Complete Guide to Probiotics | Revised

Complete guide to probiotics

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Updated October 2022 |

In this comprehensive guide to probiotics, you will learn how they work, what foods are best for them, and which ones are right for your lifestyle.

The Complete Guide to Probiotics will help you find out which probiotic supplements give your body what it needs for optimal health.

With this guide, you will learn about good bacteria, and bad bacteria, and how each one affects our bodies differently.

You’ll also discover why some of these “good” bacteria get killed off by everyday stressors like pollution or certain medications.

And finally, we’ll show you specific foods that promote healthy gut flora growth as well as those that destroy them!

We’ve created a complete guide with everything you need to know about probiotics including where they come from (foods), their benefits (weight loss & immune system), and even how long they last in your digestive tract before being eliminated (3-4 hours).

Probiotics definition

pro·bi·ot·ic ˈprōbēˌätik/ noun a preparation of or containing viable bacteria or yeast normally administered in supplement form to restore the balance of organisms residing in the gastrointestinal tract after an antibiotic course has eliminated competing microorganisms.

What are probiotics and why do we need them?

Probiotics are living bacteria that are naturally found in the digestive tract.

These probiotic bacteria have been shown to help maintain a healthy balance of gut flora, which is important for digestion and immunity.

Probiotics can be found in many food products such as yogurt or fermented foods like sauerkraut, but they also come in pill form.

Probiotics have been shown to help with digestion issues including:

  • irritable bowel syndrome
  • constipation
  • diarrhea and ulcerative colitis
  • immune system disorders like colds or flu

It’s important to remember that not all probiotic supplements will work for everyone so it’s best to consult your doctor about any medical conditions you may have before starting a probiotic regimen.

Although there are many studies that show positive results about probiotics, including weight loss and lower risk of certain cancers, there are also many health professionals who remain skeptical.

Some say that more research is needed to see if these effects can be reproduced in large populations and others suggest that the benefits may only last as long as the patient continues to take them.

Illustration about what are Probiotics - a guide to probiotics
Illustration about what are Probiotics

One question remains: Are probiotics safe?

The U.S. Food and Drug Administration (FDA) approved a few specific strains of bacteria for use as medical treatments such as VSL#3 for pouchitis and Lactobacillus rhamnosus GG (LGG) for pediatric acute diarrhea – both disorders which affect the GI tract.

The FDA regulates these products as drugs so they must meet high-quality standards.

When the FDA approves a probiotic product it means that clinical trials have shown positive results for this specific strain of bacteria in treating specific disorders, but it does not mean that these products are guaranteed to work for everyone who takes them.

The American Academy of Pediatrics recommends that probiotics be used under medical supervision, because there is an increased risk of overgrowth of harmful bacteria if they are given to people with compromised immune systems or serious underlying illnesses such as cancer, AIDS, or cystic fibrosis.

For example, when one woman received a fecal transplant from her healthy daughter she developed severe diarrhea and even had part of her colon removed because the donor stool contained C-difficile ( potentially deadly infection).

In another case, patients who had their colons removed were given fecal enemas with donor stool to help recolonize the digestive tract and it caused life-threatening blood infections in some of them.

Should I be worried?

Most commercially available probiotics are considered safe for healthy people without underlying medical conditions, but there is still no guarantee that they will work.

Probiotic supplements can interact with certain medications like antibiotics or antifungals, which may decrease the effectiveness of the drug or cause severe gastrointestinal (GI) symptoms.

Also, certain types of bacteria found in probiotics have been linked to deadly cases of clostridium difficile disease.

In addition, probiotics can worsen symptoms associated with viruses such as rotavirus diarrhea and herpes virus infections because those illnesses also affect the GI tract.

It’s important to remember that probiotics are not regulated by the FDA and it is recommended that consumers speak with a doctor before starting any supplement regimen, including probiotics.

Before purchasing any products, you should read all labels carefully to determine whether they contain live organisms.

When taking supplements, choose plain yogurt or other cultured dairy products if you have lactose intolerance because some brands may contain milk byproducts that can be harmful to some people.

If your child is on antibiotics, it is best to wait at least two hours after taking them before giving them a probiotic supplement for the best chance of success.

As with most things in life, prevention is often better than cure so enjoy fermented foods like sauerkraut, yogurt, kefir, kimchi, dark chocolate, and other high-quality dairy products because not only do they taste good but can also provide a boost to your health.

The importance of gut health

Achieving optimal wellness through a healthy lifestyle starts with maintaining proper balance within our digestive system.

The human gastrointestinal tract houses trillions of microbes that play an intricate role in digestion, nutrient absorption, immune function, and more regardless of whether we have a healthy diet or not.

While many people believe that our guts are full after eating because food doesn’t fit anymore, the reality of this matter is that our stomach acid breaks down food so it can be more easily absorbed.

Any undigested food will pass through us without being able to be absorbed by our bodies.

Not only do these trillions of microbes influence digestion, but they also have a strong effect on how we metabolize nutrients and process hormones within the body which can impact everything from weight gain to depression.

Researchers are just beginning to understand the complexities of how gut bacteria interact with human genes, but one thing is clear after decades of study:

Our digestive system plays an extremely important role in maintaining overall wellness!

These tiny creatures actually outnumber our own cells 10 – 1, which makes them incredibly important when it comes to health!

Probiotics are microorganisms that help us digest food, balance our immune system, and may even treat various chronic conditions.

They also aid in the absorption of minerals which means they impact how much or how little we retain from what we eat.

While some people think that taking very high doses of probiotics is good for them, this simply isn’t true because it can create a deficiency in key vitamins/minerals needed by the body to function optimally.

Illustration about what are Probiotics and the Digestive System - a guide to probiotics
Illustration of what are Probiotics and the Digestive System

The benefits of probiotics

Probiotics have been shown to assist with numerous health benefits including:

  • Promotes immune function
  • Boosts immunity
  • Improves digestion through better absorption of nutrients from food sources
  • Reduces gas and bloating
  • Reduces constipation
  • Help towards weight management
  • Lower cholesterol levels
  • Prevent antibiotic-associated diarrhea
  • Help with vaginal yeast infections
  • Decrease inflammation from arthritis
  • Helps control blood sugar levels by regulating insulin production
  • Helps slow down aging due to the inability to stimulate hormones that promote youthfulness

The different types of probiotics

The different types of probiotics include Lactobacillus acidophilus, Saccharomyces boulardii, and Bifidobacterium lactis.

The different types of probiotics are important to know about, especially if you’re suffering from a gastrointestinal disorder.

Probiotics can help with digestion and promote healthy gut bacteria by balancing the good and bad microbes in your intestines.

There are many types of probiotics that vary in their function, but they all do one thing: support digestive health!

As an example, Lactobacillus Acidophilus is one type of bacteria that helps maintain a healthy balance between “good” and “bad” bacteria in the intestines.

It also helps break down lactose for people who have trouble digesting milk products.

If you suffer from diarrhea or other disorders that affect your digestive system, then it may be time to start

Probiotic products come in many shapes and sizes including:

  • capsule
  • tablets
  • powders
  • liquids
  • even chewing gums

The most common probiotics found in these products are Lactobacillus acidophilus (L. acidophilus) and Bifidobacterium bifidum (B. bifidum).

There are also other probiotic strains such as Saccharomyces boulardii which are used for preventing Clostridium difficile-associated diarrhea among patients who take antibiotics.

The different types of probiotics include:

Lactobacillus acidophilus (L. acidophilus) – This strain is found in the gastrointestinal tract, mouth, and vagina. 

Its primary function is to produce lactic acid which inhibits the growth of harmful bacteria like E.coli, Salmonella, and Staphylococcus aureus.

Lactobacilli also play an important role in producing vitamins B2, K, and biotin which are essential for healthy skin, eyesight, and strong bones.

Bifidobacterium bifidum (B. bifidum) – This probiotic strain works by increasing non-specific immunity especially when there’s stress or malnutrition present in the body.

A 2003 study published in Clin Diagn Lab Immunol became the basis for Bifidobacterium animalis DN-173 010 (B. animalis) as an effective probiotic agent since it can reduce inflammation and promote immune health.

Treponema denticola – This is a potential probiotic strain that was isolated from dental caries and chronic periodontitis patients.

It has been shown to produce glucan which can be used for treating or preventing oral diseases such as yeast infections, gingivitis, and cavities caused by Streptococcus mutans.

Saccharomyces boulardii – Some studies show that this bacterium may help in the prevention of antibiotic-associated diarrhea (AAD).

A study published in the Journal of Clinical Microbiology showed that those who were given macrolide antibiotics had greater chances of having diarrhea compared to those who took S. boulardii .

This probiotic strain also boosts the immune system and, according to some studies, may be effective in treating urinary tract infections (UTI) caused by e-coli bacteria.

Illustration about Gut Bacteria - what are probiotics? - a guide to probiotics
Illustration about Gut Bacteria – what are probiotics?

How do probiotics work?

These microorganisms attach themselves to the walls of our colon where they start multiplying rapidly.

The cells inside the colon absorb these bacteria which form a protective barrier against harmful bacteria like E. coli, Staphylococcus aureus, and Salmonella typhimurium.

Aside from strengthening our gut health, taking these good bacteria has been shown to improve overall immunity because enzymes produced by these friendly organisms are able to destroy cancer cells.

When should you start taking probiotics?

You can start taking probiotics once your digestive tract is fully developed. This usually happens when you are about 2 years old.

One of the best times to take these supplements is during or after a course of antibiotics since they help restore the good bacteria that was destroyed by the drug.

You can also choose to take them during or before traveling abroad.

If you’re planning to visit a country where food sanitation is really bad, then it’s safe to say that your gut will surely get exposed to various harmful bacteria especially if you eat street foods and meals prepared in unsanitary conditions. 

A study published in Nature showed that babies who were given Bifidobacterium animalis subspecies lactis (B. lactis) or Enterococcus faecalis TH10 (E. faecalis TH10) had a reduced incidence of fever, vomiting, and diarrhea compared to those given placebos.

The results showed that taking these probiotics during their first six months will help them build a stronger immune system against bad bacteria as they grow up.

How does a probiotic supplement work?

Just like any other food supplement, it is important to know the right dosage you should take before buying one.

Most supplements come in powder form which can be added to yogurt or water before drinking it.

You may also want to chew on chewable tablets if you don’t fancy the thought of having something with your yogurt. 

There are also supplements that come in gel or cream form which can be applied to different parts of your body (e.g., your arm) before resting for 20 minutes.

This would allow the active ingredients of the probiotic supplement to get into your system.

It is best to consult a health care professional before taking these supplements so you will know which ones are right for you.

Since some people have certain medical conditions, they may not be able to benefit from these supplements effectively unless their doctors advise them otherwise.

What are some side effects?

According to a study published in Clinical and Experimental Gastroenterology, there were no significant differences in terms of adverse events after administering S boulardii while undergoing treatment for AAD (Antibiotic-Associated Diarrhea).

However, the authors of this study said that it is crucial to monitor patients taking probiotics because they can develop serious infections such as toxoplasmosis.

Women who are pregnant or breastfeeding should not take these supplements unless advised by their doctors.

There’s also a possibility that, although rare, having lactic acid bacteria may worsen the symptoms of those suffering from lactose intolerance and other food allergies related to dairy products.

What can you do if you have diarrhea?

On one hand, it is important to note that diarrhea caused by antibiotics does not require treatment since this is just a side effect.

You also don’t need medication if your body is already experiencing watery stool passed every now and then. However, there are cases when diarrhea becomes severe and constant.

If this is the case, you should go see your doctor immediately so he can prescribe the proper medication for you. 

What can you do if you have AAD?

You don’t need to worry about having AAD because it is not that difficult to treat. Like diarrhea, there are cases when it becomes rare and mild while others are more severe and annoying.

The most common way of treating AAD is by taking antibiotics but if your doctor thinks that this condition requires further treatment, he may suggest probiotics or consuming prebiotic foods instead.

Some doctors will even advise their patients to take both supplements in order to get better faster. 

What can be used as an alternative?

Although bacteria have different roles in the human body, some of them can also be harmful.

This is why there are products available in the market which contain good bacteria.

These “good” bacteria or microorganisms can be found in foods like bananas, oranges, and kiwi.

Some yogurt brands such as Activia and DanActive even claim that their products contain these healthy probiotics. 

What about food allergies?

According to a study published by the British Medical Journal, children who drink fermented milk containing Lactobacillus casei may reduce their risk of developing food allergies later on in life.

The study involved around 900 children and it tests the effects of dairy products with live cultures on preventing eczema and asthma before they turn seven years old.

However, this finding, along with other studies involving this topic, is not concrete.

This means that more research is needed to confirm whether or not consuming fermented milk has the ability to decrease the risk of children developing food allergies later on in life.

What about AAD and Lactobacillus rhamnosus?

 According to a study published by Clinical and Experimental Gastroenterology, those who were diagnosed with AAD had lower levels of Bifidobacteria as well as Lactobacilli.

In contrast, they have higher amounts of potentially harmful bacteria such as Escherichia coli compared with those who don’t have antibiotic-associated diarrhea symptoms.

The researchers also found that taking lactobacillus supplements can increase the number of beneficial bacteria found in a person’s stool and decrease the number of harmful bacteria. 

Are probiotics and prebiotics safe to take?

According to a study by Cochrane, both Lactobacillus and S boulardii supplements can prevent antibiotic-associated diarrhea.

However, there are few cases where these supplements may worsen the symptoms of people suffering from infectious diarrhea such as toxoplasmosis which is caused by a parasite found in undercooked meats such as pork, lamb, and venison or unpasteurized dairy products.

These side effects are rare but they do happen so you should speak with your doctor first before taking these kinds of supplements.

When and how to take probiotics

It’s different for all people and probiotics

For the most part, it’s best to be proactive and take probiotics on a daily basis.

Just like vitamins and minerals, taking them every day ensures that you’ll get the benefits of regular supplementation, and these benefits may not come just from one strain or multiple strains at once.

Each strain will have certain health effects that are specific to that strain alone, so taking each separate strain at the appropriate time makes sense in some way.

That said, it isn’t always easy to keep track of which supplement has what effect.

It can be daunting to buy ten different types of supplements and take all ten at once or buy one supplement with ten different strains.

How to find the right probiotic for you

The most important thing to keep in mind when transitioning to a probiotic regimen is that you need to find the right one for your personal needs.

There are many different types of bacteria, so it’s important to choose which one will work best with your digestive system.

To do this, there are three steps:

  1. determining if you have an imbalance in gut bacteria,
  2. figuring out whether or not you have any food sensitivities or allergies and
  3. finding the right type of probiotic by looking at what your symptoms might be.

The world of probiotics is confusing. There are so many different types, brands, and strains that it can be hard to know which ones you should take for your specific needs.

You want a probiotic supplement that will improve your digestion and overall health, but there’s no way of knowing which one is best without reading through dozens of reviews and studies.

How to include probiotics within your diet

Probiotics are necessary for good gut health, but most people do not get the recommended amount of probiotics in their diet.

– Improve your diet with increased consumption of naturally fermented foods such as yogurt, kimchi, sauerkraut, kombucha tea, pickles, and kefir. If you don’t like any of these options then try adding dill pickles or garlic dills on top of your favorite sandwich instead!

– Make sure that your digestive system has a healthy balance by taking a daily probiotic supplement which can be found at any drug store or health store. If you are experiencing digestive problems take two capsules three times a day until symptoms improve. Make sure that your probiotics supplement is refrigerated- otherwise, they will be ineffective!

– It is also important to note that the probiotic powders found in many yogourts, granola bars, and other products do not contain enough viable organisms to provide an effective dosage of healthy bacteria. It is especially important to make sure that your yogurt is all-natural with no added sugars or artificial sweeteners if taking it for its probiotic effects.

– Lastly, here are some foods that can inhibit the growth of beneficial bacteria in your gut:

  • sugar
  • processed foods
  • dairy products (in non-lactose intolerant individuals)
  • fried foods

– If you experience any type of digestive disorder, research has suggested that drinking two glasses of kefir a day can help to relieve common symptoms such as diarrhea, acid reflux, and bloating.

– And as always make sure to stay hydrated by drinking plenty of water (especially if you are taking probiotics because they can cause gas). Keep in mind that the best way to get probiotics is through fermented food!

Why taking a supplement might be necessary

The modern-day diet is lacking in many of the essential vitamins and minerals that our bodies need to maintain a healthy lifestyle.

This can lead to increased stress, fatigue, weight gain, lack of energy, and a weakened immune system.

Supplements are an easy way to make up for these deficiencies by giving your body what it needs without having to change your diet or lifestyle habits.

The average person eats about 2,000 calories per day. It is impossible to ingest all the necessary vitamins and minerals from food alone. There are many people who would benefit from taking a multivitamin or supplement.

There are some instances when it might be beneficial to take a multivitamin, such as if you do not eat enough fruits and vegetables on a regular basis, if you have a very restricted diet due to illness or disease, or if your doctor recommends it for other reasons.

The most common supplements are multivitamins (a mix of vitamins and minerals), omega-3 fatty acids (good for heart health), calcium (essential for bone strength), and vitamin D (key for immune system function).

Other examples include magnesium, zinc, or iron if someone is deficient in those particular areas. And if you’re pregnant or breastfeeding it’s important to take folic acid as well.

What to avoid when buying a probiotic supplement (i.e. sugar, artificial sweeteners)

The number of probiotic supplements on the market is staggering.

According to a study by Consumer Reports, there are over 100 different types of probiotics for sale in the U.S., and they come in more than 700 formulations with varying amounts and potencies.

This can be overwhelming if you’re looking for a supplement that will work for your specific needs.

The following guide provides some general guidelines that should help you avoid buying a product that may not live up to its claims or worse, could even cause harm:

  • Make sure it’s made from quality ingredients without unnecessary sugars or artificial sweeteners.
  • Read reviews from other people who have used the product before making your decision – If it doesn’t say what strain of bacteria is found in the product, then avoid buying it – If you’re looking to take the supplement for a specific health benefit, research whether any scientific studies have been conducted involving that strain of bacteria.
  • Ideally, your probiotic should be refrigerated because if it’s not alive when you get it, it won’t do you much good. This does depend on the type of probiotic.

Side effects of probiotics that can occur if not taken correctly or with other medications/supplements

Side effects of probiotics that can occur if not taken correctly or with other medications/supplements:

  • abdominal pain
  • bloatedness
  • diarrhea
  • gas
  • nausea

Probiotics may also interact with certain medications such as:

  • antibiotics (reduce effectiveness)
  • diabetic medication such as insulin and glyburide (decreased effectiveness)
  • immunosuppressants such as cyclosporine which can be found in organ transplants

However, there is not enough research to support that these interactions will occur in the majority of people so consult your doctor before adding these supplements if you are on any other medication.

Side effects of antibiotics include:

  • diarrhea/loose stool
  • nausea or vomiting
  • abdominal pain or cramping

They can also increase sun sensitivity so wear factor 30+ sunscreen when outdoors and certainly not expose yourself to the sun between the hours of 10 am and 2 pm.

Side effects of medication such as glyburide typically include:

  • nausea or vomiting
  • abdominal pain
  • diarrhea/loose stool
  • headache
  • decreased appetite

If you experience these symptoms contact your physician as they may be serious.

The side effects of immunosuppressants such as cyclosporine can be:

  • kidney damage (contact your doctor if you notice any change in the amount of wee coming out).

The best course of action

First and foremost make sure that you are taking these supplements at the same time every day (with prebiotics) and either before a meal or during a meal.

The best way to incorporate them into your diet is through foods rich in fiber such as whole grains, legumes & whole fruits & vegetables. Generally, you can find them in foods such as:

Lactobacillus/Bifidobacterium- found in fermented milk products such as yogurt, cheese, or sour cream. Prebiotics are also naturally occurring in many of these types of food.

These are the guys that will populate your gut and help regulate your digestive system while protecting against infection, inflammation, and cancer.

Probiotics are beneficial for everyone but especially for people experiencing conditions such as IBS (irritable bowel syndrome) which causes cramping, abdominal pain, diarrhea, or constipation among other things.

They have been shown to decrease the risk of mortality rates due to gastrointestinal infections caused by H.pylori as well as relieve symptoms of IBS.

Do not take these supplements if there is anything wrong with your immune system due to the risk of infection and if you are experiencing severe abdominal pain or diarrhea stop taking them and seek advice from a physician.

Common misconceptions about probiotics that could lead to an ineffective treatment plan or worse, illness

Many people don’t realize that probiotics are not a cure-all for their health problems.

A lot of people think they can take any probiotic and it will fix all their issues, but this is simply not true.

The key to choosing the right probiotic is understanding what you’re actually getting in your supplement. Here’s a quick guide on common misconceptions about probiotics and how to avoid them when shopping for supplements.

Some of the common misconceptions are listed below:

Probiotics need refrigeration.   Generally, no! In most cases, probiotic supplements do not require refrigeration. However, if a product has been opened or exposed to extreme temperatures it may be best to store it in the fridge for maximum efficacy. 

You need a lot of them. False! The recommended dosage is typically one capsule a day with food and water (though this can change depending on your needs).

They are expensive. True! Though they are affordable enough that it should not be too much of a concern. The price also depends on the manufacturer and the strain of probiotics (i.e. lactobacillus). There is a wide variety of products to choose from depending on your preferences; whether you prefer capsules, powder, liquid drops, or chewables – there’s bound to be one for you.

All probiotics work the same way. In reality, each strain has its own benefits and side effects.

Taking antibiotics will kill off both bad bacteria and good bacteria. This isn’t always the case. Antibiotics only affect certain types of gut bacteria, which can leave some beneficial strains behind unharmed.

The most important thing anyone considering taking a probiotic should do first is talk with their physician about what type might be best for them based on their symptoms or medical history.

Doing research beforehand can help you make an informed decision as well.

Guide to Probiotics – Final thoughts

You have the power to improve your health by taking probiotics.

The benefits of this supplement are vast and can be felt in many different ways, from improved moods to better digestion.

Thank you for reading our comprehensive guide and we hope we answered as many questions in relation to probiotics as much as possible.

A quick reminder .. aim to provide the most up-to-date information, help, and advice for YOU to make informed decisions. If you are unsure or uncertain and require more clarity, please reach out to us and we will gladly come back and advise you as best we can.

The best means to reach us is via email at or fill out the form on our Contact Us page – click here.

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Our goal is to empower you with concise probiotic guidance for a healthier gut. With expert advice, we provide the knowledge to improve your well-being and navigate the world of probiotics efficiently, ensuring you achieve optimal gut health.


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