Eating high-processed foods impacts muscle quality

 

Reports and Proceedings

Radiological Society of North America

 

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Axial T1-weighted bilateral thigh MR images and magnified frames providing a closer look at the areas in lateral aspects of quadriceps femoris muscles (knee extensors) from two obese, female participants, aged 58 (A) and 62 years (B), respectively. In A, the thigh muscles on both sides demonstrate abundant fatty streaks, consistent with a high Goutallier grade of 45 for this participant, whose diet from the past 12 months consisted 68% of ultra-processed foods. In B, the thigh muscles show fewer fatty streaks as highlighted in the magnified image, consistent with a low Goutallier grade of 17 for this participant, whose diet contained only 36% ultra-processed foods.

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Credit: Radiological Society of North Aurora (RSNA) and Zehra Akkaya, M.D.

CHICAGO – A diet high in ultra-processed foods is associated with higher amounts of fat stored inside thigh muscles, regardless of the amount of calories consumed or level of physical activity, according to a study being presented today at the annual meeting of the Radiological Society of North America (RSNA). Higher amounts of intramuscular fat in the thigh could also increase the risk for knee osteoarthritis.

The use of natural and minimally processed ingredients in many modern diets has decreased, more often being replaced with ingredients that have been industrially processed, artificially flavored, colored or chemically altered.

Foods such as breakfast cereals, margarines/spreads, packaged snacks, hot dogs, soft drinks and energy drinks, candies and desserts, frozen pizzas, ready-to-eat meals, mass-produced packaged breads and buns, and more, include synthesized ingredients and are highly processed.

These ultra-processed foods usually have longer shelf lives and are highly appealing, as they are convenient and contain a combination of sugar, fat, salt and carbohydrates which affect the brain’s reward system, making it hard to stop eating.

For the study, researchers set out to assess the association of ultra-processed food intake and their relationship to intramuscular fat in the thigh.

“The novelty of this study is that it investigates the impact of diet quality, specifically the role of ultra-processed foods in relation to intramuscular fat in the thigh muscles assessed by MRI,” said author Zehra Akkaya, M.D., researcher and former Fulbright Scholar in the Department of Radiology and Biomedical Imaging at the University of California, San Francisco. “This is the first imaging study looking into the relationship between MRI-based skeletal muscle quality and quality of diet.”

For the study, researchers analyzed data from 666 individuals who participated in the Osteoarthritis Initiative who were not yet affected by osteoarthritis, based on imaging. The Osteoarthritis Initiative is a nationwide research study, sponsored by the National Institutes of Health, that helps researchers better understand how to prevent and treat knee osteoarthritis.

“Research from our group and others has previously shown that quantitative and functional decline in thigh muscles is potentially associated with onset and progression of knee osteoarthritis,” Dr. Akkaya said. “On MRI images, this decline can be seen as fatty degeneration of the muscle, where streaks of fat replace muscle fibers.”

Of the 666 individuals, (455 men, 211 women) the average age was 60 years. On average, participants were overweight with a body mass index (BMI) of 27. Approximately 40% of the foods that they ate in the past year were ultra-processed.  

The researchers found that the more ultra-processed foods people consumed, the more intramuscular fat they had in their thigh muscles, regardless of energy (caloric) intake.

“In an adult population at risk for but without knee or hip osteoarthritis, consuming ultra-processed foods is linked to increased fat within the thigh muscles,” Dr. Akkaya said. “These findings held true regardless of dietary energy content, BMI, sociodemographic factors or physical activity levels.”

Targeting modifiable lifestyle factors—mainly prevention of obesity via a healthy, balanced diet and adequate exercise—has been the mainstay of initial management for knee osteoarthritis, Dr. Akkaya noted.

“Osteoarthritis is an increasingly prevalent and costly global health issue. It is the largest contributor to non-cancer related health care costs in the U.S. and around the world,” Dr. Akkaya said. “Since this condition is highly linked to obesity and unhealthy lifestyle choices, there are potential avenues for lifestyle modification and disease management.”

By exploring how ultra-processed food consumption impacts muscle composition, this study provides valuable insights into dietary influences on muscle health.

“Understanding this relationship could have important clinical implications, as it offers a new perspective on how diet quality affects musculoskeletal health,” Dr. Akkaya said.

Daily coffee consumption can add up to two extra years of healthy aging to your life

 

A new review paper review paper1 published in Ageing Research Reviews and supported by the Institute for Scientific Information on Coffee (ISIC) explores the science behind coffee’s relationship with healthy aging.  

The percentage of the global population aged 65 and above is growing rapidly and only expected to continue to rise - expanding from 10% in 2022 to 16% in 20502. This paper underlines the important role that regular, moderate coffee consumption can play for people in this aging population, as part of a healthy and balanced lifestyle.  

For context, the European Food Safety Authority consider consuming up to 400mg of caffeine (3-5 cups of coffee) per day to be a moderate and safe amount for most adults. For pregnant or lactating women, caffeine intake should be reduced to 200mg per day3. 

As one of the most widely studied commodities worldwide, over 50 studies have already observed coffee’s potential role in mitigating against all-cause mortality – playing a discrete but nonetheless significant role in reducing risk of cardiovascular disease, cancers, respiratory diseases, cognitive decline, and frailty.  

The new review found that regular coffee consumption adds an average of 1.8 years of healthy living to a person’s life – meaning not only do they live longer, but also healthier lives. Some research suggests that other nutritional ‘anti-aging’ interventions may have a gender bias, however the review concluded the increased healthy life expectancy attributed to regular coffee consumption is seen in both men and women.  

In addition to coffee’s role in reducing the risk of some major chronic diseases, the team behind the review also specifically explored existing research around coffee’s important role in biological mechanisms linked with the aging process. This included coffee’s influence in mitigating genomic instability or cell mutations, which are a known trigger of aging, and strengthening regular cell function. Importantly, the review focused on studies on humans and human tissue only for these mechanisms - highlighting results that provide a more accurate and reliable understanding of coffee’s effects on human health. 

Many traditional clinical recommendations for older people have advised decreasing or even avoiding coffee consumption altogether4,5,6,7. This review suggests that these guidelines should now be re-evaluated on the basis of the existing compelling scientific evidence for coffee’s role in healthy aging.  

While coffee is most commonly associated with its caffeine content, it also includes a mixture of over 2,000 potentially bioactive compounds. Polyphenol components may provide antioxidant and anti-inflammatory properties, with roles including reducing neuroinflammation or regulating insulin sensitivity.  

While both caffeine and non-caffeine components of coffee can help extend healthy lifespan, there is still much we don’t know about the exact mechanisms behind the role these components play. The authors highlight the strong potential for a wealth of further research on coffee’s health benefits in this field.  

Lead author Rodrigo Cunha, University of Coimbra said: “We know that the world’s population is aging faster than ever, which is why it’s increasingly important to explore dietary interventions which may allow people to not only live longer but also healthier lives.  

“Traditional clinical recommendations have at times overlooked coffee’s role in healthy aging, but with a strong research base around how regular consumption can potentially reduce some of the most chronic diseases facing society, it is likely time to re-evaluate these. 

“Our review underlines the role regular, moderate coffee consumption can play in mediating against the biological mechanisms which naturally slow or fail as we get older – triggering a range of potential health issues and comorbidities. And there is still room to understand more about exactly how these mechanisms work, as well as which individuals may be biologically pre-disposed to benefitting most from coffee’s interactions with them.”  

Readers interested in finding out more about coffee and health can visit: www.coffeeandscience.org/health 

Paternal weight influences baby’s size at birth

A study in Brazil involving 89 father-mother-baby triads points to an association between paternal overweight and newborn birth weight: the higher the father’s body mass index (BMI, weight divided by height squared), the lower the baby’s birth weight.

An article on the study is published in the International Journal of Obesity. 

The findings reinforce the idea that anthropometric issues are not the sole responsibility of the mother and that the father should also strive to maintain a healthy lifestyle during a partner’s pregnancy.

“There is a great deal of discussion and research regarding the link between fetal development and maternal health, including issues such as overweight before and during pregnancy, but the fact is that the father’s health also has a significant impact on the development of the baby both during pregnancy and after birth. Our study was the first involving Brazilian families to show that the higher the father’s BMI, the lower the baby’s birth weight, evidencing the father’s importance to the baby’s health and development,” said Mariana Rinaldi Carvalho, first author of the article and a researcher at the University of São Paulo’s Ribeirão Preto Medical School (FMRP-USP). She was supported by FAPESP via a PhD scholarship. 

Birth weight is considered a key predictor of health not just in early childhood but for life. A great deal of research has shown that babies born with low (or high) weight run a higher risk of death and of developing non-transmissible diseases later in life, such as type 2 diabetes, cancer and cardiovascular disorders.

The study by researchers at FMRP-USP was a follow-up to a clinical trial that investigated the effect of nutritional counseling intervention on weight gain for 350 overweight pregnant women attending public primary health clinics. The trial was supported by FAPESP.

“Having noticed that most studies involving fetal and neonatal health fail to take the parents’ lifestyle into account, we set out to include paternal anthropometry as a factor affecting fetal development,” said Carvalho’s thesis advisor, Daniela Saes Sartorelli, last author of the study and a professor in the Department of Social Medicine at FMRP-USP.

The group plans to analyze the effect of paternal diet on neonatal anthropometry and adiposity, focusing on consumption of ultra-processed foods and fat quality.

Public health

Maternal overweight is considered a public health problem. Many studies have shown that excessive weight gain during pregnancy is a major short- and long-term health hazard for both mother and baby. In the case of the mother, it heightens the risk of gestational diabetes, hypertension and preeclampsia, often making a cesarean section inevitable. For the baby, it increases the likelihood of low or high birth weight and the risk of obesity and associated disorders such as type 2 diabetes and hypertension at an early age.

While in the case of the mother there is a direct link via the placenta and other cells between obesity and fetal development, paternal overweight can lead to epigenetic alterations (biochemical changes to DNA that reprogram gene expression). According to Carvalho, previous studies involving animals showed that some genes expressed by the father can affect fetoplacental growth.

The fetus can suffer growth restrictions influenced by paternal overweight and fail to realize its genetic growth potential, she explained. Briefly, preconception paternal exposure to environmental stressors such as an unhealthy diet, a sedentary lifestyle and smoking, for example, can lead to metabolic disorders in offspring via epigenetic alterations (read more at: agencia.fapesp.br/44803 and agencia.fapesp.br/22005). 

“We now know that environmental stressors such as overweight can influence the structure and quality of the father’s sperm, altering gene expression and affecting the DNA of his children. This influence relates to epigenetics, the scientific field that studies how environmental stimuli can activate or silence genes,” Carvalho explained.

“The mother’s health is evidently a key factor, and research has shown the importance of a healthy diet during pregnancy, but more attention needs to be paid to paternal overweight in the period prior to conception. Our research findings show that just as maternal nutritional counseling is important, so is the need for a preconception change in paternal habits.” 

The study involving 89 parents and babies also found that the higher the father’s BMI and waist circumference, the smaller the baby’s head circumference at birth. “We didn’t detect any anomalies or malformations, but the correlation is important because head circumference at birth is a key growth parameter. Nevertheless, more research is needed to evaluate the real significance of this finding,” Carvalho said, adding that previous studies of obesity found overweight to influence neonatal bone mineralization. 

“A limitation of this study was lack of access to information on the time these women took to deliver their babies [in cases of vaginal birth]. We know head circumference at birth can be altered temporarily when the baby has spent a long time in the vaginal canal,” she said.

Too much sitting hurts even young, active people

 

Get up and move!

Peer-Reviewed Publication

University of California - Riverside

 

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Prolonged sitting harms even young, active people, research finds. 

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A new study reveals that prolonged sitting significantly harms even young, active adults, increasing the risk of heart disease and obseity. Researchers also found that current federal exercise guidelines are insufficient to offset these negative effects.

While a great deal of research on aging examines populations in their 60s, this study focused on younger adults. Researchers from UC Riverside and the University of Colorado, Boulder examined health data from over 1,000 men and women in Colorado whose average age was 33. 

Published in the journal PLOS One, the study shows that sitting for 8 or more hours per day increases cholesterol ratios and BMI, even in physically active individuals. Cholesterol ratios, which combine triglyceride and cholesterol levels to gauge heart disease risk, and BMI, a measure of body fat, are early indicators that can predict more severe health issues.

Lengthy sitting sessions can raise even a younger adult’s BMI nearly a full point compared to people who sit only a few hours out of the average day. “Though unhealthy diet and smoking play a major role in increasing BMI, the full-point jump we saw in the data was just due to sitting alone,” said Ryan Bruellman, lead researcher and doctoral candidate in UCR’s Department of Genetics, Genomics and Bioinformatics.

Similarly, sitting for 8 or more hours a day tended to move men in their early 30s and women in their mid 30s from healthy to higher-risk cholesterol ratios. Because many of the study participants already had cholesterol levels on the high end of optimal, too much sitting made the difference between no and moderate cardiac risk.

While current U.S. Department of Health and Human Services guidelines recommend 2.5 hours of moderate exercise or 1 hour and 15 minutes of vigorous exercise weekly, these levels appeared inadequate for people who sit extensively throughout the day. 

“People don’t often think about how much time they spend sitting, especially in their 20s and 30s, but it matters,” said Bruellman.

Participants self-reported their weekly sitting habits, including time spent sitting at work, during leisure activities, and while traveling. They also detailed their physical activity, categorized as moderate or vigorous. Moderate activities, such as brisk walking, allow for conversation, while vigorous activities, like running, leave participants breathless, according to the researchers. 

Biological markers, such as cholesterol ratios—a key indicator of cardiovascular risk—and BMI, were measured in person.

Importantly, the research findings show that reducing sitting time significantly improves health outcomes. For those unable to limit their sitting time, increasing the intensity and duration of physical activity is crucial. 

Doubling the recommended amount of weekly exercise — either 5 hours of moderate activity or 2.5 hours of vigorous activity — was more effective at lowering health risks associated with prolonged sitting.

The researchers also explored the role of genetics and environment by studying identical twin pairs. This unique approach helped isolate behavioral choices as the key factor in health differences. 

Among twins, those who reduced their sitting time or engaged in higher levels of vigorous activity consistently showed healthier cholesterol ratios and BMIs than their siblings who sat longer or exercised less. 

"This study makes it clear: if you sit for long periods, the standard exercise recommendations are not enough,” Bruellman said. “All adults, even the younger ones, need to move more, and exercise harder, to counteract the impact of sitting.”

While reducing sitting time remains the most effective strategy, the researchers hope to emphasize that all is not lost for individuals with sedentary jobs or lifestyles. Increasing the intensity and duration of exercise—especially vigorous activities—can help offset the damage.

Notably, even 10 minutes of vigorous exercise for every additional hour of sitting significantly mitigated the negative effects of sedentary behavior.

Beyond individual health benefits, the researchers hope the findings help inform future updates to national physical activity guidelines. It is not only the duration but also the intensity of physical activity that makes a difference, particularly for those with predominantly sedentary routines.

“Young adulthood is a critical time to establish healthy habits. If you don’t prioritize movement now, it only gets harder as life fills up with more responsibilities,” Bruellman said.

 “Get up and move—it’s never too early to start.”

Eating dark but not milk chocolate linked to reduced risk of type 2 diabetes

Eating five servings of dark chocolate a week is associated with a reduction in the risk of type 2 diabetes, according to a long-term US study published by The BMJ today.

Global rates of type 2 diabetes are set to rise to 700 million by 2045. Chocolate contains high levels of flavanols (a natural compound found in fruits and vegetables) which have been shown to promote heart health and reduce the risk of type 2 diabetes. But the link between chocolate consumption and risk of type 2 diabetes remains controversial due to inconsistent results.

In addition, most previous studies have not looked at whether eating dark and milk chocolate – which have different cocoa, milk and sugar content – might have different impacts on the risk of type 2 diabetes.

To explore this further, researchers combined data from three long-term US observational studies of female nurses and male healthcare professionals with no history of diabetes, heart disease or cancer when they were recruited.

Using food frequency questionnaires completed every four years, they analysed associations between type 2 diabetes and total chocolate consumption for 192,208 participants, and chocolate subtype (dark and milk) consumption for 111,654 participants over an average monitoring period of 25 years.

As changes in bodyweight strongly predict risks of type 2 diabetes, the authors also used these food questionnaires to assess participants’ total energy intake.

In the analyses for total chocolate, 18,862 people developed type 2 diabetes. After adjusting for personal, lifestyle, and dietary risk factors, the authors found that people who ate at least five servings a week of any type of chocolate (where one serving is equal to a standard chocolate bar/pack or 1 oz) showed a significant 10% lower rate of type 2 diabetes compared with those who rarely or never ate chocolate.

In analyses by chocolate subtypes, 4,771 people developed type 2 diabetes. After adjusting for the same risk factors, people who ate at least five servings a week of dark chocolate showed a significant 21% lower risk of type 2 diabetes, but no significant associations were found for milk chocolate intake.

The researchers also found a 3% reduced risk of type 2 diabetes for each additional weekly serving of dark chocolate (a dose-response effect). Increased consumption of milk, but not dark, chocolate was associated with long term weight gain.

Although dark chocolate has similar levels of energy and saturated fat to milk chocolate, the authors explain that the high levels of flavanols in dark chocolate might offset the effects of saturated fat and sugar on weight gain and the risk of other cardiometabolic diseases such as diabetes.

The authors acknowledge that the observational nature of this study prevents firm conclusions from being drawn about causality and, although they took account of lifestyle and dietary factors linked to type 2 diabetes, other unknown factors may have affected the results. Most participants were non-Hispanic older white adults, so the findings may not apply to other groups, they add.

However, they point out that results remained largely unchanged after adjusting for additional factors, suggesting that they are robust. 

As such, they conclude: “Increased consumption of dark, but not milk, chocolate was associated with lower risk of type 2 diabetes. Increased consumption of milk, but not dark, chocolate was associated with long term weight gain. Further randomized controlled trials are needed to replicate these findings and further explore the mechanisms.”

[Ends]

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Journal

The BMJ

DOI

10.1136/bmj-2023-078386 

Tiny, daily bursts of vigorous incidental physical activity could almost halve cardiovascular risk in middle-aged women

 

Four minutes of daily vigorous physical activity greatly reduces the risk of heart attacks and heart failure among middle-aged women

 

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Woman walking up stairs

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An average of four minutes of incidental vigorous physical activity a day could almost halve the risk of major cardiovascular events, such as heart attacks, for middle-aged women who do not engage in structured exercise, according to new research from the University of Sydney, published in the British Journal of Sports Medicine. 

“We found that a minimum of 1.5 minutes to an average of 4 minutes of daily vigorous physical activity, completed in short bursts lasting up to 1 minute, were associated with improved cardiovascular health outcomes in middle-aged women who do no structured exercise,” said lead author Professor Emmanuel Stamatakis, Director of the Mackenzie Wearable Hub at the Charles Perkins Centre and the Faculty of Medicine and Health. 

High-intensity physical activity that forms part of a daily routine is known as “vigorous intermittent lifestyle physical activity” (VILPA). Longer sessions of VILPA are linked to significantly lower cardiovascular disease risk. The researchers say that, given fewer than 20 percent of middle-aged or older adults engage in regular structured exercise, engaging in VILPA could be a good alternative.  

“Making short bursts of vigorous physical activity a lifestyle habit could be a promising option for women who are not keen on structured exercise or are unable to do it for any reason. As a starting point, it could be as simple as incorporating throughout the day a few minutes of activities like stair climbing, carrying shopping, uphill walking, playing tag with a child or pet, or either uphill or power walking,” said Professor Stamatakis. 

The study drew on data from 22,368 participants (13,018 women and 9,350 men) aged 40–79 who reported they did not engage in regular structured exercise. The data was collected from the UK Biobank, whose participants wore physical activity trackers for almost 24 hours a day for 7 days between 2013 and 2015. 

Cardiovascular health was monitored through hospital and mortality records, tracking major adverse cardiovascular events (MACE), such as heart attack, stroke, and heart failure, until November 2022. 

After adjusting for factors such as lifestyle, socioeconomic position, cardiovascular health, co-existing conditions, and ethnicity, the researchers found that the more VILPA women did, the lower their risk of a major cardiovascular event. Women who averaged 3.4 minutes of VILPA daily were 45 percent less likely to experience a major cardiovascular event. They were also 51 percent less likely to have a heart attack and 67 percent less likely to develop heart failure than women who did no VILPA. 

Even when amounts of daily VILPA were lower than 3.4 minutes they were still linked to lower cardiovascular event risk. A minimum of 1.2 to 1.6 minutes of VILPA per day was associated with a 30 percent lower risk of total major cardiovascular events, a 33 percent lower risk of heart attack, and a 40 percent lower risk of heart failure. 

However, men reaped fewer benefits from tiny bursts of VILPA. Those who averaged 5.6 minutes daily were only 16 percent less likely to experience a major cardiovascular event compared with men who did none. A minimum of 2.3 minutes per day was associated with only an 11 percent risk reduction. 

Professor Stamatakis said more testing was needed to understand how VILPA may improve cardiovascular health.  

“To date, it hasn’t been clear whether short bursts of VILPA lower the risk of specific types of cardiovascular events, like heart attack or stroke. We aimed to identify minimum daily thresholds and feasible amounts for testing in community programs and future trials,” he said. 

“Importantly, the beneficial associations we observed were in women who committed to short bursts of VILPA almost daily. This highlights the importance of habit formation, which is not always easy. VILPA should not be seen as a quick fix—there are no magic bullets for health. But our results show that even a little bit higher intensity activity can help and might be just the thing to help people develop a regular physical activity – or even exercise – habit,” he said. 

Research: Stamatakis, et al, Device-measured vigorous intermittent lifestyle physical activity (VILPA) and major adverse cardiovascular events: evidence of sex differences, British Journal of Sports Medicine. DOI: 10.1136/bjsports-2024-108484  

For the purposes of this story, physical activity is incidental, e.g. carrying shopping or briefly power walking, and exercise is structured, e.g. going to the gym or playing sport.

Higher ratio of plant protein to animal protein may improve heart health

 

Key points:

• In a 30-year study of American adults’ diets, those who consumed the highest ratio of plant-based protein to animal-based protein had a 19% lower risk of cardiovascular disease (CVD) and a 27% lower risk of coronary heart disease (CHD) compared to those who consumed the lowest ratio. 
• According to the researchers, the findings suggest that a 1:2 ratio of plant to animal protein is effective in preventing CVD—and that an even higher ratio (1:1.3) may be needed to protect against CHD. 
• While global dietary guidelines recommend higher intake of plant protein, the ideal ratio of plant to animal protein remains unknown. The study is the first to investigate this ratio and how it impacts health, specifically heart health.

Boston, MA—Eating a diet with a higher ratio of plant-based protein to animal-based protein may reduce the risk of cardiovascular disease (CVD) and coronary heart disease (CHD), according to a new study led by researchers at Harvard T.H. Chan School of Public Health. According to the researchers, these risk reductions are likely driven by the replacement of red and processed meats with plant proteins. The researchers also observed that a combination of consuming more plant protein and higher protein intake overall provided the most heart health benefits.

While global dietary guidelines recommend higher intake of plant protein, the ideal ratio of plant to animal protein has remained unknown. The study is the first to investigate this ratio and how it impacts health, specifically heart health.

“The average American eats a 1:3 plant to animal protein ratio. Our findings suggest a ratio of at least 1:2 is much more effective in preventing CVD. For CHD prevention, a ratio of 1:1.3 or higher should come from plants,” said lead author Andrea Glenn, visiting scientist in the Department of Nutrition. Glenn worked on the study as a postdoctoral fellow at Harvard Chan School and is now an assistant professor in the Department of Nutrition and Food Studies at New York University.

The study will be published Dec. 2 in the American Journal of Clinical Nutrition.

The researchers used 30 years of data on diet, lifestyle, and heart health among nearly 203,000 men and women enrolled in the Nurses’ Health Studies I and II and the Health Professionals’ Follow-up Study. Participants reported their dietary intake every four years. The researchers calculated each participant’s total protein intake, measured in grams per day, as well as their specific intakes of animal and plant proteins. Over the course of the study period, 16,118 CVD cases, including over 10,000 CHD cases and over 6,000 stroke cases, were documented.

After adjusting for participants’ health history and sociodemographic and lifestyle factors, the study found that eating a higher ratio of plant to animal protein was associated with lower risks of CVD and CHD. Compared to participants who consumed the lowest plant to animal protein ratio (~1:4.2), participants who consumed the highest (~1:1.3) had a 19% lower risk of CVD and a 27% lower risk of CHD. These risk reductions were even higher among participants who ate more protein overall. Those who consumed the most protein (21% of energy coming from protein) and adhered to a higher plant to animal protein ratio saw a 28% lower risk of CVD and a 36% lower risk of CHD, compared to those who consumed the least protein (16% of energy). No significant associations were found for stroke risk and the ratio; however, replacing red and processed meat in the diet with several plant sources, such as nuts, showed a lower risk of stroke.

The researchers also examined if there’s a point at which eating more plant protein stops having added benefits or could even have negative implications. They found that risk reduction for CVD begins to plateau around a 1:2 ratio, but that CHD risk continues to decrease at higher ratios of plant to animal protein.

According to the researchers, these risk reductions are likely driven by the replacement of red and processed meat with several plant protein sources, particularly nuts and legumes. Such replacements have been found to improve cardiometabolic risk factors, including blood lipids and blood pressure as well as inflammatory biomarkers. This is partly because plant proteins are often accompanied by high amounts of fiber, antioxidant vitamins, minerals, and healthy fats.

“Most of us need to begin shifting our diets toward plant-based proteins,” said senior author Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology at Harvard Chan School. “We can do so by cutting down on meat, especially red and processed meats, and eating more legumes and nuts. Such a dietary pattern is beneficial not just for human health but also the health of our planet.”

The researchers pointed out that the ratios they identified are estimates, and that further studies are needed to determine the optimal balance between plant and animal protein. Additionally, further research is needed to determine how stroke risk may be impacted by protein intake.