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Tag: Lactobacillus

Published on Leave a comment on Could Probiotics Protect Breasts From Cancer?

Amazing!  Researchers found that the bacteria found in breast cancer patients and healthy patients are different. (See post on their earlier work on breast microbiome.) And not only that, but the types of bacteria (Lactobacillus and Streptococcus) that are more prevalent in the breasts of healthy women are considered "beneficial" and may actually protect them from breast cancer. Meanwhile, elevated levels of the bacteria Escherichia coli and Staphylococcus epidermidis found in the breast tissue adjacent to tumors are the kind that do harm (e.g., known to induce double-stranded breaks in DNA) . This research raises the question: could probiotics (beneficial bacteria) protect breasts from cancer? From Science Daily:

Beneficial bacteria may protect breasts from cancer

Bacteria that have the potential to abet breast cancer are present in the breasts of cancer patients, while beneficial bacteria are more abundant in healthy breasts, where they may actually be protecting women from cancer, according to Gregor Reid, PhD, and his collaborators. These findings may lead ultimately to the use of probiotics to protect women against breast cancer. The research is published in the ahead of print June 24 in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

In the study, Reid's PhD student Camilla Urbaniak obtained breast tissues from 58 women who were undergoing lumpectomies or mastectomies for either benign (13 women) or cancerous (45 women) tumors, as well as from 23 healthy women who had undergone breast reductions or enhancements. They used DNA sequencing to identify bacteria from the tissues, and culturing to confirm that the organisms were alive. 

Women with breast cancer had elevated levels of Escherichia coli and Staphylococcus epidermidis, are known to induce double-stranded breaks in DNA in HeLa cells, which are cultured human cells. "Double-strand breaks are the most detrimental type of DNA damage and are caused by genotoxins, reactive oxygen species, and ionizing radiation," the investigators write. The repair mechanism for double-stranded breaks is highly error prone, and such errors can lead to cancer's development.

Conversely, Lactobacillus and Streptococcus, considered to be health-promoting bacteria, were more prevalent in healthy breasts than in cancerous ones. Both groups have anticarcinogenic properties. For example, natural killer cells are critical to controlling growth of tumors, and a low level of these immune cells is associated with increased incidence of breast cancer. Streptococcus thermophilus produces anti-oxidants that neutralize reactive oxygen species, which can cause DNA damage, and thus, cancer.

The motivation for the research was the knowledge that breast cancer decreases with breast feeding, said Reid. "Since human milk contains beneficial bacteria, we wondered if they might be playing a role in lowering the risk of cancer. Or, could other bacterial types influence cancer formation in the mammary gland in women who had never lactated? To even explore the question, we needed first to show that bacteria are indeed present in breast tissue." (They had showed that in earlier research.)

But lactation might not even be necessary to improve the bacterial flora of breasts. "Colleagues in Spain have shown that probiotic lactobacilli ingested by women can reach the mammary gland," said Reid. "Combined with our work, this raises the question, should women, especially those at risk for breast cancer, take probiotic lactobacilli to increase the proportion of beneficial bacteria in the breast? To date, researchers have not even considered such questions, and indeed some have balked at there being any link between bacteria and breast cancer or health."

Besides fighting cancer directly, it might be possible to increase the abundance of beneficial bacteria at the expense of harmful ones, through probiotics, said Reid. Antibiotics targeting bacteria that abet cancer might be another option for improving breast cancer management, said Reid. In any case, something keeps bacteria in check on and in the breasts, as it does throughout the rest of the body, said Reid. "What if that something was other bacteria--in conjunction with the host immune system?

Published on Leave a comment on We Each Give Off a Personal Microbial Cloud

Amazing! We each release a "personal microbial cloud" with its own "microbial cloud signature" every day. The unique combination of millions of bacteria (from our microbiome or community of microbes - including bacteria, viruses, fungi -  that live within and on us) can identify us. Not only do we each give off a unique combination, but we each give off different amounts of microbes - some more, some less. Some very common bacteria: Streptococcus, Propionobacterium, Corynebacterium, and Lactobacillus (among women).The microbes are given off with every movement, every exhalation, every scratching of the head, every burp and fart, etc. - and they go in the air around the person and settle around the person (they researchers even collected bacteria from dishes set on the ground around the person). From Science Daily:

The 'Pig-Pen' in each of us: People emit their own personal microbial cloud

We each give off millions of bacteria from our human microbiome to the air around us every day, and that cloud of bacteria can be traced back to an individual. New research focused on the personal microbial cloud -- the airborne microbes we emit into the air -- examined the microbial connection we have with the air around us. The findings demonstrate the extent to which humans possess a unique 'microbial cloud signature'.

To test the individualized nature of the personal microbial cloud, University of Oregon researchers sequenced microbes from the air surrounding 11 different people in a sanitized experimental chamber. The study found that most of the occupants sitting alone in the chamber could be identified within 4 hours just by the unique combinations of bacteria in the surrounding air. The findings appear in the September 22 issue of the open-access, peer-reviewed journal PeerJ.

The striking results were driven by several groups of bacteria that are ubiquitous on and in humans, such as Streptococcus, which is commonly found in the mouth, and Propionibacterium and Corynebacterium, both common skin residents. While these common human-associated microbes were detected in the air around all people in the study, the authors found that the different combinations of those bacteria were the key to distinguishing among individual people.

The analyses, utilizing analysis of suspended particulate matter and short-read 16S sequencing, focused on categorizing whole microbial communities rather than identifying pathogens. The findings emerged from two different studies and more than 14 million sequences representing thousands of different types of bacteria found in the 312 samples from air and dust from the experimental chamber.

"We expected that we would be able to detect the human microbiome in the air around a person, but we were surprised to find that we could identify most of the occupants just by sampling their microbial cloud," said lead author James F. Meadow, a postdoctoral researcher formerly from the Biology and the Built Environment Center at the University of Oregon."Our results confirm that an occupied space is microbially distinct from an unoccupied one, and and demonstrate for the first time that individuals release their own personalized microbial cloud," the authors concluded.

Image result for personal microbial cloud wikipediaSneeze. Credit: Wikipedia and CDC

Published on Leave a comment on Fungi and Bacteria in Household Dust

Another article from results of the crowdsourced study in which household dust samples were sent to researchers at the University of Colorado from approximately 1200 homes across the United States. Some findings after the dust was analyzed: differences were found in the dust of households that were occupied by more males than females and vice versa, indoor fungi mainly comes from the outside and varies with the geographical location of the house, bacteria is determined by the house's inhabitants (people, pets, and insects), clothes do not prevent the spread of bacteria from our bodies, and dogs and cats had a dramatic influence on bacteria in the home. In other words: where you live determines the fungi in the house and who you live with determines the bacteria in the house. From Discovery News:

Household Dust Packed With Thousands of Microbes

Household dust is full of living organisms that are determined, in large part, by where the home is located and who is living in it, finds a new study that includes some surprising revelations. Homes with a greater ratio of male occupants, for example, were found to contain large amounts of skin and fecal-associated bacteria, while women-dominated households contained an abundance of vaginally shed bacteria that somehow wound up in dust.

He and his colleagues used DNA sequencing and high tech imaging to analyze dust samples from approximately 1,200 homes across the United States. They used volunteers to help collect the material. They discovered that indoor fungi mostly originates outside of the home, such that the geographical location of any home strongly predicts the types of fungi existing within dust.“If you want to change the types of fungi you are exposed to in your home, then it is best to move to a different home, preferably one far away,” Fierer and his team said.

Bacteria, on the other hand, were largely predicted by the home’s possible inhabitants, including humans, pets and even insects. Fierer said, “Our bodies are clearly the source for many bacteria that end up in our homes.” The researchers suspect that body size, relative abundance, and hygiene practices are why men tend to shed more Corynebacterium and Dermabacter (the skin-associated species), as well as the poop-associated Roseburia.

The vaginal-linked bacteria Lactobacillus, discovered in homes with a larger ratio of women, provides evidence that clothes do not fully contain the spread of microorganisms produced by our bodies. Members of this genus are actually thought to protect against allergies and asthma, based on earlier research, but further studies are needed to confirm how this, and other bacteria found in dust, impact human health.

Dogs and cats had such a dramatic effect on dust bacterial communities that the researchers could predict, with around 92 percent accuracy, whether or not such animals were in the home, just based on bacteria alone....So far, the news is good for dog lovers, as he pointed out that “previous work conducted by other groups has shown that living with a dog at a young age can actually reduce allergies.”

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Published on 2 Comments on Studies Look at Probiotics in Preventing Urinary Tract Infections

How does the medical profession currently view probiotics in the prevention and treatment of urinary tract infections (UTIs), especially recurrent infections? Answer: Only a few studies have been done, but what little is known is promising, which is good because traditional antibiotic treatment has problems (especially antibiotic resistance).

The following article excerpts are from Medscape. Medscape is a popular web resource for physicians and health professionals. It features peer-reviewed original medical journal articles, daily medical news, drug information, etc. To read the entire article without registering with Medscape (registration is free for everyone), just Google the title and then click on it.

From Medscape: Probiotics in Preventing Recurrent Urinary Tract Infections in Women: A Literature Review

Increasing antibiotic resistance and increasing resistance to commonly used antibiotics makes treatment and prevention of urinary tract infections difficult. Although more research is needed, probiotics should be considered a useful and safe alternative to antibiotics. Urinary tract infections (UTIs) are one of the most common bacterial infections in women, accounting for over 6 million primary care visits annually (Zak, 2014). Approximately 50% to 60% of women will develop a UTI in their lifetime...  ...continue reading "Studies Look at Probiotics in Preventing Urinary Tract Infections"

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Healthy women were followed during their pregnancies and postpartum, and it was found that vaginal microbial communities change over the course of pregnancy, and then really change postpartum. They also found differences in the predominant Lactobacillus bacteria species between the women. In this study it was found that Lactobacillus bacteria were most dominant during pregnancy, especially L. gaserii, L. crispatus, L. iners, and L. jensenii, and there were ethnic differences in the species. And they found that the vaginal microbiome changes postpartum, with bacteria becoming more diverse and the numbers of Lactobacillus dropping. The message here is that what are "normal and healthy" microbial communities can vary between women (in this study which Lactobacillus species were "healthy and normal" varied among women). Remember: dysbiosis means that the normal microbial community is "out of whack". And sequenced the microbiomes means state of the art genetic analysis of the microbial communities From American Microbiome Institute:

The vaginal microbiome changes during and after pregnancy

The vaginal microbiome is critically important to a healthy pregnancy, and studies have shown that vaginal dysbiosis during pregnancy can lead to infection and preterm birth.  In order to help understand what the microbiome looks like throughout and just after pregnancy, researchers from England performed longitudinal studies on 42 pregnant women.  They published their results last week in Nature Scientific Reports.

The scientists sequenced the microbiomes of the 42 women throughout their pregnancies, and then for the 6 weeks afterwards for some of the women.  They discovered, in agreement with other literature on the subject, that the vaginal microbiome becomes dominated by Lactobacilli species during pregnancy.  The Lactobacilli are thought to prevent pathogens from colonizing the vagina because they produce lactic acid which decreases the overall pH of the vagina, and they secrete antibacterial toxins.  These Lactobacilli are also important as they are normally the first to colonize the new infants' guts after they pass through the birth canal. 

The researchers also learned that the microbiome shifts away from Lactobacilli and towards a more diverse microbiome in the period immediately following birth.  The new bacteria that colonize are often associated with vaginosis, and these can lead to inflammation and infection of the birth canal in some women.  The scientists suspect this shift occurs because there is a sudden drop in estrogen production upon removal of the placenta.  The increase in circulating estrogen is thought to be important for Lactobacilli colonization, so it makes sense that the rapid decrease in estrogen decreases Lactobacilli abundance.

Finally, this study showed that there were geographic and ethnic variations to the pregnant microbiome.  While each microbiome was associated with a healthy pregnancy, there were important differences, especially on the species level.  For example, Asian and Caucasian women’s pregnant microbiomes were dominated by Lactobacillus gasseri, while this species was absent in black women’s pregnant microbiomes.

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Amazing how long the bacteria persisted in the air. From Science Daily:

Hand dryers can spread bacteria in public toilets, research finds

Modern hand dryers are much worse than paper towels when it comes to spreading germs, according to new research. Scientists from the University of Leeds have found that high-powered 'jet-air' and warm air hand dryers can spread bacteria in public toilets. Airborne germ counts were 27 times higher around jet air dryers in comparison with the air around paper towel dispensers.

The study shows that both jet and warm air hand dryers spread bacteria into the air and onto users and those nearby.

The research team, led by Professor Mark Wilcox of the School of Medicine, contaminated hands with a harmless type of bacteria called Lactobacillus, which is not normally found in public bathrooms. This was done to mimic hands that have been poorly washed.

Subsequent detection of the Lactobacillus in the air proved that it must have come from the hands during drying. The experts collected air samples around the hand dryers and also at distances of one and two metres away. Air bacterial counts close to jet air dryers were found to be 4.5 times higher than around warm air dryers and 27 times higher compared with the air when using paper towels. Next to the dryers, bacteria persisted in the air well beyond the 15 second hand-drying time, with approximately half (48%) of the Lactobacilli collected more than five minutes after drying ended. Lactobacilli were still detected in the air 15 minutes after hand drying.

Professor Wilcox said: "Next time you dry your hands in a public toilet using an electric hand dryer, you may be spreading bacteria without knowing it. You may also be splattered with 'bugs' from other people's hands.

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This exciting new research is just the beginning knowledge about our virome (the virus community within us). Note that they only looked at viruses in a few areas of our bodies - the rest is still a mystery. But note that it is normal for healthy individuals to carry viruses, and that we have "distinct viral fingerprints". We don't know if the viruses are beneficial or not to us at this time. From Science Daily:

Healthy humans make nice homes for viruses

The same viruses that make us sick can take up residence in and on the human body without provoking a sneeze, cough or other troublesome symptom, according to new research. On average, healthy individuals carry about five types of viruses on their bodies, the researchers report. The study is the first comprehensive analysis to describe the diversity of viruses in healthy people.

The research was conducted as part of the Human Microbiome Project, a major initiative funded by the National Institutes of Health (NIH) that largely has focused on cataloging the body's bacterial ecosystems. ..."Lots of people have asked whether there is a viral counterpart, and we haven't had a clear answer. But now we know there is a normal viral flora, and it's rich and complex."

In 102 healthy young adults ages 18 to 40, the researchers sampled up to five body habitats: nose, skin, mouth, stool and vagina. The study's subjects were nearly evenly split by gender.

At least one virus was detected in 92 percent of the people sampled, and some individuals harbored 10 to 15 viruses...."We only sampled up to five body sites in each person and would expect to see many more viruses if we had sampled the entire body."

Scientists led by George Weinstock, PhD, at Washington University's Genome Institute, sequenced the DNA of the viruses recovered from the body, finding that each individual had a distinct viral fingerprint. (Weinstock is now at The Jackson Laboratory in Connecticut.) About half of people were sampled at two or three points in time, and the researchers noted that some of the viruses established stable, low-level infections.

The researchers don't know yet whether the viruses have a positive or negative effect on overall health but speculate that in some cases, they may keep the immune system primed to respond to dangerous pathogens while in others, lingering viruses increase the risk of disease.

Study volunteers were screened carefully to confirm they were healthy and did not have symptoms of acute infection. They also could not have been diagnosed in the past two years with human papillomavirus infection (HPV), which can cause cervical and throat cancer, or have an active genital herpes infection.

Analyzing the samples, the scientists found seven families of viruses, including strains of herpes viruses that are not sexually transmitted. For example, herpesvirus 6 or herpesvirus 7 was found in 98 percent of individuals sampled from the mouth. Certain strains of papillomaviruses were found in about 75 percent of skin samples and 50 percent of samples from the nose. Novel strains of the virus were found in both sites.

Not surprisingly, the vagina was dominated by papillomaviruses, with 38 percent of female subjects carrying such strains. Some of the women harbored certain high-risk strains that increase the risk of cervical cancer. These strains were more common in women with communities of vaginal bacteria that had lower levels of Lactobacillus and an increase in bacteria such as Gardnerella, which is associated with bacterial vaginosis.

Adenoviruses, the viruses that cause the common cold and pneumonia, also were common at many sites in the body.

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I keep overhearing misguided statements like these all the time: that somehow any and all probiotic (beneficial) bacteria offered for sale, whether in foods such as yogurt, or in probiotic capsules, are wonderful and beneficial, and will reseed your gut as well as do all sorts of miraculous things for your health. And while in reality, there are many, many bacterial species living in a healthy person's gut, it's the same few species that seem to be offered everywhere.

But if you look at the scientific research for even a few minutes, you realize that NO, we actually know very little about the health benefits of these bacteria species now in stores, and that all the claims out there don't have evidence backing them up. Perhaps taking megadoses of certain bacteria even has some negative effects. Yes, Lactobacillus species are generally considered beneficial by scientists. But even in the Lactobacillus family, there are many more types than the few now available in stores. For example. I can not find Lactobacillus sakei (which is found in kimchi and we use to successfully treat sinusitis - see Sinusitis Treatment link) in any store at this time.

Another problem is that sometimes you don't even get the desired bacteria that has been added to the food or cosmetic. For example, this occurs when some Lactobacillus or other bacteria are added to yogurt or some other food, but then the food is pasteurized, which kills off the bacteria. Duh...This is why I liked the following  opinion piece by Julianne Wyrick. From Scientific American:

Are probiotics helping you?

Consuming probiotics – also know as “good” bacteria – via supplements or yogurt has been popularized as a way to maintain gut health. While taking a daily dose of probiotics may not be harming you, it also may not be helping. The idea that every probiotic is good for every disease or condition is oversimplified, according to Catherine Lozupone, an assistant professor of medicine at the University of Colorado School of Medicine.

Lozupone spoke on a panel about the human microbiome, or the bacteria that reside in and on our bodies, that I attended at the Association of Health Care Journalists Conference last month. The panel touched on misconceptions related to probiotics, so I gave Lozupone a call post-conference to learn more.

One misconception Lozupone brought up was the idea that probiotic supplements should be used for “reseeding the good bacteria” missing in a person’s gut. Probiotic supplements often only contain a few species of bacteria, whereas a healthy gut generally has hundreds of species. In addition, the microbes that are abundant in a healthy gut are often different than those found in many supplements. A healthy gut is mostly composed of bacterial species that fall within a two different groups of bacteria: the phyla Bacteroidetes and Firmicutes. One group of bacteria commonly found in probiotics is known as Lactobacillus. While Lactobacillus is a type of Firmicute, it isn’t a type of Firmicute that is typically found in great abundance in a healthy adult gut, according to Lozupone. While Lactobacillus may be helpful for some people in some situations, the idea that everyone needs to repopulate their gut with this “good” bacteria is an overgeneralization.

“I think probiotics have a ton of potential, but different bacteria are going to do different things in different contexts,” Lozupone said. “This notion [of] ‘oh just reseed the good bacteria … they’re good for you’ is definitely very oversimplified.”

But while some general probiotic health claims are ahead of the research, studies do suggest that particular types of probiotic bacteria have potential for specific uses.

For example, Lozupone noted some rodent studies suggest certain microbes might mitigate certain effects of a high-fat diet, which could be helpful to treating obesity and associated health problems.

“There’s just lots of different contexts where the microbiome has been shown to be important,” Lozupone said. Going forward, researchers hope to not only find microbes that have health effects, but also understand why they have these effects. If you’re interested in keeping track of the current research into our body’s bacteria, keep your eye on the NIH’s Human Microbiome Project, an international effort to study the role of the body’s bacteria in our health.

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Lactobacilli

The human vagina is another microbial community that is nowhere as simple as earlier thought - and it's not just Lactobacillus bacteria.

From The Scientist: Characterizing the “Healthy” Vagina

For years, researchers characterized the microbial community of women’s vaginas as being dominated by Lactobacillus bacteria, which ferment carbohydrates to lactic acid, yielding a low pH that is toxic to many pathogenic microbes. When levels of Lactobacillus drop, the pH becomes more neutral, and the risk of infection rises.

But with research revealing notable variation among women’s vaginal microbiomes, as well as some interesting dynamics of the microbial communities within a single organ, “that dogma is changing a little bit,” said Gregory Buck of the Vaginal Microbiome Consortium at Virginia Commonwealth University (VCU).

The composition and stability of the vaginal microbiome varies by race, age, even within an individual—and it’s quickly become clear that the formula for a “normal,” “healthy” microbial community cannot be computed by ratios of bacterial species. “In the past we’ve made some generalizations about what kinds of bacteria are found in the vagina, what kinds of bacteria are good or healthy or protective,” said microbial ecologist Larry Forney of the University of Idaho. “What the research is showing is there are tremendous differences between women in terms of the kinds of bacteria that are present and the changes in the communities that occur over time.”

In June 2010, Forney, Jacques Ravel of the University of Maryland School of Medicine, and their collaborators published a survey of the vaginal microbiomes of nearly 400 women and found that the majority harbored bacterial communities dominated by one of four Lactobacillus strains. More than a quarter of the women studied, however, did not follow this pattern. Instead, their vaginas had fewer Lactobacillus and greater numbers of other anaerobic bacteria, although the bacterial communities always included members of genera known to produce lactic acid.

In many ways, the microbiome of these women resembled the bacterial communities of women suffering from bacterial vaginosis (BV), an infection characterized by an odorous vaginal discharge, Buck noted. “By looking at the microbial components, you’d say they have BV, but they have no clinical symptoms,” he said. “These people are not unhealthy.”

The researchers also found that the composition of a woman’s vaginal microbiome was linked to her race. Eighty percent of Asian women and nearly 90 percent of white women harbored vaginal microbiomes that were dominated by Lactobacillus, while only about 60 percent of Hispanic and black women did. Moreover, vaginal pH varied with ethnicity as well, with Hispanic and black women averaging 5.0 and 4.7, respectively, and Asian and white women averaging 4.4 and 4.2. 

This raises questions about the role of the commensal bacteria and risk of preterm labor , which has been linked to BV—and to low levels of Lactobacillus in particular—and is one-and-a-half times more common among African American women than Caucasian women.

Meanwhile, the researchers continue to sort through 40,000 swabs from more than 6,000 women to better characterize the bacterial communities living in the vagina. But Fettweis and her colleagues face a common problem in microbiome research. “In many samples, only a fraction of [the genetic sequences] align to anything we have in our databases,” she said. “So I think there’s still a lot of work to be done in terms of actually understanding: What are these organisms?”

Another question facing researchers probing the vaginal microbiome is how it is initially colonized. “Where do [the bacteria] come from?” said Forney.

Many suspect that the process occurs during vaginal childbirth. But the adolescent microbiome does not resemble that of a sexually mature woman, having far less Lactobacillus, leading some to suspect that there may be a second colonization of the vagina later in life. And if the birthing process is important to establish the vaginal microbiome, what happens in the case of C-sections? “We have more questions than answers,” Forney said.

The microbiome is also not stable later in life. It is now well known that the vaginal microbiome changes after menopause, containing fewer Lactobacillus than the vaginas of reproductive-aged women, with the notable exception of women on hormone-replacement therapies.

Moreover, recent research has revealed that the composition of the vaginal microbiome can change in as little as 24 hours.

The temporal dynamics of the vaginal microbiome raise important questions about developing microbiota-based diagnostics and therapeutics, said Forney. “If you perform a diagnostic test, would you get a different result tomorrow or the day after? In some cases, yes. How do you incorporate that into [a] decision about whether some kind of intervention is required?”

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Excerpts from a very interesting NPR interview with Dr. Martin Blaser and his views on the human microbiome. The big take-away: our modern life-style is not good for the gut microbiome. His recently published book is Missing Microbes: How the Overuse of Antibiotics is Fueling Our Modern Plagues.

From NPR News: Modern Medicine May Not Be Doing Your Microbiome Any Favors

There are lots of theories about why food allergies, asthma, celiac disease and intestinal disorders like Crohn's disease have been on the rise. Dr. Martin Blaser speculates that it may be connected to the overuse of antibiotics, which has resulted in killing off strains of bacteria that typically live in the gut.

Blaser is an expert on the human microbiome, which is the collection of bacteria, viruses, fungi and other microbes that live in and on the body. In fact, up to 90 percent of all the cells in the human body aren't human at all — they're micro-organisms. Blaser is the director of NYU's Human Microbiome Program and a former chairman of medicine there. His new book is called Missing Microbes: How the Overuse of Antibiotics Is Fueling Our Modern Plagues.

"Since World War II, we've seen big rises in a number of diseases: asthma, allergies, food allergies, wheat allergy, juvenile diabetes, obesity. ... These are all diseases that have gone up dramatically in the last 50 or 70 years. One of the questions is: Why are they going up? Are they going up for 10 different reasons, or perhaps there is one reason that is fueling all of them."

"My theory is that the one reason is the changing microbiome; that we evolved a certain stable situation with our microbiome and with the modern advances of modern life, including modern medical practices, we have been disrupting the microbiome. And there's evidence for that, especially early in life, and it's changing how our children develop."

"There's a choreography; there's a normal developmental cycle of the microbiome from birth over the first few years of life, especially the first three years, [that] appear[s] to be the most important. And that's how nature has, how we have, evolved together so that we can maximize health and create a new generation, which is nature's great purpose. And because of modern practices, we have disrupted that. And then the question is: Does that have consequence[s]?"

"As far as we know, when the baby is inside the womb it is apparently sterile. ... The big moment of truth is when the membranes rupture, the water breaks, and the baby starts coming out. And that's where they first get exposed to the bacteria of the world, and the first bacteria they're exposed to is their mother's bacteria in the birth canal. So as labor proceeds, the babies are in contact with the microbes lining their mother's vagina and, as they're going out, they're covered by these bacteria. They swallow the bacteria; it's on their skin. ..."

"That's their initial exposure to the world of bacteria. That's how mammals have been doing it for the last 150 million years, whether they're dolphins or elephants or humans. ... And we know a little about what those bacteria are. The most common bacteria are lactobacillus and there's evidence that over the course of pregnancy the microbiome in the vagina changes, just as many other parts of the body are changing. The microbiome is changing in its composition in terms of maximizing lactobacilli, and these are bacteria that eat lactose, which is the main component of milk. So the baby's mouth is filled with lactobacilli. The first thing that happens is they go up against their mom's breast and they inoculate the nipple with lactobacilli and now milk and lactobacilli go into the new baby and that's the foundation for their microbiome and that's how they start their life. ..."

"You could project that if they didn't acquire these organisms or they didn't acquire them normally or at the normal time, then the foundations might be a little shaky."

"Shortly after birth, they compared the microbiomes in the babies that came out. The babies that were born vaginally, their microbiome, not surprisingly, looked like the mom's vagina everywhere in the body — in their GI tract, on their skin, in their mouth. But the babies born by C-section, their microbiome looked like skin and it didn't even necessarily look like the mom's skin, maybe it was somebody else in the operating room. So it's clear that the microbiome is different immediately depending on the kind of birth."

"What I can tell you is that our immune system is quite complex. There are many kinds of immune cells. There are cells that strongly recognize foreign substances, there are ones that try to damp [the immune system] and down-regulate it. There's what we call innate immunity, which is the immunity we're all born with, and then there's adaptive immunity — the immunity that develops when we experience different kinds of exposures. So it's very complex."

"There are many different probiotics.  I think I can say three things: The first is that they're almost completely unregulated; second is that they seem to be generally safe; and third is that they're mostly untested. ... I'm actually a big believer in probiotics; I think that's going to be part of the future of medicine, that we're going to understand the science of the microbiome well enough so that we can look at a sample from a child and say this child is lacking such-and-such an organism and now we're going to take it off the shelf and we're going to give it back to that child. ... "