Five Whole-Body Benefits of Probiotics

Did you know an estimated 61% of Americans suffer from digestive discomfort?¹ For many, probiotics may offer a potential solution to this problem. Specific strains of probiotics have been shown to support ease of bloating and promote healthy regularity. But the benefits of probiotics go far beyond the gut. Certain probiotic strains can impact your systemic health — think improvements in everything from the health of your skin to heart function. Choosing the right probiotic is vital, and to do that, we need to understand not only how probiotics work, but also their impact on whole-body health.

1. Probiotics and Digestion

In search of a way to support your gut health? A daily probiotic may help. Often the most immediate effects of starting a probiotic are recognizable improvements to digestion. In addition to supporting ease of bloating and expulsion, certain probiotic strains can trigger neurotransmitters that stimulate muscle contractions for increased motility (yes, we’re talking smooth, regular stools). For instance, in a 300-person study, researchers discovered certain strains supported gastrointestinal functions: bowel movement regularity, stool consistency, ease of expulsion, bowel movement comfort, and ease of occasional bloating.²

2. Probiotics and Gut Barrier Integrity

The human intestinal lining is formed by a single layer of epithelial (or “surface”) cells and a thick layer of mucus. This is part of what we call your gut barrier. Two of its vital jobs include absorbing beneficial nutrients and providing protection against harmful substances.

On a daily basis, your gut barrier interacts with the food you eat, the molecules you breathe, and at times, potential toxins that might attempt to invade your body. Because of this, your gut faces many perturbations (think: NSAIDs such as aspirin and ibuprofen, overuse of antibiotics, and alcohol). If your intestinal barrier is weakened, substances that don’t belong in your body can enter the bloodstream, potentially triggering immune responses such as inflammation, allergies, inflammatory bowel disease, irritable bowel syndrome,³ migraines,⁴ fatigue,⁵ and more.⁶

So, what do probiotics have to do with this? Certain strains have been studied to maintain healthy gut barrier function and integrity. For example, in one study researchers found that the Bifidobactrium longum strain was shown to influence mucus composition and enhance the gene expressions involved in tight junction signaling — in other words, promoting the integrity and “tightness” of the gut barrier, effectively keeping the good in and sealing the bad out.⁷

3. Probiotics and Skin Health

While the skin microbiome isn’t as vast as the gut microbiome, its estimated trillions of microbial cells⁸ play a vital role in our body’s outermost defense system, from identifying unknown organisms to managing inflammation. The skin microbiome also helps determine skin texture and appearance. For instance, an overabundance of one kind bacteria may be related to oily skin; a deficiency in another may be related to dryness or itchiness.⁹

In a small 2016 study, scientists looked at two of the root causes of adult acne — an imbalance in the gut-skin axis, and irregular insulin production. They found that when a specific oral probiotic strain was consumed over a twelve week period, the skin expression of genes involved in insulin signaling was normalized and the appearance of adult acne was improved in participants.¹⁰

Another 2016 study looked at the link between a bacterial imbalance and rosacea, and found that 64.5% of patients who completed oral probiotic treatment were still in remission 3 years later.¹¹ A consumer warning, however: while “probiotic” eye creams and skin serums may sound promising, these topical formulations aren’t proven to have the same effects as ingesting the specific validated strains highlighted in these studies (that’s because there’s little regulation in the probiotic market — more on that later!).

4. Probiotics and Mental Health

Have you heard of the gut-brain axis? The human gut also plays home to over 100 million nerve cells,¹² part of a complex system called the enteric nervous system (ENS). These neural circuits control the gastrointestinal system from your mouth to your intestines, and by emitting hormones into the bloodstream, they provide constant feedback to your brain. This is the reason you know you’re hungry, or if your last meal made you feel overly full — and it’s this network that researchers are investigating for the potential benefits of probiotics on mental health.

While it’s certainly too early to say that any one probiotic could “cure” a serious mental health disorder, researchers are working to uncover links between microbes and conditions such as anxiety and depression. For example, a 2019 review of 21 studies on probiotics and anxiety found that more than half of the studies included showed it was positive to treat anxiety symptoms by regulation of intestinal microbiota, whether through probiotic therapy or diet changes, suggesting the potential for treating mental health from the gut up.¹³

5. Probiotics and Vitamin Synthesis

While they are often found in the same aisle at the pharmacy, probiotics aren’t vitamins. However, certain probiotics can create them. You’ve likely heard about folate, an essential B vitamin that is not only important for fertility and during pregnancy, but is also responsible for DNA and red blood cell production, helping prevent anemia and contributing to cellular health. Certain probiotics contain strains that can actually synthesize folate from within the body according to animal studies providing an endogenous source of folate locally in the gut.¹⁴

Let’s back up for a minute — before we talk about how to find a probiotic that can support the benefits above, we have to first answer this question: What are probiotics?

According to a 2002 United Nations / WHO Expert Panel chaired by scientist and researcher Dr. Gregor Reid (who just happens to be Seed’s Chief Scientist), the globally-accepted, scientific definition of a probiotic is: Live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.¹⁵ Let’s break that down:

• Live Microorganisms: This means exactly what it sounds like — the beneficial microbes must be “alive” upon consumption. In science, we refer to this as “viability.” We take this one step further and ensure our probiotic organisms survive the stages of digestion, and make it alive, to the colon.

• Adequate Amounts: The number of the microbes in a probiotic dose will be listed on the label, measured in either CFU (Colony Forming Units) or, our preferred method, AFU (Active Fluorescent Units). This amount should match the dosage used in the corresponding clinical trial demonstrating the benefit of the particular bacterial strain.

• Health Benefit: Why would you take something that hasn’t been studied to be effective? Each specific strain of bacteria (not just the species — more on this later) must have been shown through scientific research to be beneficial.

• Host: That’s you! (Or your mom, or a dog, or a colony of honey bees, or for whom the probiotic is intended.)

With this in mind, it’s important to understand that there’s no such thing as a “best” probiotic. Why? Well, your physiology and experiences are unique — as are your particular needs. That’s why it’s more important to focus on strain specificity, and to look for probiotics that have been shown to provide your desired outcomes.

However, there is such a thing as a “scientifically validated” probiotic. As gut mania takes over the shelves of pharmacies and grocery stores, it’s important to discern between products that meet the scientific definition of a probiotic, versus those that are just co-opting the term (like those eye creams we mentioned above).

The next time you’re navigating a crowded probiotics aisle, here are three key questions to consider:

1. Which strains — not just species — are included in this probiotic?

Within each species of bacteria, there can be hundreds or thousands of strains — and each strain differs as much from each other as a golden retriever does from a french bulldog. When you’re looking for a probiotic, you’ll want to examine the specific strains it contains (it’s the long, difficult-to-pronounce name followed by a set of numbers or letters). Here’s an example:

Escherichia coli O157:NH is a strain of E. coli famously known for causing hemorrhagic diarrhea and mass lettuce recalls. However, a different strain, E. coli Nissle 1917 was actually one of the earliest probiotics ever developed, during World War I, and has been studied as a treatment for ulcerative colitis¹⁶ and irritable bowel syndrome.¹⁷

2. Are the strains in this probiotic included in clinically studied dosages?

You’ll likely see something called CFU (Colony Forming Units) on a probiotic label. The CFU indicates the amount per dose, and will usually be enormous (in the billions). While it’s common to think “bigger = better,” what’s actually important is whether that dose matches the dose used in clinical trials or scientific studies. Which brings us to our next point…

3. Have these strains, in these amounts, been studied in human clinical trials or scientific studies to demonstrate the intended effect?

Why invite billions of bacteria into your body if you don’t expect them to support your gastrointestinal health? When choosing a probiotic, look for clinical and scientific evidence that taking a specific strain at a specific dose will produce the desired health benefit.

As you can see, the notion of a “best” probiotic is far more complicated than it seems. One thing we do know is this: When it comes to probiotics, we’re just beginning to uncover their potential.

1. Almario, C. V., Ballal, M. L., Chey, W. D., Nordstrom, C., Khanna, D., & Spiegel, B. M. R. (2018). Burden of Gastrointestinal Symptoms in the United States: Results of a Nationally Representative Survey of Over 71,000 Americans. American Journal of Gastroenterology, 113(11), 1701–1710. https://doi.org/10.1038/s41395-018-0256-8
2. del Piano, M., Carmagnola, S., Anderloni, A., Andorno, S., Ballarè, M., Balzarini, M., Montino, F., Orsello, M., Pagliarulo, M., Sartori, M., Tari, R., Sforza, F., & Capurso, L. (2010). The Use of Probiotics in Healthy Volunteers With Evacuation Disorders and Hard Stools. Journal of Clinical Gastroenterology, 44(Supplement 1), S30–S34. https://doi.org/10.1097/mcg.0b013e3181ee31c3
3. Bischoff, S. C., Barbara, G., Buurman, W., Ockhuizen, T., Schulzke, J. D., Serino, M., Tilg, H., Watson, A., & Wells, J. M. (2014). Intestinal permeability – a new target for disease prevention and therapy. BMC Gastroenterology, 14(1). https://doi.org/10.1186/s12876-014-0189-7
4. van Hemert, S., Breedveld, A. C., Rovers, J. M. P., Vermeiden, J. P. W., Witteman, B. J. M., Smits, M. G., & de Roos, N. M. (2014). Migraine Associated with Gastrointestinal Disorders: Review of the Literature and Clinical Implications. Frontiers in Neurology, 5. https://doi.org/10.3389/fneur.2014.00241
5. Lakhan, S. E., & Kirchgessner, A. (2010). Gut inflammation in chronic fatigue syndrome. Nutrition & metabolism, 7, 79. https://doi.org/10.1186/1743-7075-7-79
6. Chelakkot, C., Ghim, J., & Ryu, S. H. (2018). Mechanisms regulating intestinal barrier integrity and its pathological implications. Experimental & Molecular Medicine, 50(8), 1–9. https://doi.org/10.1038/s12276-018-0126-x
7. Takeda, Y., Nakase, H., Namba, K., Inoue, S., Ueno, S., Uza, N., & Chiba, T. (2009). Upregulation of T-bet and tight junction molecules by Bifidobactrium longum improves colonic inflammation of ulcerative colitis. Inflammatory Bowel Diseases, 15(11), 1617–1618. https://doi.org/10.1002/ibd.20861
8. de Pessemier, B., Grine, L., Debaere, M., Maes, A., Paetzold, B., & Callewaert, C. (2021). Gut–Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions. Microorganisms, 9(2), 353. https://doi.org/10.3390/microorganisms9020353
9. Byrd, A. L., Belkaid, Y., & Segre, J. A. (2018). The human skin microbiome. Nature Reviews Microbiology, 16(3), 143–155. https://doi.org/10.1038/nrmicro.2017.157
10. Fabbrocini, G., Bertona, M., Picazo, Ó., Pareja-Galeano, H., Monfrecola, G., & Emanuele, E. (2016). Supplementation with Lactobacillus rhamnosus SP1 normalises skin expression of genes implicated in insulin signalling and improves adult acne. Beneficial microbes, 7(5), 625–630. https://doi.org/10.3920/BM2016.0089
11. Drago, F., de Col, E., Agnoletti, A. F., Schiavetti, I., Savarino, V., Rebora, A., Paolino, S., Cozzani, E., & Parodi, A. (2016b). The role of small intestinal bacterial overgrowth in rosacea: A 3-year follow-up. Journal of the American Academy of Dermatology, 75(3), e113–e115. https://doi.org/10.1016/j.jaad.2016.01.059
12. Kulkarni, S., Ganz, J., Bayrer, J., Becker, L., Bogunovic, M., & Rao, M. (2018). Advances in Enteric Neurobiology: The “Brain” in the Gut in Health and Disease. The Journal of Neuroscience, 38(44), 9346–9354. https://doi.org/10.1523/jneurosci.1663-18.2018
13. Yang, B., Wei, J., Ju, P., & Chen, J. (2019). Effects of regulating intestinal microbiota on anxiety symptoms: A systematic review. General Psychiatry, 32(2), e100056. https://doi.org/10.1136/gpsych-2019-100056
14. Sugahara, H., Odamaki, T., Hashikura, N., Abe, F., & Xiao, J. Z. (2015). Differences in folate production by bifidobacteria of different origins. Bioscience of microbiota, food and health, 34(4), 87–93. https://doi.org/10.12938/bmfh.2015-003
15. Hill, C., Guarner, F., Reid, G. et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology 11, 506–514 (2014). https://doi.org/10.1038/nrgastro.2014.66
16. Kruis, W. (2004). Maintaining remission of ulcerative colitis with the probiotic Escherichia coli Nissle 1917 is as effective as with standard mesalazine. Gut, 53(11), 1617–1623. https://doi.org/10.1136/gut.2003.037747
17. Kruis, W., Chrubasik, S., Boehm, S., Stange, C., & Schulze, J. (2011). A double-blind placebo-controlled trial to study therapeutic effects of probiotic Escherichia coli Nissle 1917 in subgroups of patients with irritable bowel syndrome. International Journal of Colorectal Disease, 27(4), 467–474. https://doi.org/10.1007/s00384-011-1363-9