A lot of Americans know about the Battle of Thermopylae during the Persian Wars.
It's not necessarily because we're well educated but because a lot of us saw the sweaty, oily, sepia-toned 2006 action movie, 300, which told a fictionalized version of the ancient battle.
To refresh your memory, Xerxes, the king of Persia, attacked Greece with a huge army. Depending on who or what you believe, the army consisted of anywhere from 50,000 soldiers to millions of soldiers, along with some angried-up elephants. Either way, there were a fuck-ton of soldiers who lit on Greece.
The opposing Greek force was comparatively tiny. It consisted of about 7,000 Greeks and about 300 Spartans, who, in addition to their training in the martial arts, appeared to have spent a lot of time blasting their cores on their Ab Rocket Abdominal Trainers (at least in the movie).
The Greeks had made a tactical decision to make their last stand at Thermopylae, a narrow passage of land surrounded by hills that measured about 5 meters wide at the ends and 15 meters wide at the center.
Its narrowness prevented the Persians from using their normal battle tactic of lobbing volley after volley of arrows down onto the opposing pin-cushions-in- waiting and then overwhelming them with sheer numbers.
As soon as a small number of Persians would trickle into the pass, the Greeks sliced and diced them up.
"Would you like to fillet this one, King Leonidas?"
"Oh no, brave Dienekes, be my guest."
It was like a sushi assembly line. This allowed the small army of Greeks to oppose division after division of frustrated and increasingly limbless Persians for three days. They might have held them off even longer were it not for a local Greek telling the Persians about an alternate path that led to a point behind the Greek army lines.
The reason I bring all this up in an article about probiotics is because there's a similarity between the Battle of Thermopylae and probiotics and no, it's not really that much of a stretch.
The 300 In Reverse
The whole concept behind probiotics is to introduce certain strains of bacteria into the human gut to influence health. Superficially it makes sense but when you look at the numbers, you begin to see how futile an endeavor it is.
The human gut contains tens of trillions of bacteria. The average probiotic (yogurt or microbe-filled pill) contains somewhere between 100 million and a few hundred billion bacteria. To get a sense of scale, a billion is a thousand million, whereas a trillion is a thousand billion.
To make the distinction even clearer, stacking a billion pennies atop one another would give you a stack 870 miles high. If you stacked a trillion pennies atop one another, the stack would go to the moon, come back to earth for a snack, and then go to the moon again.
So yeah, a few billion bacteria trying to fight tens of trillions of bacteria is like the 300 but in reverse, with the Greeks attacking the Persians at the ileocecal junction instead of the pass at Thermopylae, but in this case the odds are much, much worse that the Greeks, or more aptly, the Greek yogurt, will win.
If only that were the sole problem with probiotics.
They Go Donner Party On Each Other
More often than not, the strains of bacteria used to infiltrate your gut aren't chosen because they're known to adapt to the human gut or improve health in any way. Instead, they're chosen because manufacturers know how to grow large numbers of those particular strains really well.
It's possible the manufacturers made a sincere determination that Bifidobacterium and Lactobacillus (the most commonly encountered store-bought bacteria) were the way to go for a happy gut, but unfortunately the particular strains they chose to propagate might not be ones that can even survive the acid cauldron of your gut.
And even if you choose to ignore all that, there's the problem I harp about all the time, and that's "temperature chain of command." Say you choose to take probiotics in pill form. Okay, but you have no idea of whether they're still viable. These products generally need to be chilled so that all microbial metabolism stalls. Others are freeze-dried and blister packed but they still can't be exposed to anything above room temperature.
That means that the bottles or packets of pills can't be left, even temporarily, on some sun-drenched CVS loading dock or on your front porch. The rise in temperature would "wake" the bacteria up, at which point they'd start looking for things to metabolize.
Since there's no carbon source available to them other than each other, they soon cannibalize each other, leaving you with a bottle of bacterial dust and broken bacterial dreams.
But forget all that. Let's see what the actual research has to say.
The Probiotics' Batting Average is Below the Mendoza Line
I'll throw it right out there: There's little evidence to show that probiotics do much to extend life or prevent or treat any of the things they're often purported to, including treating depression, eczema, bacterial vaginosis, allergic diseases, or urinary tract infections.
And while they're often recommended to treat or prevent some of the side effects of antibiotics, using probiotics in such situations might actually make such side effects worse. A recent study published in Cell found that probiotics actually delayed reconstitution of antibiotic-ravaged microbiomes of human guts, if it occurred at all.
What probiotics might do, though, is help people who are suffering from a few specific gastrointestinal disorders, like irritable bowel syndrome or necrotizing enterocolitis in infants.
A 2014 review of more than 30 studies found that probiotics, in some cases, really did help relieve some of the symptoms of irritable bowel disease. The trouble is, the scientists don't know why it worked, but one of the theories is that the probiotics somehow stunted the growth of harmful bacteria.
Even so, the general consensus is that everyone has a unique microbiome and treating them effectively with probiotics would require a customized approach that's just not currently possible, especially in the numbers it would take to affect such a change.
Jamie Lee Curtis is Going to be so Pissed
If your faith in probiotics continues unabated, even after reading all of the above, then God bless ya', you poor bastard. No, I get it. Intuitively, probiotics make sense. Still, there's just way too much we don't know about them.
If you still insist on using them, then at least use one that has a fighting chance of working; in other words, drink kefir.
Kefir is a milk product made from starter grains of bacteria and yeast. The end product is a slightly sour, slightly fermented beverage that even lactose intolerant people can drink. What's particularly cool about kefir is that it contains between 10 and 34 strains of "good" bacteria, whereas yogurt contains only 2 to 7 strains.
The best strategy of all, though, might be in eating prebiotic, aka synbiotic foods – things like sauerkraut, pickled foods, kimchi, and kombucha tea that not only introduce hopefully beneficial bacteria to your gastrointestinal tract, but also provide food for them at the same time. They're like bacterial versions of those Turf Builder® combos of grass seed and fertilizer.
Why Do We Even Care About these Bacteria?
Maybe I should have discussed this earlier, but the reason we're interested in the bacteria in our guts in the first place is actually because of their waste products; that, and their ability to help us digest otherwise indigestible foods (various types of fiber).
I hate to introduce another "biotic" into the discussion, but these waste products are known as postbiotics. They include things like:
- Short-chain fatty acids – End products like acetic acid and butyric acid that help modulate blood sugar levels.
- Indole – This chemical is largely responsible for the characteristic smell of feces, but it's recently been found to help animals retain a youthful gene expression, theoretically leading to extended life spans.
- Hydrogen peroxide – Production of this well-known chemical can thwart the rise of salmonella and other pathogenic bacterial bad guys.
- Muramyl peptide – This protein can help regulate human sleep.
- p40 – This protein is a key driver of cell-mediated immunity.
- Nutrients – Bacteria produce several B vitamins, vitamin K, and even some amino acids.
So yes, it's a good idea to influence the production of these postbiotics, but it probably isn't going to be accomplished by eating yogurt and probiotic supplements. Instead, you can eat foods that allow your native bacteria to "poop" more postbiotics than they might ordinarily, foods like apple cider vinegar, spirulina, and even the pulp and skins of grapes and olives.
There's also some overlap between prebiotic and postbiotic foods in that you can increase the production of the latter by eating more of the former, things like the following traditional probiotic foods mentioned earlier:
- Pickled vegetables
The Two Main Points: Take 'Em or Leave 'Em
- Probiotics like yogurts and capsules of bacteria seem to have little effect on human health, except maybe in specific instances like irritable bowel syndrome (IBS) and necrotizing enterocolitis in infants. If you do choose to use them anyhow, choose kefir as your weapon of choice and try to drink 4 ounces a day.
- Fermented foods like kimchi, pickled vegetables are a much better route to establishing a plush, thriving, microbiome. Try to eat a serving or two a day.