Probiotics—A “60 Minutes” Fantasy
Have you taken your bacteria and fungus, aka probiotics, today? If you watched the June 28, 2020 episode of 60 Minutes, you might have come away thinking that probiotics might just be the answer to everything that ails you. Or maybe you were just as confused as I was. I’m not sure what message they meant to send—which is troubling, considering that I had spent hours and hours of my time in 2019 and 2020 painstakingly answering the show’s editor’s questions on what is and is not known about probiotics (she had called me because I was one of the lead authors on a couple of major reviews of the scientific literature on probiotics—and she called me back numerous times to answer even more questions). Despite the show’s rosy message, I can assure you the news about probiotics is not all sweetness and light. But nothing I told her made it onto the show! If you’ve gotten the idea that I’m “a little steamed” about what was aired on “60 Minutes,” you’re right, but before I get into why I, as well as a number of other contributors to that “airing” are upset, I need to give a little background on probiotics to make sure we’re all on the same page.
Probiotics—A History
If you hate history, feel free to skip this paragraph, but if you’re wondering what all this probiotics “hubbub” is about, read on. What are probiotics anyway, and could they help you? Make things worse? Or do nothing but cost a lot?
So, if you didn’t learn this in high school biology, our lower (large) intestines (guts), the part of our body that assembles and gets rid of fecal matter (poop), are teeming with millions of different microbes, which scientists now refer to as the microbiome (the microbiome also includes the bugs that reside on our skin and in our mouths…). Although humans have been intentionally or unintentionally consuming foods fermented by micro-organisms (microbes) for thousands of years, the idea that consuming certain bacteria and fungi might improve health may have originated in the very early 20th or late 19th century with the Russian scientist, Elie Metchnikoff the 1908 Nobel Prize winner in medicine. Metchnikoff fed a concoction of certain bacteria in the form of a fermented yogurt-like drink to people in the belief that it would help them live longer. Or the idea may have been the slightly earlier brainchild of a Polish scientist, Jozef Brudzinski, who began using a different type of bacteria to treat infants with acute infectious diarrhea. However, the actual term, “probiotic,” referring to a substance produced by one type of living organism that benefits another, is attributed to two researchers, Daniel Lilly and Rosalie Stillwell, in a 1965 paper in the journal, Science. Suffice it to say, I’m sure none of these folks foresaw their idea blooming into a multi-million-dollar industry of questionable commercial products.
Probiotics Research?
As research into the new field of “probiotics” started to take hold—mostly in rats and mice—scientists began to see links between changes in the kinds of bugs in the intestines and some health conditions. No one has quite established whether changes in the bugs that normally populate the intestines can lead to illness or whether the changes are just an effect of the illness. But this didn’t stop a number of scientists from conjecturing that it might be possible to help prevent or minimize a couple of intestinal maladies by feeding people random doses of what they thought might be the normal bacteria that are supposed to live in our intestines. In short, the idea was that maybe good bacteria can crowd out any bad bacteria and prevent them from getting a toehold. The problem is that before any credible research was completed and analyzed, a number of practitioners and scientists jumped to the conclusion that feeding people microbes should naturally resolve or prevent any condition affecting the digestive system…and any number of other conditions as well.
There are so many erroneous assumptions here, it’s almost hard to know where to begin, as I tried to explain to the 60 Minutes editor. First, no one actually knows what the normal gut flora (as the bugs are sometimes called) are supposed to be, or if there even is a “normal.” But scientists are now able to finely (and finally) identify and count pretty much every organism in anyone’s gut at any time. So some scientists jumped to the conclusion that it should be possible to feed everyone the bugs found in the average person’s gut and that this would keep us all healthy or restore health in anyone with digestive issues. But the problem is we don’t know what is supposed to be there in the first place.
Let’s take two people living in the same household—Jack and Jill: They probably have similar but by no means identical microbiomes. They share the air and most meals. But Jill drinks beer and tap water, eat processed meats, and vapes on the weekend, while Jack prefers wine and bottled water, eats mostly salads, and doesn’t use nicotine products. Jill travels a lot, to different places for her work. Jack takes ibuprofen for migraines. He also takes medication for heartburn. All these things can and DO affect their personal microbiomes. Now, Jack gets sick and goes to the doctor. If his doctor was to measure his microbiome it would no doubt be different from before he got sick, but his doctor wouldn’t know what it was “before” or what that even means. Would making the bugs in his gut more like Jill’s restore his health? How could we make that happen? And if we fed him a dose of what we think are normal bugs and he did recover, how would we know if it was the bugs that actually helped him or which ones? Now, this was a simple hypothetical of two people living together. I don’t even want to get into the added complications of people living in or traveling to different countries with different diets and environments! Are you starting to see the problem researchers face in trying to disentangle this mess?
When my colleagues and I did a large review for the federal government of all the probiotics research that had ever been done, we discovered that most studies failed to characterize the bugs residing in people’s guts before they got sick or before they were treated with the probiotics, so they actually had no idea what was required to attempt to restore them to “normal!” In addition, almost no studies assess people’s gut bacteria after treatment, so even if treatments appeared to work, it’s not even possible to know whether the “good” bacteria actually “moved in” to the person’s intestines, NOR do we know if they moved the so-called “bad” bacteria out.
And by the way, we know that the bugs that reside in our lower intestines live on the fiber we consume in the form of fruits, vegetables, whole grains, and legumes—the stuff we ourselves can’t digest. This family of various food fibers is referred to as prebiotics (Great! A new term to remember!). Could this explain why our salad eater, Jack, has different bugs than Jill does? We don’t know. But we do know we need to consume those prebiotic foods to keep the friendly bugs in our guts at least somewhat happy.
Do Probiotic Supplements Work?
Now, let me try to separate fact from fantasy regarding the evidence presented on that 60 Minutes episode for what probiotics are supposed to do for us. According to some of the folks who appeared on the show, probiotics can do anything and everything from helping us lose (or not gain) weight to making our babies smarter. If that pipe-dream fantasy were true, trust me, I’d be at the front of the line to buy them!
When we did our review, we discovered that most studies failed to determine or to report what microbes were actually in the supplements they were giving their study subjects. Or if they did know the exact contents, they often reported that this information was proprietary and could not be divulged. What this means in plain English is that the research was being done AND paid for by a probiotics manufacturer, so they weren’t about to tell us what they really did! And here’s what’s even more interesting: You might have guessed that probiotics, being micro-organisms, need to be alive in order to work, right? You didn’t? Well, they do, because the bugs have to be able to multiply to fill your gut and fight off the bad bugs. However, most studies failed to determine whether the bugs they gave study participants were alive and could multiply. And another concerning problem is that commercial probiotic supplements are not regulated by the FDA! So, consumers have no way to be sure that these costly products they are buying actually contain what the label says they do, if the organisms they contain are alive, or if the products are effective! This is what I, as well as a number of other researchers tried to tell the 60 Minutes show’s editor but we were ignored. This “we” included a group of Israeli scientists who had conducted a study that the show seemed to kind of “bury” in the middle, giving it a lot less air time than they gave the “miracle cure” proponents who were shown at the start and finish of the show. Here’s a good summary of what the Israeli study found. I will return to it below.
Because the review my colleagues and I did was a few years ago, I decided to revisit the topic anew before writing this blog, so I searched for and read all the reviews published over this past year. Like our earlier review, these recent reviews examined all the studies ever conducted on the effects of probiotics on various conditions and on their safety. Of the hundreds of reviews available, I selected only the ones about humans and published in the highest quality journals, which happened to be about 10. Some of the journal reviews contained only two or three studies, and most of the studies included in these reviews tended to have very small numbers of participants and to be relatively poor quality. Let me be clear: The journal reviews were well done. They just happened to have reviewed poor studies—because those are the only studies that exist!
The kinds of conditions that were studied in these reviews included colon cancer risk, infertility (in women with polycystic ovary disease), weight issues, diabetes during pregnancy, general gastric distress like irritable bowel syndrome (IBS), a serious digestive condition of premature infants called necrotizing enterocolitis (NEC for short), as well as a number of other conditions.
Of all the conditions studied, only one seemed to benefit from probiotics: infantile NEC. No beneficial effects were found for people with IBS (the condition for which people most often take probiotics), for lowering the risk for diabetes or infertility, or for helping with weight loss—despite the “mice-weight-loss” lead-in to the 60 Minutes episode!
Are Probiotics Safe?
As it happens, for several years, doctors have already been giving severely premature, very low birth weight infants probiotics to try to prevent NEC. When we did our review, we found that probiotics are usually fairly safe for healthy people, but probably not so safe when given to severely ill people. So unfortunately, the very infants with NEC who are the intended targets of probiotic treatment are the most at risk for side effects, and a few cases of severe, even fatal, sepsis have been reported in these infants.
What about other safety issues…in less severely ill people? Well, the review that examined whether probiotics prevent diabetes in pregnant women found that in addition to not preventing diabetes, probiotics actually increased pregnant women’s risk of developing a severe life-threatening, little understood condition called preeclampsia and potentially increased the risk for developing pregnancy hypertension.
And in the well-publicized Israeli study I mentioned above, people who were given probiotics to hasten recovery from a round of antibiotic medications (which are known to disrupt normal gut function and cause temporary digestive distress) recovered less well than those who took nothing or who took non-viable probiotics (those essentially dead probiotics that couldn’t reproduce). This is a highly troubling finding for Team Probiotics (and actually contradicts the weak findings of a review I helped conduct a few years ago, but that’s why we keep doing research). The Israeli scientists were actually surprised by their findings and are currently doing additional research to determine what might help improve recovery time.
If you’re wondering why the safety issue is so important, it’s worth noting that some species of organisms that naturally reside in our guts and may be beneficial have subspecies that are lethal (think of that E. coli O157:H7 that tainted hamburger meat and caused a number of deaths). That’s because microbes divide—and therefore can mutate—rapidly. So, it’s crucial to know exactly what is in a product you’re considering taking.
Given the findings I’ve now seen on both benefits and safety, I would seriously question intentionally swallowing a pill for any reason that claims to contain probiotics.
What About Foods That Contain Probiotics?
So many commercial food products now claim to contain probiotics that they could start their own supermarket. Are these foods useful? And are they safe?
Probably the most well-studied probiotic-containing food is yogurt. When I was being interviewed by NPR about the review I co-authored on whether probiotics help avert antibiotic-associated diarrhea, the interviewer asked me if I would read—while on the air—the labels of all the yogurt brands at the particular LA supermarket where the interview was happening and tell her which had the most probiotics. I told her that I could read the product labels but that the information would be meaningless, because time and storage conditions affect probiotics’ viability (the same is true for the probiotic supplements you see all over supermarket shelves!). More importantly, as with the supplements, we don’t know how many of what kind of bug in foods might be helpful for what condition. The condition for which yogurt is most advertised is probably IBS, a common but poorly understood condition without effective treatments, but, as I mentioned above, the reviews of the effects of probiotic supplements on IBS found no real benefit, and studies of the effects of yogurt are almost all conducted by the manufacturers, who clearly have a pony in that race. At least yogurt is probably not harmful (unless you’re very lactose intolerant), and it’s pretty healthy, especially the unsweetened variety. So, if you love yogurt, go for it!!
Another food touted for its potential probiotic content is kimchi, a Korean fermented cabbage dish (the process of fermentation is done by microbes). And being cabbage, it’s also a rich source of prebiotics. The kimchi we see at our local markets is undoubtedly safe, but I can’t vouch for the stuff you make on your own, especially if you use the traditional fermentation method of burying the cabbage in the ground (the way the kimchi was made at the Asian grocery store my mom worked at and managed when I was in college. It was delicious, but I sometimes felt like I was playing dinnertime Russian roulette)! But as you may have experienced, cabbage tends to cause gas (in short because the good bugs that consume it in your intestines multiply and produce gas as a byproduct of digestion!). So, if you’re considering trying kimchi to relieve stomach upset, you could really be making it worse. But if you like the taste and can tolerate its gastric effects, go for it!
Then there’s kombucha, a fuzzy fermented tea that a friend of mine likens to the half empty bottle of sweetened iced tea your coworker left in the cafeteria all summer and then dares you to drink! Is it effective? Is it safe? Who knows?
And in case you’re wondering, food products that advertise they contain probiotics are not required to provide proof of content or amount. Probiotic poptarts, anyone?
What Else to Think About
The review articles I read on the effects of probiotics all emphasized that even when individual studies reported a beneficial effect, it was impossible to determine which microbes actually did the work because studies rarely identified what microbes and subspecies they used, and when studies did identify what species they used, oftentimes no two studies used the same ones.
Two commercial brands of probiotics may be manufactured under more stringent conditions than most (meaning they probably have a better chance of containing what their labels say they do), and they are probably the most well studied and the most expensive! When doctors recommend a specific probiotic, it’s often one of these two. However, they tend to be the most costly as well. Prescription-only forms of these probiotic are available and may be covered by some insurance plans, but again, the evidence for widespread benefits is weak. A third commercial brand is actually the only one verified by the US Pharmacopeia (USP) and is sold at one of the big nationwide discount stores quite inexpensively, but research on the effects of this particular mixture is lacking. Before using any of these products, consult your health care provider: They are in the best position to explain the pros and cons to you.
But before spending your hard-earned money for a product with little evidence of benefit, why not try upping your food game? Replace some breakfast or snack choices with plain yogurt and fruit. Increase your intake of fiber-rich vegetables, whole grains, and beans. And if IBS is an issue, work with your health care provider and a nutritionist trained to work with people with digestive issues like lactose intolerance and sensitivity to foods that contain Fermentable Oligo-, Di-, Mono-saccharides And Polyols (FODMAPs, for short: carbs found in certain fruits and vegetables like garlic, onions, and broccoli that can create intolerable digestive symptoms in some people).
Just try to avoid blindly swallow expensive bugs. You may regret the result!