Algae shown to improve gastrointestinal health
Project is the first to test green algae on symptoms related to human digestion
January 27, 2020
Science Daily/University of California - San Diego
A green, single-celled organism called Chlamydomonas reinhardtii has served as a model species for topics spanning algae-based biofuels to plant evolution. While algae have been used as dietary nutraceuticals that provide beneficial oils, vitamins, proteins, carbohydrates and antioxidants, the benefits of consuming C. reinhardtii were previously unexplored. Researchers have now completed the first study in humans demonstrating that C. reinhardtii helps improve human gastrointestinal problems related to irritable bowel syndrome, including diarrhea, gas and bloating.
A widespread, fast-growing plant called Chlamydomonas reinhardtii is famous in scientific laboratories due to its position as the world's most exhaustively studied algae.
For decades, the green, single-celled organism, which primarily grows in wet soil, has served as a model species for research topics spanning from algae-based biofuels to plant evolution. While other species of algae have been used as dietary nutraceuticals that provide beneficial oils, vitamins, proteins, carbohydrates, antioxidants and fiber, the benefits of consuming C. reinhardtii were previously unexplored.
Researchers at the University of California San Diego recently completed the first study examining the effects of consuming C. reinhardtii and demonstrated that the algae improves human gastrointestinal issues associated with irritable bowel syndrome (IBS) such as diarrhea, gas and bloating. Results of the project are published in the Journal of Functional Foods.
"People have been looking at this algae for decades, but this is the first study to show what many of us have suspected -- it's good for you," said principal investigator and algae expert Stephen Mayfield, a distinguished professor in UC San Diego's Division of Biological Sciences and co-director of the Food and Fuel for the 21st Century Program (FF21). "This is exciting because it demonstrates a clear benefit: If you have IBS-like symptoms, this is good for you."
For years researchers in Mayfield's laboratory have been exploring C. reinhardtii as a cost-competitive and sustainable source of valuable plant-based products, specifically pharmaceuticals and biofuels. Now, working with several collaborators, including UC San Diego's John Chang (School of Medicine), Rob Knight (School of Medicine, Jacobs School of Engineering and Center for Microbiome Innovation) and the San Diego-based startup Triton Algae Innovations, they turned their attention towards investigating the algae as a nutritious food additive for improving human health.
The C. reinhardtii biomass used in the study, which was grown by Triton Algae Innovations, was subject to rigorous safety testing and designated as "Generally Recognized As Safe" by the U.S. Food and Drug Administration, green-lighting the use of the organism in a human study.
Preliminary data in mouse studies demonstrated that consuming C. reinhardtii significantly reduced the rate of weight loss in mice with acute colitis, which is generally linked to inflammation of the digestive tract. Building off these results, the researchers set out to test for a similar effect when the algae was consumed by human volunteers, including those with and without symptoms associated with IBS. Volunteers consumed daily spoonfuls of powdered C. reinhardtii biomass and reported their gastrointestinal health for one month. Of the hundreds of interested participants in the project, data from 51 volunteers met the study's requirements for inclusion in the final data analyses.
Results showed that participants who suffered from a history of frequent gastrointestinal symptoms reported significantly less bowel discomfort and diarrhea, significantly less gas or bloating and more regular bowel movements.
"The benefits of consuming this species of algae were immediately obvious when examining the data from both mice and humans who suffered from gastrointestinal symptoms," said Frank Fields, a research scientist in Mayfield's lab and lead author of the paper. "I hope that this study helps destigmatize the thought of incorporating algae and algae-based products into your diet -- it is a fantastic source of nutrition and we have now shown that this species of algae has additional benefits to animal and human health."
Volunteers also were provided with stool sampling kits and sent samples to the American Gut Project, a citizen science effort led by Knight and his lab, to assess any changes in their microbiomes. The results indicated that the gut microbiome composition remained diverse, which is typical of healthier individuals, and that no significant changes to the composition of their gut microbiome occurred during the study as a result of consuming the algae.
The researchers say much more testing with larger groups of participants across longer time periods is needed. At this point, they are unclear about how the algae works to improve gastrointestinal health. The scientists believe the benefits could be traced to a bioactive molecule in algae or perhaps a change in gene expression of gut bacteria caused by algae consumption.
Still, the observed results in human volunteers led them to conclude in the paper that "the addition of C. reinhardtii into the diet will not only add nutritional value but may also function to relieve some gastrointestinal symptoms of certain individuals."
https://www.sciencedaily.com/releases/2020/01/200127134813.htm
Should you eat a low-gluten diet?
November 15, 2018
Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
When healthy people eat a low-gluten and fiber-rich diet compared with a high-gluten diet they experience less intestinal discomfort including less bloating which researchers show are due to changes of the composition and function of gut bacteria. The new study also shows a modest weight loss following low-gluten dieting. The researchers attribute the impact of diet on healthy adults more to change in composition of dietary fibers than gluten itself.
An increasing number of people choose a low-gluten diet, even though they are not allergic to the dietary substance. This trend has sparked public debate about whether or not low-gluten diets are recommendable for people without allergies. Now, researchers from University of Copenhagen among others have looked into just that.
In an intervention study of healthy Danish adults, reported today in Nature Communications, an international team of scientists shows that a low-gluten but fibre-rich diet changes the community of gut bacteria and decreases gastrointestinal discomfort such as bloating and is linked to a modest weight loss. The changes in intestinal comfort and body weight relate to changes in gut bacteria composition and function.
"We demonstrate that, in comparison with a high-gluten diet, a low-gluten, fibre-rich diet induces changes in the structure and function of the complex intestinal ecosystem of bacteria, reduces hydrogen exhalation, and leads to improvements in self-reported bloating. Moreover, we observed a modest weight loss, likely due to increased body combustion triggered by the altered gut bacterial functions," explains the leading principal investigator of the trial, Professor Oluf Pedersen, Novo Nordisk Foundation Center for Basic Metabolic Research at University of Copenhagen.
Change in dietary fibre composition seems to be the cause
The researchers undertook a randomised, controlled, cross-over trial involving 60 middle-aged healthy Danish adults with two eight week interventions comparing a low-gluten diet (2 g gluten per day) and a high-gluten diet (18 g gluten per day), separated by a washout period of at least six weeks with habitual diet (12 g gluten per day).
The two diets were balanced in number of calories and nutrients including the same amount of dietary fibres. However, the composition of fibres differed markedly between the two diets.
Based on their observations of altered food fermentation patterns of the gut bacteria, the researchers conclude that the effects of low-gluten dieting in healthy people may not be primarily due to reduced intake of gluten itself but rather to a change in dietary fibre composition by reducing fibres from wheat and rye and replacing them with fibres from vegetables, brown rice, corn, oat and quinoa.
No basis for change of diet recommendation yet
A low-gluten diet has previously been proposed to diminish gastrointestinal symptoms in patients with inflammatory bowel diseases and irritable bowel syndrome, disorders which occur in up to 20 percent of the general Western population.
The present study suggests that even some healthy individuals may prefer a low-gluten diet to combat intestinal discomfort or excess body weight.
"More long-term studies are definitely needed before any public health advice can be given to the general population. Especially, because we find dietary fibres -- not the absence of gluten alone -- to be the primary cause of the changes in intestinal discomfort and body weight. By now we think that our study is a wake-up call to the food industry. Gluten-free may not necessarily be the healthy choice many people think it is.
Most gluten-free food items available on the market today are massively deprived of dietary fibers and natural nutritional ingredients. Therefore, there is an obvious need for availability of fibre-enriched, nutritionally high-quality gluten-free food items which are fresh or minimally processed to consumers who prefer a low-gluten diet. Such initiatives may turn out to be key for alleviating gastro-intestinal discomfort and in addition to help facilitating weight control in the general population via modification of the gut microbiota," concludes senior lead investigator, Professor Oluf Pedersen.
https://www.sciencedaily.com/releases/2018/11/181115115340.htm
Here’s how stress may be making you sick
January 10, 2018
Michigan State University
A researcher is providing new insight into how certain types of stress interact with immune cells and can regulate how these cells respond to allergens, ultimately causing physical symptoms and disease.
The federally funded study, published in the Journal of Leukocyte Biology, showed how a stress receptor, known as corticotropin-releasing factor, or CRF1, can send signals to certain immune cells, called mast cells, and control how they defend the body.
During the study, Moeser compared the histamine responses of mice to two types of stress conditions -- psychological and allergic -- where the immune system becomes overworked. One group of mice was considered "normal" with CRF1 receptors on their mast cells and the other group had cells that lacked CRF1.
"While the 'normal' mice exposed to stress exhibited high histamine levels and disease, the mice without CRF1 had low histamine levels, less disease and were protected against both types of stress," Moeser said. "This tells us that CRF1 is critically involved in some diseases initiated by these stressors."
The CRF1-deficient mice exposed to allergic stress had a 54 percent reduction in disease, while those mice who experienced psychological stress had a 63 percent decrease.
The results could change the way everyday disorders such as asthma and the debilitating gastrointestinal symptoms of irritable bowel syndrome are treated.
"We all know that stress affects the mind-body connection and increases the risk for many diseases," Moeser said. "The question is, how?"
"This work is a critical step forward in decoding how stress makes us sick and provides a new target pathway in the mast cell for therapies to improve the quality of life of people suffering from common stress-related diseases."
https://www.sciencedaily.com/releases/2018/01/180110132958.htm