Skip to content

Category: pregnancy and childbirth

Published on Leave a comment on Endocrine Disrupting Chemicals and Male Infertility

Recent research looked at environmental causes of male infertility, specifically endocrine-disrupting chemicals. Poor semen quality contributes to increases in infertility and the use of assisted reproductive technology.The researchers also discuss the higher incidence of testicular cancer worldwide, lower levels of testosterone in men, and poor semen quality among men aged 20 to 25 (with the average man having up to 90% abnormal sperm). From Science Daily:

Endocrine-disrupting chemicals may be threatening fertility in industrialized countries

The birth rate is declining in all industrialised countries, and socioeconomic factors and women's age are not solely to blame. Male reproductive health and environmental factors are also significant, as concluded in a new scientific review article. ...Behind the article are fertility researchers from Denmark, the US and Finland. The researchers studied a number of factors related to fertility, and one of the main conclusions of their study was that poor semen quality contributed to increases in infertility and the use of assisted reproductive technology.

The study also revealed higher incidence of testicular cancer worldwide, with the greatest frequency among Caucasian populations. Moreover, the researchers also observed lower levels of testosterone in average men. "I was surprised that we found such poor semen quality among young men aged 20 to 25. The average man had up to 90% of abnormal sperm. Normally, there would be so many sperms that a few abnormal ones would not affect fertility. However, it appears that we are at a tipping point in industrialised countries where poor semen quality is so widespread that we must suspect that it results in low pregnancy rates," said first author of the article, Professor Niels E. Skakkebaek from the Department of Growth and Reproduction (EDMaRC) at Rigshospitalet and the University of Copenhagen.

"The article also demonstrates the impact of the increasing number of male reproductive problems on low birth rates. There is no doubt that environmental factors are playing a role. These are the correlations we are researching at the new research centre EDMaRC at Rigshospitalet," added Professor Anders Juul, who is the last author of the article.

Many of the male reproductive problems could be due to damage to the testes during embryonic development. While the reproductive problems could arise from genetic changes, "recent evidence suggests that most often they are related to environmental exposures of the fetal testes," the researcher team wrote."Since the disorders in male genitals have increased over a relatively short period of time, genetics alone cannot explain this development. There is no doubt that environmental factors are playing a role and that endocrine-disrupting chemicals, which have the same effect on animals, are under great suspicion. The exposure that young people are subjected to today can determine not only their own, but also their children's, ability to procreate," explained Professor Skakkebaek.

Published on Leave a comment on More Negative News About Hormone Disrupting Chemicals

More and more studies are finding negative health effects from hormone disrupting chemicals (which we are exposed to every single day, and subsequently which are in all of us), such as parabens, phthalates, Bisphenol-A (BPA), and chemical substitutes for BPA such as Bisphenol-S (BPS) and BPF. The following are a few recent studies and one article from my files. Also check out the other endocrine disrupting chemical studies I've posted (SEARCH: 'endocrine disruptors', and 'phthalates').

Bottom line: Read labels and try to minimize plastics in personal care products (e.g., lotion) and your food if possible (e.g., choose glass, stainless steel, wax paper, aluminum foil). This is especially important during pregnancy.  Even BPA alternatives (labeled BPA-free) should be viewed as the same as BPA - as endocrine disruptors. In other words, currently there are no good BPA substitutes. Don't microwave food in a plastic dish or container, or covered with plastic wrap. Eat fresh foods rather than packaged, processed foods. From Newsweek:

BPA Is Fine, If You Ignore Most Studies About It

Bisphenol-A (BPA) is either a harmless chemical that’s great for making plastic or one of modern society’s more dangerous problems. Depends whom you ask. BPA is in many types of plastics and the epoxy resins that line most aluminum cans, as well as thermal papers like receipts. It is an endocrine disruptor that mimics estrogen, a hormone especially important in sexual development, and the fact that it’s all over the place worries many people. Newsweek spoke with about 20 scientists, leaders in the field of BPA research, and the majority say it is likely (though not certain) that the chemical plays a role in a litany of health concerns: obesity, diabetes, problems with fertility and reproductive organs, susceptibility to various cancers and cognitive/behavioral deficits like ADHD.  ...continue reading "More Negative News About Hormone Disrupting Chemicals"

Published on Leave a comment on Missing Microbes in Infancy and Asthma

An interesting Canadian study that followed young children for 3 years found that young infants may be more likely to develop allergic asthma if they lack four beneficial bacteria in their gut. Children with low levels of Lachnospira, Veillonella, Faecalibacterium, and Rothia bacteria in their gut in their first 3 months were at higher risk for asthma and tended to receive more antibiotics than healthier children before they turned 1 year old.

Other studies have shown that the risk of developing asthma and allergies has been linked with such things as taking antibiotics, cesarean birth, bottle fed with formula, not living on a farm, and not having furry pets in the first year of life.

The researchers wrote: "Our findings indicate that in humans, the first 100 days of life represent an early-life critical window in which gut microbial dysbiosis {the microbial community being out of whack} is linked to the risk of asthma and allergic disease." How do the infants get these microbes? It is thought that infants get exposed to the mother's microbiome (microbial community) via vaginal birth, breast-milk, and mouth contact with the mother's skin.  From NPR News:

Missing Microbes Provide Clues About Asthma Risk

The composition of the microbes living in babies' guts appears to play a role in whether the children develop asthma later on, researchers reported Wednesday. The researchers sampled the microbes living in the digestive tracts of 319 babies, and followed up on the children to see if there was a relationship between their microbes and their risk for the breathing disorder. In the journal Science Translational Medicine, the researchers report Wednesday that those who had low levels of four bacteria were more likely to develop asthma by the time they were 3-years-old.

Specifically, the researchers focused on 22 children who showed early signs of asthma, such as wheezing, when they were 1-year-old. They were much more likely than the other children to have had low levels of the four bacteria when they were 3-months-old. By the time they turned 3, most had developed full-blown asthma."The bottom line is that if you have these four microbes in high levels you have a very low risk of getting asthma," says Brett Finlay, a microbiologist at the University of British Columbia who helped conduct the research. "If you don't have these four microbes or low levels of these microbes you have a much greater chance of asthma."

Asthma is a common and growing problem among children. Evidence has been accumulating that one reason may be a disruption in the healthful microbes children get early in life, Finlay says."There's all these smoking guns like, for example, if you breast-feed versus bottle feed you have less asthma," he says. "If you're born by C-section instead of vaginal birth you have a 20 percent higher rate of asthma. If you get antibiotics in the first year of life you have more asthma." The microbiomes of kids who aren't breast-fed and are born by Caesarean section may miss out on getting helpful bugs. Antibiotics can kill off the good bacteria that seem important for the development of healthy immune systems.

"What's become clear recently is that microbes play a major role in shaping how the immune system develops. And asthma is really an immune allergic-type reaction in the lungs," Finlay says. "And so our best guess is the way these microbes are working is they are influencing how our immune system is shaped really early in life."

To further test their theory, the researchers gave laboratory mice bred to have a condition resembling asthma in humans the four missing microbes. The intervention reduced the signs of levels of inflammation in their lungs, which is a risk factor for developing asthma.

The bacteria are from four genuses: Lachnospira, Veillonella, Faecalibacterium and Rothia. The researchers aren't exactly sure how the microbes may protect against asthma. But babies with few or none of them had low levels of a substance known as acetate, which is believed to be involved with regulating the immune system.

Published on Leave a comment on Home Pesticide Use Linked to Childhood Cancer

Children exposed to insecticides (pesticides) at home have an increased risk of developing leukemia or lymphoma, a new review finds.The analysis, of 16 studies done since the 1990s, found that children exposed to indoor insecticides had an elevated risk of developing the blood cancers. There was also a weaker link between exposure to weed killers and the risk of leukemia.

There is also evidence from studies linking pesticides with neurological consequences, such as lower IQ and attention deficit hyperactivity disorder. Note: insecticides and weed-killers (herbicides) are both pesticides. The article also gives some non-chemical approaches to treating pests with non-chemical means.

From CNN: Report: Pesticide exposure linked to childhood cancer and lower IQ

Pesticide use in homes may increase the risk of children developing leukemia or lymphoma, a new report suggests. Researchers combined data from 16 earlier studies that had compared pesticide exposure between children who developed leukemia or lymphoma and those who did not. These studies estimated the level of insecticides and herbicides both inside the home and in the yard and outdoor residential space.

The researchers concluded that children who had been exposed to insecticides indoors were 47% more likely to have leukemia and 43% more likely to have lymphoma. Although leukemia and lymphoma are rare -- leukemia affects about five in 100,000 children in the United States -- they are among the common types of childhood cancers. "Childhood cancers are increasing year by year in this country....  ...continue reading "Home Pesticide Use Linked to Childhood Cancer"

Published on Leave a comment on Are All These Prescription Meds During Pregnancy Really Necessary?

Disturbing results from a study looking at data from over 1 million women enrolled in Medicaid before pregnancy from 2000 to 2007. More than four of five (82.5%) pregnant women were prescribed at least one medication, and 42.0% were prescribed a drug that is potentially harmful to the developing fetus.From Medscape:

Prescription Meds Common in Pregnancy; Maybe Too Common

Although most physicians acknowledge the complexity of prescribing drugs to pregnant women, they nonetheless prescribe them frequently. More than four of five (82.5%) pregnant women were prescribed at least one medication, and 42.0% were prescribed a drug that is potentially harmful to the developing fetus, researchers found in a large, population-based study.The study, which details the type and timing of medications prescribed to pregnant Medicaid patients, presents a disturbing pattern, according to Kristin Palmsten, ScD, from the University of California, San Diego, in La Jolla, and colleagues. 

Dr Palmsten and colleagues found that the most commonly dispensed medications are those used to treat infections. They also report that dispensing is more common for younger pregnant women and white women. The researchers examined data for women enrolled in Medicaid before pregnancy (n = 1,106,757), using 2000 to 2007 Medicaid Analytic eXtract data for prospectively collected medication information. The analysis included over-the-counter medications dispensed by a pharmacist, but excluded medications purchased over the counter directly or prescribed during hospitalizations.

The most commonly dispensed medications were nitrofurantoin (21.6%), metronidazole (19.4%), amoxicillin (18.0%), azithromycin (19.9%), and promethazine (13.5%). Other frequently dispensed medications include promethazine cephalexin and codeine with acetaminophen.....The investigators also note that nine of the 20 most commonly dispensed medications are rated as having limited to fair data quality and quantity to inform human teratogenic risk assessments by the Teratogen Information System.

Dr Palmsten and colleagues also found that 42.0% of pregnant women filled a prescription for a former US Food and Drug Administration (FDA) category D or X drug during pregnancy. Category D medications are associated with evidence of human fetal risk based on adverse reaction data. The top five most commonly prescribed category D medications were codeine (11.9%), hydrocodone (10.2%), ibuprofen (4.9%), sulfamethoxazole (4.0%), and hydrocortisone (4.0%). The authors note that some of those agents are considered category B or C drugs, depending on the circumstances of use.

Class X medications have been tested in animals or humans and found to cause fetal abnormalities. The five most commonly prescribed category X drugs were hormonal contraceptives (4.9%), temazepam (0.11%), atorvastatin (0.07%), simvastatin (0.04%), and warfarin (0.04%).

Moreover, the researchers note that many of the most commonly dispensed medications have limited or low-quality data available regarding safety during pregnancy. “Lack of unambiguous safety information may lead to the use of medications with potential to cause adverse pregnancy outcomes, whereas beneficial medications may be avoided,” they write. Many opioids are category N, meaning the FDA has not classified the drug. 

Although the solution to the complex problem of drug use by pregnant women is not clear, the FDA has made a change that is designed to better inform healthcare providers and patients about the risks of drugs. As of June 30, 2015, the FDA has changed the way it labels human prescription medications and biologic preparations for use in pregnancy and lactation. The new labels will include a summary of the risks of the drug during pregnancy.

Published on

Several recent studies have found that constant exposure to high levels of air pollution has negative effects on the brain. The last post described negative effects on the gray matter in brains (resulting in smaller brain volumes) of elderly women from air pollution, but this study found negative effects (lower grade point averages) in young children from high air pollution. From Environmental Health News:

Bad air means lower grade point averages in Texas

Fourth and fifth graders in El Paso, Texas, are more likely to have lower grade point averages if heavily exposed to contaminated air at home, according to a new study.It bolsters a growing body of evidence that air pollution can impair success in school.

They found that for all types of air pollution sources, more exposure corresponded with lower grade point averages. Only one type of pollution—point sources such as factories—was not significantly linked to lower grade point averages.University of Texas at El Paso researchers analyzed the grade point averages of 1,895 children and, using their home location, estimated their exposure to air toxics—such as benzene, arsenic, lead, mercury, hydrochloric acid, toluene, vinyl bromide, xylenes, and diesel particulate matter—using federal data.

“Effects appear to be insidious, since they are mild, unlikely to be perceived, and, hence, unlikely to be addressed in any way … seemingly trivial effects on children’s development may translate into substantial impacts throughout the life course in terms of physical and mental health and personal success,” the authors wrote.The researchers did control for some other things that can affect children’s grades such as poverty, mother’s age, education and ability to speak English, and the child’s race and sex.

Still, the study doesn’t prove that dirty air makes kids do worse in school. It does, however, suggest children’s developing bodies are more susceptible to air pollution, which can harm their respiratory systems and brain.Air pollution might hamper kids’ grades via two primary ways: Illnesses, mostly respiratory, that would make them miss school, and developmental problems resulting from long-term exposure, said Sara Grineski, an associate professor of sociology at The University of Texas at El Paso and co-author of the new study.

Others have found similar links between air pollution and academic performance. Three months ago Columbia University's Perera and colleagues reported that New York City children born to mothers in poverty and exposed to certain air toxics during pregnancy had lower IQs.  Perera, tracking the mothers and children since before birth, said the pollution exposure prior to birth is more strongly linked to learning and behavioral problems. 

In the current study it’s unclear if the children were exposed in their mothers’ womb—an exposure window that is critical to brain development, Perera said....Other studies support this—in February Calderón-Garcidueñas and colleagues reported Mexico City smog was linked to impaired short-term memory and IQ in children.

The city is more than 80 percent Hispanic....Previous studies have shown that El Paso’s minorities are disproportionately impacted by toxics, Grineski said. The city of 675,000 is one of the worst when it comes to particulate matter—a mix of substances emitted by combustion sources, including cars, trucks, industrial plants and wood burning—especially coarse particulates, PM10, those between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair, according to the EPA). El Paso’s 24-hour PM10 average is about 233 micrograms per cubic meter of air, according to the latest EPA data from 2013, which was eighth highest among more than 500 U.S. cities. El Paso, along with Laredo, has the highest carbon monoxide levels in Texas.

Published on

There is growing evidence that women around a lot of endocrine disrupting chemicals at home or in jobs such as cleaners, hairdressers and laboratory workers during pregnancy are more likely to have baby boys with a genital defect called hypospadias (a condition where the opening of the urethra is on the underside of the penis rather than at the tip). From Environmental Health News:

Genital defect in baby boys linked to moms’ chemical exposure

Mothers around a lot of endocrine disrupting chemicals at home or in jobs such as cleaners, hairdressers and laboratory workers during pregnancy are more likely to have baby boys with a genital defect, according to a new study in the south of France.The study adds to mounting evidence that fetal exposure to chemicals that mimic people’s natural hormones may cause hypospadias, a condition where the opening of the urethra is on the underside of the penis rather than at the tip.

French researchers examined more than 600 children in the south of France and found that babies exposed to endocrine disrupting chemicals while their genitals were developing were more likely to suffer from hypospadias. Half the boys had hypospadias and half did not. The risk for those exposed was 68 percent higher than the unexposed boys. The researchers ruled out baby boys with known genetic risks for such defects.

The defect, which can be minor or quite severe depending on how far the opening is from the tip, can lead to problems with urination and, later in life, sexual difficulty....It is one of the most common genital defects in baby boys, and most cases require surgery, often done before they reach two years old. In the United States, an estimated five out of 1,000 boys are born annually with hypospadias, while Europe’s rate is slightly less than two out of 1,000.

The researchers estimated the unborn babies’ exposure by looking at their parents’ jobs and where they lived. Working with hormone disrupting chemicals and living in homes near heavy polluters were both linked to more baby boys having the defect. However, the researchers did say a limit of the study was attempting to estimate fetal exposure to such chemicals.Mothers were most likely to have boys with hypospadias if they worked as a cleaner, hairdresser or beautician.  

Some of the endocrine disrupting chemicals linked to the professions involved in the study were bisphenol-A (BPA), phthalates, polychlorinated compounds, alkylphenolic compounds and organic solvents. Most exposures—78 percent—occurred in the window of development when babies’ genitals are forming.... but detergents, pesticides, and cosmetics accounted for 75 percent of the cases,” the authors wrote in the study published in the European Urology journal this month.

Other possible causes of the birth defect include older, obese mothers, and fertility or hormone treatments during pregnancy, according to the U.S. Centers for Disease Control and Prevention.

This wasn’t the first time scientists have found a link between certain chemicals and hypospadias. Mothers in southeast England who were heavily exposed to endocrine disrupting phthalates on the job were about three times as likely to have a baby boy with hypospadias. Phthalates are used in some cosmetics, fragrances, food packaging and PVC plastics.

Published on

Two studies showing detrimental effects on children from pyrethroids in 2 weeks! The June 3 post was about research linking household pyrethroid exposure to ADHD in children and young teens. The second study found that low level childhood exposures to pyrethroid insecticides was linked to lower scores on an IQ test (Wechsler Intelligence Scale for Children - verbal comprehension and working memory) in 6 year old children. The researchers viewed this as evidence that pyrethroid insecticides may "negatively affect neurocognitive development".

Bottom line: even though pyrethroid pesticides are considered safer than many other pesticides, they still can have undesirable effects on humans, especially developing children. To be safe, use least toxic pest control that uses non-toxic, safe "alternative" or "natural" methods rather than just "spraying a chemical". Another possibility is looking for "organic pest control" or"least-toxic Integrated Pest Management" (IPM) that looks to deal with pest problems with non-toxic methods (which may include sealing holes, heat, caulking, trapping, using sticky traps, and even vacuuming up insects). From Science Daily:

Impact of insecticides on the cognitive development of 6-year-old children

Researchers have provided new evidence of neurotoxicity in humans from pyrethroid insecticides, which are found in a wide variety of products and uses. An increase in the urinary levels of two pyrethroid metabolites (3-PBA and cis-DBCA) in children is associated with a significant decrease in their cognitive performances , particularly verbal comprehension and working memory. This study was carried out on nearly 300 mother and child pairs from the PELAGIE cohort (Brittany).

Pyrethroids constitute a family of insecticides widely used in a variety of sectors: agriculture (various crops), veterinary (antiparasitics) and domestic (lice shampoo, mosquito products). Their mode of action involves blocking neurotransmission in insects, leading to paralysis. Because of their efficacy and relative safety for humans and mammals, they have replaced older compounds (organochlorides, organophosphates, carbamate) considered more toxic.

Exposure of children to pyrethroids is common. It is different to adult exposure, due to the closer proximity of children to ground-level dust (which stores pollutants), more frequent hand-to-mouth contact, lice shampoos, etc. In children, pyrethroids are mainly absorbed via the digestive system, but are also absorbed through the skin. They are rapidly metabolised in the liver, and mainly eliminated in the urine as metabolites within 48 hours.

Pregnancy is also an important period of life for the future health of the child. For this reason, the researchers studied the PELAGIE mother-child cohort established between 2002 and 2006, which monitors 3,500 mother-child pairs. This cohort simultaneously considers exposure to pyrethroid insecticides during fetal life and childhood. A total of 287 women, randomly selected from the PELAGIE cohort and contacted successfully on their child's sixth birthday, agreed to participate in this study.

Two psychologists visited them at home. One assessed the child's neurocognitive performances using the WISC scale (verbal comprehension index, VCI, and working memory index, WMI). The other psychologist characterised the family environment and stimuli that might have had a role on the child's intellectual development, collected a urine sample from the child, and collected dust samples. Exposure to pyrethroid insecticides was estimated by measuring levels of five metabolites (3-PBA, 4-F-3-PBA, cis-DCCA, trans-DCCA and cis-DBCA) in urine from the mother (collected between the 6th and 19th weeks of pregnancy) and from the child (collected on his/her 6th birthday).

Results show that an increase in children's urinary levels of two metabolites (3 PBA and cis-DBCA) was associated with a significant decrease in cognitive performances, whereas no association was observed for the other three metabolites (4-F-3-PBA, cis-DCCA and trans-DCCA). With respect to metabolite concentrations during pregnancy, there was no demonstrable association with neurocognitive scores.

Published on

Another good reason to breastfeed. Exposure to pollutants like nitrogen dioxide and airborne particles can cause negative effects on motor and mental development in infants, but a new study says those effects are countered in babies who are breast-fed for at least 4 months by their mothers. Researchers in Spain began monitoring rural, pregnant women in 2006 and analyzed samples from 638 women and their infants at 15 months. They reported that babies who are breast-fed did not suffer from the potentially harmful developmental impact of PM2.5 (pollution particle matter) and NO2 (nitrogen dioxide). From Science Daily:

Breastfeeding protects against environmental pollution

Living in a city with a high level of vehicle traffic or close to a steel works means living with two intense sources of environmental pollution. However, a study conducted by the UPV/EHU researcher Aitana Lertxundi indicates that the harmful effect of PM2.5 pollution particle matter and nitrogen dioxide (NO2) disappears in breastfed babies during the first four months of life. According to the results of the research, breastfeeding plays a protective role in the presence of these two atmospheric pollutants.

Lertxundi's study focusses on the repercussions on motor and mental development during the first years of life caused by exposure to the PM2.5 and NO2 atmospheric pollutants .... "In the fetal phase the central nervous system is being formed and lacks sufficient detoxification mechanisms to eliminate the toxins that build up," pointed out Aitana Lertxundi.

The PM2.5 particles measure less than 2.5 micra, in other words, they are four times thinner that a single hair and are suspended in the air. As they are so small they can easily penetrate the body and as they weigh so little they can spread without any difficulty through the air and can move far away from the initial emission source. The composition of these neurotoxic particles depends on the emission sources in the area. The INMA Gipuzkoa area under study has a high presence of neurotoxic particle matter made up of lead, arsenic and manganese from industrial activity and traffic. In comparison with urban averages where the main source of pollution is traffic, the concentration is lower.

One result of the study is that the existence of an inverse relationship has been detected between exposure to pollution particle matter and the motor development of babies. In this respect, the researcher highlights the fact that "these indices display an alteration with respect to the average and, even if they are not worrying, they are significant in that they reveal the relationship existing between air quality and motor development." The analysis of the data also shows that neither the PM2.5 particle matter nor the NO2 exert a harmful effect on babies breastfed on mother's milk for at least four months.

Published on

In a newly published study looking at how infant gut microbes change over time, once again babies had differences in gut bacteria depending on whether they were delivered vaginally or by Cesarean section.

But what's interesting is that stopping breastfeeding changed their gut bacteria  more (to more adult-like species) than just introducing solid foods. Certain types of bacteria thrive on the nutrients breast milk provides and once these nutrients are no longer available, then other bacteria emerge that are more commonly seen in adults. In other words, stopping breastfeeding seems to drive "maturation" of the gut bacteria.

From The Scientist: Maturation of the Infant Microbiome

Like babies themselves, the intestinal microbiomes of infants start out in an immature state and over time grow into communities similar to those of adults. In a new survey of 98 Swedish babies whose microbiota were sampled several times during their first year of life, researchers found that the microbiomes of breastfed infants persisted in a “younger” state longer than those of non-breastfed babies, even after the introduction of solid foods.

The conclusion that “stopping breastfeeding—rather than introducing solids—drives maturation is a new idea, because we all thought so far that solids introduction was a key factor in changing the microbiota,” said Maria Gloria Dominguez-Bello, a microbiologist at New York University School of Medicine who did not participate in the study.

Researchers from University of Gothenburg in Sweden and their colleagues found more adult-like taxa in the microbiomes of babies who stopped breastfeeding earlier, while the microbiota of babies breastfed for longer were dominated by bacteria present in breastmilk. The results, published today (May 13) in Cell Host & Microbe, are part of an effort to catalog the microbial changes that occur as children age and to note how those changes correlate with health and disease. Fredrik Bäckhed of Gothenburg and his colleagues collected stool samples from 98 moms and their newborns, and again sampled the babies’ stool at four and 12 months.

Confirming previous work, his team’s analysis found that the 15 babies born via cesarean section were colonized by different bacteria—many from oral and skin communities—than babies born vaginally, who shared numerous microbes with those present in their mothers’ stool.

For instance, in the vaginally delivered newborns’ microbiomes, genes that break down sugars in breastmilk were common. As these babies celebrated their first birthdays, the genes in their microbiomes favored the ability to breakdown starches, pectins, and more complex sugars.

“What’s nice about this paper is that they show this maturation [of the microbiome] in normal, healthy kids in a Western population follows this transition based on diet,” said Steven Frese, a postdoc at the University of California, Davis, who penned a commentary accompanying the study with his advisor, David Mills. “Being exposed to new foods promotes the growth of new bacteria that can consume them,” Frese told The Scientist.