How Bacteria In The Gut Help Fight Off Viruses : Goats and Soda : NPR

So what is this magic antiviral bullet?

It’s those hairlike threads that dangle off some bacteria and help them swim. Yup, that’s right, the flagella.

When Gewirtz and his team injected pieces of the flagella under the mice’s skin, a part of the immune system kicked into action and stopped the rotavirus infection dead in its tracks.But these bacteria — and their flagella — are in our gut. Would they still be able to talk to the immune system? Hooper thinks so. Here’s why.

Just like our hair, flagella are constantly falling off the surfaces of bacteria as they swim around in the gut. “Cool immune cells, called dendritic cells, are constantly surveying what’s going on in the body,” Hooper says. They can bind to the pieces of flagella in the gut and then mobilize other immune cells to come and fight the viral infection.

via How Bacteria In The Gut Help Fight Off Viruses : Goats and Soda : NPR.


Why The U.S. Chills Its Eggs And Most Of The World Doesn’t : The Salt : NPR

Why The U.S. Chills Its Eggs And Most Of The World Doesn’t


To refrigerate or not to refrigerate? It boils down to bacteria, aesthetics and how much energy you’re willing to use. Go in search of eggs in most foreign countries and you might encounter a strange scene: eggs on a shelf or out in the open air, nowhere near a refrigerator.Shock and confusion may ensue. What are they doing there? And are they safe to eat?

We Americans, along with the Japanese, Australians and Scandinavians, tend to be squeamish about our chicken eggs, so we bathe them and then have to refrigerate them.

But we’re oddballs. Most other countries don’t mind letting unwashed eggs sit next to bread or onions.The difference boils down to two key things: how to go after bacteria that could contaminate them, and how much energy we’re willing to use in the name of safe eggs.

To understand when the rift happened, let’s rewind. About a hundred years ago, many people around the world washed their eggs. But there are a lot of ways to do it wrong, so the method got a bad reputation in certain parts of the world. A batch of rotten eggs, which had been washed in Australia, left a bad impression on its British importers.

By 1970, the U.S. Department of Agriculture had perfected the art of the wash with the help of fancy machines, and it required all egg producers to do it. Meanwhile, many European countries were prohibiting washing, and Asian countries never got on board with it. The exception was Japan, which joined the egg-washers after a bad spate of salmonella in the 1990s.

So what’s the deal with washing and refrigeration? Soon after eggs pop out of the chicken, American producers put them straight to a machine that shampoos them with soap and hot water. The steamy shower leaves the shells squeaky clean. But it also compromises them, by washing away a barely visible sheen that naturally envelops each egg.”The egg is a marvel in terms of protecting itself, and one of the protections is this coating, which prevents them from being porous,” says food writer Michael Ruhlman, author of Egg: A Culinary Exploration of the World’s Most Versatile Ingredient.

Keep reading ….

via Why The U.S. Chills Its Eggs And Most Of The World Doesn’t : The Salt : NPR.

Gut bacteria diversity improves with exercise, study shows – Medical News Today

Exercise is held up as one of the most important aspects of a healthy lifestyle. It burns calories, it is good for your heart and it can make you happier. Its benefits do not end there, though; new research has found that exercise also boosts the diversity of bacteria found in the gut, which can have positive long-term health implications.

The gastrointestinal (GI) tract – the stomach and intestines – is home to a complex community of bacteria referred to as the gut microbiota.

The gut microbiota contributes to the metabolism and the development of the immune system, and previous research has linked changes in its composition with conditions such as diabetes, GI diseases and obesity.

Reduced variation in microbiota has been associated with these health problems, while increased diversity has been linked to a favorable metabolic profile and immune system response.

Diet has already been found to be key in influencing the gut microbiota. Other areas of modern lifestyle have also been found to affect the microbiota population, but the degree to which these do is not clear.

The study, carried out by a team of researchers based in Ireland and published in Gut, is the first to specifically examine the link between exercise and its impact on gut microbiota.

As extremes of exercise are often associated with extremes of diet, the researchers focused their study on a group of athletes. They analyzed fecal and blood samples from 40 professional rugby players during their preseason training program in order to assess the range of their gut microbiota.

Two control groups were also assessed; one group matched with the athletes by size with a comparable body mass index (BMI), and one group matched by age but with lower BMI scores.

Each participant in the study completed a food frequency questionnaire and answered questions about their normal levels of physical activity. The questionnaire detailed how much and how often they had eaten different food items over the preceding 4 weeks.

Exercise found to boost gut microbiota diversity

The results found that the athletes had a significantly wider range of gut microbiota than the men in the comparison groups, and in particular the control group containing men with a high BMI.

Athletes running
Athletes undergoing a rigorous training program were found to have a high diversity of gut bacteria.

The athletes also had better metabolic profiles than the men with a high BMI and much higher proportions of Akkermansiaceae, a type of bacteria that is known to be linked with lower rates of obesity and associated metabolic disorders.

The dietary analysis found that the athletes ate more of all of the food groups than the control participants. Protein accounted for more of their energy intake (22%) than the comparison groups (15-16%), and they also ate more fruits and vegetables and fewer snacks.

The authors say their findings indicate that exercise is another important factor in the relationship between microbiota, host immunity and host metabolism, with diet playing an important role.

They say that in future research, intervention-based studies to tease apart the relationship between lifestyle changes and the microbiota will be important and provide further insights into optimal therapies to influence the gut microbiota and its relationship with health and disease.

In a linked editorial, Dr. Georgina Hold, of the Institute of Medical Sciences, Aberdeen University, emphasizes the importance of investigating how different lifestyle changes can affect the bacteria in the GI tract:

“By being able to identify the impact of such activities, we can aim to reproduce the positive impacts through manipulation of the gut microbiota.

As life expectancy continues to increase, it is important that we understand how best to maintain good health. Never has this been more relevant than in respect of our resident microbiota. Understanding the complex relationship among what we choose to eat, activity levels and gut microbiota richness is essential.”

“Developing new ways to manipulate the beneficial properties of our microbiota by finding ways to integrate health-promoting properties into modern living should be the goal,” she concludes.via Gut bacteria diversity improves with exercise, study shows – Medical News Today.

Malnutrition: Starving Children Lack Crucial Gut Bacteria –

When children are starving, the bacteria that live in their intestines may determine whether they can be saved, scientists working in Bangladesh are reporting. And they say it may become imperative to find a way to give children bacteria as well as food.

The study, done by researchers from Washington University School of Medicine in St. Louis and the International Center for Diarrheal Disease Research in Dhaka, the Bangladeshi capital, was published by Nature last week.

Trillions of bacteria in the human gut help digest food and produce vitamins, and they amount to “a microbial organ within an organ,” said Dr. Jeffrey I. Gordon, an author of the paper. It takes up to about age 3 for a child to get all the species that seem to be needed, he said.

But stool samples showed that severely malnourished children often lack the needed species and do not acquire them even when they are fed nutrition-dense therapeutic foods like the peanut-based Plumpy’Nut or lentil-based porridges for weeks. As a result, they may remain stunted and mentally handicapped although they are getting enough calories to live.

Dr. Gordon said researchers were dosing sterile mice with different human gut microbes, hoping to discover which functions each performs. The goal may be to produce a sort of bacterial soup for children. Fecal transplants, sometimes used to cure severe gut infections in adults, are now unthinkable for Bangladeshi infants, he said, because they would probably also contain dangerous pathogens.

Dirty Baby, Healthy Baby? Early Filth May Reduce Allergies – NBC

Dirty Baby, Healthy Baby? Early Filth May Reduce Allergies

Want a healthy baby? You may want to roll her around in dirt.

For decades, parents have shielded infants from bacteria and other possible triggers for illness, allergies and asthma.

But a surprising new study suggests that exposure to cat dander, a wide variety of household bacteria — and even rodent and roach allergens — may help protect infants against future allergies and wheezing.

Interestingly, contact with bacteria and dander after age 1 was not protective — it actually increased the risk.

“It was the opposite of what we expected,” said Dr. Robert Wood, chief of the division of allergy and immunology at the Johns Hopkins Children’s Center and co-author of the study in the Journal of Allergy and Clinical Immunology. “We’re not promoting bringing rodents and cockroaches into the home, but this data does suggest that being too clean may not be good.”

The new findings may help explain some contradictions in research on the so-called hygiene hypothesis, which suggested that kids growing up in a super clean environment were more likely to develop allergies.

“This doesn’t completely resolve the controversy, but it does add a big piece of the puzzle,” said Dr. Jonathan Spergel, a professor of pediatrics and chief of allergy at the Children’s Hospital of Philadelphia.

The hygiene hypothesis was developed after researchers noticed that farm kids were less likely to have allergies. Dirty environments, experts suggested, might be protective. The hypothesis seemed to explain why developed countries had skyrocketing rates of allergies and asthma.

Study Sees Bigger Role for Placenta in Newborns’ Health:NYTimes

Not nutrition, but related..

A study led by Dr. Kjersti Aagaard found that the placenta has its own microbiome that may help shape the health of an infant.

The placenta, once thought sterile, actually harbors a world of bacteria that may influence the course of pregnancy and help shape an infant’s health and the bacterial makeup of its gut, a new study has found.

The research is part of a broader scientific effort to explore the microbiome, the trillions of microbes — bacteria, viruses and fungi — that colonize the human body. Those organisms affect digestion, metabolism and an unknown array of biological processes, and may play a role in the development of obesity, diabetes and other illnesses.

During pregnancy, the authors of the new study suspect, the wrong mix of bacteria in the placenta may contribute to premature births. Although the research is preliminary, it may help explain why periodontal disease and urinary infections in pregnant women are linked to an increased risk of premature birth. The findings also suggest a need for more studies on the effects of antibiotics taken during pregnancy.

The new study suggests that babies may acquire an important part of their normal gut bacteria from the placenta. If further research confirms the findings, that may be reassuring news for women who have had cesareans. Some researchers have suggested that babies born by cesarean miss out on helpful bacteria that they would normally be exposed to in the birth canal.

“I think women can be reassured that they have not doomed their infant’s microbiome for the rest of its life,” said Dr. Kjersti Aagaard, the first author of the new study, published on Wednesday in Science Translational Medicine. She added that studies were needed to determine the influence of cesareans on the microbiome.

Previous studies have looked at bacteria that inhabit the mouth, skin, vagina and intestines. But only recently has attention turned to the placenta, an organ that forms inside the uterus and acts as a life support system for the fetus. It provides oxygen and nutrients, removes wastes and secretes hormones.

“People are intrigued by the role of the placenta,” said Dr. Aagaard, an associate professor of obstetrics and gynecology at the Baylor College of Medicine and Texas Children’s Hospital in Houston. “There’s no other time in life that we acquire a totally new organ. And then we get rid of it.”

She added, “We are just starting to catch a glimmer of this amazing organ that defines placental mammalian biology.”

Dr. Aagaard and her team became curious about the placenta when they noticed something puzzling in earlier research on the vaginal microbiome in pregnant women: The microbes that were most abundant in the mother’s vagina did not match the population in a newborn’s intestine. Scientists had assumed the bacterial profiles would be similar, particularly in babies born vaginally, who were thought to pick up the mother’s bacteria during birth. Dr. Aagaard and her colleagues began to question that assumption.

“It didn’t make a whole lot of sense to us,” she said. “It’s not like babies are hanging out in the vagina. They come shooting out pretty fast.” Also, she said, they emerge covered in a waxy substance called vernix, which most likely helps keep bacteria from latching on.

The researchers wondered if babies might acquire some of their intestinal bacteria before birth, maybe from the placenta.

So they collected placentas in the delivery room from 320 women, mostly black and Hispanic. Most had vaginal deliveries, and some had cesareans. Most of the births were at term, but some were premature.

The scientists searched the placental tissue for bacterial DNA, using a technique called shotgun metagenomic sequencing. They shaved off the outer layer of each placenta and tested samples from the inside, to avoid surface contamination.

“The placenta is not teeming with bacteria, but we can find them, and we can find them without looking too hard,” Dr. Aagaard said.

She said the placenta was less than 10 percent bacteria by mass, comparable to the eye or deeper regions of the skin, but very different from the intestine, which is 90 percent bacteria.

The study provides an “initial snapshot” of the placental microbiome, Dr. Aagaard said. About 300 different types of bacteria turned up, most of them harmless. The team compared the distribution of the types with what had been found previously in other parts of the body, including the mouth, skin, nose, vagina and gut. The closest match by far was between the placenta and the mouth, which, in turn, was much like that in babies’ intestines in the first week of life.

A scientist not involved in the study, Dr. David A. Relman, a microbiome expert at Stanford, said that Dr. Aagaard’s results agreed with those from his lab and others, which had found microbial DNA in amniotic fluid, apparently from the mother’s mouth, gut and vagina.

Dr. Aagaard said she thought that oral bacteria travel through the mother’s bloodstream to the placenta, take up residence there and find their way into the fetus. This is a theory. But research in animals supports it: Oral bacteria injected into a vein in mice home in on the placenta.

The idea also meshes with something that obstetricians have long noted: Women with periodontal disease have a higher risk of having premature or low-birth-weight babies. Treating the disease during pregnancy does not lower the risk. Preventing the disease or treating it before pregnancy seems more important, Dr. Aagaard said.

The study did not provide definitive evidence about periodontal disease because only one participant had it.

A disturbing finding was that when women had urinary infections early in pregnancy, even if the infections were cured, evidence of the bacteria still turned up in the placenta. Those infections increase the risk of premature birth.

The study also found that the microbiome of the placenta in women who had full-term pregnancies differed from that in women who had preterm births. But Dr. Aagaard said the researchers did not know if the difference contributed to the early birth, or was just characteristic of an earlier stage of pregnancy.

Dr. Martin J. Blaser, director of the human microbiome program at NYU Langone Medical Center, and the author of a recently published book, “Missing Microbes,” said that Dr. Aagaard’s study was important, but preliminary, and that it did not provide information that could be used in treating pregnant women.

“I’m intrigued by the findings about the mouth and also the relationship with preterm labor, which is a really important clinical question,” Dr. Blaser said. “Will this be a productive lead, or will it fizzle out? Time will tell us.”

He said that pregnant women were often given antibiotics, “for all kinds of reasons, many justified, but there’s a slippery slope.” Assuming that the placenta was sterile anyway, he said, doctors thought antibiotics would not affect the fetus. But if the placenta is not sterile, and is instead a portal for bacteria from the mother, he asked, “What are the antibiotics doing?”

Got Gas? It Could Mean You’ve Got Healthy Gut Microbes : The Salt : NPR

Got Gas? It Could Mean You’ve Got Healthy Gut Microbes


April 28, 2014 1:43 PM ET

Sulfur-rich foods, such as cabbage, bok choy and kale, can be popular with gut bacteria. And we all know how much the critters enjoy beans.

Not long ago, we heard about a catchy idea for a cookbook: “Fart-free food for everybody.”

In theory, these recipes would be helpful for some people — and those in their vicinity.

But being a bit gassy may actually be a small price to pay for a lot of benefits to our health.

We know that air often comes after eating nutrient-packed vegetables, such as cabbage, kale and broccoli. And researchers have found that fiber-rich foods, like beans and lentils, boost the levels of beneficial gut bacteria after only a few days, as we reported in December.

So all this got us wondering: Could passing gas, in some instances, be a sign that our gut microbes are busy keeping us healthy?

Absolutely, says Purna Kashyap, a gastroenterologist at the Mayo Clinic in Rochester, Minn.

“Eating foods that cause gas is the only way for the microbes in the gut to get nutrients,” he says. “If we didn’t feed them carbohydrates, it would be harder for them to live in our gut.”

And we need to keep these colon-dwelling critters content, Kashyap says. When they gobble up food — and create gas — they also make molecules that boost the immune system, protect the lining of the intestine and prevent infections.

“A healthy individual can have up to 18 flatulences per day and be perfectly normal,” he adds.

Gas gets into the digestive tract primarily through two routes: Swallowing air (which we all do when we eat and chew gum) and your microbiome. That’s the collection of organisms in the GI tract that scientists and doctors are currently all fired up about. (Check our colleague Rob Stein’s recent series on it.)

That microbiome includes hundreds of different bacteria. But there are also organisms from another kingdom shacking up with them: the archaea.

All these microbes are gas-making fools. They eat up unused food in your large intestine, like fiber and other carbohydrates we don’t digest, and churn out a bunch of gases as waste.

But that’s not all they make. They also produce a slew of molecules (called short chain fatty acids) that may promote the growth of other beneficial bacteria and archaea.

And the more fiber you feed these friendly inhabitants, the more types of species appear, studies have found. This bump in microbial diversity has been linked to a slimmer waistline.

“Undigested carbohydrates allow the whole ecosystem to thrive and flourish,” Kashyap says.

Most gas made by the microbiome is odorless. It’s simply carbon dioxide, hydrogen or methane. But sometimes a little sulfur slips in there.

“That’s when it gets smelly,” Kashyap says.

But here’s the hitch: Many of the smelly sulfur compounds in vegetables have healthful properties.

Take for instance, the broccoli, mustard and cabbage family. These Brassica vegetables are packed with a sulfur compound, called sulforaphane, that is strongly associated with a reduced risk of cancer.

Another possible benefit of a little smelly gas? It may reduce the total volume of air in the gut, Kashyap says.

Why? Because bacteria and archaea make the sulfur gas from other gases in the gut, like hydrogen.

“Bacteria that make sulfide gas are really important,” Kashyap says. “They can cause smelliness, but they can reduce the total amount of gas flow.”

Of course, having too much of anything can be bad. If gas and bloating start interfering with your quality of life, Kashayps recommends seeing a doctor.

But don’t immediately blame your diet, Kashyap says.

In many cases, people who complain about too much gas actually don’t generate more than others, he says. Instead, they perceive the passing more intensely. Or they pass it more often.

“Yes, a more fiber-rich diet will produce more gas,” Kashyap adds. “But completely eliminating fiber from the diet should not be the first option. You don’t want to starve your microbes.”

So go ahead. Enjoy those lentils. Chow down on the cabbage. Then if you stink a little, think of it as a thank you gesture from your microbiome.

via Got Gas? It Could Mean You’ve Got Healthy Gut Microbes : The Salt : NPR.

The 8 Best Foods for Your Gut | Rodale News

The 8 Best Foods for Your Gut

Your immune system will sing when you work these digestive wonder foods onto the menu.

best foods for your gut

Your gut is like a forest, full of diverse life that—if kept in check—helps your whole natural system flourish. The problem is, food isn’t as simple as it used to be, and modern cuisine, even modern medicine like antibiotics, can do a real number on the biodiversity in your digestive tract—your beneficial bacteria. In fact, too many meds and eating too much sugar and processed foods can actually suppress this protective gastrointestinal army, so it’s important to bring balance and stability back to your gut for optimal health to avoid diarrhea and diseases. In fact, many of these probiotic-rich foods will actually help you glow on the outside, too. Studies have found probiotics help combat skin problems.

For better gut health, these 8 foods will help!

#1: Kefir
The Benefit: Kind of like a drinkable yogurt, kefir is a fermented dairy product that contains oligosaccharides, complex carbs, that feed beneficial bacteria. And keeping those tiny microorganisms content will help supercharge your immune system.

Healthy Tip: Keep your kefir cold—the live and active cultures are sensitive to heat—and be sure to avoid kefir with sky-high sugar content. Too much sugar damages your healthy intestinal flora.

Try This: Lifeway Organic Whole Milk Kefir, Plain

#2: Greek Yogurt
The Benefit: Like kefir, Greek yogurt also serves as a potent dairy-based probiotic, and also boasts 15 to 20 grams of protein per 6-ounce serving and amino acids that will jump-start your metabolism.

Healthy Tip: Some companies market “Greek style” yogurt products that are nothing more than regular yogurt containing additives like gelatin and milk solids to thicken the consistency. For true Greek yogurt, check the ingredients list. It should only read: Milk and cultures.

Try This: Stonyfield Organic Greek

#3: Real Sauerkraut
The Benefit: Sauerkraut is really fermented cabbage, a preservation technique that far precedes modern-day refrigeration.

Healthy Tip: For true probiotic muscle, avoid canned sauerkraut, because it’s pasteurized, meaning the healthy bacteria is mostly killed off. Instead, make your own homemade sauerkraut in a crock.

Try This: Real Pickles Organic Sauerkraut

#4: Kimchi
The Benefit: A standby for centuries in Korean culture, this spicy fermented cabbage dish acts like a tonic for your gastrointestinal tract. A 2005 Seoul National University study found it’s so beneficial to the immune system that it helped speed recovery in chickens stricken with the virulent avian flu.

Healthy Tip: Add kimchi to organic mashed potatoes, rice, or salads if the distinctly sour, fizzy fare isn’t appetizing to you on its own.

Try This: ozuké’s Kim Chi

#5: Artichokes
The Benefit: Artichokes are potent prebiotics, meaning they contain undigestible nutrients that help feed the beneficial bacteria growth within your digestive system. Think of them like a healthy meal for the helpful bacteria in your gut.

Healthy Tip: If artichokes don’t delight your taste buds, try other potent prebiotics like bananas, lentils, and asparagus.

Try This: Grow your own!

#6: Kombucha
The Benefit: With its naturally fizzy profile, this fermented tea serves as a healthy replacement for carbonated drinks like soda. Mildly tart and effervescent, kombucha is teeming with beneficial bacteria to coat your digestive tract. The fermentation process also creates healthy B vitamins that can activate energy.

Healthy Tip: This ancient, nourishing tonic has boosted immune systems for centuries; however, if you have certain digestive-tract diseases or candida, kombucha may aggravate symptoms because it’s considered a wild ferment and could contain irritating yeasts for susceptible individuals.

Try This: GT’s Organic Raw Kombucha, Original

#7: Miso Soup
The Benefit: While there’s debate surrounding the health benefits of soy, the truth is fermented soybeans contain an abundance of beneficial bacteria and isoflavones, which can protect against cancer and possibly halt the production of fat cells.

Healthy Tip: Look for organic miso soup to avoid harmful additives and genetically engineered soy, which has never been tested for long-term impact on human health.

Try This: Eden Foods Hacho Miso

#8: Dark Chocolate 
The Benefit: This is not too good to be true! Louisiana State University researchers recently discovered that certain bacteria in the stomach gobble down the chocolate and ferment it into anti-inflammatory compounds that are good for the heart!

The good microbes, such as Bifidobacterium and lactic acid bacteria, feast on chocolate, explains study author Maria Moore, and undergraduate and research at the university. “When these compounds are absorbed by the body, they lessen the inflammation of cardiovascular tissue, reducing the long-term risk of stroke,” said John Finley, PhD, who led the work. He said that this study is the first to look at the effects of dark chocolate on the various types of bacteria in the stomach.

Healthy Tip: Look for chocolate with at least 70 percent cacao and eat it regularly to help build up levels of cocoa’s polyphenols, which help regulate your stress hormones, explains Will Clower, PhD, neurophysiologist, neuroscientist, nutritionist, and author of the new book Eat Chocolate, Lose Weight. Clower says the higher the cocoa, the lower the sugar. Translation? He recommends an adult can enjoy a full ounce of chocolate during the day if it’s 70 percent cocoa; 1¼ ounces if it’s 85 percent cocoa.

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

According to Dr. Martin Blaser, the overuse of antibiotics has contributed to killing off strains of bacteria that typically live in the gut.

According to Dr. Martin Blaser, the overuse of antibiotics has contributed to killing off strains of bacteria that typically live in the gut.

Joe Raedle/Getty Images

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.

Missing Microbes
Missing Microbes

How the Overuse of Antibiotics Is Fueling Our Modern Plagues

by Martin Blaser

He tells Fresh Air‘s Terry Gross that with the overuse of antibiotics, as well as some other now-common practices like cesarean sections, we’ve entered a danger zone — a no man’s land between the world of our ancient microbiome and an uncharted modern world.

Interview Highlights

On why he thinks the number of diseases has risen

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.

On the potential link between antibiotics and obesity

We have experiments in mice where, since we’re very interested in obesity, if we put mice on a high-fat diet, they gain weight; they get fat. If we put them on antibiotics early in life, they also get fat. If we put [them] on both together, they get very fat. … It’s clear that the effects of the antibiotics potentiate the effects of the high-fat diet. We’re not letting [the] high-fat diet off the hook, we’re saying that there’s another factor there. …

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]? Our studies in mice show that it does have consequences. We’ve done epidemiologic studies in people that show that some of these modern practices are increasing the risk of obesity as well.

On how the birth process informs a baby’s microbiome

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.

On a study comparing the microbiomes of babies born via C-section and those born vaginally

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.

There have been more and more epidemiologic studies asking the question, really for the first time: Are there long-term health consequences of being born by C-section?


On how the microbiome can determine a person’s immunity and allergies

I’m concerned that the microbiome is part of our whole developmental process and if we disrupt it early, there are potentially consequences. …

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.

It’s developing early in life. That’s what sets, in essence, [the] immunological tone that will determine how allergic a person is, or how stoical a person is in an immunologic sense.

On probiotics

There are many different probiotics. If you go to the grocery store, the health food store, the drugstore, there are shelves and shelves full of probiotics [with] different names, different compositions. 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. …

Right now, it’s the Wild West. 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. … Just as today the kids are lining up for the vaccines, in the future, maybe the kids are going to be drinking certain organisms so that we can replace the ones that they’ve lost.

Scientists Study What to Do If You Drop a Cookie on the Floor

Scientists Study What to Do If You Drop a Cookie on the Floor

The five-second rule: New study says it’s safe to eat food that’s been on the floor … or is it?

Scientists Study What to Do If You Drop a Cookie on the Floor

Is this delicious bologna sandwich contaminated with bacteria?


Sarah Whitman-Salkin

for National Geographic


Once again, you’ve dropped your snack. You bend down, snatch it up, and gently blow off any dust—and, you hope, deadly germs. You’re about to put it in your mouth because, after all, you’ve got the “five-second rule” on your side: Food that’s been dropped is safe to consume if it’s been on the floor for five seconds or less.

But really, should you eat it? Is the piece of toast or the potato chip or the cookie you just rescued from the ground safe to eat, or contaminated by bacteria? Science says … maybe.

Researchers at Aston University in Birmingham, England, now suggest that the five-second rule is indeed true.

But a 2007 study of the five-second rule from Clemson University in South Carolina argues that there is no safe window for dropped food. Their data points to a “zero-second rule.”

Here’s the strange thing: Both the Aston study and the Clemson study used nearly identical methods of investigation, and ultimately had the same results—but with staggeringly different conclusions. So is the five-second rule legit or not?

The Science: It’s All About Bacteria

When you drop a piece of food on the floor, any bacteria living on the floor will adhere to it. So if you eat the food you’ve dropped, you’re also eating any bacteria the food picked up. Both studies set out to determine how long it takes for bacteria on the floor to stick to food.

The studies tested three different floor surfaces: tile, laminate or wood, and carpet. The Aston study used the bacteria Escherichia coli and Staphylococcus aureus, while the Clemson study used Salmonella typhimurium. Clemson tested only bologna and bread, but the Aston study tested a variety of foods with varying degrees of moisture (a piece of dry toast versus a sticky candy).

The studies agree on several points. When food comes into contact with a contaminated surface, the transfer of bacteria to the food is immediate. And tile, wood, and laminate surfaces transfer much more bacteria than carpeted surfaces. The Aston study found, not surprisingly, that moist foods (cooked pasta or sticky candy) were more likely to pick up bacteria than were drier foods (a cookie or piece of toast).

So Is the Five-Second Rule True?

“It appears that Professor [Anthony] Hilton [who led the Aston study] has substantiated our findings,” says Paul Dawson, professor of food, nutrition, and packaging sciences at Clemson University and the scientist behind the 2007 study.

Aston University’s Hilton agrees: “Our findings support Professor Dawson’s,” he says, “in that bacteria are transferred immediately on contact.” But, he adds, “the transfer efficacy is extremely low … hence the five-second rule.”

But the two professors disagree as to the degree of contamination.

In Hilton’s interpretation, “the initial transfer [of bacteria to food] is insufficient [to contaminate the food]. In our study only one millionth of the bacterial population present on the floor was transferred to the dry food, and approximately 20 times more to the moist. For moist foods, on these flooring types, there is underpinning evidence that fewer bacteria will be transferred to food picked up quickly.”

Dawson disagrees. “No matter what the surface or contact time,” he says, “enough bacteria was transferred to be detected and to make someone sick.”

Would the Scientists Eat It?

Not surprisingly, professors Dawson and Hilton each behave differently when it comes to the five-second rule.

“I compare picking up dropped food and eating it to not wearing a seatbelt,” says Dawson. “Someone can drive a lifetime without wearing a seatbelt, never have an accident, and not get injured. Someone can also eat dropped food for a lifetime and never get sick. But in the first case, if you have a serious accident you will probably get hurt. In the second case, if the food you ate was dropped on a surface contaminated with a high concentration of a pathogen, you will probably get sick.

“I still stand by the ‘zero-second rule,'” he says. “If I drop food on the floor, I don’t see the need to eat it even though the odds are it is perfectly safe.”

Hilton, of course, takes the opposite approach: “I have three young boys who have grown up dropping toast on the floor and picking it up again,” he says. “In my own home, which I know to be hygienically clean, the risk of them picking anything nasty up with the toast is very, very low.” But, he adds, “dropping food on the sidewalk is entirely a different matter.”

via Scientists Study What to Do If You Drop a Cookie on the Floor.