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A Dirty Baby is a Healthy Baby!

July 16, 2014

Is it good for babies to be exposed to dirt and germs?

I laugh when I think about it. This must be why my own children, now young adults, have taken antibiotics only a few times in their lives. One thing you can say about my children is that they have grown up in their fair share of dirt (and mess). A good housekeeper I am NOT. My two step-children, on the other hand, are among the worst ear infection and allergy sufferers I have known, and my husband’s best friend before we met was a bottle of household bleach. I am grateful to him, however, as our home is much tidier since we got married. Go figure.

Chuckles aside, there is really some very important science here. The “hygiene hypothesis” suggests that:

Infants who are reared in an environment without many germs and allergens

may develop more significant allergies and illnesses

than those who are brought up exposed to “normal” germs and allergens.

Infants who are reared in an environment without many germs and allergens may develop more significant allergies and illnesses than those who are brought up exposed to "normal" germs and allergens. The hypothesis was born out of the observation that children who grew up on farms had fewer allergies and illnesses than those who grew up in clean urban or suburban homes. This makes sense when you think about how the immune system develops. Newer information regarding the human microbiome (the bacteria that normally live in and on us all) and its effect on many aspects of our health adds even more to the idea that we are not meant to grow and develop in an overly “clean” environment.

How “good” bacteria helps our bodies

When we are born, the first thing that is supposed to happen is that we are supposed to get colonized by all of the bacteria in our mother’s vaginal passage and beyond. We are sterile inside of the womb, but as we enter the world we become covered, both inside and out, by germs that are a normal part of us. This is called “the human microbiome.” If we are born by C-section, we miss out on that natural colonization. Instead, we get colonized by hospital germs, which are likely not normal inhabitants of the human body like mom-germs. Interestingly, there is a whole project going on right now called The Human Microbiome Project. Part of that project has discovered that people born by C-section have a much higher risk of obesity than those born vaginally. It may be that having nice, normal bacteria in our guts helps us to maintain a healthy body weight. There is research being done painting babies born by C-section with swabs taken from inside of moms’ birth canals, to try to imitate normal birth germs for those babies to see if this will prevent obesity and other diseases later in life.

For years, studies have shown that exposure to a normal degree of germs and allergens early in life help us to develop what is called “tolerance.” This prevents us from reacting to ourselves, limiting “auto-immune” diseases, where our immune system attacks our own bodies. In other words, early in life our immune system is open-minded. It is busy figuring out what “self” is so that later on it can recognize and attack “non-self.” What has been found is that children who are exposed to lots of normal healthy germs and antigens early in life become more tolerant and less reactive. They are less likely to have allergies, develop secondary infections like ear and sinus infections, and have complications such as bronchiolitis and allergic asthma. They are probably also less likely to have autoimmune diseases,such as diabetes and inflammatory bowel disease, and may even suffer from less obesity and depression. This all may happen due to differences in the microbiome.

Maybe dogs are our kids’ best friends

Recent studies also show that early exposure to dogs protects children from the development of allergic asthma. Early exposure to cats seems to help too, but to a lesser extent than exposure to dogs. These studies showed that exposure to dust containing dog dander actually led to children having more of certain protective bacteria in their intestines. Dog exposure led to a different microbiome in the child, which was directly linked to a decrease in allergic asthma.

Of course, there are genetic factors that play a role here, too. Families who tend to develop allergies and asthma are at higher risk than those who do not. However, the protective effect of early exposure works for everyone to a degree. Also, and this is VERY important, we are not talking here about exposure to bad germs like those from unpasteurized milk or exposure to contaminated feces or meats. Many bacteria cause very serious illness. These are very different from the nice helpful bacteria we are talking about here, and are easy to avoid with good hand-washing, healthy food preparation, and avoidance of fads like unpasteurized products and raw eggs (these fads would take us back to the dark ages).

So what should you do?

Relax! Get a nice dog (my dog, Ben, keeps me healthy both physically and mentally). Let your children play with toys on the floor. Don’t worry about hand-sanitizing every minute, but be sure to wash your hands before you eat and cook your food appropriately.

Live a normal, relaxed life and you may find that your children are healthier for it!