The Microbiome | thirdAGE

Microbiome

What is the Microbiome?

Our brain, gut, immune, and hormonal systems are intricately interconnected—and recent research has brought many fascinating studies about how crucial our microflora is to our bodies. These microorganisms are now understood to be crucial to genetic expression, body weight, mental health, memory, and risk of diseases as varied as Crohn’s, IBD, obesity, to diabetes and cancer.

The human body functions largely due to the presence of microorganisms including bacteria, fungi, and viruses. It is estimated that approximately 90% of the cells in and on the human body are those of microorganisms, and only 10% are actually human cells. Though there are microorganisms living on virtually every surface of the body, there are a few areas of interest that are generally referred to when one speaks of the microbiome. These are:

Gastrointestinal tract. This is the most commonly talked about area of the microbiome, largely to its diverse and vast population of microorganisms, and its wide-reaching effects on the body. According to the European Society of Neurogastroenterology and Motility, the gut microbiota includes tens of trillions of microorganisms, including over 1000 different species of bacteria, and can weigh up to 4.5 pounds. The gut microbiome aids the body in food digestion and nutrient absorption, and also plays an important part in immune functioning.
Mouth. Like the gut, the mouth has a large population of microorganisms. According to a recent study published in the American Society for Microbiology, the mouth is estimated to house anywhere from 500-700 species of bacteria. The same study also reports that the mouth microbiome composition may also be responsible for oral infectious diseases (tooth decay, gum disease, etc.) as well as systemic diseases such as cardiovascular disease, stroke, preterm birth, diabetes, and pneumonia. [NOTE: hyperlink to all relevant condition centers]
Skin. The skin is the body’s largest organ, accounting for approximately 15% of the average human’s body weight. The skin is host to a multitude of microorganisms that assist it in its many functions, including sweating, heat and fluid retention, and acting as an immune barrier. The constitution of the skin microbiome is largely dependent on the skin surface, the individual’s health, and the external conditions. Because of the variety of factors affecting the skin microbiome, these microorganismal populations tend to be extremely unique. A 2013 study published in Natural Reviews Microbiology found that an average of 68.1% of the bacteria found on a subject’s skin was only found on that particular subject.
Vagina. The vagina is populated by trillions of microorganisms that change throughout a woman’s lifetime. Potential factors affecting vaginal microbiome include menstruation, sexual intercourse, douching, and pregnancy. According to the vaginal microbiome consortium, a healthy vaginal microbiome can help prevent sexually transmitted infections, urinary tract infections, and bacterial vaginosis as well as help promote healthy pregnancy.

There is still much ongoing research into the human microbiome; the full effect of the microbiome constitution on human health is not yet known.

What Causes an Imbalanced Microbiome?

A healthy microbiome has a diverse population of microorganisms with no one population outgrowing the others. There are many factors that can cause disruptions to a healthy microbiome. These include:

Stress. Stress affects the level of stress hormones within the body and can make an individual more susceptible to changes in his or her microbiome.
Diet. The connection between diet and microbiome is one of the most highly contested and controversial areas of microbiome research. Many insist that relatively recent shift to high-fat and high sugar foods has caused shifts in the microbiome that have made the modern human more susceptible to diseases such as cancer, diabetes, inflammatory bowel disease, and obesity. Other controversial dietary items include meat raised with antibiotics and genetically modified organisms (GMOs).
Disease. Certain conditions, such as irritable bowel syndrome (IBS) and Crohn’s disease are thought to affect microbiome constitution. It is not known for certain if a disruption to the microbiome is a cause or effect of these conditions.
Antibiotic usage. It can take the body up to six months to return to a healthy microbiome state after a single round of antibiotics. Though antibiotics can be critical in treating a patient with a bacterial infection, there is fear that the over-prescription of antibiotics (and the lack of complimentary probiotic treatment) can lead to imbalances in the microbiome responsible for health problems such as obesity and chronic illness.
Environment. Humans are always engaging with the microorganisms in their environment; microorganisms cover nearly every surface we touch. The microorganisms in one’s home environment are likely to be found within that person’s healthy flora. Interacting with microorganisms from unfamiliar environments (i.e. while travelling) can have potentially disruptive effects on the health and microbiome (i.e. diarrhea, bacterial infection, etc.)
Family history. While microbial communities vary greatly between different households, they are similar amongst members of the same household according to research published in Science—and certain microbiota imbalances may carry throughout.

What is the Function of the Microbiome?

Researchers have already identified many possible functions of the microbiome. The functions of the microbiome can vary from location to location, though it is important to note that the microorganismal populations in these areas can and do interact with each other.

The known functions of the microbiome according to location are as follows:

Gut

Immune functioning. The microorganisms lining the gut form a barrier that can prevent potentially harmful bacterial populations from colonizing.
Production of vitamins. Microorganisms within the gut can help in the production of B and K vitamins.
Aids digestion of otherwise indigestible foods such as cellulose (found in plant cell walls).

Mouth

Immune functioning. The microorganisms within the mouth play an important role as a barrier from potentially harmful microorganismal populations. This can protect against systemic illnesses and those specific to the mouth (tooth decay, gum disease, etc.)

Skin

Immune functioning. Like the other microbiome locations, the skin and the microorganisms on it function as an important barrier for the body against disease.
Health/appearance of skin. The appearance/health of skin is largely influenced by the microbiome population of the skin. The skin microbiome constitution can contribute to conditions such as dry skin, oily skin, acne, and various skin rashes.

Vagina

Immune functioning. The vaginal microbiome can help protect against diseases such as:
- Bacterial Vaginosis (BV)
- Sexually transmitted infections
- Urinary tract infections (UTIs)
- Yeast infections
- A healthy microbiome promotes fertility as well as decreases the risk of pregnancy complications.
- A fetus does not have a microbiome until birth. According to the Vaginal Microbiome Consortium, a mother’s vaginal microbiome plays a critical role in establishing her baby’s microbiome during its passage through the birth canal. Babies that are born via cesarean section do not pass through the birth canal and instead begin populating their microbiome once they are removed from the womb.

Microbiome

What is the Microbiome?

What Causes an Imbalanced Microbiome?

What is the Function of the Microbiome?

Microbiome at Birth

Symptoms of Imbalance in Your Microbiome

Prognosis

Choosing the Right Probiotic

Questions For A Doctor

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