Going With the Gut May Prevent Allergy, Asthma

From the WebMD Archives

April 5, 2001 -- A new Finnish study provides more evidence that some germs can be good for you.

Researchers say they seem to have cut in half a baby's risk of developing allergic conditions early in life by giving a beneficial bacteria to expectant mothers and their newborns who were predisposed to eczema, hay fever, and asthma.

"Our new insight might provide an opportunity to devise strategies against allergy, the pandemic that affects almost half the population in more-developed countries," write Marko Kalliomäki, MD, and colleagues in the April 7 issue of the medical journal The Lancet.

The researchers recruited near-term pregnant women who had a family history of allergic diseases -- such as asthma, hay fever, or atopic eczema (a type of reactive skin rash) -- into a clinical trial in which they and their infants would receive either placebo capsules or capsules containing a potentially beneficial type of bacteria called Lactobacillus GG.

Lactobacilli normally are found in the healthy gut in humans but may be missing or present only in reduced numbers in children born in developed countries, where attention to strict hygiene and smaller family sizes mean that infants are less likely to be exposed to the bacteria once common in the environment.

Some researchers speculate that alarming increases in allergies and asthma over the last few decades may be due to an overactive immune system in the first months of life -- a result of children not having enough "good" bacteria like lactobacilli to keep the immune system in check. Such germs prevent the immune system from going into alarm mode when it detects an otherwise harmless intruder, such as pollen, dust, or a specific food, such as peanuts.

"Why is allergy becoming more of a problem? Everyone knows this; the incidence of asthma has gone up, the incidence of atopic eczema has gone up, it's becoming a huge problem. The prevailing theory is that we're too clean," says Sherwood Gorbach, MD, professor of community health and medicine at Tufts University School of Medicine in Boston, who was co-discoverer of Lactobacillus GG (the "G"s stand for Gorbach and Goldin).


Researchers have been investigating whether giving a mixture of "good" bacteria, known as probiotics, would prevent overactivity of the immature immune system.

"There's been a series of studies [the Finnish group has] published over the last five or six years showing that infants taking probiotics have decreased milk allergies and they have fewer skin complications," notes Barry Goldin, PhD, professor of family medicine and community health at Tufts University School of Medicine, Gorbach's colleague, and the other "G" in GG, who reviewed the study for WebMD.

In the current study, Kalliomäki and colleagues gave women placebo capsules or capsules containing Lactobacillus GG to take from two to four weeks before their anticipated delivery dates. After birth, they either took the capsules themselves and passed the bacteria to their infants through breast milk, or gave their infants the bacteria diluted in water. The capsules were given until the infants were 6 months old. Researchers then followed the children until the age of 2 years and determined which had developed allergic diseases

The researchers found that 46 of the 132 children who were enrolled in the study had atopic eczema at age 2; six of these children had all the signs of asthma, and one had evidence of hay fever.

Of the 46 children, 15 had received Lactobacillus GG capsules, and 31 had received placebo. In other words, kids who were given the probiotics were only half as likely to have common allergic diseases as those who received the placebo.

"These figures are remarkable and, if confirmed in other studies and applicable to other allergic diseases, probiotics would represent an important therapeutic advance," writes Simon H Murch, MD, PhD, from the Center for Pediatric Gastroenterology at Royal Free and University College School of Medicine in London, in an editorial accompanying the Finnish study.

In an interview with WebMD, Murch notes, "most people in the field recognize that children today are getting very different infection exposures. I think most of the interest prior to this was in relation to infection exposures in an older age group. What this study suggests is that the very first exposure of the immune system may also be important."


He cautions that more testing needs to be done and the safety of probiotics in infancy be confirmed before the idea of "allergy-proofing" infants with probiotics becomes routine.

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