How Friendly Bacteria Can Help Eczema
Normally, the human gut flora is made up of 80% beneficial microbes most of which are bacteria. However, when pathogens predominate the gut flora, the lining of the gastrointestinal tract is progressively destroyed. Studies show that the destruction of the gut flora can cause eczema and that restoring the normal flora is an important step in the treatment of eczema. How is the gut linked to the skin? What determines the types of bacteria growing in the gut? How can probiotics help eczema? Read on to find out.
It is becoming increasingly clear that the gut is the battleground between microbes and the immune system. In fact, pathogens that overcome the immune defense at the gut are seldom contained and, therefore, go on to infect other organs of the body.
Therefore, it is important to prevent pathogens from overrunning the gastrointestinal tract before they reach the bloodstream.
Eczema is one of the first results of the bacterial invasion of the gut. Infants who develop atopic eczema early in life have very high risks of also developing diseases involving allergy such as asthma and hay fever.
Studies show that the key difference between infants who develop eczema and those who do not is the diversity in gut flora.
There are more microbial cells in the human gut than there are cells in the body. Normally, most of these microbes are quite beneficial and are essential for different roles including carbohydrate and fat metabolism as well as the syntheses of certain vitamins.
However, not all of the microbes found in the gut are beneficial. About 1 in 5 microbes found in the normal gut flora is a potential pathogen. However, the beneficial microbes prevent the pathogens from taking over the gut.
When this balance is lost, pathogenic microbes colonize the gut and damage the lining of the gastrointestinal tract.
This damage does two things. First, it increases the permeability of the gut mucosa leading to a condition known as leaky gut syndrome. This means that pathogens, toxins, undigested foods and other foreign substances can now reach the bloodstream.
Secondly, the damage to the mucosa triggers an inflammatory reaction from the immune system. The continuous cycle of inflammation only worsens the state of the gut.
Damage to the gut flora and the lining of the gastrointestinal tract can have far-reaching consequences. One of these is eczema.
Probiotics are live, beneficial bacteria that can help restore the healthy balance of gut flora.
Essentially, probiotic bacteria outcompete pathogens for nutrients and other resources in the gut. By doing this, probiotics can significantly reduce the population of pathogenic bacteria and, therefore, protect the gut mucosa from further damage.
Studies show that probiotics can reduce the permeability of the gastrointestinal tract and, therefore, reverse leaky gut syndrome. Therefore, probiotics can help prevent the leakage of pathogens, toxins, undigested foods and other foreign substances into the blood.
By introducing probiotics into a gut heavily colonized with pathogens, the destruction of the lining of the gastrointestinal tract is arrested while the body gets the chance to heal itself.
Besides promoting the healing of the gut, probiotics also reduce inflammation caused by bacterial action and immune dysfunction.
All of these benefits suggests that probiotics will be effective in the treatment of eczema. But is this belief backed by solid evidence from well-designed studies? The answer is yes.
The 2 commonly used bacteria in studies that have successfully proven the usefulness of probiotics in the treatment of eczema are Lactobacillus rhamnosus GG and Bifidobacteria species. These clinical trials not demonstrate that probiotics are effective for preventing atopic eczema but also that they are effective for reducing the severity of the skin disease.
By introducing probiotics early in the life of a child, it is possible to influence the diversity of the child’s gut flora.
This is important for 2 reasons. First, probiotics can help provide the first seeds of gut microbial content and help establish the kinds of microbes that colonize the gut later in life.
Secondly, and more importantly, probiotics can help train the rapidly developing immune system of an infant to cope well with allergens, toxins and pathogenic microbes. Challenging the immune system early in life and with safe probiotic strains is “good education” for the immune system.
In fact, studies show that the gut flora of an infant in (as early as) the first week will largely determine her risks of developing chronic diseases with allergy components later in life.
Therefore, probiotics can reduce your child’s risk of developing eczema as well as other allergic diseases such as asthma and hay fever.
How early should probiotics be given? The overwhelming answer from recent studies is right from the womb.
A Finnish study published in the Journal of Allergy and Clinical Immunology found that a baby’s risk of developing eczema is reduced if the mother took probiotics during pregnancy and while breastfeeding.
Specifically, this study and some others found that probiotics stimulate the release of certain immune cells that can cross the placental barrier into the fetus.
In addition, probiotics can increase the levels of protective immune factors in breast milk.
For the study mentioned above, the researchers divided 241 pregnant women into 3 groups and gave the groups placebo or one of two probiotics.
The follow-up after childbirth showed that 71% of the babies whose mothers got placebo developed eczema at least once while 26% had chronic eczema. In contrast, only 29% of the babies from the probiotic groups developed eczema once during the follow-up period and only 10% (actually, 6% for the second probiotic group) of them developed chronic eczema.
At childbirth, the infant’s gastrointestinal tract is sterile. The first microbes to reach the gut are the ones acquired from the birth canal during childbirth. Therefore, if the mother’s vaginal microbial flora is abnormal, it is very likely that the infant’s gut flora will be.
However, breastfeeding can help inoculate the infant’s flora with the right microbes and quickly establish a healthy gut flora.
Studies show that infants who enjoyed breastfeeding for at least 2 years are significantly less likely to develop atopic eczema than those who were weaned earlier.
In addition, these studies also indicate that giving infants probiotics early in life can also reduce their risks of eczema by half even after they have been weaned.
A two-year study funded by the Health Research Council of New Zealand and published in Journal of Allergy and Immunology in 2008 showed once again that Lactobacillus rhamnosus HN001 (or GG) can reduce the risk of eczema in infants by half.
Just as importantly, the study found that the protection against eczema persisted for 2 years after the infants received the probiotic strain.
In another paper published in the journal, Clinical and Experimental Allergy in 2012, the same researchers reported that the Lactobacillus probiotic sustained its eczema protection even after 4 years. Currently, they are preparing their findings after a 6-year follow-up period.
The researchers believed that probiotics stimulate “attack” or Th1 arm of the immune system and prevent the “defense” or Th2 arm from dominating.
When the Th2 arm of the immune system dominates, the body tries to defend itself against infections by releasing pro-inflammatory cytokines. This can quickly escalate into widespread inflammation that leads to eczema and other allergic diseases such as asthma.
Basically, probiotics are act by modulating the composition of the gut flora by reducing the population of pathogenic microbes such as Clostridium difficile and Candida albicans while increasing the population of beneficial microbes such as bifidobacteria.
To achieve these, probiotics
One of the first studies to demonstrate the effectiveness of specific probiotic strains for lowering the risk of atopic eczema was published in the journal, Clinical and Experimental Allergy in 2000.
For this study, the researchers recruited 27 infants who were diagnosed with atopic eczema even though they were exclusively breastfed. These infants were divided into 3 groups. One group was given placebo; the second group received the probiotic, Lactobacillus GG; and the last group got the probiotic, Bifidobacterium lactis.
The results of the study showed that the two groups of infants who received probiotics improved significantly while the placebo group did not.
This finding was further confirmed by a 2003 study published in The Journal of Allergy and Clinical Immunology. In this study, the combination of 2 strains of Lactobacillus (L. rhamnosus and L. reuteri) were given to children aged 1 – 13 years for 6 weeks.
To determine the effectiveness of the probiotics, the researchers used the SCORAD (scoring atopic dermatitis) index.
The results of this study showed that 56% of the children who were given the 2 probiotic strains got better but only 15% of the placebo group improved.
In addition, the researchers found that probiotics were more effective for eczema patients with positive skin prick test response (a test of allergen sensitivity) and those with high IgE (immunoglobulin E) levels.
A similar 2007 study also investigated whether probiotics can help prevent IgE-related eczema.
The researchers recruited 188 pregnant women from families with history of allergic diseases and very high risk of IgE-associated eczema. They gave some of these women L. reuteri from week 36 of gestation until delivery. Thereafter, they gave the infants born from those women the same probiotic from birth until the 12th month.
The results of the study showed that while the infants born from both the placebo and probiotic groups had similar incidences of eczema, the probiotic group had significantly lower rate of IgE-associated eczema.
The protection offered by the probiotic treatment was still effective 12 months later.
This study shows that probiotics, especially Lactobacillus strains, are effective for atopic eczema and IgE-related eczema in patients most likely to suffer from allergic diseases.
Probiotic trials do not always produce positive results. However, the major reason for these mixed results was clearly demonstrated in a 2008 study published in the Journal of Allergy and Clinical Immunology.
In this study, the researchers compared the effectiveness of 2 different probiotic strains to placebo in the prevention of atopic eczema.
They divided the pregnant women recruited for this study into 3 groups. While one group was given placebo, the other two groups were given either Lactobacillus rhamnosus HN001 or Bifidobacterium animalis subsp lactis strain HN019.
The pregnant women followed these treatments from 35th week of gestation to 6 months after delivery as long as they were breastfeeding. Their infants were also randomized to receive the 3 treatments until they turned 2.
The results of the study showed that L. rhamnosus but not B. animalis significantly reduced the risk of eczema.
This study shows that not all probiotics are effective for treating or preventing eczema. In fact, the most consistent probiotics are the strains of Lactobacillus.
Prebiotics are food-derived compounds that can improve gut flora by encouraging the growth of beneficial bacteria. Therefore, combining probiotics and prebioitcs should produce better results in the management of eczema.
A 2007 study published in The Journal of Allergy and Clinical Immunology compared a mixture of prebiotics and 4 probiotic strains to placebo in the prevention of atopic eczema.
The researchers gave over 1200 pregnant women either placebo or the probiotic-prebiotic mixture during their last months of gestation. Thereafter, they gave the same treatment to their infants for 6 months.
After 2 years, the results of the study showed that the probiotic-prebiotic combination reduced the incidence of IgE-related eczema and also increased the population of lactobacillus and bifidobacteria species in the gut of the infants.
A 2008 review of the benefits of probiotics and prebiotics in the treatment and prevention of eczema arrived at the same conclusions.
The reviewers found that probiotics tend to stimulate low-grade inflammation in infants through the activation of the innate immune system.
This shows that probiotics can help train the immune system as it matures especially when given early in life. This early supplementation with probiotics can significantly reduce the risks of allergic diseases later in life.
Although prebiotics have been confirmed to enhance the efficacy of probiotics, they are not all good news.
Of particular concern is the prebiotic known as inulin. Inulin is naturally found in chicory root, asparagus, garlic and Jerusalem artichoke. It fulfils the two major requirements of a prebiotic: be indigestible for humans and serve as a food source for “good” bacteria (Bifidobacteria species) in the gut.
However, inulin can serve as a food source to pathogens or “bad” bacteria too.
There are evidences to suggest that inulin and other prebiotics can be broken down in the gastrointestinal tract by pathogens such as Klebsiella, a bacterium known to increase intestinal permeability and cause leaky gut syndrome.
In addition, prebiotics have been shown to serve as energy sources for pathogenic bacteria like Escherichia coli, Clostridium species and even certain yeasts.
Lastly, there is also the danger that pathogenic bacteria and yeasts will adapt and adopt prebiotics as a food source.
When that happens, prebiotics will not selectively promote the growth of probiotics. Rather, prebiotics will likely fuel the spread of highly competitive pathogens and their dominance in the gut flora.
The role of prebiotics as a fuel source for yeast overgrowth and the unchecked replication of harmful bacteria is important because more manufacturers are adding prebiotics to probiotic products as the medical community rapidly embraces the health benefits of probiotics.
The most common prebiotic added to probiotic products is a sugar polymer called FOS or fructooligosaccharides.
Also known as oligofructose and oligofructan, FOS is a produced by breaking down inulin.
Inulin is a polymer of D-fructose and contains a chain of 10 – 70 fructose molecules. FOS, on the other hand, is a degradation product of inulin and contains up to 7 fructose molecules.
FOS is naturally produced from inulin in plants such as chicory and Jerusalem artichoke. The mold known as Aspergillus niger can also make shorter-chain FOS from sucrose.
As a natural constituent of foods, FOS is present in lower concentrations and its effects are masked by other healthful food constituents.
However, once extracted and used in high concentrations in probiotics as an alternative sweetener and a microbial food source, FOS and other inulin-based prebiotics can be potentially harmful to a healthy gut flora.
Common side effects of FOS include gas, bloating, diarrhea, abdominal pain and cramps. These are due to the release of gas from the breakdown of prebiotics by the bacteria living in the large intestine.
However, the potential to also promote the growth of pathogens in the gut means that you should avoid probiotics fortified with prebiotics. If you cannot find prebiotic-free probiotics where you live, you can make your probiotics in form of fermented foods such as homemade yogurt.
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