Are Probiotics the Key To Avoiding Traveler's Diarrhea?

Guys, I'm, like, soooo vaccinated right now!

​In just a few days, I'm headed to Thailand. Then Sri Lanka. Then Vietnam. Then... who knows? And, at the last minute, I decided to do the responsible thing and get my vaccines.

No, they didn't give me adult-onset autism. Just a slightly sore arm.

And knowledge! 

Okay, the vaccines didn't give me knowledge. But the doctor did. 

She said that probiotics can help prevent (and treat) traveler's diarrhea. They contain helpful, healthy microbes that compete with stomach-upsetting bacteria and other organisms that you might accidentally ingest. 

Who said competition isn't a good thing? (I mean, other than educators who don't fully understand motivation and developmental psychology?)

But, she said, not all probiotics are created equal. The most effective bacteria are Lactobacillus acidophilus and Bifidobacterium bifidum. The yeast you want is Saccharomyces boulardii. 

However, it isn't just the contents of the pills, but also how they are delivered, that matters. In order to work, they need to make it through the stomach to the intestine without being dissolved. 

The brand my doctor recommended is Ortho Molecular Ortho Biotic, which is $33 for 30 capsules ot $60 for 60. 

​That's a little pricey. I did some research online and found a cheaper equivalent: NexaBiotic Advanced Multi-Biotic, which contains Lactobacillus acidophilus, 
Bifidobacterium bifidum and Saccharomyces boulardii, and claims to have stomach-acid resistant delayed-release capsules. And! It's half the price: 30 for $14.82 or 60 for $26.57.

Plus, the little intestine guy on the bottle is SO cute!

So that's what I ended up ordering, even though it might not be as effective as the doctor-recommended brand. I wasn't especially worried about contracting the infamous Bangkok Belly, as I've never really had traveler's diarrhea before... but I figured it's always better not to be exploding out of both ends.

Now, as anyone who's read my blog before knows, I HATE pseudoscience. So before I ordered, I did some research with my boyfriend, who has a Ph.D. in genetics. We're both passionate about scientific literacy, so I wanted to share some of the articles we read about these probiotics. 

The first, and most compelling, is McFarland's Meta-analysis of probiotics for the prevention of traveler's diarrhea (2007). This study is reputable because:

a) The research came out of the Department of Health Services Research and Development, VA Puget Sound Health Care System -- not some random institution, not some company that has a conflict of interests. 

b) Meta-analyses are studies of studies. Rather than doing one study and publishing the results, they examine the results of many or all available studies on a specific topic, evaluate the quality of the studies, and look for consensus and reproducibility. It's a valuable to weed out bad or biased "pseudo" studies. In other words, it's a rigorous methodology that helps filter out bad research.

McFarland found that "twelve of 940 screened studies met the inclusion and exclusion criteria. The pooled relative risk indicates that probiotics significantly prevent TD (RR=0.85, 95% CI 0.79,0.91, p<0.001)... Several probiotics (Saccharomyces boulardii and a mixture of Lactobacillus acidophilus and Bifidobacterium bifidum) had significant efficacy. No serious adverse reactions were reported in the 12 trials. Probiotics may offer a safe and effective method to prevent TD."

Interesting to note: most people think of "probiotics," but Saccharomyces boulardii, the yeast my doctor recommended, is actually the most studied, most effective ingredients. 

Other interesting studies: 

Randomized controlled trial of live lactobacillus acidophilus plus bifidobacterium bifidum in prophylaxis of diarrhea during radiotherapy in cervical cancer patients (Chitapanarux et al., 2010)  found that "Grade 2 -3 diarrhea was observed in 45% of the placebo group (n = 31) and 9% of the study drug group (n = 32) (p = 0.002). Anti-diarrheal medication use was significantly reduced in the placebo group (p = 0.03). The patients in the study drug group had a significantly improved stool consistency (p < 0.001)." 

Efficacy and Safety of Saccharomyces boulardii in Acute Rotavirus Diarrhea: Double Blind Randomized Controlled Trial from a Developing Country (Das et al., 2016) found that "the median duration (hours) of diarrhea was significantly shorter in the intervention group (60 vs. 89; 95% CI: -41.2 to - 16.8). A significantly shorter duration of hospitalization (74 vs. 91; 95% CI: -33.46 to - 0.54) was also seen in the intervention group, but no significant difference was seen for fever and vomiting... The present trial showed that SB is effective and safe in acute rotavirus diarrhea."

Lactobacillus acidophilus and Bifidobacterium bifidum stored at ambient temperature are effective in the treatment of acute diarrhoea (Rerksuppaphol and Rerksuppaphol, 2010) found that "probiotics shortened duration of diarrhoea (34.1 and 34.8 hrs when stored either at 4°C or at room temperature, respectively, and 58 hrs with placebo, p<0.01) and reduced the number of stools (7.3 and 8 vs 15.9 with placebo, p<0.01)... Administration of probiotics is beneficial as additional treatment of acute diarrhoea and efficacy is not affected by storage temperature."

TL;DR: There is strong evidence that these three probiotics can help prevent and treat traveler's (and other) diarrhea -- if they're formulated properly. There's no point taking a probiotic if it gets dissolved and destroyed in the stomach. My doctor recommended Ortho Molecular Ortho Biotic, which meets all the scientific criteria, and a less expensive option is NexaBiotic Advanced Multi-Biotic. 

Now go eat some delicious street food. (Assuming you can see them making it; there are locals in line; and you're getting it around the time when locals eat -- that way you know it hasn't been sitting out all day.)