5-minute workout lowers blood pressure as much as exercise, drugs

'Strength training for breathing muscles' holds promise for host of health benefits

UNIVERSITY OF COLORADO AT BOULDER

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IMAGE: TOM HEINBOCKEL, A MASTERS STUDENT IN THE INTEGRATIVE PHYSIOLOGY DEPARTMENT AT THE UNIVERSITY OF COLORADO BOULDER, DEMONSTRATES USING A POWER BREATHE DEVICE. view more 

CREDIT: (PHOTO BY CASEY A. CASS/UNIVERSITY OF COLORADO)

Working out just five minutes daily via a practice described as "strength training for your breathing muscles" lowers blood pressure and improves some measures of vascular health as well as, or even more than, aerobic exercise or medication, new CU Boulder research shows.

The study, published June 29 in the Journal of the American Heart Association, provides the strongest evidence yet that the ultra-time-efficient maneuver known as High-Resistance Inspiratory Muscle Strength Training (IMST) could play a key role in helping aging adults fend off cardiovascular disease - the nation's leading killer.

In the United States alone, 65% of adults over age 50 have above-normal blood pressure - putting them at greater risk of heart attack or stroke. Yet fewer than 40% meet recommended aerobic exercise guidelines.

"There are a lot of lifestyle strategies that we know can help people maintain cardiovascular health as they age. But the reality is, they take a lot of time and effort and can be expensive and hard for some people to access," said lead author Daniel Craighead, an assistant research professor in the Department of Integrative Physiology. "IMST can be done in five minutes in your own home while you watch TV."

Developed in the 1980s as a way to help critically ill respiratory disease patients strengthen their diaphragm and other inspiratory (breathing) muscles, IMST involves inhaling vigorously through a hand-held device which provides resistance. Imagine sucking hard through a tube that sucks back.

Initially, when prescribing it for breathing disorders, doctors recommended a 30-minute-per-day regimen at low resistance. But in recent years, Craighead and colleagues have been testing whether a more time-efficient protocol--30 inhalations per day at high resistance, six days per week--could also reap cardiovascular, cognitive and sports performance improvements.

For the new study, they recruited 36 otherwise healthy adults ages 50 to 79 with above normal systolic blood pressure (120 millimeters of mercury or higher). Half did High-Resistance IMST for six weeks and half did a placebo protocol in which the resistance was much lower.

After six weeks, the IMST group saw their systolic blood pressure (the top number) dip nine points on average, a reduction which generally exceeds that achieved by walking 30 minutes a day five days a week. That decline is also equal to the effects of some blood pressure-lowering drug regimens.

Even six weeks after they quit doing IMST, the IMST group maintained most of that improvement.

"We found that not only is it more time-efficient than traditional exercise programs, the benefits may be longer lasting," Craighead said.

The treatment group also saw a 45% improvement in vascular endothelial function, or the ability for arteries to expand upon stimulation, and a significant increase in levels of nitric oxide, a molecule key for dilating arteries and preventing plaque buildup. Nitric oxide levels naturally decline with age.

Markers of inflammation and oxidative stress, which can also boost heart attack risk, were significantly lower after people did IMST.

And, remarkably, those in the IMST group completed 95% of the sessions.

"We have identified a novel form of therapy that lowers blood pressure without giving people pharmacological compounds and with much higher adherence than aerobic exercise," said senior author Doug Seals, a Distinguished Professor of Integrative Physiology. "That's noteworthy."

The practice may be particularly helpful for postmenopausal women.

In previous research, Seals' lab showed that postmenopausal women who are not taking supplemental estrogen don't reap as much benefit from aerobic exercise programs as men do when it comes to vascular endothelial function. IMST, the new study showed, improved it just as much in these women as in men.

"If aerobic exercise won't improve this key measure of cardiovascular health for postmenopausal women, they need another lifestyle intervention that will," said Craighead. "This could be it."

Preliminary results suggest MST also improved some measures of brain function and physical fitness. And previous studies from other researchers have shown it can be useful for improving sports performance.

"If you're running a marathon, your respiratory muscles get tired and begin to steal blood from your skeletal muscles," said Craighead, who uses IMST in his own marathon training. "The idea is that if you build up endurance of those respiratory muscles, that won't happen and your legs won't get as fatigued."

Seals said they're uncertain exactly how a maneuver to strengthen breathing muscles ends up lowering blood pressure, but they suspect it prompts the cells lining blood vessels to produce more nitric oxide, enabling them to relax.

The National Institutes of Health recently awarded Seals $4 million to launch a larger follow-up study of about 100 people, comparing a 12-week IMST protocol head-to-head with an aerobic exercise program.

Meanwhile, the research group is developing a smartphone app to enable people to do the protocol at home using already commercially available devices.

Those considering IMST should consult with their doctor first. But thus far, IMST has proven remarkably safe, they said.

"It's easy to do, it doesn't take long, and we think it has a lot of potential to help a lot of people," said Craighead.

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The Southern diet - fried foods and sugary drinks - may raise risk of sudden cardiac death

Journal of the American Heart Association Report

AMERICAN HEART ASSOCIATION

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DALLAS, June 30, 2021 -- Regularly eating a Southern-style diet may increase the risk of sudden cardiac death, while routinely consuming a Mediterranean diet may reduce that risk, according to new research published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

The Southern diet is characterized by added fats, fried foods, eggs, organ meats (such as liver or giblets), processed meats (such as deli meat, bacon and hotdogs) and sugar-sweetened beverages. The Mediterranean diet is high in fruits, vegetables, fish, whole grains and legumes and low in meat and dairy.

"While this study was observational in nature, the results suggest that diet may be a modifiable risk factor for sudden cardiac death, and, therefore, diet is a risk factor that we have some control over," said James M. Shikany, Dr.P.H., F.A.H.A., the study's lead author and professor of medicine and associate director for research in the Division of Preventive Medicine at the University of Alabama at Birmingham.

"Improving one's diet - by eating a diet abundant in fruits, vegetables, whole grains and fish such as the Mediterranean diet and low in fried foods, organ meats and processed meats, characteristics of the Southern-style dietary pattern, may decrease one's risk for sudden cardiac death," he said.

The study examined data from more than 21,000 people ages 45 and older enrolled in an ongoing national research project called REasons for Geographic and Racial Differences in Stroke (REGARDS), which is examining geographic and racial differences in stroke. Participants were recruited between 2003 and 2007. Of the participants in this analysis, 56% were women; 33% were Black adults; and 56% lived in the southeastern U.S., which is noteworthy as a region recognized as the Stroke Belt because of its higher stroke death rate. The Stroke Belt states included in this study were North Carolina, South Carolina, Georgia, Tennessee, Alabama, Mississippi, Arkansas and Louisiana.

This study is the latest research to investigate the association between cardiovascular disease and diet - which foods have a positive vs. negative impact on cardiovascular disease risk. It may be the only study to-date to examine the association between dietary patterns with the risk of sudden cardiac death, which is the abrupt loss of heart function that leads to death within an hour of symptom onset. Sudden cardiac death is a common cause of death and accounted for 1 in every 7.5 deaths in the United States in 2016, or nearly 367,000 deaths, according to 2019 American Heart Association statistics.

Researchers included participants with and without a history of coronary heart disease at the beginning of the study and assessed diets through a food frequency questionnaire completed at the beginning of the study. Participants were asked how often and in what quantities they had consumed 110 different food items in the previous year.

Researchers calculated a Mediterranean diet score based on specific food groups considered beneficial or detrimental to health. They also derived five dietary patterns. Along with the Southern-style eating pattern, the analysis included a "sweets" dietary pattern, which features foods with added sugars, such as desserts, chocolate, candy and sweetened breakfast foods; a "convenience" eating pattern which relied on easy-to-make foods like mixed dishes, pasta dishes, or items likely to be ordered as take-out such as pizza, Mexican food and Chinese food; a "plant-based" dietary pattern was classified as being high in vegetables, fruits, fruit juices, cereal, bean, fish, poultry and yogurt; and an "alcohol and salad" dietary pattern, which was highly reliant on beer, wine, liquor along with green leafy vegetables, tomatoes and salad dressing.

Shikany noted that the patterns are not mutually exclusive. "All participants had some level of adherence to each pattern, but usually adhered more to some patterns and less to others," he explained. "For example, it would not be unusual for an individual who adheres highly to the Southern pattern to also adhere to the plant-based pattern, but to a much lower degree."

After an average of nearly 10 years of follow-up every six months to check for cardiovascular disease events, more than 400 sudden cardiac deaths had occurred among the 21,000 study participants.

The study found:

Overall, participants who ate a Southern-style diet most regularly had a 46% higher risk of sudden cardiac death than people who had the least adherence to this dietary pattern. Also, participants who most closely followed the traditional Mediterranean diet had a 26% lower risk of sudden cardiac death than those with the least adherence to this eating style. The American Heart Association's Diet and Lifestyle recommendations emphasize eating vegetables, fruits, whole grains, lean protein, fish, beans, legumes, nuts and non-tropical vegetable cooking oils such as olive and canola oil. Limiting saturated fats, sodium, added sugar and processed meat are also recommended. Sugary drinks are the number one source of added sugar in the U.S. diet, according to the Centers for Disease Control and Prevention, and the American Heart Association supports sugary drink taxes to drive down consumption of these products.

"These findings support the notion that a healthier diet would prevent fatal cardiovascular disease and should encourage all of us to adopt a healthier diet as part of our lifestyles," said Stephen Juraschek, M.D., Ph.D., a member of the American Heart Association's Nutrition Committee of the Lifestyle and Cardiometabolic Health Council. "To the extent that they can, people should evaluate the number of servings of fruit and vegetables they consume each day and try to increase the number to at least 5-6 servings per day, as recommended by the American Heart Association. Optimal would be 8-9 servings per day.

"This study also raises important points about health equity, food security and social determinants of health," he continued. "The authors describe the "Southern Diet" based on the U.S. geography associated with this dietary pattern, yet it would be a mistake for us to assume that this is a diet of choice. I think American society needs to look more broadly at why this type of diet is more common in the South and clusters among some racial, ethnic or socioeconomic groups to devise interventions that can improve diet quality. The gap in healthy eating between people with means and those without continues to grow in the U.S., and there is an incredible need to understand the complex societal factors that have led and continue to perpetuate these disparities."

This current research expands on earlier studies on participants from the same national stroke project, REGARDS. In a 2018 analysis, Shikany and colleagues reported that adults ages 45 and older with heart disease who had an affinity for the Southern diet had a higher risk of death from any cause, while greater adherence to the Mediterranean diet was associated with a lower risk of death from any cause. And in a 2015 study, the Southern diet was linked to a greater risk of coronary heart disease in the same population.

The large population sample and regional diversity, including a significant number of Black participants, are considered strengths of the REGARDS research project. However, potential limitations of this study include that that dietary intake was based on one-time, self-reported questionnaires, thus, it relied on the participants' memory. Self-reported diet can include inaccuracies leading to bias that could reduce the strength of the associations observed.

One usual association that remains unexplained is that among individuals with a history of heart disease, those who most adhered to the sweets dietary pattern had a 51% lower risk of sudden cardiac death than participants who followed that pattern the least. Researchers note that they found "no viable explanation for the inverse association of the sweets dietary pattern with risk of sudden cardiac death in those with a history of coronary heart disease."

Organic food intake in childhood = better cognitive development

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Analysis of multiple prenatal and childhood environmental risk factors suggests that poor nutrition, house crowding and indoor air pollution are associated with poorer cognitive function

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A study analysing the association between a wide variety of prenatal and childhood exposures and neuropsychological development in school-age children has found that organic food intake is associated with better scores on tests of fluid intelligence (ability to solve novel reasoning problems) and working memory (ability of the brain to retain new information while it is needed in the short term). The study, published in Environmental Pollution, was conceived and designed by researchers at the Barcelona Institute for Global Health (ISGlobal)--a centre supported by the "la Caixa" Foundation--and the Pere Virgili Health Research Institute (IISPV-CERCA).

The explanation for this association may be that "healthy diets, including organic diets, are richer than fast food diets in nutrients necessary for the brain, such as fatty acids, vitamins and antioxidants, which together may enhance cognitive function in childhood," commented lead author Jordi Júlvez, a researcher at IISPV-CERCA who works closely with ISGlobal.

The study also found that fast food intake, house crowding and environmental tobacco smoke during childhood were associated with lower fluid intelligence scores. In addition, exposure to fine particulate matter (PM2.5) indoors was associated with lower working memory scores.

The study, titled "Early life multiple exposures and child cognitive function: A multi-centric birth cohort study in six European countries", used data on 1,298 children aged 6-11 years from six European country-specific birth cohorts (United Kingdom, France, Spain, Greece, Lithuania and Norway). The researchers looked at 87 environmental factors the children were exposed to in utero (air pollution, traffic, noise, various chemicals and lifestyle factors) and another 122 factors they were exposed to during childhood.

A Pioneering Study

The aim of the study was to analyse the influence of these exposures on the development and maturation of the human brain, since during childhood the brain is not yet fully developed for efficient defence against environmental chemicals and is particularly sensitive to toxicity, even at low levels that do not necessarily pose a risk to a healthy mature brain.

The originality of the study lies in its use of an exposome approach, i.e. the fact that it takes into account the totality of exposures rather than focusing on a single one. This approach aims to achieve a better understanding of the complexity of multiple environmental exposures and their simultaneous effect on children's neurodevelopment.

Another strength of the study, which analyses cohorts from six European countries, is its diversity, although this factor also poses the additional challenge of cultural differences, which can influence exposure levels and cognitive outcomes.

Notable Associations

The study found that the main determinants of fluid intelligence and working memory in children are organic diet, fast food diet, crowdedness of the family home, indoor air pollution and tobacco smoke. To date, there has been little research on the relationship between type of diet and cognitive function, but fast food intake has been associated with lower academic development success and some studies have also reported positive associations between organic diets and executive function scores. "In our study," explained Júlvez, "we found better scores in fluid intelligence and working memory with higher organic food intake and lower fast food intake."

In contrast, exposure to tobacco smoke and indoor PM2.5 during childhood may negatively affect cognitive function by enhancing pro-inflammatory reactions in the brain. Still, according to Júlvez, it is worth bearing in mind that "the number of people living together in a home is often an indicator of the family's economic status, and that contexts of poverty favour less healthy lifestyles, which in turn may affect children's cognitive test scores".

Some Surprising Findings

The study also found some unexpected associations, which could be explained by confounding and reverse causality. For example, a positive association was found between childhood exposure to perfluorooctane sulfonic acid (PFOS) and cognitive function, even though PFOS is considered an endocrine disruptor that may alter thyroid function and negatively influence cognitive development.

The study forms part of the large European project Human Early-Life Exposome (HELIX), as does another recent paper that used the same exposome and the same participants but looked at symptoms of attention deficit hyperactivity disorder (ADHD) and childhood behavioural problems. "We observed that several prenatal environmental pollutants (indoor air pollution and tobacco smoke) and lifestyle habits during childhood (diet, sleep and family social capital) were associated with behavioural problems in children," explained Martine Vrijheid, last author of the study and head of ISGlobal's Childhood and Environment programme.

"One of the strengths of this study on cognition and the earlier study on behavioural problems is that we systematically analysed a much wider range of exposure biomarkers in blood and urine to determine the internal levels in the model and that we analysed both prenatal and childhood exposure variables," concluded Vrijheid.

Eating prunes daily improves risk factors for heart disease and inflammation

CALIFORNIA PRUNE BOARD

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New research published in the Journal of Medicinal Food suggests eating prunes each day can improve risk factors for cardiovascular disease (CVD) including raising antioxidant capacity and reducing inflammation among healthy, postmenopausal women.

Cardiovascular disease is the number one cause of death worldwide posing a significant public health challenge.

The research led by San Diego State University reveals that prunes can positively affect heart disease risk.

"When you look at our prior research and the research of others combined with this new data, you'll see consistent evidence that eating prunes can promote health," said lead researcher Shirin Hooshmand, Ph.D., RD, Professor at the School of Exercise and Nutritional Sciences at San Diego State University.

In this randomized, controlled study, researchers found that eating 50 grams of prunes (about 5-6 prunes) each day for just 6 months resulted in improved CVD risk biomarkers - including raising the body's "good" cholesterol, known as HDL, and lowering the ratio of total cholesterol to HDL.

Eating prunes daily also promoted higher antioxidant capacity and lowered levels of the inflammatory cytokines interleukin-6 and tumor necrosis factor-alpha associated with CVD risk. Notably, body mass index and weight of the study participants were maintained during the trial despite adding prunes to the usual diet.

Researchers recruited 48 healthy, postmenopausal women who were divided into three groups - a control group who ate no prunes, and two treatment groups who consumed either 50 grams or 100 grams of prunes daily, throughout the six-month study. All other aspects of the women's diets and lifestyles remained similar to before the study. Various biomarkers of CVD risk were collected at the beginning and conclusion of the study to determine if there were any improvements in those biomarkers among those who consumed prunes. Interestingly, there were some similar positive results among those who ate 50 grams of prunes and those consuming 100 grams - suggesting that adding 5-6 prunes or more into the daily diet may have a positive effect on CVD risk.

"Reducing chronic inflammation and increasing antioxidant capacity in the body is associated with lower risk of CVD, along with many other diseases," said Mark Kern, Ph.D., RD, CSSD, Professor of Nutrition at the School of Exercise and Nutritional Sciences at San Diego State University. "Not only does this study show that prunes may be a good way to reduce inflammation and increase antioxidant capacity, it also suggests that eating prunes every day may improve cholesterol levels in postmenopausal women."

While the precise mechanisms and specific compounds that contribute to these beneficial effects have yet to be determined, naturally occurring antioxidant-powered phenolic compounds, fiber and other nutrients are thought to play a role. This study demonstrates that prunes may be a promising and convenient addition to the diet to reduce CVD risk and inflammation, while also improving antioxidant capacity.

The study adds to a growing body of evidence about the overall health and nutrition benefits of prunes, including bone health. Previous clinical research demonstrates a favorable bone response to prunes among postmenopausal women. Most recently, researchers reported that total bone mineral density increased in a postmenopausal woman with osteopenia after she consumed 50 grams of prunes daily for 16 months. This case study was published in the Bone Reports in May of this year.

Running to music combats mental fatigue a study suggests

 

Listening to music while running might be the key to improving people's performance when they feel mentally fatigued a study suggests

UNIVERSITY OF EDINBURGH

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Listening to music while running might be the key to improving people's performance when they feel mentally fatigued a study suggests.

The performance of runners who listened to a self-selected playlist after completing a demanding thinking task was at the same level as when they were not mentally fatigued, the research found.

The study is the first to investigate the effect of listening to music playlists on endurance running capacity and performance when mentally fatigued.

Researchers at the University of Edinburgh used two tests to study how listening to music affected the running performance of eighteen fitness enthusiasts.

One test looked at the effects on interval running capacity - alternating between high intensity running and lower intensity jogging - with a group of nine physically active exercisers, and the other on a 5km time-trial with a group of nine trained runners.

The groups completed a 30 minute computer based cognitive test which put them in a mentally fatigued state before completing high intensity exercise. The runners were tested with and without self-selected motivational music.

Researchers assisted participants in choosing motivational songs with a pre-test questionnaire asking them to rate the rhythm, style, melody, tempo, sound and beat of the music.

Examples of songs participants listened to were: Everyday by A$ap Rocky; Addicted To You by Avicii; Run This Town by Jay-Z; Power by Kanye West; No One Knows by Queens of the Stone Age; and Eye of the Tiger by Survivor.

During the exercise, heart rate and rating of perceived exertion were measured at multiple points.

The team took into account the results of a baseline test taken by participants which was without a mentally demanding test beforehand - and without the use of music.

The researchers found the interval running capacity among the mentally fatigued fitness enthusiasts was moderately greater with music compared to without music, and was the same as when the participants were not mentally fatigued.

The 5km time-trial performances also showed small improvements with self-selected music versus no music.

Researchers say the positive effects of music could potentially be due to altered perception of effort when listening to tunes.

Dr Shaun Phillips, of the University of Edinburgh's Moray House School of Education and Sport, said: "Mental fatigue is a common occurrence for many of us, and can negatively impact many of our day-to-day activities, including exercise. Finding safe and effective ways to reduce this negative impact is therefore useful.

"The findings indicate that listening to self-selected motivational music may be a useful strategy to help active people improve their endurance running capacity and performance when mentally fatigued. This positive impact of self-selected music could help people to better maintain the quality and beneficial impact of their exercise sessions."

Researchers say there are opportunities for further study into how listening to music while running affects larger and different groups of people, in different settings, and using different exercise challenges. Work in these areas is ongoing at the University of Edinburgh.

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The study is published in the Journal of Human Sport and Exercise.

Switching from Western diet to a balanced diet may reduce skin, joint inflammation

Foods high in sugar and fat disrupt the gut and trigger psoriasis flares

UNIVERSITY OF CALIFORNIA - DAVIS HEALTH

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(SACRAMENTO, Calif.) -- The secret to healthier skin and joints may reside in gut microorganisms. A study led by UC Davis Health researchers has found that a diet rich in sugar and fat leads to an imbalance in the gut's microbial culture and may contribute to inflammatory skin diseases such as psoriasis.

The study, published in the Journal of Investigative Dermatology, suggests that switching to a more balanced diet restores the gut's health and suppresses skin inflammation.

"Earlier studies have shown that Western diet, characterized by its high sugar and fat content, can lead to significant skin inflammation and psoriasis flares," said Sam T. Hwang, professor and chair of dermatology at UC Davis Health and senior author on the study. "Despite having powerful anti-inflammatory drugs for the skin condition, our study indicates that simple changes in diet may also have significant effects on psoriasis."

What is psoriasis?

Psoriasis is a stubborn skin condition linked to the body's immune system. When immune cells mistakenly attack healthy skin cells, they cause skin inflammation and the formation of scales and itchy red patches.

Up to 30% of patients with psoriasis also have psoriatic arthritis with symptoms such as morning stiffness and fatigue, swollen fingers and toes, pain in joints and changes to nails.

Diet affects the microbial balance in the intestines and skin inflammation

Food is one of the major modifiable factors regulating the gut microbiota, the community of microorganisms living in the intestines. Eating a Western diet can cause rapid change to the gut's microbial community and its functions. This disruption in microbial balance - known as dysbiosis- contributes to gut inflammation.

Since bacteria in the gut may play key roles in shaping inflammation, the researchers wanted to test whether intestinal dysbiosis affects skin and joint inflammation. They used a mouse model to study the effect of diet on psoriasis and psoriatic arthritis. They injected mice with Interleukin-23 (IL-23) minicircle DNA to induce a response mimicking psoriasis-like skin and joint diseases.

IL-23 is a protein generated by the immune cells responsible for many inflammatory autoimmune reactions, including psoriasis and inflammatory bowel disease (IBD).

Hwang and his colleagues found that a short-term Western diet appears sufficient to cause microbial imbalance and to enhance susceptibility to IL-23?mediated psoriasis-like skin inflammation.

"There is a clear link between skin inflammation and changes in the gut microbiome due to food intake," Hwang said. "The bacterial balance in the gut disrupted shortly after starting a Western diet, and worsened psoriatic skin and joint inflammation."

One critical finding of their work was identifying the intestinal microbiota as a pathogenic link between diet and the displays of psoriatic inflammation. The study also found that antibiotics block the effects of the Western diet, reducing skin and joint inflammation.

Is the damage caused by an unhealthy diet reversible?

The researchers wanted to test if switching to a balanced diet can restore the gut microbiota, despite the presence of IL-23 inflammatory proteins. They fed mice a Western diet for six weeks before giving them an IL-23-inducing agent to trigger psoriasis and psoriatic arthritis features. Then, they randomly divided the mice into two groups: a group that continued the Western diet for another four weeks and a group that switched to a balanced diet for the same duration.

Their study showed that eating a diet high in sugar and fat for 10 weeks predisposed mice to skin and joint inflammation. Mice that were switched to a balanced diet had less scaling of the skin and reduced ear thickness than mice on a Western diet. The improvement in skin inflammation for mice taken off the Western diet indicates a short-term impact of the Western diet on skin inflammation.

This suggests that changes in diet could partially reverse the proinflammatory effects and alteration of gut microbiota caused by the Western diet.

"It was quite surprising that a simple diet modification of less sugar and fat may have significant effects on psoriasis," said Zhenrui Shi, visiting assistant researcher in the UC Davis Department of Dermatology and lead author on the study. "These findings reveal that patients with psoriatic skin and joint disease should consider changing to a healthier dietary pattern."

"This work reflects a successful collaboration among researchers, especially with Professor Satya Dandekar and her team at the Department of Medical Microbiology and Immunology and Professor Yu-Jui Yvonne Wan at the Department of Medical Pathology and Laboratory Medicine," Hwang said.

Not all dietary proteins are created equal

New study published in the Journal of Nutrition concluded that 'ounce equivalents' of animal- and plant-based protein-rich foods may not be metabolically equivalent after all

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Dietary protein is needed to supply essential amino acids for the synthesis of the structural and functional components of living cells. Thus, food protein quantity and quality are both essential for good health. The 2020-2025 Dietary Guidelines for Americans (DGAs) published an "ounce equivalents" recommendation to help consumers meet protein requirements with a variety of protein food sources. For example, the DGAs present a variety of "ounce equivalents" in the protein food groups stating that 1 ounce of meat is equivalent to 1 cooked egg, ¼ cup of red kidney beans, 1 tablespoon of peanut butter, 2 ounces of tofu, and ½ ounce of mixed nuts. However, the DGAs do not currently address the issue of differences in protein quality associated with varied food sources. In general, animal proteins have higher protein digestibility and a better essential amino acid profile relative to dietary requirements. These measures of protein quality indicate that animal proteins can more readily provide the daily requirement of essential amino acids than plant protein.

A new manuscript recently published in The Journal of Nutrition investigated the physiological response to various ounce equivalents of protein food sources and found that the consumption of ounce equivalents of animal-based protein food sources resulted in greater gain in whole-body net protein balance above baseline than the ounce equivalents of plant-based protein food sources. (1) Robert Wolfe (University of Arkansas for Medical Sciences) and colleagues randomly assigned 56 young healthy adult participants to one of seven food intervention groups: 2 ounces of cooked beef sirloin, 2 ounces of cooked pork loin, 2 cooked eggs, ½ cup of red kidney beans, 2 tablespoons of peanut butter, 4 ounces of tofu, or 1 ounce of mixed nuts. Prior to the onset of the study, participants followed a 3-day dietary weight maintenance. Participants' net whole-body protein balance was assessed using a stable isotope tracer infusion protocol. The changes from baseline following consumption of the different protein food sources were compared with the baseline value for that individual.

Overall, investigators found that animal-based protein food sources elicited greater anabolic responses than plant-based protein food sources. Whole body protein balance increased more in the beef, pork, and eggs groups than all of the groups consuming plant-based protein food sources. Protein synthesis increased more in the beef group than in the groups consuming plant protein foods, kidney beans, peanut butter, or mixed nuts, while the egg and pork groups suppressed protein breakdown more compared with mixed nuts. The magnitude of the whole-body net balance response was correlated with the essential amino acid content of the protein food source. The researchers concluded that "ounce equivalents" of protein food sources as expressed in the DGAs are not metabolically equivalent in terms of either the anabolic response or caloric value and this should be considered as the DGAs develop approaches to establish healthy eating patterns.

"Our research illustrates that animal-based protein foods, such as beef, eggs and pork, and plant-based protein foods, such as kidney beans, peanut butter, tofu and mixed nuts, cannot be considered to be equivalent, or a substitute for each other, when developing healthy dietary patterns, given their unique physiological effects," said lead researcher Robert Wolfe, PhD, Director, Center for Translational Research in Aging and Longevity, and Professor of Geriatrics, University of Arkansas for Medical Sciences. "While it's well-established that animal proteins can more readily provide essential amino acids than plant protein foods, our study also indicates that eating animal protein foods such as beef, pork and eggs may lead to increased protein synthesis, which has been shown to have benefits such as improved satiety and lean muscle mass maintenance."

A corresponding editorial by Glenda Courtney-Martin (University of Toronto) stresses the importance and timely contribution of this study, which could guide future decisions regarding how protein foods can be better categorized by the DGAs. (2)

 

Review shows minimal, high-quality evidence dietary supplements lead to weight loss

THE OBESITY SOCIETY

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Although Americans spend billions on them, published research shows a lack of strong evidence that dietary supplements and alternative therapies help adults lose weight, according to a new study published in Obesity, the flagship journal of The Obesity Society (TOS).

There are hundreds of weight-loss supplements like green tea extract, chitosan, guar gum and conjugated linoleic acid, and an estimated 34% of Americans who are trying to lose weight have used one.

For the study, researchers completed a comprehensive review of 315 existing clinical trials of weight loss supplements and therapies, and most of the studies showed the supplements did not produce weight loss among users.

"Our findings are important for clinicians, researchers, and industry alike as they suggest the need for rigorous evaluation of products for weight loss," said corresponding author John Batsis, MD, associate professor in the Division of Geriatric Medicine at the University of North Carolina (UNC) School of Medicine, and in the Department of Nutrition at the UNC Gillings School of Global Public Health. "Only then can we produce data that allows clinicians to provide input and advice with a higher degree of certainty to our patients."

The evaluation should also be collaborative as the supplement industry and academics work together to design high-quality clinical trials of weight loss supplements, Batsis added.

The paper's authors explain that patients often struggle to lose or maintain weight either because of a lack of efficacy of existing Federal Drug Administration (FDA)-approved therapies or a lack of access to healthcare professionals who provide treatments for obesity.

Even though the National Institutes of Health's Office of Dietary Supplements has advanced the science of dietary supplements by evaluating information, and stimulating and supporting research, members of TOS decided it was important to evaluate and perform a qualitative synthesis of non-FDA therapies to provide scientific evidence to guide its membership.

Researchers conducted a systematic literature review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged 18 and older. Searches of Medline (Pubmed), Cochrane Library, Web of Science, CINAHL and Embase (Ovid) were performed.

Researchers focused on 315 peer-reviewed randomized-controlled trials and analyzed them for risk of bias. Results classified 52 studies as low risk of bias and sufficient to support efficacy. Of these, 16 studies demonstrated significant pre/post intergroup differences in weight compared with placebos. In these methodologically distinct studies, the weight loss ranged widely from 0.3 to 4.93 kg.

In a perspective written by members of TOS's Clinical Committee led by Srividya Kidambi, MD, MS, Division of Endocrinology and Molecular Medicine, Medical College of Wisconsin in Milwaukee who also co-authored the paper, members recommend to clinicians to consider the lack of evidence of non-FDA-approved dietary supplements and therapies and guide their patients toward tested weight-management approaches. "Public and private entities should provide adequate resources for obesity management. We call on regulatory authorities to critically examine the dietary supplement industry, including their role in promoting misleading claims and marketing products that have the potential to harm patients," the authors write in the paper.

The paper, titled "A Systematic Review of Dietary Supplements and Alternative Therapies for Weight Loss", will be published in the July 2021 print issue. A perspective titled "Dietary Supplements and Alternative Therapies for Obesity: A Perspective from The Obesity Society's Clinical Committee" will accompany the paper

Starchy snacks may increase CVD risk; fruits and veggies at certain meals decreases risk

 

Journal of the American Heart Association report

AMERICAN HEART ASSOCIATION

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DALLAS, June 23, 2021 —Can starchy snacks harm heart health? New research published today in the Journal of the American Heart Association, an open access journal of the American Heart Association, found eating starchy snacks high in white potato or other starches after any meal was associated at least a 50% increased risk of mortality and a 44-57% increased risk of CVD-related death. Conversely, eating fruits, vegetables or dairy at specific meals is associated with a reduced risk of death from cardiovascular disease, cancer or any cause.  

“People are increasingly concerned about what they eat as well as when they eat,” said Ying Li, Ph.D., lead study author and professor in the department of nutrition and food hygiene at Harbin Medical University School of Public Health in Harbin, China. “Our team sought to better understand the effects different foods have when consumed at certain meals.”

Li and colleagues analyzed the results of 21,503 participants in the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2014 in the U.S. to assess dietary patterns across all meals. Among the study population, 51% of participants were women and all participants were ages 30 or older at the start of the study. To determine patient outcomes, researchers used the U.S. Centers for Disease Control and Prevention’s National Death Index to note participants who died through December 31, 2015, due to CVD, cancer or any cause.

Researchers categorized participants’ dietary patterns by analyzing what types of food they ate at different meals. For the main meals, three main dietary patterns were identified for the morning meal: Western breakfast, starchy breakfast and fruit breakfast. Western lunch, vegetable lunch and fruit lunch were identified as the main dietary patterns for the mid-day meal. Western dinner, vegetable dinner and fruit dinner were identified as the main dietary patterns for the evening meal.

For snacks, grain snack, starchy snack, fruit snack and dairy snack were identified as the main snack patterns in between meals. Additionally, participants who did not fit into specific meal patterns were analyzed as a reference group. The researchers noted that the Western dietary pattern has higher proportions of fat and protein, which is similar to many North American meals.

Participants in the Western lunch group consumed the most servings of refined grain, solid fats, cheese, added sugars and cured meat. Participants in the fruit-based lunch group consumed the most servings of whole grain, fruits, yogurt and nuts. Participants in the vegetable-based dinner group consumed the most servings of dark vegetables, red and orange vegetables, tomatoes, other vegetables and legumes. Participants who consumed starchy snacks consumed the most servings of white potatoes.

According to their findings:

• Eating a Western lunch (typically containing refined grains, cheese, cured meat) was associated with a 44% increased risk of CVD death;
• Eating a fruit-based lunch was associated with a 34% reduced risk of CVD death;
• Eating a vegetable-based dinner was associated with a 23% and 31% reduction in CVD and all-cause mortality, respectively; and
• Consuming a snack high in starch after any meal was associated with a 50-52% increased risk of all-cause mortality and a 44-57% increased risk in CVD-related mortality.

“Our results revealed that the amount and the intake time of various types of foods are equally critical for maintaining optimal health,” said Li. “Future nutrition guidelines and interventional strategies could integrate optimal consumption times for foods across the day.”

Limitations to this study include that dietary data was self-reported by participants, which may lead to recall bias. And, although the researchers controlled for potential confounders, other unmeasured confounding factors cannot be ruled out.