The rising popularity of probiotics is a testament to the increasing awareness of their potential benefits. According to the 2012 National Health Interview Survey (NHIS), approximately 4 million U.S. adults had used probiotics or prebiotics in the past month, making these supplements the third most commonly used dietary supplement among adults (48). As more people turn to probiotics to enhance their digestive health, it is important to understand how to gauge their effectiveness and best use them to reap their benefits.
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Understanding Probiotics
Probiotics, often called "good bacteria," are live microorganisms that confer benefits to human health when taken in sufficient doses. They help to balance the human microbiome – the collection of bacteria, viruses, fungi, and other microbes that reside on and in the body. Research has continued to expose the numerous actions that our microbiome is responsible for overseeing. A healthy microbiome translates to optimal digestion, mood, energy, skin, metabolism, sleep, immune function, and hormonal balance.
Among other functions, the microbiota possesses antimicrobial properties, maintains the health of the intestinal lining, modulates the immune system, communicates with the central nervous system, and synthesizes bioactive compounds called postbiotics that further extend health benefits to the host. An imbalance of the microbiome, called dysbiosis, predisposes the human body to infection and inflammation.
Probiotics can be generally grouped into the following three categories:
1. Lactobacillus and Bifidobacterium Blends
These probiotic formulas contain a variety of Lactobacillus and Bifidobacterium species and have been documented to ease irritable bowel syndrome (IBS) symptoms, reduce GI inflammation, improve mood, and support weight loss. There is also research to support the adjunctive role of these probiotics in treating allergies, vaginal infections, and urinary tract infections (UTIs).
2. Saccharomyces boulardii
Saccharomyces boulardii (often abbreviated as S. boulardii or Saccharo-B) is a non-pathogenic and beneficial yeast that can rebalance the human microbiome. Clinical research demonstrates S. boulardii's ability to successfully treat a variety of GI diseases, including:
- IBS
- Diarrhea
- Inflammatory bowel disease (IBD)
- Parasitic infections
- Helicobacter pylori (H. pylori) infection
3. Soil-Based Probiotics
Species of bacteria belonging to the Bacillus genus are the most well-studied type of soil-based probiotics. Soil-based, or spore-forming, probiotics colonize the digestive tract to maintain digestive health and regulate the immune system. (22, 46)
Evidence has associated the use of Bacillus coagulans, Bacillus subtilis, and Bacillus clausii spore-forming probiotics with the following health benefits:
- Improve stool consistency, pain, and bloating in IBS
- Reduce acute and chronic diarrhea
- Decrease symptoms of constipation
- Reduce "leaky gut syndrome"
- Dampen inflammation
Signs Probiotics Are Working
You can tell probiotics are working if you notice improvements in the specific symptoms you are targeting. Responses can vary widely since individuals take probiotics for different reasons, and the benefits may manifest uniquely based on each person's health condition and microbiome composition.
These are just some of the signs that probiotics are working to support health, based on available research findings:
Digestion
Probiotics support gut health and digestive function by modifying the gut microbiota, improving intestinal transit time, and reducing intestinal inflammation. In doing so, many patients who take probiotics for digestive concerns may begin to experience improvements in:
- Gas and bloating
- Abdominal pain
- Bowel movement regularity and stool consistency
- Acid reflux
Immune Function
A diverse and abundant microbiome prevents infection by producing antimicrobial substances and outcompeting pathogenic invaders for nutrients and space. Additionally, the beneficial microbes in the gut communicate with immune cells to maintain immunological homeostasis. (29)
Therefore, improved immune resiliency is a sign that probiotics are working. In one study, consistent use of probiotics reduced the frequency of common colds by 30%. Another study concluded that supplementing probiotics during respiratory infection significantly reduced viral and bacterial concentrations, translating to a faster recovery time.
Mood and Cognition
The gut-brain axis is the bidirectional communication network between the gut microbiome and the brain, involving neural, hormonal, and immune pathways. The gut microbiome produces neurotransmitters like serotonin and gamma-aminobutyric acid (GABA), which can influence mood and brain function. Dysbiosis has been associated with mood disorders and cognitive impairments, likely due to impairments in neurotransmitter signaling and the upregulation of neuroinflammation.
Probiotics positively influence mental-emotional wellness and cognitive function through their actions on the nervous system via the gut-brain axis. Probiotic supplements, specifically those containing species of Lactobacillus and Bifidobacterium, have been shown to improve depression, anxiety, and cognitive function scores.
Energy
Imbalances in the gut microbiota can trigger pro-inflammatory immune responses, intestinal inflammation, and increased intestinal permeability (otherwise known as "leaky gut"). Among many other symptoms, fatigue is a common symptom of leaky gut syndrome. Interestingly, patients with chronic fatigue syndrome (CFS) have been documented to have distinct dysbiotic patterns, including lesser concentrations of Lactobacillus and Bifidobacterium bacteria, compared to healthy controls.
Probiotics can restore and protect a healthy intestinal barrier. Improvements in energy, stamina, and performance can be used as markers (among other symptoms) to track the success of a gut-healing protocol.
Skin Health
While much attention is often centered on the gut microbiome, the skin also has its own distinct community of microorganisms responsible for maintaining a healthy skin barrier. A leaky skin barrier, to which dysbiosis can contribute, has been implicated in skin inflammation and the pathogenesis of many skin conditions, such as psoriasis, eczema, rosacea, and acne.
The use of probiotics has been correlated to improvements in skin elasticity, moisture, and inflammation. Probiotics can also modulate the production of sebum, which helps to moisturize and protect the skin (6, 55). As such, oral and topical probiotics can be used to prevent signs of aging (e.g., wrinkles) and treat dermatologic conditions, such as acne, eczema, psoriasis, and seborrheic dermatitis.
Signs You Should Stop Taking Probiotics
Probiotics are safe for most healthy people to take. However, as with all supplements, they aren't for everyone.
Probiotics are metabolically active organisms that produce metabolic byproducts like short-chain fatty acids and gases. Intestinal bacterial overgrowth can cause digestive symptoms, including irregular bowel movements, gas, bloating, and abdominal pain. If you experience persistent or worsening GI discomfort after starting probiotics, it is advisable to discontinue use and consult a healthcare provider for personalized advice and alternative treatment options.
There is a small risk of severe infection with probiotics due to the risk of the product being contaminated with pathogenic bacterial species. This risk is greater in people with compromised immune systems, such as those with chronic infections, taking immunosuppressive medications, or premature infants. (48) To mitigate this risk, consult a healthcare provider before starting a probiotic supplement and choose a high-quality product from a reputable manufacturer.
Lab Testing for the Gut Microbiome
Gut microbiome testing through stool analysis can help identify specific dysbiotic patterns to tailor probiotic therapy to achieve the best clinical results. After a patient has collected at-home stool samples, the lab can map out the beneficial and pathogenic microorganisms colonizing their gut through microscopy, PCR (DNA quantification), and culture testing methods.
These results qualify and quantify the various microorganisms that comprise an individual's microbiome and can give specific insights into patterns contributing to poor gut health and clinical symptoms. Such insights can be used to tailor probiotic use, dietary changes, and other interventions to promote gut health.
Maximizing Probiotic Benefits
Research suggests multi-strain probiotics yield better results than single-strain probiotics because different probiotics work synergistically to improve health.
Probiotics are also strain- and disease-specific, meaning that some probiotics will work better to address certain health concerns than others. For example, one study demonstrated that Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, Lactobacillus rhamnosus CLR2, Lactobacillus casei DN114001, and Lactobacillus reuteri 55730 prevented antibiotic-associated diarrhea, while other Lactobacillus strains did not. (42)
Probiotic recommendations can, therefore, be customized to an individual's needs based on their presenting symptoms, health goals, and microbiome stool results. This website can be used as a clinical decision-making tool to help patients and doctors select the appropriate probiotic formulation for a specific indication.
In addition to probiotic supplements, a healthy microbiome can be fostered through certain dietary and lifestyle habits:
- Eat an anti-inflammatory, plant-based diet. Diets high in refined sugars, saturated fats, processed foods, and low in fiber favor dysbiotic states. Conversely, a diet rich in fiber, healthy fats, polyphenols, and antioxidants nourishes beneficial microbes. The Mediterranean diet is one such dietary plan that favors gut health. (39)
- Prebiotics are selectively fermentable substances that nourish the gut microbiota. Examples include fructooligosaccharides (FOS), inulin, and galactooligosaccharides (GOS). Prebiotics are often added to probiotic supplements (called "synbiotics") but are also found naturally in foods like bananas, onions, and garlic.
- High stress, poor sleep habits, excessive alcohol consumption, and smoking contribute to dysbiosis. Managing stress, prioritizing sleep, and avoiding alcohol and tobacco are foundational habits that protect the microbiome. (39)
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Key Takeaways
- Probiotics are live microorganisms that can be used to treat a variety of health conditions by rebalancing the body's microbiome.
- You can tell if probiotics are working if you notice improvements in your symptoms. If you start to experience unwanted side effects or observe that your symptoms are no longer improving, it may be an indication that you should stop taking probiotic supplements.
- While probiotics confer a wide range of health benefits, they might not be the "magic pill" solution, and sometimes, other interventions are required. Therefore, patients should consult with their doctors to discuss probiotics and other gut-healing options.
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