A spread of colorful pills.
Mindy D. had suffered from constipation for years when her gastroenterologist advised her, at 38, to take a popular over-the-counter probiotic. Over the next two years, she experimented with different dosages, sometimes taking it three times a day. But she kept getting sicker—sometimes so ill she couldn't work.
"We shouldn't just presume probiotics are safe."
Her symptoms improved only after she traveled from Long Island to Georgia to see Satish S. C. Rao, a gastroenterologist at Augusta University. "The key thing was taking her off probiotics and treating her with antibiotics," he says.
That solution sounds bizarre, if, like many, you believe that antibiotics are bad and probiotics good. Millions of Americans take probiotics—live bacteria deemed useful—assuming there can be only positive effects. The truth is that you really don't know how any probiotic will affect you. To quote the American Gastroenterological Association Center for Gut Microbiome Research and Education, "It remains unclear what strains of bacteria at what dose by what route of administration are safe and effective for which patients."
"We shouldn't just presume probiotics are safe," says Purna Kashyap, a gastroenterologist from the Mayo Clinic, in Rochester, Minnesota, and a member of the Center's scientific advisory board. Neither the U.S. Food and Drug Administration or the European Food Safety Authority have approved probiotics as a medical treatment. Things can go very wrong in the ill: Among patients with severe acute pancreatitis, one study found that a dose of probiotics increased the chance of death. Even randomized controlled trials of probiotics rarely report harms adequately and the effect over the long-term has not been studied.
Many people pick up a product at a drug store or health store without ever telling a doctor. Doctors are fans, too: in a 2017 survey of healthcare providers at Stanford, more than 60 percent of the respondents said they prescribed probiotics. Many did so inconsistently, leaving the choice of which probiotic up to the patient. Healthy people take them for a range of unproven benefits, including protection from infections or heart disease or to sharpen their brains.
It's fine—unless it isn't. "Probiotics are capable of altering the microbiome in unpredictable ways," explains Leo Galland, an internist in New York who specializes in difficult digestions. "I've had patients who got gas and bloating, constipation or diarrhea from probiotics."
Your Microbiome Is Unique
The booming probiotic market has fed on excitement about the new science of the microbiome, the genetic material of all the microbes that live in our bodies and on our skin. Microbes make up 1 to 3 percent of every human being's body mass—you carry trillions of them, including more than a hundred species and thousands of strains. To identify a microbe, you need to know the genus, species and strain. For example, in Lactobacillus rhamnosus GG, the ingredient in the OTC probiotic Culturelle, Lactobacillus is the genus, rhamnosus is the species and GG is the strain designation.
Variations in your microbiome could help explain why you put on weight or suffer from Crohn's or depression. Each of us has our own unique mix.
A decade ago, the U.S. National Institute of Health (NIH) launched the Microbiome Project to establish a baseline description of health. Scientists sequenced the DNA in more than 2,200 strains, still a small fraction of the whole.
Within a couple of years, we had evidence that our microbiomes are distinctive. Another team used the NIH data set to look into the idea of microbial "fingerprints." A classic computer science algorithm allowed it to assign individuals "codes" defined by DNA sequences of their microbes—no human DNA required. Using information solely from the guts, "Eighty percent of individuals could still be uniquely identified up to a year later," they wrote.
That distinctiveness makes a difference when we try to change our mix by swallowing bacteria considered "pro." Even in healthy people, the reactions to probiotics vary widely, according to a study in Cell in September. The team examined the intestines of healthy volunteers who had taken a cocktail of eleven strains of probiotics for the experiment. Which took up residence in the intestinal lining? The answer depended on the person. Led by Eran Segal and colleagues at the Weizmann Institute of Science, in Rehovot, Israel, the authors concluded that effective supplements would have to be personalized.
Patients with "brain fog" improved dramatically when they were taken off their probiotics and given antibiotics as well.
To truly customize a probiotic, however, we'd have to know the state of an individual's gut microbiome, identify danger signs and link them to symptoms, isolate relevant strains of probiotics that might be needed, and get them into the gut lining effectively. Commercial tests are still at step one. Several companies claim to assess your microbiome based on a stool sample—but the Weizmann team has also shown that the differences between our gut linings aren't apparent from our stool. Galland has explored testing his patients looking for ways to help. "I've concluded that uBiome, American Gut Project, and others don't yield useful information," he observes.
Can A Probiotic Make Your Brain Foggy?
Besides taking her probiotic, Mindy D. had cut out gluten and upped her vegetables and fruits. But soon after she ate her seemingly healthy meals, she would begin to feel dizzy and sometimes even slurred her words, as if she were drunk. "It was such an intense feeling," she said.
A slender 5 ft. 2 inches, she dropped 20 pounds, becoming unhealthily thin. She traveled to see specialists in Minnesota and Connecticut and took two month-long medical leaves before she found Rao in Georgia.
In June, Rao created a stir when he and his coauthors reported that a cluster of his patients with "brain fog"—the "intense feeling" Mindy D. described—improved dramatically when they were taken off their probiotics and given antibiotics as well.
His idea was that lactobacilli and other bacteria colonized their small intestines, rather than making it to the colon as intended—a condition known as "small intestinal bacteria overgrowth" (SIB0) that some gastroenterologists treat with antibiotics. In this group, he argues, the small intestine produced the brain fog symptoms as a consequence of D-lactic acidosis, a phenomenon usually associated with damaged intestines. "If you have brain fogginess along with gas and bloating, please don't take probiotics," Rao says.
The paper prompted a rebuttal at the end of September from Eamonn Quigley, a gastroenterologist at Houston Methodist, who criticized the methodology in detail. Kashyap, of the Mayo Clinic, is skeptical as well. "People were picked for their brain fogginess and they were taking probiotics. Probiotics could be an innocent bystander," he says.
"It's hard for me to imagine the mechanism of say, Culturelle, causing SIB0," says Shira Doron, a specialist in infectious diseases and associate professor at Tufts University School of Medicine who studies probiotics. "The vast majority of people will never suffer a side effect from a probiotic. But probiotics are a live organism so they have a unique set of potential risks that other supplements don't have. They can give you a severe infection in very rare circumstances."
The larger point is that probiotics should be used under a doctor's care. In April, a panel of 14 experts on behalf of the European Society for Primary Care Gastroenterology concluded that "specific probiotics are beneficial in certain lower GI problems." That does not mean any over-the-counter probiotic is likely to help you because it helped your cousin.
"Even your doctor may be going by anecdotal experience, rather than hard science."
Both Galland and Rao use probiotics in their practice, but carefully. "We advise caution against excessive and indiscriminate use of probiotics especially without a well-defined medical indication, and particularly in patients with gastrointestinal dysmotility," when the muscles of the digestive system don't work normally, Rao's team wrote.
"Because there are so many studies out there that are poorly done, that aren't looking at side effects, the science is murky. Even your doctor may be going by anecdotal experience, rather than hard science," Doron adds. Your doctor may tell you that many of his patients report a great experience with probiotics. As Doron points out, however, with disorders like irritable bowel syndrome, the most common gastrointestinal diagnosis, the placebo effect is very strong. Many patients could "respond to anything if they believe it works," she says.
One Day, There Might Be a Drug for a Broken Heart
A sad woman peering through sunlit blinds.
For Tony Y., 37, healing from heartbreak is slow and incomplete. Each of several exes is associated with a cluster of sore memories. Although he loves the Blue Ridge Mountains, he can't visit because they remind him of a romantic holiday years ago.
If a new drug made rejections less painful, one expert argues, it could relieve or even prevent major depression.
Like some 30 to 40 percent of depressed patients, Tony hasn't had success with current anti-depressants. One day, psychiatrists may be able to offer him a new kind of opioid, an anti-depressant for people suffering from the cruel pain of rejection.
A Surprising Discovery
As we move through life, rejections -- bullying in school, romantic breakups, and divorces -- are powerful triggers to depressive episodes, observes David Hsu, a neuroscientist at Stony Brook University School of Medicine in Long Island, New York. If a new drug made them less painful, he argues, it could relieve or even prevent major depression.
Our bodies naturally produce opioids to soothe physical pain, and opioid drugs like morphine and oxycodone work by plugging into the same receptors in our brains. The same natural opioids may also respond to emotional hurts, and painkillers can dramatically affect mood. Today's epidemic of opioid abuse raises the question: How many lives might have been saved if we had a safe, non-addictive option for medicating emotional pain?
Already one anti-depressant, tianeptine, locks into the mu opioid receptor, the target of morphine and oxycodone. Scientists knew that tianeptine, prescribed in some countries in Europe, Asia, and Latin America, acted differently than the most common anti-depressants in use today, which affect the levels of other brain chemicals, serotonin and norepinephrine. But the discovery in 2014 that tianeptine tapped the mu receptor was a "huge surprise," says co-author Jonathan Javitch, chief of the Division of Molecular Therapeutics at Columbia University.
The news arrived when scientists' basic understanding of depression is in flux; viewed biologically, it may cover several disorders. One of them could hinge on opioids. It's possible that some people release fewer opioids naturally or that the receptors for it are less effective.
Javitch has launched a startup, Kures, to make tianeptine more effective and convenient and to find other opioid-modulators. That may seem quixotic in the midst of an opioid epidemic, but tianeptine doesn't create dependency in low, prescription doses and has been used safely around the world for decades. To identify likely patients, cofounder Andrew Kruegel is looking for ways to "segment the depressed population by measures that have to do with opioid release," he says.
Is Emotional Pain Actually "Pain"?
No one imagines that the pain from rejection or loss is the same as pain from a broken leg. Physical pain is two perceptions—a sensory perception and an "affective" one, which makes pain unpleasant.
Exploration of an overlap between physical and what research psychologists call "social pain" has heated up since the mid-2000s.
The sensory perception, processed by regions of the brain called the primary and secondary somatosensory cortices and the posterior insula, tells us whether the pain is in your arm or your leg, how strong it is and whether it is a sting, ache, or has some other quality. The affective perception, in another part of the brain called the dorsal anterior cingulate cortex and the anterior insula, tells us that we want the pain to stop, fast! When people with lesions in the latter areas experience a stimulus that ordinarily would be painful, they don't mind it.
Science now suggests that emotional pain arises in the affective brain circuits. Exploration of an overlap between physical and what research psychologists call "social pain" has heated up since the mid-2000s. Animal evidence goes back to the 1970s: babies separated from their mothers showed less distress when given morphine, and more if dosed with naloxone, the opioid antagonist.
Parents, of course, face the question of whether Baby feels alone or wet whenever she howls. And the answer is: both hurt. Being abandoned is the ultimate threat in our early life, and it makes sense that a brain system to monitor social threats would piggyback upon an existing system for pain. Piggybacking is a feature of evolution. An ancestor who felt "hurt" when threatened by rejection might learn adaptive behavior: to cooperate or run.
In 2010, a large multi-university team led by Nathan DeWall at the University of Kentucky, reported that acetaminophen (Tylenol) reduced social pain. Undergraduates took 500 mg of acetaminophen upon awakening and at bedtime every day for three weeks and reported nightly about their day using a previously-tested "Hurt Feelings Scale," rating how strongly they agreed with questions like, "Today, being teased hurt my feelings."
Over the weeks, their reports of hurt feelings steadily declined, while remaining flat in a control group that took placebos. In a second experiment, the research group showed that, compared to controls, people who had taken acetaminophen for three weeks showed less brain activity in the affective brain circuits while they experienced rejection during a virtual ball-tossing game. Later, Hsu's brain scan research supported the idea that rejection triggers the mu opioid receptor system, which normally provides pain-dampening opioids.
More evidence comes from nonhuman primates with lesions in the affective circuits: They cry less when separated from caregivers or social groups.
Heartbreak seems to lie in those regions: women with major depression are more hurt by romantic rejection than normal controls are and show more activity in those areas in brain scans, Hsu found. Also, factors that make us more vulnerable to rejection -- like low self-esteem -- are linked to more activity in the key areas, studies show.
The trait "high rejection sensitivity" increases your risk of depression more than "global neuroticism" does, Hsu observes, and predicts a poor recovery from depression. Pain sensitivity is another clue: People with a gene linked to it seem to be more hurt by social exclusion. Once you're depressed, you become more rejection-sensitive and prone to pain—a classic bad feedback loop.
"Ideally, we'd have biomarkers to distinguish when loss becomes complicated grief and then depression, and we might prevent the transition with a drug."
Helen Mayberg, a neurologist renowned for her study of brain circuits in depression, sees, as Hsu does, the possibility of preventing depressions. "Nobody would suggest we treat routine bad social pain with drugs. But it is true that in susceptible people, losing a partner, for example, can lead to a full-blown depression," says Mayberg, who is the founding director of The Center for Advanced Circuit Therapeutics at Mount Sinai's Icahn School of Medicine in New York City. "Ideally, we'd have biomarkers to distinguish when loss becomes complicated grief and then depression, and we might prevent the transition with a drug. It would be like taking medication when you feel the warning symptoms of a headache to prevent a full-blown migraine."
A Way Out of the Opioid Crisis?
The exploration of social pain should lead us to a deeper understanding of pain, beyond the sharp distinctions between "physical" and "psychological." Finding our way out of the current crisis may require that deeper understanding. About half of the people with opioid prescriptions have mental health disorders. "I expect there are a lot of people using street opioids—heroin or prescriptions purchased from others--to self-medicate psychological pain," Kreugel says.
What we may need, he suggests, is "a new paradigm for using opioids in psychiatry: low, sub-analgesic, sub-euphoric dosing." But so far it hasn't been easy. Investors don't flock to fund psychiatric drugs and in 2018, the word opioid is poison.
As for Tony Y., he's struggled for three years to recover from his most serious relationship. "Driving around highways looking at exit signs toward places we visited together sometimes fills me with unbearable anguish," he admits. "And because we used to do so much bird watching together, sometimes a mere glimpse of a random bird sets me off." He perks up at the idea of a heartbreak drug. "If the side effects didn't seem bad, I would consider it, absolutely."