My Supplement Shelf:  Probiotics 

Probiotics are often discussed as if all probiotics were interchangeable—or as if swallowing a few billion “good bacteria” could permanently redesign the intestinal microbiome. Neither is true. 

A probiotic is a live microorganism that, when given in an adequate amount, produces a health benefit. Its effects depend on the particular strain, dose, formulation, and reason for taking it. Nevertheless, probiotics have earned a regular place on my supplement shelf. I generally alternate either Ortho Biotic by Ortho Molecular Products or CoreBiotic by Researched Nutritionals. 

These are different formulations. Ortho Biotic contains traditional bacterial strains plus the beneficial yeast Saccharomyces boulardii.  Its freeze-dried organisms are protected from moisture and heat, and the product does not require refrigeration.  CoreBiotic uses hardy, spore-forming Bacillus strains together with a prebiotic fiber, that provides food for beneficial organisms.  I like having these two approaches available rather than assuming that one product is ideal for every situation (supporting gut lining, supporting regularity, crowding out less helpful bacteria, etc.) 

Our intestinal tract contains trillions of microorganisms with various roles in digestion, vitamin production, immune signaling, and maintenance of the intestinal lining. This intestinal barrier is resilient, but it can be disturbed by antibiotics, illness, travel, dietary changes, stress, and aging. Probiotics are one of the more evidence-backed ways to help nudge things back toward equilibrium.  

Symptom-wise, selected probiotics may improve bowel regularity, bloating, gas, and other functional digestive complaints. A 2023 systematic review suggested that some probiotic combinations and individual strains improved symptoms of irritable bowel syndrome.  It should be noted that a benefit from one strain doesn’t mean that other probiotics will have the same result.  Every probiotic is different, which is why it’s important to vary the probiotic you use. 

The digestive tract is the barrier (along with the skin) between the outside world and inside our bodies, and most of the immune signaling takes place in the gut.  In fact, 70% of our immune systems live around the intestines.  And, a well-balanced microbiome helps train and regulate immune responses.  It can support appropriate reactions to actual threats while helping dampen the kind of low-grade, chronic inflammation that's been linked to a long list of medical conditions. Since I live in a world of multiple stresses of all sorts, I feel that it’s necessary to pay attention to this aspect of my health.  

A meta-analysis of randomized trials in adults found that taking probiotics with antibiotics reduced the risk of antibiotic-associated diarrhea by approximately 37 percent. This does not mean that every probiotic prevents every case, but it is an important result.   This is one reason I appreciate that Ortho Biotic contains Saccharomyces boulardii. Because it is a yeast rather than a bacterium, it is not directly killed by antibacterial drugs. It has been studied for antibiotic-associated diarrhea. 

I also view probiotics as potentially helpful when travel, an intestinal illness, or a major change in diet has unsettled my digestive system. I am not trying to “sterilize” or completely rebuild my microbiome. I am simply giving it some temporary reinforcements while it reestablishes equilibrium. 

The gut and brain are in constant two-way communication — through the vagus nerve, through immune signaling, through hormones, and through metabolites your gut bacteria actually produce, including precursors to neurotransmitters like serotonin and GABA. A lot of your body's serotonin, in fact, is made in the gut, not the brain. Research on this "gut-brain axis" has found that certain probiotic strains can have a modest but real effect on mood and anxiety symptoms, likely by way of reducing systemic inflammation and supporting healthier neurotransmitter signaling. I don't take probiotics as a mood intervention, but knowing that gut health and mental well-being are this intertwined makes the daily habit feel more worthwhile. 

Constipation is one of the most common non-motor symptoms of Parkinson's, and for a lot of us, it shows up years before the motor symptoms do — some researchers think gut changes may actually be an early part of how the disease develops, not just a side effect of it. There's a real hypothesis in the field that Parkinson's-related protein changes may start in the gut and travel to the brain along the vagus nerve, long before diagnosis.  In fact, my Parkinson symptoms showed up as a gut issue before any tremor or motor symptoms occurred. 

The good news is that probiotics have actually been studied specifically in Parkinson's patients, and the results are encouraging. In a randomized, double-blind, placebo-controlled trial, a multi-strain probiotic increased spontaneous bowel movements and improved stool consistency and constipation-related quality of life.  A subsequent meta-analysis found that probiotics increased bowel-movement frequency in people with Parkinson’s by approximately one movement per week and improved stool consistency. More recent reviews have reached similar conclusions.