gestational diabetes. 

The study will be published March 10 in the American Journal of Obstetrics and Gynecology Maternal Fetal Medicine. 

Gestational diabetes rise is ‘alarming’ 

Gestational diabetes is on the rise in the U.S. and globally. About 4.5% of first-time pregnant women with a baby born between 2011 and 2013 developed gestational diabetes, which has been increasing on average 3.4% per three-year period until 2019. In 2020, the rate of gestational diabetes was 7.8% of all births in the U.S.  

“It’s alarming,” Kim said. “Gestational diabetes is known to increase obstetric complications, and the mother’s risk of diabetes, heart disease and dementia. The offspring also are more likely to have obesity and hypertension as they grow up.” 

Data show that women who have gestational diabetes are nearly 10 times more likely to develop type 2 diabetes mellitus compared to those do not have glucose issues during pregnancy, Kim said. 

Bright light exposure prior to sleep can come from bright lights in your home and from devices like TVs, computers and smartphones.

 “We don’t think about the potential harm of keeping the environment bright from the moment we wake up until we go to bed,” Kim said. “But it should be pretty dim for several hours before we go to bed. We probably don’t need that much light for whatever we do routinely in the evening.”

Scientists don’t know which source of bright light causes the problem, but it might all add up, Kim said. 

“Try to reduce whatever light is in your environment in those three hours before you go to bed,” Kim said. “It’s best not to use your computer or phone during this period. But if you have to use them, keep the screens as dim as possible,” Kim said, suggesting people use the night light option and turn off the blue light. 

If pregnant persons develop gestational diabetes with the first pregnancy, they are more likely to have it with the next pregnancy. 

Pre-sleep light exposure increases heart rate and may lead to abdominal obesity, insulin resistance, increased blood pressure

Pre-sleep light exposure may affect glucose metabolism through sympathetic overactivity, meaning the heart rate goes up before bed when it should go down. “It seems there is inappropriate activation of the fight or flight response when it is time to rest,” Kim said. 

Data shows the sympathetic overactivity may lead to cardiometabolic disease, which is a cluster of conditions including abdominal obesity, insulin resistance, increased blood pressure and an imbalance of lipids, all leading to cardiovascular disease. 

The study of 741 women in their second trimester was conducted at eight clinical U.S. sites between 2011 and 2013. The participants’ light exposure was measured by an actigraph worn on their wrists. The women were measured during the second trimester of pregnancy, the time when they receive routine screening for gestational diabetes.

After adjusting separately for age, BMI, race/ethnicity, education, commercial insurance, employment schedule, season, sleep duration, sleep midpoint, sleep regularity index, and daytime light exposure, pre-sleep light exposure remained significantly associated with gestational diabetes.

The growing rate of gestational diabetes has been partially attributed to increasing body mass index and the older age of pregnant persons. 

“But even after adjusting for BMI and age, gestational diabetes is still rising,” Kim said. “We have a lot to prove, but my personal worry is that light may be silently contributing to this problem without most people realizing the potential harm.”

Losing body weight and exercising also reduce the risk of developing gestational diabetes, which are important but take some effort.

Turning down lights is an easy modification

“Turning down the lights is an easy modification you can make,” Kim said. 

“Now I’m the light police at home,” Kim said. “I see all this light I never thought about before. I try to dim the light as much as possible. Just for evening activities such as dinner and bathing the kids, you don’t need bright light.”  

“This study highlights the importance of reducing light exposure in the hours before bedtime” said senior author Kathryn Reid, research professor of neurology at Feinberg.

The name of the paper is “The association between light exposure before bedtime in pregnancy and the risk of developing gestational diabetes mellitus.”

Other Northwestern authors are Dr. Phyllis Zee, Rosemary Braun, Blas Garcia-Canga and Michael Wolf.

The research was supported  by grant R01HL105549 from the National Heart, Lung, and Blood Institute of the National Institutes of Health. 

 

 

 

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JOURNAL

American Journal of Obstetrics & Gynecology MFM

MIND and Mediterranean diets associated with fewer Alzheimer's plaques and tangles

People who eat diets rich in green leafy vegetables as well as other vegetables, fruits, whole grains, olive oil, beans, nuts and fish may have fewer amyloid plaques and tau tangles in their brain—signs of Alzheimer’s disease—than people who do not consume such diets, according to a study published in the March 8, 2023, online issue of Neurology®, the medical journal of the American Academy of Neurology.

The study examined how closely people followed the MIND and Mediterranean diets. While similar, the Mediterranean diet recommends vegetables, fruit, and three or more servings of fish per week while the MIND diet prioritizes green leafy vegetables like spinach, kale and collard greens along with other vegetables. The MIND diet also prioritizes berries over other fruit and recommends one or more servings of fish per week. Both the MIND and Mediterranean diet recommend small amounts of wine.

While this study shows an association of regularly consuming these diets with fewer Alzheimer’s disease plaques and tangles, it does not establish a cause and effect relationship.

“These results are exciting—improvement in people’s diets in just one area—such as eating more than six servings of green leafy vegetables per week, or not eating fried foods—was associated with fewer amyloid plaques in the brain similar to being about four years younger,” said study author Puja Agarwal, PhD, of RUSH University in Chicago. “While our research doesn’t prove that a healthy diet resulted in fewer brain deposits of amyloid plaques, also known as an indicator of Alzheimer’s disease, we know there is a relationship and following the MIND and Mediterranean diets may be one way that people can improve their brain health and protect cognition as they age.”

The study involved 581 people with an average age of 84 at the time of diet assessment who agreed to donate their brains at death to advance research on dementia. Participants completed annual questionnaires asking how much they ate of food items in various categories.

The participants died an average of seven years after the start of the study. Right before death, 39% of participants had been diagnosed with dementia. When examined after death, 66% met the criteria for Alzheimer’s disease.

At autopsy, researchers examined participants’ brains to determine the amounts of amyloid plaques and tau tangles. Both are found in the brains of people with Alzheimer’s disease but may also be found in the brains of older people with normal cognition. Researchers then looked back at the food questionnaires which were collected during follow-up and ranked the quality of diet for each person.

For the Mediterranean diet, there were 11 food categories. Participants were given a score of zero to 55, with higher scores if they adhered to the diet in these categories: whole grain cereals, fruits, vegetables, legumes, olive oil, fish and potatoes. They were given lower scores if they ate red meat, poultry and full-fat dairy products.

For the MIND diet, there were 15 categories. Participants were given a score of zero to 15, with one point each for 10 brain-healthy food groups including green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil, and wine. They lost a point if they ate foods more than recommended in five unhealthy food groups, including red meats, butter and margarine, cheese, pastries and sweets, and fried and fast food.

Researchers then divided participants into three groups for each diet and compared those in the highest groups to those in the lowest groups. For the Mediterranean diet, people in the highest group had an average score of 35 while those in the lowest group had an average score of 26. For the MIND diet, the highest group had an average score of 9 while the lowest group had an average score of 6.

After adjusting for age at death, sex, education, total calorie intake and whether people had a gene linked to a greater risk of Alzheimer’s disease, researchers found people who scored highest for adhering to the Mediterranean diet had average plaque and tangle amounts in their brains similar to being 18 years younger than people who scored lowest. Researchers also found people who scored highest for adhering to the MIND diet had average plaque and tangle amounts similar to being 12 years younger than those who scored lowest.

A MIND diet score one point higher corresponded to typical plaque amounts of participants who were 4.25 years younger in age.

When looking at single diet components, researchers found people who ate the highest amounts of green leafy vegetables, or seven or more servings per week, had plaque amounts in their brains corresponding to being almost 19 years younger than people who ate the fewest, with one or fewer servings per week.

“Our finding that eating more green leafy vegetables is in itself associated with fewer signs of  Alzheimer’s disease in the brain is intriguing enough for people to consider adding more of these vegetables to their diet,” said Agarwal. “Future studies are needed to establish our findings further.”

A limitation of the study was that participants were mostly white, non-Hispanic, and older so the results cannot be generalized to other populations.

Mediterranean diet the best prevention against prostate cancer

 

Peer-Reviewed Publication

UNIVERSITY OF SOUTH AUSTRALIA

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Men who consume colourful fruits and vegetables on a regular basis are less likely to be diagnosed with prostate cancer (PC), according to new research by University of South Australia scientists.

A rainbow of foods rich in certain micronutrients helps to prevent prostate cancer (PC) as well as speed up recovery among men who undergo radiation treatment for the disease.

The findings, from two studies published in the journal Cancers, highlight the importance of a Mediterranean or Asian diet that includes these foods.

Researchers compared micronutrient plasma concentrations of prostate cancer patients with a healthy control group, revealing low levels of lutein, lycopene, alpha-carotene, and selenium in PC patients and high levels of iron, sulphur, and calcium in the same group, relative to controls.

Increased DNA damage after radiation exposure was also associated with low lycopene and selenium in blood plasma.

Men with plasma concentrations lower than 0.25 micrograms (ug) per millilitre (mL) for lycopene and/or lower than 120ug/L for selenium have an increased risk of prostate cancer and are likely to be more sensitive to the damaging effects of radiation.

Foods that are rich in lycopene include tomatoes, melons, papayas, grapes, peaches, watermelons, and cranberries. Selenium-rich foods include white meat, fish, shellfish, eggs, and nuts.

Study co-author  Dr Permal Deo says eating foods that are naturally rich in lycopene and selenium is preferable to taking supplements, where the benefits are limited, according to previous studies.

“Our recommendation is to adopt a Mediterranean diet enlisting the help of a dietician because people absorb nutrients in different ways, depending on the food, the digestive system, the person’s genotype and possibly their microbiome,” Dr Deo says.

Prostate cancer remains one of the most common and fatal cancers in men, but the nutritional deficiencies associated with it remain largely unknown, hence this study.

Other risk factors, such as ethnicity, family history and age have previously been linked to prostate cancer.

“There is strong evidence that being overweight and tall increases the risk of prostate cancer. Diets high in dairy products and low in vitamin E may also increase the risk but the evidence is less clear.”

Vitamin E is found in plant-based oils, nuts, seeds, fruits, and vegetables.

The research is the first to evaluate plasma concentrations of micronutrients and trace elements with respect to prostate cancer in the South Australian population.