Are Biomes Important to Health? Part II

Biomes probably have more to do with your health than anything else. Moreover, we know from recent studies that your diet can increase or decrease the risk of cardiovascular disease in both men and women, which is the most common cause of death in developing countries. The differences in gut microbiota are unambiguous in lean versus obese people; they are startlingly different. However, the good news is that a diet of meat, rich in sugar and replete with processed foods, may adversely affect the balance of microbes in the gut and support the extraction of calories from food. On the other hand, a plant-based diet may be more sensible, providing fiber and vitamins without all the sugar.  Studies in mice suggest that obesity depends on their bowels' microbiome.  A lean mouse given a stool transplant from a fat mouse results in the lean mouse gaining tremendous amounts of weight in a short period. This suggests that we have the power to positively influence our gut microbiota through our dietary choices.

The 27 feet of bowels we all have not only help us to digest food and absorb it, but they also play a crucial role in protecting us from harmful organisms. They prevent the colonization of harmful organisms like the lady in my previous article, Melanie’s Clostridium difficile (C. diff), from gaining a foothold. This microbe-host relationship is vital to our well-being, and it was the imbalance caused by the many antibiotics that Melanie took that caused her to be infected and almost killed by the organism C. diff. To be sure, any disruption of the bowel wall results in an invasion of bad microorganisms and subsequent inflammation. Our bodies have a natural defense system in place, and understanding the role of the gut microbiota can help us appreciate its protective function.

Although I am speaking mainly about the gut microbiome here, I want to shout out to other biomes as well.   In urban environments, allergic diseases are more familiar to dogs and their owners than dogs living in rural areas. A study from Finland indicates that urban dogs are more likely to have allergies when their owners suffer from allergic symptoms. The study involved the biome of the skin.  The Finns suggest that the living environment had a more significant effect on the skins of humans and dogs, which is typical of humans who live close to their dogs in apartments. Both living habits and living environment affected canine skin microbiota. Unfortunately, this research is early; no specific organisms have been identified in dogs or humans. Still, it indicates that the biome of other areas, like the skin, might be just as crucial to the immune system as the bowel.  Many investigators believe the skin biome changes regularly and is essential in some body regions, such as areas with more sweat glands.

At what age is the biome important?

We know that the organisms in your bowel are vital to good health and that this essential balance starts at birth. The “hygiene theory” within medicine says that exposure of children to dirt and germs early in life is good and results in a robust immune system and less asthma or allergic diseases like eczema.  Living on a farm and being around manure, which farm children probably breathe and ingest, results in fewer allergies and healthier immune systems.  This gives credence to the fact that even urban children who eat dirt, pick their noses and eat the snot, and luxuriate in covering themselves in the mud might have healthier immune systems because of “antigen exposure or foreign materials “at a young age, essentially enlarging their microbiomes.

Prenatal and early stressors in the infant can affect the immune system and its development very early and subsequently for the rest of the person’s life. Hormone levels are affected by diet and the microbiome, which communicates with the infant’s brain and his developing immune system. Studies are now geared to look at the infant’s “imprinting,” or epigenetics, from the early presence of specific organisms or lack thereof in the infant's bowel. Imprinting is epigenetic and comparable to temporarily changing the genetics or nature of gene expression.  No one has explained the high rates of asthma and allergy among the urban poor children in the USA. Still, I have heard that air pollution from auto exhaust and the aerosolization of automobile rubber tires along roads and highways are culprits (traffic-related pollutants were responsible for a 12% increase in asthma in children by age 4).  If true, this is extraordinary and needs our public health attention.  I can only imagine that such pollutants affect every biome of the child’s body.