C-sections, processed food, antibiotics, anti-bacterial wipes, telling your kids not to play in the sandbox: what do all of these have in common?
All of these aspects of contemporary life that we perform to be germ-free and healthy could actually be connected to an increase in autoimmune disorders, as writer Michael Pollan writes in the New York Times Magazine. The reason stems from new research by scientists about microbiomes.
The Trillion Microbes We Carry Around
Inside us — specifically, in our intestines and nasal passages and on our skin and tongue and elsewhere — are some one trillion microorganisms. These bacteria or “microbial inhabitants” form an internal ecosystem in our bodies that we’re just beginning to learn about. The implications for our health are huge, according to Pollan. Depending on factors such as what we eat or don’t, this internal system can become imbalanced when the “wrong” kinds of microbes proliferate or there’s a loss in the biodiversity of the microbes. The result is that we may be predisposed to “obesity and a whole range of chronic diseases, as well as some infections.”
That is, research about those trillion microorganisms or microbiota inhabits our bodies is revealing that bacteria and germs play a part in maintaining, rather than lessening, our health. It’s an apparently counter-logical notion but one that some recent developments have given weight to. “Fecal transplants,” in which one person’s microbiota is put into another’s gut, have been shown to be an effective treatment for C. difficile, an antibiotic-resistant intestinal pathogen that kills 14,000 Americans a year. Transplanting the microbiota of lean mice into the intestines of obese ones led to the latter losing weight.
Scientists are also finding that the microbiota of people in the U.S. and Europe are very different — specifically, far less biodiverse — than those of rural populations in West Africa and of Amerindians in Venezuela. This difference could be due to our overuse of antibiotics in our health care and also in our food supply. Other reasons, Pollan writes, are “our diet of processed food (which has generally been cleansed of all bacteria, the good and the bad), environmental toxins and generally less ‘microbial pressure’ — i.e., exposure to bacteria — in everyday life.” People from rural populations have lower life expectancies and greater susceptibility to infectious diseases than those in the West, but they also have lower rates of the chronic disorders that too many of Americans and Europeans have, including allergies, asthma, Type 2 diabetes and cardiovascular disease.
Adding Prebiotics to Your Diet
The scientists Pollan interviewed indeed single out the Western diet to blame for “altering our gut microbiome in troubling ways.” While most scientists are hesitant to make any actual recommendations about what to eat, they are wary about the use of probiotics to add “beneficial bacteria” to one’s gut. A study has found that, out of 14 commercial probiotics, only one contained the specific bacteria noted on the label.
But scientists seem to put more store in “prebiotics — foods likely to encourage the growth of ‘good bacteria’ already present.” As Justin Sonnenburg, a microbiologist at Stanford, says to Pollan, “there’s a case for dirtying up your diet.”
It’s not that you shouldn’t wash fresh produce you’ve purchased (it might contain pesticide residues). Not eating enough fiber can lower microbial diversity; to increase prebiotics in your diet, you can minimize the amount of processed foods you consume and eat a “variety of whole grains and a diverse diet of plants and vegetables as well as fruits.” Sonnenburg says that his own diet now includes fermented foods (yogurt, kimchi, sauerkraut) as these can promote the growth of the “good” bacteria that’s already in you.
Of course you should wash your hands “in situations when pathogens or toxic chemicals are likely present.” But, writes Pollan, “maybe not after petting your dog.”
Microbiota Growth Starts When We Are (Literally) Being Born
We start acquiring this “internal ecosystem” during birth. In fact, babies born via the “comparatively sterile procedure” of a Caesarean section in effect lose out on their chance to acquire their mother’s vaginal and intestinal microbes. They end up with “gut communities” that are similar to that of their mother’s and father’s skin which, says Pollan, “is less than ideal and may account for higher rates of autoimmune problems” — allergies, asthma — in C-section babies. Due to their “not having been seeded with the optimal assortment of microbes at birth,” these babies’ immune systems may actual fail to develop properly.
This last finding is of particular interest to me as I was delivered via C-section and had severe asthma (requiring hospitalization and numerous visits to the emergency room, all in the age before inhalers were developed) as a child. After my family moved back to to the city after a few years in the northern California suburbs, my asthma lessened, to the point that I became a cross-country runner in high school.
Research on microbiomes and how they affect our guts and health is still at a very early stage but can offer new insights. At the least, parents who see their child with playground dirt on their hands can perhaps breath a bit easier and know that a few germs can’t hurt you.
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