Everything You Ever Wanted To Know About Choosing A Good Probiotic

Board-Certified Internist By Vincent M. Pedre, M.D.
Board-Certified Internist
Dr. Vincent M. Pedre is a board-certified internist in private practice in New York City since 2004. He serves as medical director of Pedre Integrative Health, president of Dr. Pedre Wellness, and is the author of Happy Gut.
Everything You Ever Wanted To Know About Choosing A Good Probiotic

Photo by Tatjana Zlatkovic

Many patients arrive in my office with gut imbalances that manifest in all sorts of ways, including weight gain, chronic inflammatory diseases, fatigue, and skin conditions like eczema.

These gut imbalances result from numerous culprits. Chief among them are chronic stress, a high-sugar/processed-foods diet, other dietary extremes, certain diseases, and specific gut insults, including unfavorable bacterial infections, parasites, and yeast.

What is gut health?

When I say gut health, I'm talking about the more than 500 different species—trillions of microorganisms altogether—residing in your gut, whose delicate balance influences gut function, your metabolism, your hormone balance, and your overall health.

A disrupted gut flora opens the door for unfriendly microbes to step in and take over, creating all sorts of pandemonium that causes patients to gain weight, feel sick and tired, and become more disease-prone.

Those problems aren't as far-reaching as they might seem when you consider how much of your health begins in your gut. An out-of-whack gut can result in allergies, autoimmunity, weight gain, acne, skin rashes, yeast infections, hormonal imbalances, fatigue, depression and even accentuate the way you sense pain.


The basics of probiotics.  


Reset your gut, beat bloating, and help reduce waist circumference.*

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One way I help restore a patient's gut to balance is with probiotics. The term, derived from Latin, means "for life."

Among probiotics' numerous health benefits, research shows these friendly microorganisms support a healthy bowel and immune system; fend off traveler's diarrhea; help you maintain a healthy weight, manage various skin conditions, and improve bloating and other uncomfortable GI symptoms; and even affect your mood, helping to reduce the effects of stress.*

Think of probiotics as your little helpers that restore order and help maintain harmony in your gut ecosystem. You want them to outnumber and antagonize the unwelcome pathogens, including unfavorable bacteria, yeast, and parasites.

Probiotic bacteria actually compete against unfriendly flora for bacterial binding sites on the inside lining of your intestines, further protecting you from harmful pathogens. One way to repopulate your gut with probiotics, to restore harmony and get all their many benefits, is with the right foods, which support the growth and proliferation of the good bacteria that crowd out the bad ones.

These include cultured foods (such as yogurts or kefir); fermented foods like sauerkraut, miso, pickled vegetables, and kimchi; and cultured beverages, like kombucha—that all contain favorable live bacteria.

During my recent trip to Japan, one thing I noticed was the inclusion of pickled vegetables in almost every traditional Japanese meal. Unfortunately, most Americans don't consume enough of these probiotic-rich foods and drinks. Even when they do, restoring equilibrium oftentimes requires therapeutic doses of these microorganisms because almost everyone has been on several rounds of antibiotic therapy. That's where a probiotic supplement comes in.

Bifido-what? Understanding probiotic species.

You'll find probiotic supplements that contain freeze-dried bacteria in powders, tablets, and capsules. That's the easy part: Turn the label around and you'll see a list of unpronounceable ingredients. Many of my patients say choosing the right probiotic supplement is baffling.

While there are endless species of beneficial bacteria, the ones you'll most commonly find in probiotic supplements are Lactobacillus, Bifidobacterium, and Saccharomyces boulardii (which is actually a favorable, noncolonizing yeast, not a bacteria).

Among these three strains (or families) are specific species. Lactobacillus, for instance, includes the individual species L. acidophilus, L. rhamnosus, L. bulgaricus, L. reuteri, and L. casei. The most common Bifidobacterium species include B. animalis, B. infanti, B. lactis, and B. longum.

Let's look at the benefits of these three families—Lactobacillus, Bifidobacterium, and Saccharomyces—more closely:



Lactobacillus bacteria predominantly live in your small bowel (the portion of your gut that follows the stomach). Probiotics that contain Lactobacillus species help to repopulate the small intestine with these friendly organisms that aid in supporting digestion and immune function.* The most beneficial species are L. acidophilus, L. plantarum, and L. paracasei.* One study found Lactobacillus acidophilus maintained normal gut inflammation.* L. rhamnosus helps increase GABA expression (an inhibitory neurotransmitter that helps you feel relaxed) in the brain, resulting in lower stress-related behavior.* Another found that a combination of Lactobacillus and Bifidobacteria (which we'll talk about next) improved symptoms of bloating in patients who had functional bowel disorders, and yet another found that when individuals took the Lactobacillus rhamnosus GG strain, it significantly reduced the risk for antibiotic-associated diarrhea.*


The Bifidobacteria (Bifidus) bacteria predominantly live in your colon or large intestine. They produce the very important short-chain fatty acid butyrate, which supplies energy to your colon cells to keep them functioning optimally. But butyrate is also absorbed by the body, where it regulates a variety of metabolic processes, including your sensitivity to the hormone insulin (which regulates your blood sugar) and even memory formation in the brain.* The most beneficial of the Bifidobacteria are B. lactis and B. longum. Research shows the benefits for Bifidobacteria in maintaining a healthy bowel.* Another study showed that a specific strain of Bifidobacterium lactis helped control body fat mass, waist circumference, and food intake.*



Saccharomyces is a friendly yeast that can be given concurrently with antibiotic therapy, which supports the gut lining from the effects of antibiotic-induced dysbiosis leading to leaky gut syndrome.* S. boulardii can also outcompete other unfriendly yeast that is cohabitating in the gut.*

If that sounds confusing, don't worry. With the following three strategies, you don't need to remember those names to choose the right probiotic supplement.

How to tell if probiotics are high-quality.

I like a bargain as much as anyone, but buying a probiotic supplement is something you don't want to skimp on. Warehouse stores are great to buy paper towels and grass-fed beef in bulk, but those mega-containers of probiotics are hardly the great deal they might seem.

Quality matters for any supplement, and that goes triple for probiotics. Many commercial brands lack the technology to identify specific strains and how much of that strain each dose contains. That could mean you get an ineffective or potentially harmful dose. It's a great sign if the company is using strains that have been used specifically in clinical trials at a dose similar to or the same as that used in the study. This is one of the only ways to guarantee a probiotic's clinical effectiveness.

And even then, with probiotics, it's all about survival. These delicate microorganisms must survive several obstacles—the manufacturing process, shelf life, and (once you take them) the acid in your stomach environment—to reach your intestines, where they do their job.

Keep in mind that when supplements contain a specific number of organisms, this number may not be what is actually within each capsule at the time of purchase. Probiotics are living organisms and can die easily. Especially if that supplement sits on your drugstore or warehouse shelf for months or longer, the number of organisms you get may be far less than what the bottle claims. Hardier strains have a longer shelf life. Capsule strength decays faster if the probiotic has been sitting around at elevated temperatures during transport to the store. Companies actually have to produce probiotics with a much higher CFU (colony-forming unit; see below) count in each capsule in order to guarantee the label potency by the expiration date.

Unfortunately, many commercial brands don't measure up. They are unstable in stomach acid. Quality control measures aren't intact, including ensuring supplements have been handled correctly and maintain their freshness. Moisture slipping into probiotic supplements can reduce their efficacy. Companies that use bioshield capsules produce higher-quality probiotic supplements that are able to endure the stomach acid, releasing their contents within the small intestine, where a more alkaline environment ensures the survival of the bacteria.

To avoid those and other problems, I strongly recommend buying a professional brand from a reputable health care professional or another vendor who stands by their products and submits their products for third-party testing. Some of these professional brands have created advanced technology that preserves a probiotic supplement's survival on the shelf and in your gut.


How to know which probiotics to buy.

If you do choose a commercial probiotic supplement, or if you're curious about the brand your health care professional recommends or sells, then here are some things to consider:

Billions is better.

Millions sounds like a lot, but not with probiotic supplements. You want a prebiotic dose that contains billions of organisms. A probiotic dose will range from 5 to 100 billion colony-forming units (CFUs), the measure used to express its potency. Start low and increase as you can tolerate it.


Diversity is your best friend.

Your gut is diverse, so your probiotic should be too. Look for a supplement that contains multiple strains, sometimes listed as a proprietary blend. Inferior brands might contain only one probiotic strain such as Lactobacillus acidophilus. Aside from the beneficial Lactobacillus and Bifidobacterium strains, a good probiotic may contain Strep. thermophilus and Saccharomyces boulardii, among others.

Go for dairy-free.

Ideally, look for a dairy-free probiotic supplement that contains at least 15 billion CFUs each of Lactobacillus and Bifidobacterium strains (a total of 30 billion CFUs) guaranteed by the manufacturer through the expiration date.

Watch out for binders and fillers.

Read the other ingredients on the label. Some commercial probiotic supplements contain undesirable binders and fillers, including lactose or cornstarch that may cause a reaction, like gas and bloating, if you are sensitive to these ingredients.

Make sure your probiotics don't go bad.

Always look at the expiration date, after which the potency on the bottle can no longer be guaranteed. Some, but not all, probiotics require refrigeration. The label should tell you specifically whether or not to refrigerate.

How to find the right probiotic dose.

If you're most interested in taking a probiotic supplement for overall gut health, I suggest starting with 30 to 50 billion CFUs. Take your chosen probiotic on an empty stomach once or twice a day for at least three months. After that time, reassess and decide if the benefits you achieved warrant continuing a maintenance dose of the probiotic supplement. However, if you have SIBO, then be careful of starting a probiotic too soon after your SIBO treatment. In this case, it's best to work with a health practitioner on which probiotic is right for each stage of your SIBO treatment.

The sicker your gut is—in other words, the more imbalanced it is—the higher the probiotic dose that will be required to create a positive effect.* If you have a leaky gut or inflammatory bowel disease (such as Crohn's or ulcerative colitis), for instance, then you may need to take up to a total of 200 to 400 billion CFUs daily.*

To determine how specific bacterial strains can benefit your condition or to utilize higher doses, I strongly suggest working with a functional medicine doctor or other qualified health care professional.

Potential side effects of probiotics.

You'll be happy to know that generally, probiotic supplements cause no significant side effects, other than the intended improvement in your gut health. However, probiotics can be tricky. Not every probiotic is right for each person. Sometimes it's about finding the right fit. For example, signs that a probiotic might not be right for you include:

  • Bloating after taking it
  • Constipation or diarrhea that resolves when you stop it
  • Irritability that increases when you take the probiotic

If this happens, then it's time to consider switching to a new probiotic. Other reasons a probiotic might not be the right fit: SIBO or Candida. If you have either of these conditions, then the strain of the probiotic could potentially make your symptoms worse. Remember, if you think a probiotic is not helping, then seek the advice of a functional medicine provider to help you navigate the choices out there.

Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D., medical director of Pedre Integrative Health and president of Dr. Pedre...
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