Tag: dietary fibre

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A ‘Non-industrialised’ Style Diet can Reduce Risk of Chronic Disease

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Photo by Charlotte Karlsen on Unsplash

Researchers have found that a newly developed diet inspired by the eating habits of non-industrialised societies can significantly reduce the risk of a number of chronic diseases typical of processed, low-fibre industrialised diets – and are to share recipes with the public.

Their paper, published in Cell, shows that a newly developed diet that mimics eating habits in non-industrialised communities led to significant metabolic and immunological improvements in a human intervention study. In just three weeks the diet:

  • Promoted weight loss
  • Decreased bad cholesterol by 17%
  • Reduced blood sugar by 6%
  • Reduced C-reactive Protein (a marker of inflammation and heart disease) by 14%

These improvements were linked to beneficial changes in the participants’ gut microbiome, the home to trillions of bacteria that play a vital role in our health, influencing digestion, immunity, and metabolism. The research was conducted by an international teams of scientists led by Professor Jens Walter, a leading scientist at University College Cork. The human trial was performed at the University of Alberta in Canada, Prof Walter’s previous institution.

“Industrialisation has drastically impacted our gut microbiome, likely increasing the risk of chronic diseases.” explained Prof Walter, who is also a Principal Investigator at APC Microbiome Ireland, a world-renowned Research Ireland centre

“To counter this, we developed a diet that mimics traditional, non-industrialised dietary habits and is compatible with our understanding on diet-microbiome interactions. In a strictly controlled human trial, participants followed this diet and consumed L. reuteri, a beneficial bacterium prevalent in the gut of Papua New Guineans but rarely found in the industrialised microbiomes.”

The study demonstrated that the new diet entitled NiMeTM (Non-industrialised Microbiome Restore) diet enhanced short-term persistence of L. reuteri in the gut.

However it also improved microbiome features damaged by industrialisation, such as reducing pro-inflammatory bacteria and bacterial genes that degrade the mucus layer in the gut. These changes were linked to improvements in cardiometabolic markers of chronic disease risk.

Although participants did not consume fewer calories on the NiMe diet, they lost weight, and the diet alone led to considerable cardiometabolic benefits.

In previous research, Prof Walter’s team, studying the gut microbiome in rural Papua New Guinea, found that individuals there have a much more diverse microbiome, enriched in bacteria that thrive from dietary fibre, and with lower levels of pro-inflammatory bacteria linked to western diet. This information was used to design the NiMeTM diet.

The NiMeTM diet shares key characteristics of non-industrialised diets:

  • Plant-based focus, but not vegetarian: Primarily made up of vegetables, legumes, and other whole-plant foods. One small serving of animal protein per day (salmon, chicken, or pork).
  • No dairy, beef, or wheat: Excluded simply because they are not part of the traditional foods consumed by rural Papua New Guineans.
  • Very low in processed foods that are high in sugar and saturated fat.
  • Fibre-rich: Fibre content was 22 grams per 1000 calories – exceeding current dietary recommendations.

“Everybody knows that diet influences health, but many underestimate the magnitude”, said Prof. Walter.

Commenting on this study, Prof. Paul Ross, Director of APC Microbiome Ireland, said: “This study shows that we can target the gut microbiome through specific diets to improve health and reduce disease risk. These findings could shape future dietary guidelines and inspire the development of new food products and ingredients, as well as therapeutics, which target the microbiome”.

“The recipes from the NiMe Diet will be posted to our Instagram ( @nimediet ) and Facebook pages, and they will also be included in an online cookbook soon. It is important to us to make these recipes freely available so that everyone can enjoy them and improve their health by feeding their gut microbiome,” said Dr Anissa Armet from the University of Alberta, a registered dietitian that designed the NiMe diet and one of the lead authors of the publication.

Source: University College Cork

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More Protein and Fibre While Dropping Calories is Key for Weight Loss

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Photo by Andres Ayrton on Pexels

Participants on a self-directed dietary education program who had the greatest success at losing weight across a 25-month period consumed greater amounts of protein and fibre, found a study published in Obesity Science and Practice. Personalisation and flexibility also were key in creating plans that dieters could adhere to over time. 

At the one-year mark, successful dieters (41% of participants) had lost 12.9% of their body weight, compared with the remainder of the study sample, who lost slightly more than 2% of their starting weight. 

The dieters were participants in the Individualised Diet Improvement Program, which uses data visualisation tools and intensive dietary education sessions to increase dieters’ knowledge of key nutrients, enabling them to create a personalised, safe and effective weight-loss plan, said Manabu T. Nakamura, a professor of nutrition at the University of Illinois Urbana-Champaign and the leader of the research.

“Flexibility and personalisation are key in creating programs that optimise dieters’ success at losing weight and keeping it off,” Nakamura said. “Sustainable dietary change, which varies from person to person, must be achieved to maintain a healthy weight. The iDip approach allows participants to experiment with various dietary iterations, and the knowledge and skills they develop while losing weight serve as the foundation for sustainable maintenance.”

The pillars of iDip are increasing protein and fibre consumption along with consuming 1500 calories or less daily. 

Based on the dietary guidelines issued by the Institutes of Medicine, the iDip team created a one-of-a-kind, two-dimensional quantitative data visualisation tool that plots foods’ protein and fibre densities per calorie and provides a target range for each meal. Starting with foods they habitually ate, the dieters created an individualised plan, increasing their protein intake to about 80g and their fibre intake to about 20g daily.

In tracking the participants’ eating habits and their weights with Wi-Fi enabled scales, the team found strong inverse correlations between the percentages of fibre and protein eaten and dieters’ weight loss.    

“The research strongly suggests that increasing protein and fibre intake while simultaneously reducing calories is required to optimise the safety and efficacy of weight loss diets,” said first author and U. of I. alumna Mindy H. Lee, a then-graduate student and registered dietitian-nutritionist for the iDip program. 

Nakamura said the preservation of lean mass is very important while losing weight, especially when using weight-loss drugs.

 “Recently, the popularity of injectable weight loss medications has been increasing,” Nakamura said. “However, using these medications when food intake is strongly limited will cause serious side effects of muscle and bone loss unless protein intake is increased during weight loss.”

A total of 22 people who enrolled in the program completed it, including nine men and 13 women. Most of the dieters were between the ages of 30–64. Participants reported they had made two or more prior attempts to lose weight. They also had a variety of comorbidities – 54% had high cholesterol, 50% had skeletal problems and 36% had hypertension and/or sleep apnoea. Additionally, the dieters reported diagnoses of diabetes, nonalcoholic fatty liver disease, cancer and depression, according to the study.

The seven dieters who reported they had been diagnosed with depression lost significantly less weight: about 2.4% of their starting weight compared with those without depression, who lost 8.39% of their initial weight. The team found that weight loss did not differ significantly among participants with other comorbidities, or between younger and older participants or between men and women.

Body composition analysis indicated that dieters maintained their lean body mass, losing an average of 7.1kg of fat mass and minimal muscle mass at the six-month interval. Among those who lost greater than 5% of their starting weight, 78% of the weight they lost was fat, according to the study.

Overall, the participants reduced their fat mass from an average of 42.6kg at the beginning of the program to 35.7kg at the 15-month mark. Likewise, the dieters reduced their waists by about 7cm at six months and by a total of 9cm at 15 months, the team found. 

In tracking dieters’ protein and fibre intake, the team found a strong correlation between protein and fibre consumption and weight loss at three months and 12 months.

“The strong correlation suggests that participants who were able to develop sustainable dietary changes within the first three months kept losing weight in the subsequent months, whereas those who had difficulty implementing sustainable dietary patterns early on rarely succeeded in changing their diet in the later months,” Nakamura said.

The team hypothesised that this correlation could also have been associated with some dieters’ early weight loss success, which may have bolstered their motivation and adherence to their program.

Source: University of Illinois at Urbana-Champaign

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Specific Type of Dietary Fibre Could Stimulate GLP-1 Release

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Gut Microbiome. Credit Darryl Leja National Human Genome Research Institute National Institutes Of Health

New research led by Frank Duca, associate professor at the University of Arizona, suggests that consuming foods rich in beta-glucan, a type of fibre found in oats and barley, can reduce body weight and obesity by stimulating the release of glucagon-like peptide-1 (GLP-1). The study, published in The Journal of Nutrition, analysed the impact of different fibres on gut microbiota.

“We know that fibre is important and beneficial; the problem is that there are so many different types of fibre,” Duca said. “We wanted to know what kind of fibre would be most beneficial for weight loss and improvements in glucose homeostasis so that we can inform the community, the consumer and then also inform the agricultural industry.”

Not all fibre is created equal

The researchers looked at the effect of five different plant-based fibres in rodent diets: pectin, beta-glucan, wheat dextrin, starch and cellulose. Only beta-glucan resulted in reduction of body weight and fat, as well as improvements in glucose homeostasis. Beta-glucan is a unique fibre that is found in many foods, including oats, barley, mushrooms and yeasts, and future studies will examine how different sources of beta-glucan could differ in their effectiveness.

Changes in metabolites – the molecules produced when gut bacteria interact with fibre – seemed to be responsible for the weight-loss effects,  particularly a specific metabolite called butyrate. Butyrate is a key fuel source for colon cells, promoting a healthy gut barrier to reduce systemic inflammation. Butyrate also induces the release of gut peptides, or messengers that regulate the functions of the gut, such GLP-1.

Drugs like semaglutide are synthetic versions of GLP-1, which stimulate insulin and can also help people feel full. One key difference of naturally occurring GLP-1 is its rapid degradation near the intestine, whereas semaglutide is made to last longer and target the brain.

“Part of the benefits of consuming dietary fibre is through the release of GLP-1 and other gut peptides that regulate appetite and body weight,” Duca said. “However, we don’t think that’s all of the effect. We think that there are other beneficial things that butyrate could be doing that are not gut peptide related, such as improving gut barrier health and targeting peripheral organs like the liver.”

Duca is researching other types of fibre that can be beneficial for weight reduction. In a previous study, the Duca Lab discovered that barley flour was the most effective in promoting weight loss compared to several other commercially available flours. Other studies involving oligofructose have also demonstrated beneficial effects. In the future, Duca hopes to collaborate with other researchers to develop enhanced fibres that can optimise the release of butyrate.

Source: University of Arizona

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Surprisingly, Benefits of Dietary Fibre Vary Significantly between Individuals

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Photo by Mariana Kurnyk

Nutritionists generally advise everyone to eat more dietary fibre, but a new study suggests that its effects on health can vary, suggesting that recommendations should be tailored to each individual’s gut microbiome. The study, published in Gut Microbes, focused on resistant starch, a category of dietary fibre found in such foods as bread, cereals, green bananas, whole-grain pasta, brown rice and potatoes.

The researchers identified the gut microbe species that change in response to two different types of resistant starch. They found evidence that each individual may have a unique response to eating a resistant starch, with some people benefiting and others experiencing little or no effect. The reason for the variation appears tied to the level of diversity and composition of a person’s gut microbiome.

“Precision nutrition definitely has a use in determining what dietary fibre we should tell people to eat,” said Angela Poole, assistant professor of molecular nutrition and senior author of the study.

“This is critical because we’ve had public messaging advising people to eat more dietary fibre for decades,” Poole said. “At the same time, less than 10% of people eat the recommended intake. Since there are many different types of dietary fibre and carbohydrates, a better strategy would be to collect data on each person and tell them which dietary fibre they can eat to get the most bang for their buck.”

Resistant starch comes in five types, and resists degradation by human digestive enzymes until it reaches the gut. There, it acts as a substrate for certain gut microbes to produce short chain fatty acids, which are important in signaling pathways that regulate glucose and lipid metabolism. Multiple microbe species may work together to create the fatty acids.

In the study, Poole and colleagues tested three dietary treatments on 59 participants over seven weeks.

The team had three different types of crackers manufactured. Two crackers had the same ingredients, except one contained resistant starch type 2, which occurs naturally, and the other contained resistant starch type 4, which is human-made. A third control cracker was digestible by human enzymes, similar to white bread, and the researchers expected none of the bacteria to act on the control.

Subjects were then divided into two groups. The first group ate the resistant starch type 2 cracker first, followed by the control, and then resistant starch type 4. Each cracker type was eaten for 10 days, with five days of no cracker consumption between treatments. The second group reversed the order, also with the control in the middle.

They then sequenced the microbiomes of each participant before and after each treatment. For resistant starch type 2, more than 30 bacteria changed in abundance, including Ruminococcus bromii, which is considered a keystone resistant starch degrader in the human gut. For type 4, more than 20 bacteria changed. And for the control, nothing changed.

“For the resistant starch crackers, we could detect that 20 or 30 of them were changing, but how much they changed and whether they changed at all, for each of those bacteria, depended on the person,” Poole said.

Similarly, each resistant starch type changed different short chain fatty acids, with variable levels of fatty acid increases and decreases based on the individual. For resistant starch type 2, the researchers identified a subset of 13 bacteria that predicted change in amounts of propionate, a type of short chain fatty acid. Also for resistant starch 2, by knowing the diversity of an individual’s gut microbiome, the researchers could roughly predict if two types of short chain fatty acids (acetate and butyrate) were going to increase.

The most surprising result was that the control digestible cracker led to the greatest gains of short chain fatty acids. More work is needed to understand why, but Poole suspects that the order of cracker consumption was key to the result. Since many microbes are involved in making short chain fatty acids, she hypothesises that eating a resistant starch first primed the gut to produce the fatty acids when that person ate the digestible starch.

“That’s one of the major takeaways, maybe I can get away with eating a French baguette some of the time, and it may be better than just eating whole grain all the time,” Poole said. “But I have to test that, and it probably varies between people.”

Source: Cornell University

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Changing the Structure of Fibre to be Even Better for the Gut

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Gut microbiome. Credit: Darryl Leja, NIH

Changing the structure of a dietary fibre commonly found in a range of food products has been found to promote healthy gut bacteria and reduce gas formation, a finding that could help people with intolerances to fibre and irritable bowel conditions. The findings have been published in Food Hydrocolloids.

A team of scientists from the University of Nottingham, Quadram Institute Biosciences and the University of East Anglia examined psyllium, a type of natural dietary fibre that is used in a range of products including cereals and yoghurts. They showed that the physical state of the fibre has a major impact on gas production which often is linked to bowel discomfort.

The team performed in vitro fermentation experiments seeded with human stool. They conducted analysis of fermentation products and evaluated the impact of different structures on the broad categories of microorganisms.

Dr Gleb Yakubov, Associate Professor in Food Physics at the University of Nottingham was one of the lead researchers on the study, he explains: “Although fibre is an important part of any diet, for many people it can cause bowel discomfort and for people with IBS or IBD fibre can be a trigger. This is because some foods cause bacterial interactions in the gut that create gas that can lead to pain or discomfort. Our study shows that the physical state of the fibre has a major impact on gas production by creating beneficial compounds that promote the creation of the good bacteria in the gut.”

Psyllium fibre comes from the seeds of Plantago ovata plants, known by many common names such as blond plantain. These seeds produce a jelly-like material called mucilage, which comes in a variety of shapes and forms and these feature long-chain sugars, called polysaccharides. It is these polysaccharides that lead to the production of beneficial short-chain fatty acids that contribute positively to gut health and systemic metabolism. This study shows that different physical states of fibre impact the way dietary fibre breaks down and that microbes ‘colonise fibre’ during fermentation.

Professor Yakubov continues: “These findings show that there are new opportunities for designing targeted structures using psyllium, either through seed processing or selective breeding, to achieve new fibre materials with clear clinical benefit above that of unrefined psyllium powders aiding in the treatment of gastrointestinal discomfort.”

Research is already underway to create and test psyllium-mimicking materials as medical nutrition which could provide a source of fibre for people with some bowel conditions.

Source: University of Nottingham

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Dietary Fibre Shown to Protect Against Atopic Dermatitis

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Research suggests that the gut-skin axis may have an influence on skin conditions. Photo by Romina Farias on Unsplash

A study published in Mucosal Immunology into the emerging gut-skin axis has found that microbial fermentation of dietary fibre in the gut can protect against atopic dermatitis. The research could potentially lead to novel treatments to prevent or treat allergies.

The Monash University led by Professor Ben Marsland showed that fermentation of fibre in the gut by bacteria and subsequent production of short chain fatty acids (SCFAs), in particular butyrate, protected against atopic dermatitis in mice.

Previous work had found that dietary fibre was connected to protection against flu through SFCAs activating cytotoxic T cells. SCFAs are also often found in sources including root vegetables such as chicory roots or the skins of citrus fruits

While it is well established that the gut microbiome shapes the immune system, the influence it has on the skin is less explored.

“Previous work from our group, and others, has focused on the local health benefits of SCFAs in the gut as well as at distal sites such as the lung and cardiovascular system,” Professor Marsland said. “We wondered if this might also extend to the skin, which is an area that has not really been investigated.

“People speculate that diet can influence skin health, but there is not a great deal of science behind this.”

The researchers fed mice a diet high in fermentable fibre or gave them purified SCFAs. “This treatment was profoundly protective against allergic skin inflammation,” Professor Marsland said.

They labelled the butyrate with isotopes and tracked it in the body, taking only minutes to reach the skin where it enhanced the metabolism of keratinocytes, priming them to mature and produce the key structural components required for a healthy skin barrier.

“The upshot of this was that the skin barrier was fortified against allergens – we were using house dust mite allergens – that would normally penetrate the skin barrier, activate the immune system and start an allergic reaction in these models,” he said.

“It turns out the immune system was secondary to this skin barrier function.”

Actively improving the skin barrier could have protective effects against environmental exposures that cause allergies and perhaps even other skin diseases which are underpinned by a damaged or weak skin barrier. SCFAs could be administered orally or directly on the skin as a cream, bypassing the gut, he said.

“The fact that short chain fatty acids can be given topically and are well-tolerated opens up possibilities for development of preventative strategies or disease-modifying interventions – that represents the most significant translational potential of our research.”

One possibility to explore is whether this could help children who are at risk of developing skin allergies that cascade towards food allergies and asthma, the so-called ‘Atopic March’.

Source: Monash University

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Soluble Fibre is Associated with Lower Dementia Risk

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Source: Pixabay

Drawing on a decades-long cohort study, researchers in Japan have found that higher levels of dietary fibre, particularly soluble fibre, are associated with a lower risk of dementia.

Fibre is known to have vital importance for a healthy digestive system and also has cardiovascular benefits like reduced cholesterol. In a new study published in Nutritional Neuroscience, researchers have shown that a high-fibre diet is also associated with a reduced risk of developing dementia, adding to evidence that fibre is also important for a healthy brain.

“Dementia is a devastating disease that usually requires long-term care,” says lead author of the study Professor Kazumasa Yamagishi. “We were interested in some recent research which suggested that dietary fibre may play a preventative role. We investigated this using data that were collected from thousands of adults in Japan for a large study that started in the 1980s.”

Between 1985 and 1999, 3739 participants who were generally healthy and aged between 40–64 completed dietary information surveys. They were then followed up from 1999 until 2020, and it was noted whether they developed dementia that required care.

Participants were assigned into four groups according to the amount of fibre in their diets. They found that the groups who ate higher levels of fibre had a lower risk of developing dementia.

The team also examined whether there were differences for the two main types of fibre: soluble and insoluble fibres. Soluble fibres, found in foods such as oats and legumes, are important for the beneficial bacteria that live in the gut as well as providing other health benefits. Insoluble fibres, found in whole grains, vegetables, and some other foods, are known to be important for bowel health. The researchers found that the link between fibre intake and dementia was more pronounced for soluble fibres.

The team has some ideas as to what might underlie the link between dietary fibre and the risk of dementia.

“The mechanisms are currently unknown but might involve the interactions that take place between the gut and the brain,” said Professor Yamagishi. “One possibility is that soluble fibre regulates the composition of gut bacteria. This composition may affect neuroinflammation, which plays a role in the onset of dementia. It’s also possible that dietary fibre may reduce other risk factors for dementia, such as body weight, blood pressure, lipids, and glucose levels. The work is still at an early stage, and it’s important to confirm the association in other populations.”

Source: University of Tsukuba