The Human Microbiome: Bacteria's Role In Daily Health

The instant you hear the word “bacteria” associated with your body your first instinct is probably to deploy a round of antibiotics in an effort to kill those cursed creatures before they have the chance to cause you any harm. After all, bacteria in all its mutated forms are bad, right?

Actually, the answer is somewhat complicated. These “germs” and “bugs” that have accumulated a mostly rotten reputation over the centuries can indeed conjure up a host of adverse health conditions—but as it turns out, the 100 trillion microbes taking up residence in and on you are also a fundamental part of your physiological wellbeing. 

While congregated mostly in your digestive tract, the human microbiome influences far more than the state of your gut. Sure, that’s a major aspect of their purpose, but these crucial microbes are a significant factor across your entire body. In fact, researchers studying these plumes of life have dubbed them the “second genome,” characterizing the microbiome as a source of genetic diversity, a modifier of disease, an essential component of immunity, and a functional entity that influences metabolism and modulates your body’s interaction with outside substances—all there residing in your gut, nose, lungs, skin, and other bodily locations.

Your Microbiome: Always With You

Those same researchers say that your microbiome starts to grow at or even before birth, ultimately developing into a diversified collection of symbiotic ecological systems with an array of distinct colonies living in relative harmony. And what’s really incredibly astonishing is the physical weight of these bacteria—even though they are significantly smaller than a human cell, you can carry up to five pounds of them in and on your body. 

It seems impossible that something so obvious could stay hidden for so long, but until the advent of the Human Microbiome Project in 2007, these little helpers operated basically under the radar. That project saw scientists take tissue samples from about 250 volunteers over a period of close to five years. Researchers were so surprised by what they found that these scientific minds actually used a somewhat unscientific simile to describe their findings, stating that “each body site can be inhabited by organisms as different as those in the Amazon Rainforest and the Sahara Desert.”

In all, the Human Microbiome Project successfully identified more than 10,000 microbial species inhabiting the human ecosystem, with researchers estimating that they have now classified up to 99 percent of all microorganisms in healthy adults.

They continued with the whimsical simile, stating that, "Like 15th century explorers describing the outline of a new continent, Human Microbiome Project (HMP) researchers employed a new technological strategy to define, for the first time, the normal microbial makeup of the human body. HMP created a remarkable reference database by using genome sequencing techniques to detect microbes in healthy volunteers. This lays the foundation for accelerating infectious disease research previously impossible without this community resource."

Why is Gut Bacteria So Important To Your Health?

As stated earlier, healthy and helpful bacteria are living all over and inside of your body at this very moment—but in truth, it’s your gut bacteria that are likely most important to your everyday, overall health. Most of the possibly thousands of species of bacteria in your gut belong to one of four groups: Firmicutes, Bacteroidetes, Actinobacteria or Proteobacteria.

Friendly gut bacteria, or gut flora, are vital for healthy digestion, as your friendly neighborhood microorganisms can defend against villainous versions of bacteria and other microorganisms, acting as a protective barrier against intestinal infections. Gut bacteria also helps to produce nutrients that offer an array of benefits, including vitamin K, which assists in the production of blood-clotting proteins. 

As for the good bacteria you consume as part of a healthy diet, you probably know those by the general name “probiotics,” which refers to a set of live microorganisms that provide physiological benefits when consumed.

The main dietary sources of probiotics include yogurt with live or active cultures, unpasteurized sauerkraut, kimchi, miso, kombucha, fermented soybeans, and some cheeses. 

In digestive health, probiotics are generally beneficial in gastrointestinal conditions, with studies showing that this good bacteria potentially exhibits a positive effect on certain types of diarrhea.  When the gut contains more bad bacteria than good bacteria, it can lead to inflamed bowels and a host of stomach problems. Plus, general reduction in gut flora diversity has been linked to weight gain, inflammation, obesity, and other conditions. 

Probiotic bacteria has also shown promise in supporting both the immune system and mental health. One study demonstrated that certain strains of probiotics displayed an effectiveness in protecting cells against an overabundance of yeast and fungi, along with attacks from various viruses. Meanwhile, the positive or negative state of your gut microbiota could even influence the degree of anxiety and depression you experience.

You see, the gut has been referred to as your body’s “second brain” or gut-brain axis. This second brain refers to the physiological connection between your gastrointestinal tract and your brain—a  by the fact that your gut microbiota produces much of your body’s dopamine and serotonin. This study demonstrated that strains of probiotic bacteria were possibly effective in delivering benefits for dealing with issues of anxiety, depression, and cognitive performance. 

Factors That Can Damage Your Microbiome

As impressive as your microbiome is, it’s sadly not immune to damage from outside forces—and let’s be honest, its main adversary can be us and the poor health choices we sometimes make. While many factors have the power to influence all corners of your health, when it comes to the microbiome, we’re going to focus on eight specific areas where you can have an immediate impact on the health and wellbeing of your microbiome.

Diet Diversification:

As your gut is populated by a seemingly impossible diverse cast of bacterial characters, it stands to reason that it would need a vast array of provisions in order to maintain homeostasis. Studies show that a diet that starts with a wide variety of whole foods like fruits, veggies, and whole grains can strengthen gut flora and inspire bacterial diversity. What’s more, it could conceivably take only a handful of days to positively alter the profile of your gut flora. So get to the grocery store, start diversifying, and say no to junk food!

Be A Prebiotic Pro:

You cannot simply expect to have healthy bacteria bloom in your gut without contributing something to the equation. Prebiotics are basically the nourishment your probiotics need in order to proliferate in a healthy manner and help you reap the bacterial benefits. Prebiotics are essentially dietary fiber, and are found in foods like bananas, onions, apples, oats, barley, leafy vegetables, nuts, and seeds.

Drink Responsibly:

Though a drink or two can net some positive health results, chronic alcohol consumption can have many adverse effects, not the least of which is compromising the health of your gut. One particular study showed that heavy alcohol use could potentially lead to an imbalance between good and bad bacteria, which causes a variety of gastrointestinal concerns. On the flip side, moderate red wine consumption was shown to increase the content of your gut’s polyphenols, plant compounds that can nourish probiotics as prebiotic food. 

Use Antibiotics Only As Directed:

We’ve all been prescribed antibiotics in the hopes of cutting various illnesses short. The problem is, these miracles of modern science have the same sweeping effect on both good and bad bacteria—and studies show that no matter what type of antibiotic treatment you receive, it can work to alter the harmony of your gut flora. Studies demonstrate that antibiotic use can lead to a short-term decline in beneficial bacteria and rise in harmful bacteria, as well as a more long-term reduction in the diversity of good bacteria and an increase in the number of resistant strains of bad bacteria. 

Get Physically Active:

It seems that physical activity always ranks as one of the best lifestyle changes you can make for your health—and it’s no different for the health of your microbiome. Specifically, physical fitness has been linked to an increase in the short-chain fatty acid butyrate, which has a hand in producing healthy gut bacteria. While these benefits cross gender lines, one study that focused on women showed that low-to-moderately active women had higher levels of healthy bacteria.

As Always, Quit Smoking:

Are you really still a smoker? Even with all the graphic research pointing to just how bad it is for you? Well, here’s another realm where smoking can cause adverse health effects. Smoking cigarettes is a risk factor for inflammatory bowel disease, which is caused by an inflammation of the digestive tract. What’s more, quitting smoking could actually increase the diversity of healthy gut flora. 

Sleep Well:

We all possess an internal clock that somehow steps in to wake us up when we hit the snooze button one too many times. This natural timepiece in your body is known as your circadian rhythm, and it can affect all aspects of your physiology, from your brain to your hormones. There also seems to be a connection between your microbiome and a circadian-like rhythm—and a lack of sleep could have harmful effects on your gut bacteria’s ability to operate to the best of its ability. Evidence of this connection was demonstrated in a 2016 study that showed sleep deprivation causing changes to gut flora, increasing the amount of bacteria that’s been associated with weight gain and obesity. 

Manage Stress:

It should come as no surprise that stress can cause problems for gut microbiota, given that we’ve all felt the gastrointestinal discomfort associated with mental hardship. While animal studies show that stress could potentially increase harmful bacteria in the gut, it’s a study involving college students that’s truly enlightening. The study analyzed the composition of gut bacteria at the beginning of a college semester and at the end of the semester during final exams, with the results indicating that academic stress could cause a reduction in friendly gut bacteria. 

Be Good To Your Microbiome

When you sit back and think about all the physiological functions that make up your body, it can be rather interesting. But when you consider all of the microscopic—and living—microorganisms that are hard at work at any given moment inside of you, it can be downright staggering. You are truly walking around with your very own incredibly active ecosystem—so treat your little helpers with the high regard they need to contribute to your daily health!