Natural Foods Merchandiser
Gut reaction: Probiotics boost immunity

Gut reaction: Probiotics boost immunity


probiotic supplements for digestive healthPeople have consumed probiotics for thousands of years, mostly in the form of fermented dairy products. “The World Health Organization defines them as ‘live microorganisms which, when administered in adequate amounts, confer a health benefit to the host,’ says Kevin Connolly, Ph.D., director of scientific affairs and product development for Jarrow Formulas, based in Los Angeles.

It’s that health benefit that has driven sales of probiotic supplements. As a growing body of research suggests, probiotics have a variety of positive effects on health, particularly in supporting a healthy immune system. In recent years, the number of probiotics supplements has skyrocketed, with a wide range of delivery systems available, including capsules, enteric-coated tablets, liquids and chewable lozenges.

There is also an increasing number of prebiotic products on the market, either stand-alone or in combination with probiotics. “Prebiotics include fructo-oligosaccharides, inulin and other fibers that help promote the growth of probiotics,” says Taryn Forrelli, N.D., director of medical education for New Chapter supplements, based in Brattleboro, Vt. Prebiotics serve as the medium in which probiotics are grown and, in some cases, as with New Chapter’s products, that growth medium is included in the final product. “It helps feed the probiotics in the body, and delivers millions of beneficial compounds called symbiotics, which are secreted into the medium as the probiotics grow,” Forrelli says. “The medium really is the message for health.”

How probiotics work

It may seem strange to think of the digestive tract as an external organ, but that’s precisely what it is, Forelli explains. And unlike the skin, which is relatively impenetrable, the digestive tract is easily permeable, because nutrients must be absorbed through the small intestine into the body.

“Seventy percent of our immune system function takes place in the gut, and one of the ways that probiotics work is through promotion of the integrity of the mucosal barrier, which is a direct physical barrier to pathogenic organisms,” Forelli says.

In addition, by establishing colonies of good organisms in the gut—which plays host to hundreds of millions of organisms—probiotics help discourage less friendly organisms. “They inhibit the growth of bacteria that otherwise the immune system would have to deal with,” says Udo Erasmus, founder of the Udo’s Choice line from Flora, based in Lynden, Wash., and author of the book Fats that Heal, Fats that Kill (Alive Books, 1993). “They out-populate [the bad bacteria], steal their food and also make molecules that are absorbed by the body and that help strengthen the immune system.”

Why we need probiotics

“When you look at the role of probiotics in the generally healthy population, it’s really about getting an extra edge,” says Mary Ellen Sanders, Ph.D., founder of Dairy & Food Culture Technologies, a probiotics consulting firm based in Centennial, Colo.

They play a more vital role for certain populations, including the elderly, infants and those with autoimmune conditions, as well as those who have recently taken antibiotics. Infants and small children benefit from probiotics in ways that can affect them in the long term. “If children aren’t exposed to the right types of microbes when young, it may have an impact on the immune system down the road,” Sanders says.

Because we generally live in a cleaner environment than our ancestors, our immune systems sometimes overreact when certain microbes are introduced, unable to differentiate between dangerous pathogens and positive or neutral bacteria. “Our genetics haven’t changed, but our environment has,” Sanders says.

Probiotics can help us overcome overly clean environments. “Because they help build the lining of the digestive tract, they work against the immune reactions that lead to food allergies and autoimmune diseases,” says Erasmus.

Manufacturing and delivery systems

There are many delivery forms of pro­biotics, many ways to manufacture them and many different strains of probiotic organisms that can be used, at many different potencies. This can make it difficult to decide which type to take or recommend.


Probiotic strains fall into three main categories: those native to the human gut; those native to soil; and those found in dairy products, native to the intestines of animals. Some manufacturers rely on particular strains that have been tested for efficacy, while others base their health claims for probiotics on general assumptions about their healthful activity. Generally, higher potency numbers equal better results, and many manufacturers claim to pack as many as 10 billion or more organisms into each dose, but some strains have shown efficacy at numbers as low as 500 million. The most common genii are Lactobacillus, Bifidobacterium and non-pathogenic strains of Streptococcus.

What are the best strains for supporting immune function? “That’s the $64 million question,” says Frank Hodal, founder and CEO of Little Calumet Holdings, the Beltsville, Md.-based manufacturer of Vidazorb probiotic chewable tablets. “We know we have 500 or 600 different species in our gut, and for reasons that we don’t particularly understand, particular robust strains, when consumed, can help arrange things in this incredibly complex ecology in ways that benefit the host.”

Some manufacturers, including Vidazorb and Udo’s Choice, believe liquids and chewables are the most useful delivery systems, because they allow for probiotic activity in the upper GI tract as well as in the intestines. “Chewing them does have an effect, and some studies show they can have an effect on things like gingivitis,” Hodal says.

“Our mouth and esophagus are part of the digestive system,” Erasmus says. “Probiotics should start in the mouth, where they can help prevent tooth decay, sinus and gum infections and tear-duct infections.” Erasmus believes that we should try as much as possible to recreate how humans once interacted with their natural environment; in the past, wild, edible plants delivered soil probiotics, but this is no longer the case because our soil is tilled and treated with herbicides.

Others believe an enteric-coated product is most useful, because it protects delicate strains from the high-acid environment of the stomach and delivers full potency to the small intestine. “Delivery systems that can ensure probiotic viability through the intestinal tract may increase the utility of a probiotic supplement,” Connoly says.

In many cases, a probiotic’s effectiveness depends on the robustness and natural environment of a particular strain. For example, some strains of Lactobacillus are native to ruminants, which have much less acid in their guts than humans do.

Probiotics can be manufactured through freeze-drying, centrifuging or microfiltration. Freeze-drying can preserve the growth medium, while the other methods separate the probiotic strains from their medium.

“The FDA regulates dietary supplements as foods—not drugs—and does not require ingredient testing, sourcing or proof of potency,” says Natasha Trenev, founder of Natren in Westlake Village, Calif. She advises retailers to look for a supplier that at least abides by the FDA’s new Good Manufacturing Practices—with a GMP logo on the label.

What researchers do know, beyond any studies on the particular effects of particular strains, is that healthy intestinal flora is one of the keys to well-being, and that probiotic supplements can help keep those colonies thriving. “They’re so delicate,” says Hodal. “Stress can kill them, pollution can kill them, so many things can upset the balance of that microflora. These products can really make a difference.”

Mitchell Clute is a Fort Collins, Colo.-based freelance writer.

Natural Foods Merchandiser volume XXVIII/number 9/p. 30

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