Tag: nutrition

Fermented Soy Products Found to Reduce Asthma Inflammation

A bowl of tofu, a fermented soy food. Photo by Polina Tankilevitch from Pexels

Fermented soy products are common in the Japanese diet, and one brand known as ImmuBalance has been found to suppress airway inflammation in animal models of asthma.

Bronchial asthma causes symptoms such as wheezing and cough due to chronic airway inflammation, but there is no fundamental treatment for it, leaving a desire for new prevention and treatment methods. Osaka University researchers found that in a ImmuBalance-treated group of asthma model mice, eosinophils associated with asthma were significantly reduced in the bronchoalveolar lavage fluid (BALF). As well as a decrease in inflammation and mucus around the bronchi, the team observed a suppression of proteins that induce eosinophilic inflammation.

“The relationship between soy intake and allergic diseases has been epidemiologically reported in the past,” explained first author Hideaki Kadotani, “suggesting that the components of soy may have some anti-allergic effects”

“It was reported that imbalances in the gut microbiota may be involved in immune system and allergic diseases, and fermented dietary fiber, like that found in soy, might have beneficial effects in allergic asthma models.” continues Associate Professor Kazuhisa Asai, supporting author of the study.

In the study, which appears in the journal Nutrients, such a gut imbalance’s effect on asthma were examined by giving ImmuBalance-enriched feed to asthma model mice. In the ImmuBalance-treated group, there was a significant drop in the number of eosinophils in BALF, and inflammation around the bronchi and mucus production in the bronchial epithelium was suppressed. Additionally, the expression of Th2 cytokines and the immunoglobulin serum IgE that induce eosinophilic inflammation in BALF were found to be significantly suppressed.

“In clinical practice, steroid inhalants are the basis of asthma treatments, yet they are known to have adverse side effects“, stated lead advisor to the study, Professor Tomoya Kawaguchi. “Our results suggest that the intake of fermented soybean products should be recommended as a complementary coping strategy to asthma with fewer side effects”

Source: Osaka University

Scientists Discover a New Sense for Sugars

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In a study published in PLOS ONE, scientists report the identification of a new human sensory ability to detect sugars in the mouth with a kind of a molecular ‘calorie detector’. It could help explain why artificially sweetened beverages just don’t have the same appeal as ones containing sugar.

“Our mouth can identify when a sweetener has the potential to deliver calories versus a non-caloric sweetener, which cannot,” said first author Paul Breslin, PhD, a Monell investigator and a professor of Nutritional Sciences at Rutgers University.

The paper describes the first-in-human demonstration of a signaling pathway that uses the sugar glucose, a component of table sugar and high fructose corn syrup, to signal the presence of calories, in addition to the well-studied sweet-taste receptor in taste buds. Glucose is present in many foods, and has been consumed by humans in the form of honey, fruit and other sugar-rich foods.

“Humans love fruit and sugar, as do many other apes, which obtain most of their calories from sugar,” said Prof Breslin.

Recent findings from Monell showed taste bud cells in mice could identify when a sweetener has calories to burn, which prompted the researchers to see whether the ability to sense glucose in the human mouth may also involve this additional pathway. The team wanted to know if the calorie detector is functional, and if it could affect our responses to dietary sugar.

“Now that we know this calorie-detecting taste system is operating in humans, it could help explain the overall preference for sugared beverages over non-caloric sweetener beverages,” said Prof Breslin.

In a series of three human-taste experiments, the team compared oral glucose sensitivity to the ability to sense the artificial sweetener sucralose and to a special form of glucose that cannot be metabolised. “Overall, there are two sweet-sensing pathways in the mouth: one for sweet taste, and another for detecting potential energy-burning sugars,” said coauthor Linda J. Flammer, PhD, a senior research associate at Monell.

The fact that diet fizzy drinks never captured a major share of the beverage market always puzzled Prof Breslin, but he now has a hint: “Diet drinks are not as satisfying as sugared beverages. As a public health initiative, might we get beverages and foods with lower sugar levels to be more rewarding? Now that we know there is this second glucose-sensing system in the mouth, maybe we can tap into it to make healthier beverages that people enjoy drinking.”

Sugar calories are sensed in the gut and blood after swallowing, but this study shows that sugars are identified as different from non-caloric sweeteners in the mouth. “It is remarkable that we evolved a mechanism not only to taste oral sugars as sweet, but also to sense that they have a metabolic or caloric signal,” said Breslin. “This means that the mouth is much smarter than we realised and that it will be difficult to trick it by simply providing non-caloric sweeteners.”

Source: Monell Chemical Senses Center

Moderate Carbohydrate Intake Helps CVD Health in Women

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In a surprise finding, Monash University researchers have reported that proportional carbohydrate intake and not saturated fat was significantly associated with cardiovascular disease benefit in Australian women.

Cardiovascular disease (CVD) is the leading cause of death in women. Poor diet is recognised as both an independent CVD risk factor and a contributor to other CVD risk factors, such as obesity, diabetes mellitus (DM), hypertension, and dyslipidaemia.

In middle-aged Australian women, it was found that increasing the percentage of carbohydrate intake was linked to reduced risks of CVD, hypertension, diabetes mellitus, and obesity.

Furthermore, a moderate carbohydrate intake between 41.0–44.3% of total energy intake was associated with the lowest risk of CVD, compared to women who consumed less than 37% energy as carbohydrates. However, no significant relationship was demonstrated between proportional carbohydrate intake and all-cause mortality.

Furthermore, increasing proportional saturated fat intake was not associated with cardiovascular disease or mortality in women; rather, increasing saturated fat intake correlated with lower odds of developing diabetes mellitus, hypertension, and obesity.

The findings are now published in the British Medical Journal.

The results contradict much of the historical epidemiological research that supported a link between saturated fat and CVD. Instead, the results mirror contemporary meta-analysis of prospective cohort studies where saturated fat was found to have no significant relationship with total mortality or CVD.

Historical studies neglected to adjust for fibre, which is known to help prevent plaque from forming in the arteries, which may explain this discrepancy with older literature.

“Controversy still exists surrounding the best diet to prevent CVD,” said Sarah Zaman, an associate professor at the University of Sydney.

“A low-fat diet has historically been the mainstay of primary prevention guidelines, but the major issue within our dietary guidelines is that many dietary trials have predominately involved male participants or lacked sex-specific analyses.”

She added: “Further research is needed to tailor our dietary guidelines according to sex.”

First author Sarah Gribbin, a Doctor of Medicine and BMedSc (Hons) student, said: “As an observational study, our findings only show association and not causation. Our research is purely hypothesis-generating. We are hoping that our findings will spark future research into sex-specific dietary research.”

Source: Monash University

Added Salt Found to Suppress Tumours in Mice

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new study has found that adding salt to the diet of lab mice can suppress the growth of cancerous tumours.

Dietary salt reduction has been stressed by clinicians for many years, as research has shown that a high-sodium diet can result in inflammation, high blood pressure and an increased heart attack risk. Researchers from the Translational Health Science and Technology Institute wondered if the inflammation resulting from a high-salt diet could also confer positive health benefits, such as fighting cancerous tumours. 

To find out, the researchers fed two groups of mice with implanted melanoma tumours either a normal diet or a high-sodium diet (4.0% sodium chloride above normal diet) and then measured the differences in tumour suppression abilities between the two groups. They found that the mice on the high-sodium diet had an increase in Bifidobacterium probiotics, leading to an increase in natural killer cells that attack cancerous tumors. They also found an increased ability to inhibit PD-1 proteins which have been found to prevent T cells from attacking tumours.

On close examination, it was found that the high-sodium diet caused the gut barrier to be leakier, enabling the movement of Bifidobacteria from the gut to tumour locations. In addition, they found that once the Bifidobacteria arrived at a tumour, crosstalk between them and the immune cells engaged in attacking the tumour improved the success of the attack.

However, the researchers also found that a low-sodium diet worked in conjunction with several cancer-fighting drugs, showing an increased ability to reduce tumour growth. Since the researchers hypothesised that Bifidobacteria were responsible for the tumour immunity of a high-sodium diet, they performed faecal transplants from mice on a high-sodium diet to those on a normal diet and found that it also improved their ability to fight tumour growth.

The study was published in Science Advances.

Source: MedicalXpress

Fruit and Vegetable Consumption Directly Increases Happiness

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Fruit and vegetable consumption and exercise can directly increase levels of self-reported happiness, according to findings from a new study.

Public health campaigns encourage healthier diets and exercise by virtue of the well-studied link between lifestyle and wellbeing, and will benefit from new findings published by the Journal of Happiness Studies showing that there is also a positive causation from lifestyle to life satisfaction.

This research is the first to identify the causation of happiness, the consumption of fruit and vegetables and exercising are related, rather than generalising a correlation. The researchers, Dr Adelina Gschwandtner (Kent’s School of Economics), Dr Sarah Jewell and Professor Uma Kambhampati (both from the University of Reading’s School of Economics), used an instrumental variable approach to filter out any effect from happiness to lifestyle. This approach revealed that it is the effect of fruit and vegetables and exercising that makes people happy and not the other way round.

The findings show individuals’ ability to delay gratification and apply self-control plays a major role in influencing lifestyle decisions, which in turn has a positive impact on wellbeing. The research also shows that men appear to exercise more, and women eat more fruit and vegetables.

Dr Gschwandtner said: ‘Behavioural nudges that help the planning self to reinforce long-term objectives are likely to be especially helpful in maintaining a healthy lifestyle. If a better lifestyle not only makes us healthier but also happier, then it is a clear win-win situation.’

Professor Kambhampati said: ‘There has been a bigger shift in recent years for healthier lifestyle choices. To establish that eating more fruit and vegetables and exercising can increase happiness as well as offer health benefits is a major development. This may also prove useful for policy campaigns around environment and sustainability.’

Source: University of Kent

Surprising Finding Links Asthma Risk to Meat Consumption as Infants

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Researchers looking for post-breastfeeding dietary patterns in two prospective birth cohorts, were surprised to discover meat consumption as a predictive factor.

Alexander Hose, MA, MPH, of Ludwig Maximilian University in Munich presented the study’s findings at the virtual European Respiratory Society annual meeting

After switching from breast milk, babies up to age 1 whose protein intake came largely from meat products, rather than dairy, fish, or egg proteins, had a more than eight-fold greater chance of developing asthma by age 6 versus non-meat protein consumption. Asthma prevalence reached 30% in some subgroups.

Wheezing was more common in this diet pattern, which Hose and colleagues termed “unbalanced meat consumption” (UMC); this continued up to age 10, with a five times higher odds.

The duration of breastfeeding was an important factor, likely because switching to baby foods prolonged the exposure. Odds of developing asthma by age 6 increased nearly 12-fold in UMC-fed infants whose breastfeeding stopped by week 19, versus about four-fold in those continuing longer on breast milk.

In addition, UMC was also linked to a certain intestinal microbiome profile featuring unusually high levels of Lactococcus, Granulicatella, and Acinetobacter species.

This type of microbiome scavenges iron in the gut, Hose said, which could explain why the children became especially susceptible to asthma. Additionally, milk proteins may exert an opposite effect on asthma risk by generating a type of “nutritional immunity.”

While the mechanism connecting the gut microbiome to respiratory disease is unknown, the existence of a ‘gut-lung axis‘ is well established; a recent trial showed that probiotics can prevent coughs and wheezing in older adults. The phenomenon has also been considered for COVID’s gastrointestinal symptoms.

A pair of European birth cohort studies, PASTURE and LUKAS2, provided the data for the study. In these, about 1400 infants were followed through age 10 and parents kept detailed records of their infants’ feeding, and other environmental factors, and children’s medical records were accessed as well.

However, a key limitation is the cohorts being from rural areas since investigating asthma’s relationship to animal exposure was a key goal for the studies. Partly because of this, Hose and colleagues were able to separate out ‘industrial’ meat, milk, and yoghurt from that produced at home. A trend toward greater asthma risk was observed with store-bought protein products.

Source: MedPage Today

Healthy Diets Reduce COVID Risk

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A study based on self-reported app data showed that people who eat a high quality, gut friendly diet are less likely to develop COVID-19 or become severely ill. Those eating poorer quality diets are more at risk, especially if they live in a more socioeconomically deprived area.

The study, presented in GUT, analysed data from almost 600 000 ZOE COVID Study app contributors. Participants completed a survey about the food they ate before the pandemic, in February 2020, making it the largest study in this space. 19% of these contributors contracted COVID-19.

People with the highest quality diet were around 10% less likely to develop COVID than those with the lowest quality diet, and 40% less likely to fall severely ill.

This is the first longitudinal study of diet and COVID and the first to show that a healthy diet cuts the chances of developing the disease in the first place.

Instead of looking at specific foods, the survey aimed to broadly capture people’s diets. A ‘diet quality score’ reflected the overall merit of each person’s diet. Diets with high quality scores were found to contain plant-based foods such as fruits, vegetables and whole grains, as well as oily fish, less processed foods and refined carbohydrates. A low diet quality score is associated with diets high in ultra processed foods and low amounts of plant based foods.

The researchers found that people who ate the highest quality diet were around 10% less likely to develop COVID-19 than those with the least nutritious diet and 40% less likely to become severely ill if they developed COVID.

The link between diet quality and COVID risk persisted after accounting for all potential confounding factors such as age and BMI. Mask-wearing habits and population density were also considered.

The effect of diet was amplified by individual life situations, with people living in low-income neighbourhoods with the lowest quality diet being around 25% more at risk from COVID than people in more affluent communities eating the same kind of diet.

Based on these results, the researchers estimate that nearly a quarter of COVID cases could have been prevented if these differences in diet quality and socioeconomic status had not existed. The study also showed that improved access to better food is an important public health consideration.

Dr Sarah Berry, study co-lead and Reader in nutritional sciences at the School of Life Course Sciences said: “For the first time we’ve been able to show that a healthier diet can cut the chances of developing COVID, especially for people living in the more deprived areas. Access to healthier food is important to everyone in society, but our findings tell us that helping those living in more deprived areas to eat more healthily could have the biggest public health benefits.”

Professor Tim Spector, professor of genetic epidemiology at the School of Life Course Sciences, said: “These findings chime with recent results from our landmark PREDICT study, showing that people who eat higher quality diets (with low levels of ultra-processed foods) have a healthier collection of microbes in their guts, which is linked to better health. You don’t have to go vegan, but getting more diverse plants on your plate is a great way to boost the health of your gut microbiome, improve your immunity and overall health, and potentially reduce your risk from COVID.”

Source: Kings College London

Supermarket Layout Change Encourages Healthy Food Purchases

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A study into food purchasing behaviours shows that placing fruit and vegetables near store entrances and removing confectionery and other unhealthy products from checkouts and the end of nearby aisles prompts customers to make healthier food purchases.

The study, led by Dr Christina Vogel, Principal Research Fellow in Public Health Nutrition and Janis Baird, Professor of Public Health and Epidemiology at the University’s MRC Lifecourse Epidemiology Centre, was conducted in partnership with the national supermarket chain Iceland Foods Ltd. The trial took place in a number of Iceland stores in England, monitoring store sales as well as dietary patterns of sample customers.

The results showed confectionery sales decreased throughout the store while fruit and vegetable sales increased when non-food items and water were placed at checkouts and at the end of the opposite aisles, and an expanded fruit and vegetable section was repositioned near the store entrance. Beneficial effects were also observed for household fruit and vegetable purchasing and individual dietary quality. The findings are presented in the open-access journal PLOS Medicine.

Discussing the results of the study Dr Vogel said “Altering the layouts of supermarkets could help people make healthier food choices and shift population diet towards the government’s dietary recommendations. The findings of our study suggest that a healthier store layout could lead to nearly 10 000 extra portions of fruit and vegetables and approximately 1500 fewer portions of confectionery being sold on a weekly basis in each store.”

This research is more comprehensive than previous studies testing whether placement strategies can promote healthier food purchasing which have been limited in scope, for example including only a single location (ie at checkouts) or placing healthy and unhealthy products together. This study further aimed to reduce exposure of customers to calorie opportunities by placing non-food items at checkout and aisle-ends opposite and measuring effects on store sales, purchasing patterns on customer loyalty cards and the diets of more than one household member.

Matt Downes, Head of Format Development at Iceland, said:   “We have been pleased to support this long-term study and the evaluation of how product placement in supermarkets can affect the diets of our customers. We know that childhood obesity is a growing issue and the retail industry has its part to play in tackling this. We hope that the outcomes of the study provide insights for the wider retail industry and policy makers about the impact of store merchandising on purchasing decisions.”

Prof Baird added “These results provide novel evidence to suggest that the intended UK government ban on prominent placement of unhealthy foods across retail outlets could be beneficial for population diet, and that effects may be further enhanced if requirements for a produce section near supermarket entrances were incorporated into the regulation.”

Source: University of Southampton

Body Clock Disruption on High-fat Diet Leads to Obesity

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According to a new study, when rats are fed a high fat diet, this disturbs the body clock in their brain that normally controls satiety, leading to over-eating and obesity. 

This new research, published in the Journal of Physiology, may be a cornerstone for future clinical studies that could restore the proper functioning of the body clock in the brain, to avoid overeating.

It was believed that the body clock resided only in the hypothalamus, but research over the years has clarified that some control of our body’s daily rhythms (hormone levels, appetite etc) lies in several other parts of the brain and body, including a group of neurons in the evolutionary ancient brainstem, called the dorsal vagal complex (DVC).

Specifically, the DVC has been shown to moderate food intake by inducing satiety. In obesity, research has shown that daily rhythms in food intake and the release of hormones related to eating, are blunted or eliminated. It is unclear if the malfunctioning of brain centres controlling appetite is a cause or the result of obesity.

This new study found that rats on a high-fat diet, before they started to gain weight, showed changes in the DVC’s daily neuronal rhythms and its response to appetite hormones. Thus, the researchers proposed that DVC disruption causes obesity.

Two groups of rats were used: those fed a well-balanced control diet (10% kcal from fat) and a high-fat diet (70% kcal from fat). To mimic the impact of unhealthy diet on humans, the researchers introduced the new diet to adolescent rats and monitored their food intake over 24h for four weeks.

Using multi-electrode arrays, the researchers measured DVC changes over 24h, simultaneously monitoring around a hundred DVC neurons from each brainstem slice. With this, circadian changes of neuronal activity could be assessed as well as neuronal responses to metabolically-relevant hormones in each of the diet groups.

Rats being nocturnal animals is a limitation of the study. The DVC activity peaked at the end of day, the rest phase for rodents, but an active phase for humans. Thus, it remains to be established if the phase of the brainstem clock is set to day and night, or whether it depends on patterns of rest and activity. These findings however could lead to understanding how to reset the body clock and tackle obesity.

First author Dr Lukasz Chrobok said:

“I’m really excited about this research because of the possibilities it opens up to tackle the growing health issue of obesity. We still do not know what are the time cues which are able to reset or synchronise the brainstem clock. Hopefully, the restoration of daily rhythms in this satiety centre before or after the onset of obesity may provide new therapeutic opportunities.”

Source: The Physiological Society

GPs Should Aim for Diabetes Remission Through Weight Loss

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A large-scale review of clinical evidence concluded that achieving ‘remission’ for people with type 2 diabetes through dietary approaches and weight loss should be the primary treatment goal of GPs and healthcare practitioners.

Corresponding author Dr Duane Mellor at Aston University said: “Accounting for all the evidence, our review suggests remission should be discussed as a primary treatment goal with people living with type 2 diabetes. There are multiple dietary approaches that have been shown to bring about T2DM remission though at present meal replacements offer the best quality evidence. Low carbohydrate diets have been shown to be highly effective and should also be considered as a dietary approach for remission.”

Lead author, Dr Adrian Brown, UCL Division of Medicine said: “Traditionally T2DM has focussed on managing a person’s blood glucose with medication, however the approach doesn’t address the underlying causes of T2DM. There is now a growing body of research that shows losing significant weight, 10-15kg, either through weight loss surgery or dietary approaches, can bring about type 2 diabetes remission (non-diabetic blood sugar levels).”

Expert reviewers analysed over 90 research papers covering international clinical trials and clinical practice data of dietary methods used to treat T2DM. Their findings were published in the Journal of Human Nutrition & Dietetics.

The study found that meal-replacement diets helped 36% people successfully achieve remission, while low carbohydrate diets were able to help 17.6 % of people achieve and maintain remission for at least two years. People who lost the most weight and kept the weight off using both of these dietary approaches were able to stay in remission.

Calorie restricted and Mediterranean diets were somewhat less effective, with only about 5% of people on calorie restricted diets and 15% of people on a Mediterranean diet staying in remission after one year.

There were multiple definitions of ‘remission’: one is a return to non-diabetic blood sugar levels (glycated haemoglobin less than 48mmol/mol), without diabetes drugs. Other definitions however say weight (especially fat around the midsection) must be lost to achieve remission, and others allow medication to be used.

Some reports also suggested low-carbohydrate diets can normalise blood sugar levels even without weight loss, since carbohydrates cause blood sugar levels to rise. A low-carbohydrate diet means reduced blood sugar, leading to improved blood sugar control. However, if weight is lost without blood glucose being non-diabetic, the authors are suggesting this should instead be called mitigation, as the underlying mechanisms of T2DM are not being addressed.

Dr Brown said: “The evidence is clear that the main driver of remission remains the degree of weight loss a person achieved. Therefore, for those not achieving weight loss but achieving a non-diabetic blood glucose we are suggesting this isn’t remission per se, but rather ‘mitigation’ of their diabetes.”

The review concluded that while weight loss seems to best predict remission success, it assumes fat loss from the pancreas and liver. Future studies should compare how these diets work for different ethnic groups, as T2DM can occur at different body weights in different ethnic groups.

Dr Mellor added: “Not everyone will be able to achieve remission, but people who are younger (less than 50), male, have had type 2 diabetes for less than six years and lose more weight are more likely to be successful.”

Source: Ashton University