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These functional fibers are amassing an impressive record for strengthening gut and immune health, alike.
The COVID-19 pandemic will go down in history for plenty of reasons—including its salutary effect on dietary supplement sales.
With consumers eager to shore up their inner reserves by any means necessary, everything from vitamins C and D to zinc, antioxidants, and omega-3s were, if not flying off shelves, at least seeing more turnover than they had before the coronavirus began its spread.
But shoring up our inner reserves means supporting more than the immune system alone. Immunity, after all, is a complex equation, and gut health plays an important role in it.
Which is why the pandemic may lift prebiotics’ boat along with all the others—for as science increasingly shows, these functional fibers are amassing an impressive record of their own for strengthening gut and immune health, alike.
Go with the Gut
The pandemic definitely awakened the public to the relationship between their diets and their bodies’ ability to ward off foreign invasion. As Jon Peters, sales director, Americas, Beneo (Parsippany, NJ), notes, a 2020 FMCG Gurus survey found that eight in 10 consumers want to eat more healthfully in COVID-19’s wake, “reflecting growing interest in foods and drinks that support immune health.”
And for good cause. “Balanced nutrition and a smart choice of nutrients support our inner defenses in a sustainable way,” he goes on, “and small changes to those choices can have significant effects on our bodies’ resistance to pathogens and more.”
But the more we learn about immunity, the more we understand that it’s not just about the immune system.
As Peters explains, “Our inner defense includes the immune system—which is very complex in itself—as well as a healthy, functioning gut barrier and balanced microbiota. All these elements are linked, and situated in the intestine.”
Consumers increasingly grasp this concept, and a Health Focus International 2020 Global Health report even found immune function ranking among the top-three benefits that consumers connect with gut health.
“So because the gut microbiome and immune system directly impact one another,” Peters continues, “there’s been growing interest in ingredients that can support both gut health and immune health.” Including prebiotics.
Feeding Our Immune Response
Of course, prebiotics made their name as the “preferred nutrients,” as Peters calls them, of probiotic bacteria—bacteria like Bifidobacteria, a selective increase in which is a marker of good intestinal health.
When Bifidobacteria and other probiotic species ferment prebiotic fibers like inulin and oligofructose—often derived from chicory root—they generate byproducts that influence the gut ecosystem as well as its metabolic output. “This prebiotic fermentation pattern is key to some of prebiotic fibers’ beneficial effects in the colon and beyond,” Peters says.
In fact, he continues, studies show that consumption of as little as 5 g—about 1 teaspoon—of chicory root inulin or oligofructose per day can increase numbers of Bifidobacteria significantly, “therefore supporting digestive health and overall wellbeing while helping to keep our inner defense system in good shape.”
And consumers are getting the message. Pointing to data from FMCG Gurus’ 2020 COVID-19 Report, Peters says, “Already, 53% of consumers associate prebiotics with helping boost immune health.”
But prebiotics’ benefit go beyond their ability to preferentially promote the growth of good gut bugs. As Susan J. Hewlings PhD, RD, director of scientific affairs, GRAS Associates/Nutrasource Inc. (Holmdel, NJ), notes, prebiotics can also “modulate the composition and activity of the human microbiota independent of probiotics.”
Consider that while most of our resident microbes lie in our gastrointestinal tracts, the lungs also house a small number. “This is potentially meaningful for respiratory-tract infections and one’s ability to respond to and recover from viruses and pathogens that infect the respiratory tract,” Hewlings explains. She points to research suggesting that consuming prebiotics improves immunity not just by supporting beneficial microbial populations, but possibly by increasing cytokine levels, as well.1
Further evidence for prebiotics’ direct effect on immunity comes in a 2019 study2 that explored the effects of a dietary combination of the human milk oligosaccharide 2’-fucosyllactose (2’FL) with prebiotic short-chain galactooligosaccharides (GOS) and long-chain fructooligosaccharides (FOS) on immune responsiveness in a mouse model of influenza vaccination. Researchers learned that the oligosaccharide blend improved vaccine-specific T-helper 1 responses and B-cell activation in mesenteric lymph nodes and enhanced systemic IgG1 and IgG2a concentrations in the subject mice.
From the Gut to the Lungs
“Also of interest,” Hewlings says, “it’s been suggested that bidirectional communication exists between the gut and lungs, called the gut-lung axis. This connection is thought to explain the connection between dysbiosis of gut bacteria and respiratory pathological conditions. In addition, it’s hypothesized that this connection may explain the gastrointestinal symptoms that some COVID-19-positive patients experience.”
Which factor is the chicken and which the egg—does the disruption in lung health influence gut health, or vice-versa?—remains unclear. But we do know that angiotensin-converting enzyme 2 (ACE2)—the main host cell receptor for COVID-19 and an enzyme found in both the lungs and the gastrointestinal tract—might have something to do with it.
“Probiotics have been shown to act as ACE inhibitors and may be potential blockers of the ACE receptors that act as a gateway of sorts for the virus,” Hewlings says. “Prebiotics may also benefit, as they also block ACE enzymes and enhance probiotic growth.”3
Finally, Peters points to research4 showing that inulin and oligofructose assist with blood-glucose management, “as they support a lower rise in blood-glucose response,” he says. “Having a healthy blood-glucose level is equally important, as having elevated blood-glucose levels even for a short time can harm immunity.”
But for most consumers, prebiotics’ calling card remains their role in gut health. As Pam Stauffer, global marketing programs manager, Cargill (Minneapolis), says, “We know that consumers are placing increased emphasis on digestive health and becoming more familiar with the importance of ingredients like fiber, probiotics, and prebiotics.” The most recent International Food Information Council Foundation Food & Health Survey5 found that fully 45% of U.S. consumers ranked prebiotics as healthful, up from 36% the previous year, she says.
Asked what could improve prebiotics’ prospects even more, Hewlings expressed hope that tighter regulatory standards might better “define the prebiotic space and its benefits, which would ultimately boost consumer awareness.” As yet, FDA has established no legal definition for the category.
Hewlings also believes that while prebiotics’ health benefits are manifold, “educational messages regarding those benefits should be kept simple and individualized—not lumped together with probiotics or fiber.”
As for Len Monheit, executive director, Global Prebiotic Association (Spring, TX), he thinks the biggest risk to the sector’s flourishing comes from “companies jumping on the bandwagon and just ‘fairy-dusting’”—not using efficacious prebiotic levels in their formulas—“or calling ingredients ‘prebiotic’ without substantiation.” His corrective? “Follow the science, and make sure to use efficacious doses.”
On the plus side, he notes that the Trust Transparency Center has conducted its 2020 Ingredient Transparency Center (ITC) Insights Consumer Survey of supplement users found that 81% of respondents have heard of prebiotics, with 60% of U.S. respondents saying they’re very or extremely familiar regarding the ingredients’ use.
Even better, he continues, “There’s new research coming out all the time, and industry needs to keep up with it, especially as we look beyond fiber as a source of prebiotics.” Because, as Monheit says, “Not all prebiotics are fiber, and not all fiber is prebiotic.”
Mushrooms, for example, show prebiotic promise thanks to their rich stores of chitin, hemicellulose, alpha- and beta-glucans, mannan, xylan, and galactan polysaccharides. “These compounds display immunomodulating and antitumor activity and have been linked to activity in lymphocytes, macrophages, hematopoietic stem cells, T cells, dendritic cells, and natural killer cells that play essential roles in innate and adaptive immunity,”6 Monheit says. “It’s an exciting time.” Indeed it is.