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Improving your gut health can have a profound impact on how you feel and even how you age. You’re not alone if you have some confusion around prebiotics and probiotics, however.

Probiotics and Prebiotics: What to Know for Optimal Gut Health
Probiotics and Prebiotics for Gut Health

Most of us know prebiotics and probiotics are related to gut health but are they the same thing? Are they necessary? And if so, how should we use them? Before we get into what is probiotics and prebiotics, we should first learn about gut health.

Why Does Gut Health Matter?

Gut health gets the main headline treatment in every health publication for a reason. New studies come out weekly, adding to evidence of a vital connection between the health of the gut and almost every aspect of overall health.

The term “gut” refers to that part of the gastrointestinal tract that breaks down food, extracts nutrients, and helps in delivering those nutrients to where they’re needed for the function of cells and DNA throughout the body.

The gut is where the outside world (in the form of foods we eat) comes into intimate contact with our inner physiology. This is why the majority of our immune defences are found in the gut.

A healthy gut is home to a vast army of beneficial microbes. These microscopic organisms help defend the body against pathogens and toxins and play an important role in the body’s immune responses.

Research increasingly points to gut health being critical for mood, cognitive function, the prevention of chronic disease, and longevity.

The lining of the gut is a semi-permeable mucous membrane that keeps harmful toxins, bacteria, and other pathogens out of the bloodstream while selectively allowing water and nutrients to pass through into circulation.

When gut health is compromised, the “bad” bacteria in the gut can overwhelm the “good” bacteria.[1] Some harmful bacteria may release toxins that cause inflammation and damage the gut lining, allowing toxins and pathogens into circulation. This can cause whole body or local infections and inflammation that can eventually show up as chronic disease states.

Conditions like skin irritations, mood disorders and chronic pain as well as obesity and cardiac disease can all originate from an unhealthy gut.

An abundance of helpful gut microbes protects us against these problems and many more.

What Are Probiotics?

As per the defination of Tina Salicco Jackson, Functional Diagnostic Nutrition Practitioner, probiotics are microorganisms (bacteria) introduced to the body to provide health benefits, such as taking up real estate in the gut microbiome so that other bad pathogens cannot fill this space.

Most probiotics are bacteria but certain types of yeasts also qualify.

Probiotics Support Gut Health

Probiotics support and contribute to the vast system of microbes that naturally live inside the digestive tract.

All the trillions of microorganisms living in the gut—both beneficial and harmful—make up an ecosystem called the microbiome.

A healthy microbiome exists in a delicate state of balance, with good microbes outnumbering harmful ones.[2] Probiotic bacteria help maintain this balance. They also perform important functions within the gut, such as:

  • Break down food and extract nutrients
  • Aid in nutrient absorption
  • Synthesize vitamin K and certain B vitamins
  • Produce serotonin, a neurotransmitter that helps regulate mood and sleep
  • Support a strong immune system
  • Create and maintain the protective lining of the gut
  • Protect against infections from harmful bacteria

Probiotics Combat Harmful Bacteria

Harmful bacteria are everywhere. Sometimes they even hitch a ride on the foods we eat. You already know the names of some of these bad guys if you’ve ever heard of a Staph, Salmonella, or E. coli infection. These are commonly caused by foods contaminated with pathogenic bacteria that invade the gut and lead to illnesses that can range from mild to life-threatening.

Other harmful and opportunistic microbes live naturally in the gut and only become a problem when they multiply in overwhelming numbers. Habits like eating a lot of sugar and inflammatory processed foods feed these bad bacteria, making their numbers swell. This creates an imbalance in the microbiome.

Probiotics deliver more beneficial bacteria to the gut, where they help compete against and crowd out the bacteria that cause harm.

The best first-line defences against harmful bacterial invaders are a strong immune system, lots of beneficial microbes, a healthy gut lining, and a varied diet of whole, natural foods.

Diversity is Key

People who live longer, healthier lives tend to have a wider variety of intestinal bacteria. In fact, a diverse microbiota is a marker of overall good health

Beneficial microbes all perform different jobs within the gut, so the more different kinds of good bacteria you have in your gut, the more essential jobs are getting done.

In the famous Blue Zones, which are places in the world where people tend to live much longer than the average lifespan, the microbiomes of the longest-living people harbor a more diverse Gut Microbiota which may contribute to their success in living longer, healthier lives.[3]

How to Increase Diversity in the Gut

Research indicates that a more varied diet increases gut microbiota diversity[4]. One easy way to increase the number and variety of good bacteria in the gut is to eat more fermented foods.

Fermented foods are a rich source of probiotics. They are often a dietary staple in places where people tend to stay healthy well into their later years. The benefits to gut health from eating fermented foods may be part of what contributes to population health in these regions.

Fermented foods feature in the cuisines of cultures all over the world. Some examples of probiotic-packed fermented foods are:

  • yogurt
  • cottage cheese
  • kombucha
  • cultured buttermilk
  • kimchi
  • kefir
  • fermented sauerkraut
  • fermented pickles
  • skyr
  • tempeh
  • miso

Try getting some probiotic-rich, fermented foods into your diet daily to increase the number and variety of beneficial gut microbes.

Other habits that help maintain a healthy, diverse microbiota:

Cut out sugar and processed foods

Bad bacteria feast on the typical Western diet which is heavy on sugar and processed foods. These foods allow harmful microbes to grow out of control while causing inflammation and starving beneficial bacteria. It’s hard to avoid sugar and processed foods altogether but cutting back as much as possible will help rebalance the microbiome in favor of beneficial microbes.

Drink coffee and tea

Coffee and teas contain compounds called polyphenols which help maintain balance in the microbiome by suppressing the growth of pathogenic bacteria, decreasing inflammation and reinforcing the intestinal barrier among other helpful actions.[5]

According to research on the effects of coffee on the microbiome has shown that coffee decreases numbers of the harmful bacteria E coli and Clostridium while increasing numbers of helpful bacteria called Bifidobacterium.[6]

Other good sources of polyphenols are berries, nuts, olives and spices including turmeric, cinnamon and ginger and cloves.

Go for organic

Research on the connection between microbiota composition and pesticides is ongoing but there is some evidence that common pesticides like glyphosate and chlorpyrifos can alter the microbiota adversely[7] by decreasing beneficial bacteria and increasing numbers of pathogenic bacteria.

Intermittent fasting

Some studies suggest intermittent fasting may improve gut health[8]. Intermittent fasting is a type of time restricted eating where you eat all your meals within a short window of time during the day (typically an 8 hour period).

Eating this way allows the gut a long break from the work of digestion during which the mucous lining can be repaired. Fasting may also alter the the microbiota in beneficial ways. You should check with your doctor before trying intermittent fasting because it’s not recommended for everyone.

Increase your fiber intake

One of the best ways to increase microbiome diversity and improve gut health is to eat lots of fibre in the form of prebiotics.

What Are Prebiotics?

Think of prebiotics as the food of choice for your probiotics.

Prebiotics are the fibrous or starchy parts of plants and vegetables that don’t get completely digested on their way through the upper intestinal tract.

When these undigested plant fibers reach the lower intestine, the beneficial gut microbes that live there go to work on breaking them down. This provides a rich food source for these probiotic bacteria and helps keep their populations thriving.

Some of the best prebiotic sources are foods like:

  • onions
  • garlic
  • asparagus
  • broccoli
  • spinach
  • artichokes
  • apples
  • bananas
  • nuts
  • beans

When you feed the beneficial microbes in your gut the nutrients they need, they will flourish and outcompete the bad bacteria that can cause health problems.

Should You Take Probiotic Supplements?

Probiotic supplements are generally considered safe for healthy people. Always ask your doctor before starting a new supplement, however. Probiotic supplements aren’t always helpful and can potentially cause harm. Rare cases of opportunistic infections and allergic reactions have been linked to probiotics in people with impaired immunity and severe allergies, for example.

When choosing a probiotic supplement, keep in mind that quality varies from brand to brand. Supplements are not regulated by the FDA, so what’s listed on the bottle may not necessarily be what’s inside.

High-quality supplement manufacturers take the extra step of having a third-party lab test their supplements and verify that they contain what they claim to. Look for verification of third-party testing on the label to ensure you’re choosing a quality probiotic supplement.

You can find probiotic supplements in the form of powders, capsules, and drinks.

The label of a high quality supplement will tell you how many live cultures it contains. This number is expressed as CFUs, or colony forming- units, which is the estimated number of living bacteria in a serving. The average number of CFUs in probiotic supplements ranges from 1 to 10 billion CFUs per serving.

The label should also list the different strains, or specific types, of bacteria in the supplement. Different strains perform different functions within the gut, so taking a supplement with multiple strains may be better than one that contains only one or two strains. More research is needed in this area.

Even when taking a daily probiotic supplement, it’s still a good idea to keep a varied diet rich in probiotic and prebiotic foods to optimise gut health.

How Do Antibiotics Fit In?

Antibiotics were once an almost unimaginable saving grace. Before the discovery of penicillin in 1928, young and previously healthy people routinely died of pneumonia, infections related to childbirth, and other bacterial illnesses. Even an infected cut or wound on the skin could sometimes lead to death.

In the years since, antibiotics have transformed the treatment of bacterial infections, but overuse of antibiotics has become a serious problem with the rise of antibiotic resistant strains.

When taken inappropriately (not finishing a prescribed course or taking them for a viral illness instead of a bacterial infection, for example), antibiotics can cause more harm than good.

Even when antibiotics are necessary and used as prescribed, they can lead to long-term gut health problems. This is because antibiotics kill both good and bad bacteria, wiping out the diverse population that gives you the bulk of your ability to fight off infections in the first place.

It can take months to replenish beneficial bacteria in the gut after a course of antibiotics. Taking probiotic supplements and eating probiotic and prebiotic rich foods may help to get your gut health back online faster.


Improving your gut health doesn’t happen overnight. You’ll likely need to adopt some new habits and stick with them over time. This might mean trying and experimenting with new foods, taking probiotic supplements, limiting exposure to toxins and pesticides, and cutting out foods that feed harmful gut microbes.

As you pay more attention to improving your gut health, you’ll likely start to notice the benefits that come with taming inflammation and improving digestion. These include more energy, less chronic pain, an improved mood, the ability to focus, and a shrinking waistline.

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We review published medical research in respected scientific journals to arrive at our conclusions about a product or health topic. This ensures the highest standard of scientific accuracy.

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Lisa Kaye Paskewitz

Lisa Kaye Paskewitz is a Detroit-based freelance health and wellness writer with a bachelor’s degree in biology and over 20 years of