Probiotics are live microorganisms, such as bacteria and yeasts, that offer health benefits when consumed. Often called “good” bacteria, they help maintain a balanced gut microbiome. People commonly use probiotics to support digestion, balance gut flora, and manage diarrhea. This article explores whether probiotics can sometimes worsen diarrhea and the factors involved.
Initial Digestive Adjustments
When starting probiotics, mild and temporary digestive symptoms like increased gas, bloating, or slight changes in bowel movements are common. These reactions indicate the gut microbiota is adapting to new bacterial strains. This adaptation involves shifts in microbial populations and increased bacterial activity, temporarily influencing digestive processes. These adjustments are usually transient, often subsiding within a few days to a couple of weeks as the body becomes accustomed to the new microbial balance. Such temporary effects are considered a normal physiological response, not a serious adverse reaction or true worsening of existing diarrhea.
Factors That Can Worsen Diarrhea
Pre-existing Health Conditions
Certain pre-existing health conditions can make individuals more susceptible to adverse reactions, including worsened diarrhea, when taking probiotics.
Small Intestinal Bacterial Overgrowth (SIBO)
Small Intestinal Bacterial Overgrowth (SIBO), where bacteria from the large intestine grow in the small intestine, can lead to symptoms like gas, bloating, and diarrhea, which probiotics might exacerbate.
Compromised Immune Systems
Individuals with compromised immune systems, such as those with HIV, cancer patients undergoing chemotherapy, or organ transplant recipients, face a higher risk of infection from probiotics. In these rare instances, the introduced probiotic bacteria could potentially cause serious infections like bacteremia or sepsis, leading to severe symptoms including diarrhea.
Strain Specificity and Dosage
Not all probiotic strains are suitable for every individual or condition; their effects are highly strain-specific. While probiotics often alleviate diarrhea, certain strains or combinations might paradoxically worsen it or cause other gastrointestinal distress. Very high doses of probiotics, measured in Colony-Forming Units (CFUs), might overwhelm the digestive system, potentially leading to gastrointestinal upset, including diarrhea. For example, lower doses of certain probiotics have been observed to increase the duration of diarrhea in some studies, contrasting with the effects of higher doses.
Quality and Manufacturing
The quality and manufacturing processes of probiotic supplements play a significant role in their safety and effectiveness. Products from less reputable brands might contain contaminants, unintended microorganisms, or allergens that can trigger digestive issues, including diarrhea. Lack of stringent regulation means the actual contents or viability of bacteria in some products may not match label claims, potentially leading to unexpected reactions.
Paradoxical Reactions
In rare instances, some individuals may experience paradoxical reactions to probiotics. Certain probiotic strains can produce compounds, such as D-lactic acid, which in susceptible individuals, particularly those with underlying conditions like short bowel syndrome, could lead to neurological or digestive symptoms, including an exacerbation of diarrhea.
When to Consult a Doctor
While initial digestive adjustments to probiotics are common, medical consultation is important in certain circumstances. If diarrhea significantly worsens or persists beyond a few days after starting a probiotic, stop use and seek medical attention. Immediate medical evaluation is warranted for severe symptoms like high fever, intense abdominal pain, or bloody stools. Any signs of dehydration, including reduced urination, excessive thirst, or dizziness, also indicate a need for prompt medical care. Individuals with pre-existing serious medical conditions, such as those who are immunocompromised, have severe pancreatitis, or have recently undergone major surgery, should consult a doctor at the first sign of any adverse effects from probiotics.
Selecting and Using Probiotics
When selecting and using probiotics, consider the following:
- Consult a healthcare professional: Before starting any probiotic, especially with underlying health conditions or other medications, consult a doctor. They can help determine if probiotics are appropriate and recommend specific strains.
- Start with a lower dose: To minimize potential digestive upset, begin with a lower dose and gradually increase it over time. This allows the body sufficient time to adjust to the new microorganisms and helps gauge individual tolerance.
- Research specific strains: The benefits of probiotics are often specific to particular strains, meaning different strains target different health concerns. Researching specific strains and their proven benefits, or seeking guidance from a professional, ensures the chosen product aligns with desired health outcomes.
- Check quality and reputability: Given that probiotics are often regulated as food supplements rather than medicines, checking for quality and reputability is important. Look for products from trusted brands that provide clear labeling of strains and Colony-Forming Units (CFUs), and ideally, have undergone third-party testing to verify contents and purity.