Fabulous fiber? Beta-glucan research highlights potential for immune health

27 Jun 2019 --- Dietary fibers are enjoying a place in the health spotlight thanks to the growing body of scientific evidence supporting their contribution to a lowered risk of non-communicable diseases. Notably, these fibers have been tipped as key to improving immunity. NutritionInsight spoke with Dr. Coen Govers from Wageningen Food & Biobased Research about his ongoing work to uncover how dietary fibers may benefit cancer patients’ during their recovery process.

“Dietary fibers in themselves are already being applied to lower cholesterol and can be used to modify the glycemic response, making them candidate supplements in relation to diabetes. In fact, fibers can improve digestion and overall quality of life,” explains Govers.

“We have started reading on claims that dietary fibers could be beneficial for patients being treated for cancer,” Govers explains. “In China and Japan, there is a long-lasting tradition and affinity for fibers based on their potency and benefits towards health and well-being. In this region, researchers have also performed studies with cancer patients, but mainly when patients were treated with chemotherapy rather than immunotherapy. Researchers found that dietary fibers reduced the impact of the side effects of chemotherapy.”

According to this prior research, notes Govers, when undergoing chemotherapy, dietary fibers may help the recovery of the patients’ immune cells more quickly – chemotherapy generally kills rapidly dividing cells, such as tumor cells but also (as a side effect) immune cells, and fibers may help in enabling immune cells to recover.Dietary fibers may help the recovery of the patients’ immune cells more quickly.

Many other studies demonstrated that fibers interact with innate type immune cells which are critical in orchestrating a full T cell-mediated anti-tumor response.

“Based on this rationale we set out to further investigate the exact immunomodulatory potency of the dietary fibers, with the financial support of the Dutch Cancer Society, in particular in relation to therapies that rely on immune cells, i.e., adoptive T cell therapies. Adoptive T cell therapy is a form of therapy in which patients receive an infusion of their own immune cells (in fact T lymphocytes) that are trained to recognize tumor cells,” he explains.

“Associate Professor Reno Debets, who leads the Tumor Immunology laboratory at the Department of Medical Oncology at Erasmus MC – a Cancer Institute in Rotterdam – develops and tests adoptive T cell therapies.I was trained as a Ph.D., student into T cell immunology in his laboratory and now we are both collaborating on a project to see how dietary fibers may boost adoptive T cell therapies. For this project, we perform tests with human immune cells, but also rely on a preclinical mouse model that strongly mimics the human situation in which skin tumors are combated with adoptively transferred T cells, but do show, in a fair fraction of mice, therapy resistance. Together we decided to look into beta-glucans, a potent sub-group of dietary fibers, and how these fibers affect immune cells and may improve adoptive T cell therapy,” Govers says.

One aspect of their research is that there is an endless supply of dietary fibers – whether that be directly from the plant kingdom or, after synthesis and processing, thereby modifying their bioavailability. They, therefore, investigated a number of different beta-glucans to see how structure or source might impact health effects. 

“One of the issues is that you need to describe very clearly which type of dietary fiber you use and what type of processing they have undergone, so others can copy exactly what you did in your research,” Govers explains.

The role for beta-glucan
One ingredient currently taking a leading role in meeting demands in the immunity space is yeast beta-glucan. Derived from common baker’s yeast, yeast beta-glucan has been found to maintain or stimulate the effectiveness of the immune system.

The team began with a general investigation on beta-glucans. “We have in vitro tested dietary fibers on a specific innate type immune cell type, the macrophage, which has a key regulatory role in the intestine, and provides a link to T cell responses as described earlier,” Govers notes.

Since everything we eat comes in contact with the intestine before it interacts with the rest of the immune system, Govers puts forward that by exploring how these macrophages respond to the dietary fibers, we could start identifying the first steps towards their effects on immune cells and in particular their downstream effects on anti-cancer T cell responses.Fiber is set to be a huge trend in 2019, with consumers’ knowledge around its benefits increasing.

“We started to screen nine different beta-glucans – including yeast beta-glucan – for their immunomodulatory potency and saw that beta-glucans, but also other types of dietary fibers, strongly push macrophages with an inhibitory phenotype – often seen in tumors – into a phenotype that is more favorable in combating tumors. One striking observation is the increased expression of chemokines – a set of proteins that attract immune cells towards tissues, in this case, cancers,” he notes. In fact, the limited expression of these molecules in therapy-resistant tumors (as observed by the Erasmus MC team) makes this effect of beta-glucans of exceptional therapeutic relevance.

The team is currently continuing its research by performing animal trials at the Erasmus MC in which they are testing the beta-glucans alongside the adoptive T cells therapy, with results still forthcoming.

Industry takes note
Fiber is set to be a huge trend in 2019, with consumers’ knowledge around its benefits increasing and manufacturers engaging in fibrous NPD. Innova Market Insights has tipped “A Fresh Look at Fiber” to be a key trend this year.

According to an Innova Market Insights’ consumer survey (2018) , 44 percent of US consumers are increasing their consumption of fiber and 33 percent of UK consumers following this trend. At the same time, 21 percent of average annual growth has been reported in new product launches carrying a fiber claim.

In general, immune health product launches are increasing, and Innova Market Insights noted that food and beverage initiatives featuring an immune health claim increased with a CAGR of 18 percent in Europe between 2013 and 2017.

Research such as that of Govers and Debets further highlights the vast potential of this ingredient group.

By Lucy Gunn