The gut flora, or microbiota, is a complex community of microorganisms that live in the gastrointestinal tract. Yes, our bodies host microbes — bacteria, viruses, fungi and eukaryotic species. These microorganisms outnumber our cells by ten-fold — that’s 100 trillion.
Microbiota provides a number of benefits to our bodies, including:
- Nutrient and drug metabolism
- Gut mucosal barrier
- Protection against pathogens
- Increases the immunological memory
- Enzyme capability
Research has also shown that the microbiota is crucial to our immune system. Our immune system is composed of a network of components that possess the capacity to adapt as well as respond to pathogen invasion. This network acts as a regulator, allowing restoration of tissue function after microbial and environmental encounters.
Innate Immunity
Innate immunity is comprised of cells and mechanisms, and it is our first line of defense from infection. It’s the dominant immune system response, and it responds to the pathogen in a nonspecific manner — it is not pathogen-specific.
Adaptive Immunity
Adaptive immunity, also known as acquired or specific immune system, is a sub-system composed of specialized, systematic cells that eliminate pathogens or prevent their multiplication and growth. After the initial exposure to a pathogen, our acquired immune system develops an immunological memory leading to an enhanced response to subsequent infections caused by the said pathogen. The body’s ability to avoid or fight an infection largely depends on the immunological memory of the adaptive immune system. However, the adaptive immune system responses are slow to develop and can take a few days. That’s why we rely on our innate immune system to protect us in the first critical hours. We need the innate immunity to activate the adaptive response.
The Immune-Microbial Connection
The gut microbiota is symbiotic: the body provides nutrients and environment for the microbiome to grow, while the gut flora supports the development and maturation of the intestinal immune system. Therefore the interaction between the microbiota and the immune system is critical to maintaining mucosal homeostasis. The immune-microbial system alliance, in its optimal operation, creates a connection between both the innate and adaptive system. It is this connection that selects, separates and adequately responds to pathogens.
What’s the Problem?
The microbiota typically improves our immune IQ and enhances the immune cells to discern between the pathogens that are self or foreign. An alteration on the composition and function of the gut microbiota affects our immune system and transforms our microbial allies into potential threats or liabilities. The body’s failure to recognize, respond and remember a pathogen is affected by the quality and state of the gut flora, which further predisposes one to obesity, malnutrition, Inflammatory Bowel Disease and neurological disorders. Furthermore, pathologies that affect humans such as autoimmune, allergies, and inflammatory disorders arise from a failure of the immune cells to distinguish between self, microbiota or environmental-derived antigens.
Biological and Environmental Factors That Can Influence the Gut Microbiome and Alter its Function:
Mode of Delivery
Gut flora gets colonized immediately after birth. Babies born through vaginal delivery have a slight advantage over those delivered via cesarean, but those babies delivered by cesarean do get colonized with some gut flora from the maternal skin flora.
Diet
Diet plays a vital role from infancy into adulthood. Breastfed infants tend to have a stronger gut microbiome compared to formula-fed ones. Breastmilk contains Bifidobacteria and Lactobacillus, both of which offer protection. Furthermore, it has Human Milk Oligosaccharides (HMO), which are broken down by the bacteria, and they help with nutrient digestion. Diet, however, can be a determinant in the composition of the gut flora throughout adulthood. A diet rich in vegetables, fruits and fiber can help keep the gut microbiota diversified. Fiber, meanwhile, promotes the production of Short-Chain Fatty Acids (SCFA), which may be beneficial against digestive disorders and may improve ulcerative colitis and Crohn’s disease symptoms.
Antibiotics
Antibiotics are used to fight infections and reduce the severity of the disease. However, strong evidence has demonstrated that antibiotics have short and long-term implications in the ecology of the gut microbiota. Antibiotics can affect the diversity of the gut flora and may cause the rise of opportunistic infections like Salmonella.
Genetics
A colony of gut bacteria is influenced in part by our genetic makeup. People from the same family have similar microbiota. Identical twins have more of a similar microbiome than fraternal twins.
What’s the Solution?
The diversity of the gut microbiota determines its health; the more species of bacteria, the greater the benefits. The diversity of the gut flora can be improved in various ways:
Food and Diet
A diet consisting of different foods will enhance the diversity of the microbiota. Food provides a competitive advantage for the microbiome; therefore the more diverse your diet is, the more adaptable the flora will be. Unfortunately, our diet is often lacking in diversity. Most people consume more processed foods and fewer fruits and vegetables — which are rich in nutrients beneficial for the gut microbiota.
Fruits and vegetables can prevent disease-causing bacteria. Moreover, artichokes, apples and blueberries have shown to increase Bifidobacterium, which helps to prevent intestinal inflammation as well to enhance gut health. Yogurt and other fermented foods also help to improve gut microbiome. People who consume yogurt regularly have more Lactobacillus, which has been proven to modify the intestinal bacteria and enhance the lactose intolerance symptoms in infants. However, chose natural yogurt over flavored varieties, which are very high in sugar and may disrupt the gut flora.
Avoid Artificial Sweeteners
Most people opt for artificial sweeteners as a sugar replacement. Research has shown that sugar can affect the microbiota. Aspartame, for example, can increase levels of bad bacteria in the intestines, increase blood sugar and impair insulin sensitivity.
Eat Prebiotic Foods
Prebiotics are indigestible carbs, such as fiber, that feeds the gut bacteria. These components promote healthy bacteria like Bifidobacteria that reduce insulin, cholesterol and triglycerides. Many fruits, whole grains and vegetables contain prebiotics.
Eat Food Rich in Polyphenols
Polyphenols are plant compounds that can’t be digested by our human cells. But, they are digested by the gut microbiome like Lactobacillus and Bifidobacteria. Polyphenols help to reduce blood pressure, cholesterol levels, inflammation and oxidative stress. Good sources of polyphenols include red wine, cocoa, grape skins, almonds, broccoli, blueberries and green tea.
Take Probiotic Supplements
Probiotics, usually bacteria, are live microorganisms. Even though probiotics do not permanently change the gut microbiome, they do improve the composition of the microbiota and also support your metabolism. Probiotics may not significantly alter the composition of the gut microbiota in healthy people, but they improve and restore a compromised one.
Our gut flora is crucial to our immunity and overall health. Research has indicated that disrupted gut microbiota can predispose you to chronic diseases. Maintaining a healthy gut microbiota is essential to our health. The bottom line? Adjust your diet, reduce stress and avoid taking antibiotics unless necessary.