By Sandy Hemphill, Contributing Writer, BabyMed
Autoimmune diseases are on the rise in the developed nations of the world. These diseases occur when a person’s immune system turns inward, attacking the person’s healthy tissue instead of fighting foreign invaders such as bacteria, fungi, and viruses that cause illness. It’s a puzzling situation because people in Westernized nations have cleaner air, cleaner water and food, cleaner homes, schools, offices, and lifestyles than their counterparts in less developed areas of the world where autoimmune diseases are basically non-existent. Some experts on health and the environment suggest it’s this very cleanliness itself that triggers these autoimmune diseases. That we are sanitizing ourselves into poor health. This theory, known as the hygiene hypothesis, has been strengthened by a multinational study of the infant gut microbiome.
Autoimmune Diseases
Women are more likely to develop autoimmune diseases than men and many women first experience symptoms during childbearing years. These long-term, sometimes debilitating diseases can strike at any age, however, and are believed to be an inflammatory response to immunological attack. Some of the most common are celiac disease, type 1 diabetes, Guillain-Barré syndrome, inflammatory bowel diseases (IBD), multiple sclerosis, myasthenia gravis, psoriasis, rheumatoid arthritis, scleroderma, and vitiligo.
The Human Gut Microbiome
Running the length of one’s entire digestive system is a vast population of thousands of different kinds of microbes (bacteria, fungi, and other microscopic organisms) that were once thought to benefit digestion. They do, but this microbial colony (the human gut microbiome) has been the subject of intense study in recent years and is now thought to influence health and well-being from head to toe. It has been associated with appetite control and suppression, obesity, mental health and mood, and it seems to play an important role in the strength of the individual’s immune system.
Estonia, Finland, Russia
A team of researchers from Estonia, Finland, Russia, and the US have studied the gut microbiome of 200 infants in Estonia, Finland, and Russia to determine if microbial composition changes from nation to nation, how the individual infant’s microbiome differs from the others, and how changes affect the baby’s immune strength.
Babies are born free of gut microbes; they weren’t exposed to any in the womb. The gut microbiome begins forming almost immediately, though, as the baby picks up microbes from the mother’s birth canal and through breast milk. An infant’s gut microbiome goes through several changes as it transitions from a milk diet to more solid and varied foods.
The parents of the babies in the study submitted questionnaires about breastfeeding, diet, family history, infections, allergies, and such. They also submitted samples of their babies’ stool once a month from birth to age 3. The stool samples produced the most revealing data.
Finland and Estonia are Westernized nations, with lifestyles on cleanliness par with the US and most of Europe and a rising rate of autoimmune diseases. Russian Karelia, a region of Russia that borders Finland, is not as technologically advanced. Lifestyles here are quite different from those in Estonia and Finland and autoimmune diseases are rare. Infant gut microbiomes differed accordingly.
E. Coli versus Bacteroides
Lipopolysaccharides (LPS) are fatty, starchy sugars that trigger an immune response (attack). In lab settings, LPS from the E. coli bacterium is often used to stimulate a response. E. coli is often the subject of headlines when foodborne illness causes outbreaks that sicken people but it is a primary component of the gut microbiome of healthy humans. Illness occurs when E. coli from foreign sources (livestock, rodents, sick people) is consumed by accident.
The Russian babies had an abundance of healthy E. coli in their guts. The Estonian and Finnish babies did, too, but a bacterial species called Bacteroides was more active.
The researchers found the E. coli in the Russian babies was able to trigger stronger immune responses when these children were exposed to pathogens that might cause illness. Their immune systems were strong enough to stay busy fighting true immunological threats rather than turning inward to attack healthy tissue.
The more active Bacteroides in the other children, however, suppressed action of E. coli, a finding described as “immunologically very silent,” by Aleksandar Kostic, working on the study from the Broad Institute of Massachusetts Institute of Technology and Harvard University in Boston. He added, “We believe that, later on, this makes them more prone to strong inflammatory stimuli.”
The research suggests the stronger immune response by E. coli began in times past as a part of human evolution. Bacteroides, on the other hand, seems to be an evolutionary newcomer somehow associated with the cleaner living standards of today.
Sources:
"Autoimmune diseases fact sheet."WomensHealth.gov. Office on Women's Health / US Department of Health and Human Services, 16 July 2012. Web. 6 May 2016.
Vatanen, T, et al. "Variation in Microbiome LPS Immunogenicity Contributes to Autoimmunity in Humans."PubMed. Cell / Cell Press, Elsevier, 27 Apr. 2016. US National Library of Medicine / National Institutes of Health. Web. 7 May 2016.