For many years, a widespread, fast-growing algae
plant called Chlamydomonas reinhardtii
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.
Now, medical researchers from the University of California San Diego recently completed the first study examining the effects of consuming C. reinhardtii algae
and demonstrated that the algae improves human gastrointestinal
issues associated with irritable bowel syndrome
) such as diarrhea, gas and bloating. Results of the project are published in the Journal of Functional Foods
Principal investigator and algae
expert Dr Stephen Mayfield, a distinguished Professor in University of California, San Diego's Division of Biological Sciences and co-director of the Food and Fuel for the 21st Century Program (FF21) told Thailand Medical
News, "People have been looking at this algae
for decades, but this is the first study to show what many of us have suspected ie it's good for you. This is exciting because it demonstrates a clear benefit: If you have IBS
-like symptoms, this is good for you."
For almost a decade now, researchers in Mayfield's laboratory have been exploring C. reinhardtii algae
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.
Graphical abstract for algae and human gastrointestinal health study. Credit: Mayfield Lab, UC San Diego
The algae 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 Saf
e" by the U.S. Food and Drug Administration, green-lighting the use of the organism in a human study.
Initial data in mouse studies demonstrated that consuming C. reinhardtii algae
significantly reduced the rate of weight loss in mice with acute coliti
s, 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.
The Green Algae in powedred form.
Study 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.
Dr Frank Fields, a research scientist in Mayfield's lab and lead author of the paper further added, "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. I hope that this study helps destigmatize the thought of incorporating 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."
For the human digestion study, algae were grown in a large stainless steel fermentation
tank, similar to fermentation tanks seen at beer breweries. A smaller bench-top fermentation
tank, or bioreactor, is pictured. Credit: Frank Fields, UC San Diego
Research 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 medical 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
Reference : Francis J. Fields et al, Effects of the microalgae Chlamydomonas on gastrointestinal health, Journal of Functional Foods (2019). DOI: 10.1016/j.jff.2019.103738