Exercise makes what's inside your gut healthier,

It turns out that exercise can do more than slim down your waistline and boost heart health. It might also make what's inside your gut healthier, according to a new study by San Francisco State University.

In this first-of-its-kind study, just published in the International Journal of Sport Nutrition and Exercise Metabolism, recent SF State graduate student Ryan Durk and Assistant Professor of Kinesiology Jimmy Bagley partnered with the SF State Health Equity Research (HER) Lab to test the relationship between gut health and cardiovascular fitness.

Durk (who received his master's degree in kinesiology last December) recruited 20 men and 17 women, mostly from the SF State campus, and tested their cardiovascular fitness on a treadmill. He also assessed their body composition in the lab's BOD POD, an air displacement chamber that determines a person's fat and fat-free mass. Participants kept food logs for seven days and provided stool samples at the end of the week. The HER Lab then extracted DNA to analyze the bacteria composition in the samples.

The researchers were investigating the ratio of bacteria called firmicutes to another group, bacteroides, which can be used to gauge overall gut health and composition.

Analysis showed that participants with the best cardiovascular fitness had a higher firmicutes to bacteroides ratio. While most gut bacteria can be beneficial (even bacteroides in some cases), firmicutes bacteria are associated with metabolic byproducts that help prevent bacteria in the gut from leaking into the body. "These metabolic byproducts help strengthen the intestinal lining and help prevent leaky gut syndrome," said Durk. He says this research reinforces the idea of "exercise as medicine."

"When we say that phrase, we think of it as meaning that exercise will help people stay healthier and live longer. But you don't think about your gut bacteria," Durk said. "We now know that exercise is crucial for increasing beneficial bacteria in the gut."

According to Durk, findings from this study and other studies about the gut microbiome could eventually be used to create individual exercise prescriptions to improve gut -- and overall -- health. "We're not there yet," he said, "but this helps create that foundation."

New research could banish guilty feeling for consuming whole dairy products

Enjoying full-fat milk, yogurt, cheese and butter is unlikely to send people to an early grave, according to new research by The University of Texas Health Science Center at Houston (UTHealth).
The study, published today in the American Journal of Clinical Nutrition, found no significant link between dairy fats and cause of death or, more specifically, heart disease and stroke - two of the country's biggest killers often associated with a diet high in saturated fat. In fact, certain types of dairy fat may help guard against having a severe stroke, the researchers reported.

"Our findings not only support, but also significantly strengthen, the growing body of evidence which suggests that dairy fat, contrary to popular belief, does not increase risk of heart disease or overall mortality in older adults. In addition to not contributing to death, the results suggest that one fatty acid present in dairy may lower risk of death from cardiovascular disease, particularly from stroke," said Marcia Otto, Ph.D., the study's first and corresponding author and assistant professor in the Department of Epidemiology, Human Genetics and Environmental Sciences at UTHealth School of Public Health.

Dariush Mozaffarian, M.D., of the Friedman School of Nutrition Science and Policy at Tufts University, was senior author of the study, funded by the National Institutes of Health.

The study evaluated how multiple biomarkers of fatty acid present in dairy fat related to heart disease and all-cause mortality over a 22-year period. This measurement methodology, as opposed to the more commonly used self-reported consumption, gave greater and more objective insight into the impact of long-term exposure to these fatty acids, according to the report.

Nearly 3,000 adults age 65 years and older were included in the study, which measured plasma levels of three different fatty acids found in dairy products at the beginning in 1992 and again at six and 13 years later.
None of the fatty acid types were significantly associated with total mortality. In fact one type was linked to lower cardiovascular disease deaths. People with higher fatty acid levels, suggesting higher consumption of whole-fat dairy products, had a 42 percent lower risk of dying from stroke.
The 2015-2020 Dietary Guidelines for Americans currently recommend serving fat-free or low-fat dairy, including milk, cheese, yogurt, and/or fortified soy beverages. But Otto pointed out that low-fat dairy foods such as low-fat yogurt and chocolate milk often include high amounts of added sugars, which may lead to poor cardiovascular and metabolic health.
"Consistent with previous findings, our results highlight the need to revisit current dietary guidance on whole fat dairy foods, which are rich sources of nutrients such as calcium and potassium. These are essential for health not only during childhood but throughout life, particularly also in later years when undernourishment and conditions like osteoporosis are more common," Otto said.
Evidence-based research is key to educating people about nutrition, Otto said.
"Consumers have been exposed to so much different and conflicting information about diet, particularly in relation to fats," she said. "It's therefore important to have robust studies, so people can make more balanced and informed choices based on scientific fact rather than hearsay," she added.

Health-promoting phenolic acids lost during food processing

In a Journal of Agricultural and Food Chemistry study, the research team made cornflakes from 19 corn genotypes varying in phenolic content. They wanted to know if higher ferulic acid and p-courmaric acid content in the corn kernel translated to higher concentrations of these phenolics in the final product.
"What we found was not particularly good news, but it was interesting. Regardless of the concentration in the grain at the beginning, the dry-milling process removes the majority of phenolics," says Carrie Butts-Wilmsmeyer, lead author of the two studies and research assistant professor in the Department of Crop Sciences at U of I.
The phenolic compounds in corn are primarily concentrated in the bran, or the outer covering of the corn kernel, which is removed in the first steps of the dry-milling process. The researchers wanted to determine if they could increase the remaining soluble phenolic content by heating the starchy leftovers during later processing stages. Although most of the phenolics in corn are bound to fiber, heat can release bound forms of the compounds and improve the antioxidant content of corn-based foods.
"We did see an increase in soluble phenolics, but it was so small, you could have gotten the same benefit from going to the refrigerator and eating a few blueberries," Butts-Wilmsmeyer says.
Despite the less-than-ideal outcome, the studies represent important steps forward for food science researchers and the food processing industry. First, the lab-bench-size process developed and demonstrated by the researchers in JoVE Video Journal allows testing of small batches of experimental corn lines.
"Before this project, the only published study on cornflake processing used a sample size of 45 kilograms. We worked with ag engineers to get it down to 100 grams, literally a 450th of the size," Butts-Wilmsmeyer says.
They found that the biggest changes in phenolic content were happening at three stages of the dry-milling process: whole kernel, flaking grit, and toasted cornflake.
"Since we now have the process miniaturized and can control everything in the lab, we can also start figuring out how we can change the process to recover more of these compounds in the end product," says Martin Bohn, co-author of the studies and associate professor in the Department of Crop Sciences at U of I.
Although the phenolics didn't make it to the final product, they weren't lost entirely.
"We have to focus on the bran and other 'waste' products," Bohn says. "Is it possible to extract these compounds and fortify the food with them? This is what I think is important. Our study showed that at the beginning, there's variability in corn hybrids for all these compounds but through processing, it's all leveled off, it's all gone. But they're still in the co-products, and I think we could actually recover them and add them to the end product."
Butts-Wilmsmeyer says fortifying processed foods with health-promoting, cancer-fighting phenolics could benefit people without easy access to fresh foods, such as Americans living in food deserts. "These itty-bitty compounds are tied to everything," she says.

Spending time outside is good for you

Living close to nature and spending time outside has significant and wide-ranging health benefits - according to new research.

A new report published today reveals that exposure to greenspace reduces the risk of type II diabetes, cardiovascular disease, premature death, preterm birth, stress, and high blood pressure.

Populations with higher levels of greenspace exposure are also more likely to report good overall health - according to global data involving more than 290 million people.

Lead author Caoimhe Twohig-Bennett, from UEA's Norwich Medical School, said: "Spending time in nature certainly makes us feel healthier, but until now the impact on our long-term wellbeing hasn't been fully understood.

"We gathered evidence from over 140 studies involving more than 290 million people to see whether nature really does provide a health boost."

The research team studied data from 20 countries including the UK, the US, Spain, France, Germany, Australia and Japan - where Shinrin yoku or 'forest bathing' is already a popular practice.

'Green space' was defined as open, undeveloped land with natural vegetation as well as urban greenspaces, which included urban parks and street greenery.

The team analysed how the health of people with little access to green spaces compared to that of people with the highest amounts of exposure.

"We found that spending time in, or living close to, natural green spaces is associated with diverse and significant health benefits. It reduces the risk of type II diabetes, cardiovascular disease, premature death, and preterm birth, and increases sleep duration.

"People living closer to nature also had reduced diastolic blood pressure, heart rate and stress. In fact, one of the really interesting things we found is that exposure to greenspace significantly reduces people's levels of salivary cortisol - a physiological marker of stress.

"This is really important because in the UK, 11.7 million working days are lost annually due to stress, depression or anxiety."

"Forest bathing is already really popular as a therapy in Japan - with participants spending time in the forest either sitting or lying down, or just walking around. Our study shows that perhaps they have the right idea!

"Although we have looked at a large body of research on the relationship between greenspace and health, we don't know exactly what it is that causes this relationship.

"People living near greenspace likely have more opportunities for physical activity and socialising. Meanwhile, exposure to a diverse variety of bacteria present in natural areas may also have benefits for the immune system and reduce inflammation.

"Much of the research from Japan suggests that phytoncides - organic compounds with antibacterial properties - released by trees could explain the health-boosting properties of forest bathing."

Study co-author Prof Andy Jones, also from UEA, said: "We often reach for medication when we're unwell but exposure to health-promoting environments is increasingly recognised as both preventing and helping treat disease. Our study shows that the size of these benefits can be enough to have a meaningful clinical impact."

The research team hope that their findings will prompt doctors and other healthcare professionals to recommend that patients spend more time in greenspace and natural areas.
Twohig-Bennett said: "We hope that this research will inspire people to get outside more and feel the health benefits for themselves. Hopefully our results will encourage policymakers and town planners to invest in the creation, regeneration, and maintenance of parks and greenspaces, particularly in urban residential areas and deprived communities that could benefit the most."
'The health benefits of the great outdoors: A systematic review and meta-analysis of greenspace exposure and health outcomes' is published in the journal Environmental Research on 6 July.

Savory foods may promote healthy eating through effects on the brain

Researchers have found that consuming a broth rich in umami--or savory taste--can cause subtle changes in the brain that promote healthy eating behaviors and food choices, especially in women at risk of obesity.

Umami is a Japanese word to express a delicious, savory meal, and it represents one of the five basic tastes, together with sweet, salty, bitter, and sour. A key component of umami taste is glutamate, a naturally occurring non-essential amino acid that can be found in nearly all foods, and especially in foods high in protein such as dairy products, fish, and meat.

Previous experimental studies have shown that intake of a broth or soup supplemented with monosodium glutamate (MSG), a sodium salt of glutamate, prior to a meal can decrease appetite and food intake, especially in women with a propensity to overeat and gain weight. In a study published March 30 in Neuropsychopharmacology, researchers evaluated changes in the brains of healthy young women after they consumed chicken broth with or without MSG added.

The investigators used three laboratory tools to detect changes: a computer test that measured inhibitory control (a key mental process that is necessary for self-regulation of eating), a buffet meal during which participants ate freely while wearing special glasses that tracked eye movements, and a functional brain scan that measured brain activity while participants made food choices.

Following intake of the umami-rich broth, participants performed the inhibitory control test better, had more focused gazes during the meal, and had more engagement of a brain area that is linked to successful self-regulation during food choice. Also, after consuming the umami-rich broth, those at higher risk of obesity consumed less saturated fat during the meal.

"Previous research in humans studied the effects of umami broths on appetite, which is typically assessed with subjective measures. Here, we extended these findings replicating the beneficial effects of umami on healthy eating in women at higher risk of obesity, and we used new laboratory measures that are sensitive and objective," said senior author Miguel Alonso-Alonso, MD, PhD, an Assistant Professor at the Center for the Study of Nutrition Medicine in BIDMC's Department of Surgery, BIDMC. He also noted that much research has examined the effects of sugar and sweetness on the brain, but the study of savory taste has been limited.

The results may open new ways to facilitate healthy eating and reduce food intake in the general population. "Many cultures around the world advocate drinking a broth before a meal. Our study suggests the possibility that people at high risk of obesity could benefit from an umami-rich broth before a meal to facilitate healthy eating and healthy food choice," said Alonso-Alonso. "However, here we only evaluated immediate effects and in a laboratory context. Future research should address whether these observed changes can accumulate and affect food intake over time and/or whether they can be leveraged to help people lose weight more successfully."

Feeling young could mean your brain is aging more slowly

While everyone gets older, not everyone feels their age. A recent study finds that such feelings, called subjective age, may reflect brain aging. Using MRI brain scans, researchers found that elderly people who feel younger than their age show fewer signs of brain aging, compared with those who feel their age or older than their age. Published in open-access journal Frontiers in Aging Neuroscience, this study is the first to find a link between subjective age and brain aging. The results suggest that elderly people who feel older than their age should consider caring for their brain health.
We tend to think of aging as a fixed process, where our bodies and minds change steadily. However, the passing years affect everyone differently. How old we feel, which is called our subjective age, also varies between people -- with many feeling older or younger than their actual age.
But is subjective age just a feeling or attitude, or does it reflect how our bodies are actually aging? This question intrigued Dr Jeanyung Chey of Seoul National University in Korea.
"Why do some people feel younger or older than their real age?" asks Chey. "Some possibilities include depressive states, personality differences or physical health. However, no-one had investigated brain aging processes as a possible reason for differences in subjective age."
People frequently experience some cognitive impairment as they age. In fact, the brain shows a variety of age-related changes that are reflective of declining neural health, including reductions in gray matter volumes. Recently developed techniques can help researchers to identify brain features associated with aging, to provide an estimated brain age.
Chey and her colleagues applied these techniques to investigate the link between subjective age and brain aging. They performed MRI brain scans in 68 healthy people whose ages ranged from 59-84 years and looked at gray matter volumes in various brain regions. The participants also completed a survey, which included questions on whether they felt older or younger than their age and questions assessing their cognitive abilities and perceptions of their overall health.
People who felt younger than their age were more likely to score higher on a memory test, considered their health to be better and were less likely to report depressive symptoms. Critically, those who felt younger than their age showed increased gray matter volume in key brain regions. The researchers used the MRI data to calculate estimated brain ages for the participants.
"We found that people who feel younger have the structural characteristics of a younger brain," said Chey. "Importantly, this difference remains robust even when other possible factors, including personality, subjective health, depressive symptoms, or cognitive functions, are accounted for."
The researchers hypothesize that those who feel older may be able to sense the aging process in their brain, as their loss of gray matter may make cognitive tasks more challenging.
However, at present the researchers do not know for sure if these brain characteristics are directly responsible for subjective age and will need to carry out long-term studies to understand this link further.
One intriguing possibility is that those who feel younger are more likely to lead a more physically and mentally active life, which could cause improvements in brain health. However, for those who feel older, the opposite could be true.
"If somebody feels older than their age, it could be sign for them to evaluate their lifestyle, habits and activities that could contribute to brain aging and take measures to better care for their brain health," said Chey.
The research is part of a special article collection on assessment of brain aging across the lifespan.

Expecting a stressful day may lower cognitive abilities throughout the day

There may be some truth to the saying "getting up on the wrong side of the bed," according to Penn State researchers who say starting your morning by focusing on how stressful your day will be may be harmful to your mindset throughout the day.
The researchers found that when participants woke up feeling like the day ahead would be stressful, their working memory -- which helps people learn and retain information even when they're distracted -- was lower later in the day. Anticipating something stressful had a great effect on working memory regardless of actual stressful events.
Jinshil Hyun, a doctoral student in human development and family studies, said the findings suggest that the stress process begins long before a stressful event occurs.
"Humans can think about and anticipate things before they happen, which can help us prepare for and even prevent certain events," Hyun said. "But this study suggests that this ability can also be harmful to your daily memory function, independent of whether the stressful events actually happen or not."
Martin Sliwinski, director of Penn State's Center for Healthy Aging, said working memory can affect many aspects of a person's day, and lower working memory can have a negative impact on individuals' daily lives, especially among older adults who already experience cognitive decline.
"A reduced working memory can make you more likely to make a mistake at work or maybe less able to focus," Sliwinski said. "Also, looking at this research in the context of healthy aging, there are certain high stakes cognitive errors that older adults can make. Taking the wrong pill or making a mistake while driving can all have catastrophic impacts."
While previous research has examined how stressful events can affect emotion, cognition and physiology, not as much has been done on the effects of anticipating stressful events that haven't yet happened in the context of everyday life.
The researchers recruited 240 racially and economically diverse adults to participate in the study. For two weeks, the participants responded seven times a day to questions prompted from a smartphone app: once in the morning about whether they expected their day to be stressful, five times throughout the day about current stress levels, and once at night about whether they expected the following day to be stressful. The participants also completed a working memory task five times a day.
Hyun said that while laboratory studies have the benefit of controlling the participants' experience during the study, the use of smartphones to collect data as the participants went about their daily lives had benefits, as well.
"Having the participants log their stress and cognition as they went about their day let us get a snapshot of how these processes work in the context of real, everyday life," Hyun said. "We were able to gather data throughout the day over a longer period of time, instead of just a few points in time in a lab."
The researchers found that more stress anticipation in the morning was associated with poorer working memory later in the day. Stress anticipation from the previous evening was not associated with poorer working memory.
Sliwinski said the findings -- recently published in the Journals of Gerontology: Psychological Sciences -- show the importance of a person's mindset first thing in the morning, before anything stressful has happened yet.
"When you wake up in the morning with a certain outlook for the day, in some sense the die is already cast," Sliwinski said. "If you think your day is going to be stressful, you're going to feel those effects even if nothing stressful ends up happening. That hadn't really been shown in the research until now, and it shows the impact of how we think about the world."
The researchers said the results open the door for possible interventions that can help people predict when their cognition may not be optimal.
"If you wake up and feel like the day is going to be stressful, maybe your phone can remind you to do some deep breathing relaxation before you start your day," Sliwinski said. "Or if your cognition is at a place where you might make a mistake, maybe you can get a message that says now might not be the best time to go for a drive."
Sliwinski said they're working on additional studies that will use wearable sensors to gather even more in-depth data on the effect of stress on participants' physiological states. Hyun added that she's also interested in future studies that can help uncover possible psychological or biological mechanisms behind how stress affects cognition.