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Old October 13th, 2012, 05:21 PM
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Originally Posted by marko View Post
why is that?
Sounds like research on how probiotics affect the immune system is fairly new and there are more questions than answers, but these links have a bit of info:

Mechanisms of antiallergic probiotic action

The precise mechanisms behind the favorable effects of probiotics on allergy are not entirely known. Several mechanisms have been observed in vitro and in animal studies (Fig. 2). In addition to modulation of the intestinal microbiota, probiotics have been observed to improve the barrier function of the intestinal mucosa (30), reducing leakage of antigens through the mucosa and thereby exposure to them. Direct modulation of the immune system may be through the induction of antiinflammatory cytokines or through increased production of secretory IgA (31). IgA will contribute to an exclusion of antigens from the intestinal mucosa. Further, enzymatic degradation of dietary antigens by enzymes from probiotics will reduce the load of and exposure to antigens (32). These and other mechanisms contribute to reduced exposure of the immune system to dietary antigens.

For the future, it will be important to determine the mechanisms behind the probiotic action on allergy. This will enable further improvement of the use of probiotics. A thorough knowledge of the intestinal microbiota of allergic and healthy infants presents an opportunity to select more effective strains or combinations of strains. Because probiotics modulate the composition and/or activity of the intestinal microbiota, it is important to obtain information on the intestinal microbiota, not only from fecal samples, as is common practice, but also from the mucosa-associated microbiota. In addition to probiotics, (n-3) fatty acids (33) and antioxidants (34) have been suggested to contribute to a protection against allergy. Also, prebiotics may modulate the immune response through similar mechanisms as probiotics (35) and reduce inflammation (36). The influence on allergy of the combination of these dietary components and probiotics deserves further investigation.

Thus, although probiotic therapy appears to be a promising approach in the treatment and prevention of allergy, there are still a substantial number of questions that remain to be answered.

Tuning immunity

Probiotics are usually promoted as supporting intestinal health—a polite way of hinting that they may reduce the risk of diarrhea or bloating. Far less appreciated is the broad range of immune conditions for which they show promise.

The gut "is the body's largest immune organ," notes Arthur C. Ouwehand of the University of Turku, Finland, and of Danisco Innovation, a company that makes probiotics-enhanced foods. That's why investigators at his and other research centers are exploring probiotics to improve immunity.

A study in 2005 by Schrezenmeir and his colleagues showed that daily treatment with a trio of probiotics didn't reduce the incidence of colds. But the supplementation did reduce the severity and duration of cold symptoms—including fever—compared with a group of people that didn't get probiotics.

"We don't know the mechanism" for the probiotic advantage, Schrezenmeir says. However, in individuals given probiotics, the number of activated helper T cells—white blood cells that fight infection—increased, as did the number of germ-killing cells.

Probiotics may move the immune system in the opposite direction as well. Over the past year, several research teams reported some success with probiotics in treating inflammatory bowel disease. At least one study found they could help control exaggerated inflammation in intensive care patients at high risk for multiple organ dysfunction syndrome—a hyperinflammatory condition. And in a paper last August, Ouwehand recounted how probiotics administered to pregnant women and babies reduced the likelihood that high-risk infants developed food allergies.

In its newest work, Schrezenmeir's team incubated immune cells from the blood of healthy or allergic individuals together with several immune-stimulating substances. Cells from all of the people responded, but only cells from allergic people showed an exaggerated response to allergens.

Adding four probiotic microbes or the naked DNA from probiotic bacteria to the mix substantially ratcheted down the response of immune cells, especially for people with allergies. About half of the immune-dampening effect in probiotic-treated cells was attributed to the live bugs, and half to their DNA—released when the beneficial bugs died. The work will appear in an upcoming Immunobiology.

Probiotic benefits are typically attributed to the fact that supplemented microbes were alive. However, receptors on the surfaces of both immune cells and cells lining the gut can bind DNA, Schrezenmeir notes. Probiotic DNA won't be accessible to those cells until the microbe dies. His team's new data suggest that probiotics—dead or alive—can affect systems in the body, perhaps by contributing to the communications among the gut's native microbes.

Originally Posted by marko View Post
also if you have a general link on what probiotics do (I know you keep good links) I'd love to know more.
Some links specific to pets:

The Use of Probiotics in the Diet of Dogs

The Benefits of Probiotics for Your Pet
"To close your eyes will not ease another's pain." ~ Chinese Proverb

“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler
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