A large meta-analysis (collection of multiple studies) was just published that claims probiotics don't work, and are useless.
I'm very sympathetic to the view that supplements are unnecessary and unnatural. I don't think our soils are so nutrient-depleted that we need to take multivitamins. I don't see any evidence that antioxidants or vitamins in pill form do any good for those of us not suffering from clinical nutrient deficiencies like scurvy or beri-beri, and I've come across considerable evidence that our pill popping is doing significant harm.
But the issue of probiotics is different.
I've been studying the recent science on the gut microbiome lately. Listening to lectures by Dr Pam Popper of Wellness Forum Health, and reading the books The Microbiome Solution, by Dr Robynne Chutkan, and Missing Microbes, by Martin J. Blaser, PhD.
And I'm more convinced than ever that a strong probiotic regimen can benefit a lot of us – perhaps all of us. For a few reasons.
1. We need bacteria to survive
When I was a kid, I fell in love with a book called Microbe Hunters, about the first scientists who discovered microbes under the microscope, and began putting together the connection between invisible bugs and human diseases.
What science came to believe – and what doctors, to their shame, still seem to believe, is that the only good bacterium is a dead bacterium.
And when Alexander Fleming accidentally killed some bacteria by growing mold on his PB&J in the lab, the medical world went wild in a quest to synthesize and scale the production of drugs that could wipe bacteria off the face of the earth.
While it's true that some of those microbes (bacteria, fungi, and viruses) are nasty pieces of work (the ones we call “pathogens”), there are a lot of bacteria in our bodies without which we have a hard time surviving, and an even harder time being healthy.
The current understanding is that there are about 100 trillion bacterial cells on and in our bodies, approximately 10 times more cells than human ones! Which means, essentially, that you and I are 10/11 bacteria, and 1/11 human. Which may be a humbling thought. (Probably more humbling to the bacteria.)
2. Antibiotics are Way Overused
Antibiotics kill bacteria. That's what they do. That's why we take them.
Trouble is, they kill bacteria pretty indiscriminately. And the bacteria most susceptible to antibiotics happen to be the beneficial bacteria in our guts, lactobacillus and bifidobacter. When these populations get decimated, that creates a vacuum for the pathogenic species to take hold. And since antibiotics can't kill 100% of any species of bacteria (and 0% of viruses, for which they're often prescribed), the few bacteria that remain can now reproduce unimpeded by competition.
If you've been given lots of courses of antibiotics in your life, it's pretty much a sure thing that your gut bacteria are severely depleted.
3. We're Too Clean
Our modern way of living, with lots of soap and hand-washing and Purell and Lysol and chlorinated water and triple-washed bagged greens, keeps us from getting in contact with lots of microbes. Therefore, our gut and skin microbiomes (the sum total of all our bacterial boarders) is deficient compared to previous generations, and humans in less developed parts of the world.
4. Many of Us Missed Out on the Full Birth Experience
Human birth, done naturally, consists of a vaginal delivery followed by breastfeeding.
There are times when neither is possible, due to true medical emergency.
But most c-sections are elective, and most formula feeding is based on economic, not medical necessity.
When we miss out on those experiences, we miss a crucial window in which our mother's microbes begin to colonize our own bodies. And some studies suggest that while those of us who were formula-fed c-section babies catch up to a certain extent, we never gain the same protections as our luckier counterparts.
5. Animal Agriculture
If you eat animals (or consume their bodily fluids) from any place other than a local, organic farm, you're getting a steady diet of antibiotics along with your chicken, beef, and pork. In fact, animal agriculture accounts for 80% of the antibiotic use in the United States. The main reason is that antibiotics fatten animals up, so they weigh more, and therefore command a higher price in the marketplace.
Many experts connect the introduction of antibiotics into our meat and dairy supply with the epidemic of obesity we face today. And it makes sense – if it fattens up the mammals we eat, why shouldn't it have the same effect on us.
6. Crappy Diets
Turns out we can, to some extent, choose our gut bacteria based on what we feed them. The high-fat, highly processed, low fiber, Standard American Diet creates a breeding ground for pathogenic bacteria. The good bacteria that live in our large intestines ferment and eat the fiber that we can't process by ourselves.
7. Symptoms of Dysbiosis
There are too many symptoms of dysbiosis (an imbalance of our gut microbes) to mention here, from leaky gut, to autoimmune disease, to obesity, to heart disease, to cancer, to diabetes, to you name it. The most “interesting” effects of a messed up gut microbiome, though, are emotional. Turns out our gut microbes control the gene expression that leads to production of the brain chemicals associated with mental health and illness, like dopamine and serotonin.
Unhappy bacteria can lead to unhappy us.
So what about that “probiotics don't work” meta-analysis?
Some of the studies weren't looking at pharmaceutical grade probiotics at all, but small amounts of yogurt and fermented foods. The flaw in studies like these is what Dr David Katz calls the “small parachute” problem: If you toss someone out of an airplane with a parachute the size of a Kleenex, you might assume that parachutes don't work.
Also, the studies were very short-term, ranging from 28-42 days, and they looked at biomarkers, not long-term health outcomes.
Finally, the study participants weren't asked (as far as we know) to improve their diets while they took the probiotics. As we've seen, probiotics won't seed your gut with bacteria that stick around if you continue to eat a crappy diet. That would be like filling your house with cats and feeding them only lettuce.
Are all probiotics created equal?
I wouldn't buy a probiotic off the shelf at a health food store or supermarket. They degrade over time, even under refrigeration, and who knows how long that bottle has been in a warehouse, and in a truck, and on the shelf, before you pick it up.
Also, many brands of supplements are, shall we say, fast and loose with what's actually in their pills and capsules.
Finally, there are many different strains of bacteria, and many different CFUs (strengths), and many different formulations that may or may not include prebiotics. Sometimes you want multiple strains, and sometimes you want just straight lacto and bifido. Sometimes you want prebiotics, and sometimes prebiotics are a terrible idea.
The sales clerk at the health food store does not have the background and experience to recommend the right formulation for you.
Probiotics are serious medicine, and should be approached in a serious manner.
If, after reading this article, you want to find out more about probiotics and whether they are right for you, email me at and we'll set up a time to talk.