An adult has between six and eight pounds of bacteria in his or her intestines. The total of bacterial cells in the colon is more than the number of cells in the entire body (the bacterial cells are much smaller). The bacteria belong there. The right species of bacteria will produce nutrients, remove toxins, support the intestinal lining and keep undesirable bacteria in check.
In research published in the Journal of Allergy and Clinical Immunology (2001;108:516-520) a group of scientists measured the composition of microbes in the stool of infants from Estonia and Sweden. They began testing a few days after birth and then tested periodically during the first year
They found that children who developed allergies by the time they turned 2 years of age had different amounts of certain bacteria in their guts than those without allergies.
The researchers found that more of the allergy-free children had Enterococci and Bifidobacteria. Infants with allergies had more Staphylococcus aureus and higher amounts of Clostridia. This research supports a growing body of data linking allergies to the presence or absence of different bacteria in the intestines of infants. Antibiotic use can change the bowel flora.
We cannot be sure if the difference between the bowel flora is due to cleanliness or diet. Some think that the cleaning and sterilizing of the home may be responsible for this difference in flora. More Swedish children than Estonian children develop allergies. The Swedish children grow up in more sterile environments than the Estonian children.