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Category: pregnancy and childbirth

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There has been a lot of discussion in the last few years of our gut bacteria (hundreds of species), the microbiome (the community of microbes living within and on a person (gut, nasal cavities, mouth, sinuses, etc.), probiotics, the finding of a link between bacteria and some chronic diseases, and how the modern lifestyle and antibiotics are wiping out our beneficial gut microbes. I am frequently asked how one can improve or nurture the beneficial bacteria in our bodies.

While no one knows what exactly is the "best" or "healthiest" microbial composition of the gut, it does look like a diversity of bacteria is best (may make you healthier and more able to resist diseases). Research also suggests that the diversity and balance of bacteria living in the body can be changed and improved, and changes can occur very quickly. And that the microbial communities fluctuate for various reasons (illness, diet,etc.). Diet seems to be key to the health of your gut microbial community. Prebiotics feed the beneficial bacteria in the gut, probiotics are live beneficial bacteria, and synbiotics are a combination of prebiotics and probiotics. But don't despair - you can improve your gut microbial community starting now. The following are some practical tips, based on what scientific research currently knows.

SOME STEPS TO FEED AND NURTURE YOUR GUT MICROBES:

Eat a wide variety of foods, especially whole foods that are unprocessed or as minimally processed as possible. Eat everything in moderation.

Eat a lot of plant based foods: fruits, vegetables, whole grains, seeds, nuts, and legumes. Think of Michael Pollan's advice: "Eat food. Not too much. Mostly plants."

Eat more washed and raw fruits and vegetables (lots of bacteria and fiber to feed and nurture the bacteria). Some every day would be good.

Eat more soluble and insoluble types of fiber, and increase how many servings you eat every day. A variety of  fiber foods every day, and several servings at each meal, is best. Think fruits, vegetables, whole grains, legumes, nuts, seeds. (See How Much Dietary Fiber Should We Eat? - also has a chart with high fiber foods, and Recent Studies Show Benefits of Dietary Fiber)

Eat as many organic foods as possible. There is much we don't yet know, and pesticides are like antibiotics - they kill off microbes, both good and bad. Somehow I think that lowering the levels in your body of pesticides (as measured in blood and urine) can only be beneficial. Also, organic foods don't contain added antibiotics and hormones. (Eat Organic Foods to Lower Pesticide Exposures).  But even if you can't or won't eat organic foods, it is still better to eat non-organic fruits, vegetables, and whole grains than to not eat them.

Eat some fermented foods such as kimchi and sauerkraut (they contain live bacteria), kefir, and yogurts with live bacteria. Eat other bacteria containing foods such as cheeses, and again a variety is best (different cheeses have different bacteria).

Try to avoid or eat less of mass-produced highly processed foods, fast-foods, preservatives, colors and dyes, additives, partially hydrogenated oils, and high-fructose corn syrup. Read all ingredient lists on labels, and even try to avoid as much as possible "natural flavors" (these are chemicals concocted in a lab and unnecessary). Even emulsifiers (which are very hard to avoid) are linked to inflammation and effects on gut bacteria.

Avoid the use of triclosan or other "sanitizers" in soaps and personal care products (e.g., deodorants). Triclosan promotes antibiotic resistance and also kills off beneficial bacteria. Wash with ordinary soap and water.

Avoid unnecessary antibiotics (antibiotics kill off bacteria, including beneficial bacteria).

Vaginal births are best - microbes from the birth canal populate the baby as it is being born. If one has a cesarean section, then one can immediately take a swab of microbes from the mother's vagina (e.g., using sterile gauze cloth) and swab it over the newborn baby. (See post discussing this research by Maria Gloria Dominguez Bello )

Breastfeeding is best - breastfeeding provides lots of beneficial microbes and oligosaccharides that appear to enrich good bacteria in the baby’s gut.

Live on a farm, or try to have a pet or two. Having pets, especially in the first year of life,  ups exposure to bacteria to help develop and strengthen the immune system, and prevent allergies. Pets such as dogs and cat expose humans to lots of bacteria.

Get regular exercise or physical activity. Professional athletes have more diverse gut bacterial community (considered beneficial) than sedentary people.

Can consider taking probiotics - whether in foods or supplements. They are generally considered beneficial, but not well studied, so much is unknown. The supplements are unregulated, and the ones available in stores may not be those that are most commonly found in healthy individuals. Research the specific bacteria before taking any supplements. Researchers themselves tend to stay away from probiotic supplements and focus on eating a variety of all the foods mentioned above (fruits, vegetables, whole grains, seeds, nuts, legumes, fermented foods) to feed and nurture beneficial bacteria.

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Scientists warn about endocrine disruption from 4 common chemicals in an analysis just released. This is absolutely depressing because the 4 chemicals (benzene, toluene, ethylbenzene, xylene) are so pervasive in indoor air. Especially that at levels considered "safe" by the EPA there may be disruption of our hormones (endocrine systems).

Of course the 4 chemicals are already known to have health effects on the human body other than what is discussed in this study. For example, toluene has a number of central nervous system effects. The EPA says toluene , which is found in highest concentrations in indoor air from the use of common household products (paints, paint thinners, adhesives, synthetic fragrances, and nail polish). Outside - the biggest source of toluene is from automobile emissions.

Some ways to lower exposure to these 4 chemicals: Read product labels. When using a product that says to use with proper ventilation - open the windows and let the room ventilate!  Don't smoke. (For example: the EPA says tobacco smoke contains benzene and accounts for nearly half the national exposure to benzene) The study researchers themselves said the EPA should be paying more attention to these air contaminants. I read this at Scientific American, but the following excerpts are from EHN.

From EHN: Scientists warn of hormone impacts from benzene, xylene, other common solvents.

Four chemicals present both inside and outside homes might disrupt our endocrine systems at levels considered safe by the U.S. Environmental Protection Agency, according to an analysis released today. ...continue reading "More Problems With Four Common Chemicals"

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The research finding that eating fruits and vegetables with high pesticide residues has a negative effect on sperm is disturbing. It wasn't the amount of fruits and vegetables eaten, it was eating fruits and vegetables with high levels of pesticide residues. Yes, the study does have some limitations (for example, a one time analysis, looked at men at a fertility clinic and not the general population), but...even with these limitations, the results are disturbing.

Earlier studies of children showed that switching to an organic diet has almost immediate results of reducing pesticide residues in the body (OP Pesticides in Children’s Bodies: The Effects of a Conventional versus Organic Diet). So the advice here is try to increase the amounts of organic fruits and vegetables in the diet, especially those with high pesticide residue levels.

Fruit or vegetables that were low in pesticide residues included peas, beans, grapefruit and onions. Those that had highest pesticide residues included peppers, spinach, strawberries, celery,blueberries, potatoes, peaches, plums, apples and pears.

From Time: A Diet High in Pesticides Is Linked to a Lower Sperm Count

The troubling link between pesticide exposure and fertility isn’t new; scientists have already established that people who work with pesticides tend to have lower fertility than people who don’t. But for the majority of us who don’t work with chemicals, diet is the biggest source of exposure, says Jorge Chavarro, MD, assistant professor of nutrition and epidemiology at Harvard School of Public Health and senior author of a new study published in the journal Human Reproduction.

Chavarro and his colleagues wanted to see if pesticide residues left on fruits and vegetables might have a similar effect on sperm—and their findings suggest that they did. Men who ate fruits and vegetables with a lot of pesticides had lower sperm counts and more oddly shaped sperm than those who had lower levels of dietary pesticide exposure.

Over an 18-month period, the researchers used data from the Environment and Reproductive Health (EARTH) study, including semen samples from 155 men who were being treated at a Boston fertility clinic and a food frequency questionnaire they completed. The researchers determined pesticide exposure by comparing the questionnaire answers with government data about produce pesticide levels in the USDA’s Pesticide Data Program.

The study didn’t tease out individual foods, but the researchers classified produce according to whether it had high or low-to-moderate levels of pesticides. Men who ate the most high-pesticide fruits and vegetables had a 49% lower total sperm count and 32% fewer sperm that were shaped normally, compared to men who ate the least amount of the high-pesticide produce.

Researchers gave each piece of produce a score based on its level of detectable pesticides, its level of pesticides that exceeded the tolerance level established by the U.S. Environmental Protection Agency, and whether the produce had three or more types of detectable pesticides. (The bigger the score, the more it hit all three measures.) Ranked from highest pesticide contamination to lowest, here were the top fruits and vegetables: Green, yellow and red peppers (6), Spinach (6), Strawberries (6), Celery (6), Blueberries (5), Potatoes (5), Peaches and plums (5), Apples or pears (5), Winter squash (4), Kale, mustard greens and chard greens (4), Grapes and raisins (4).

The team didn’t tease out associations with individual pesticides. But they believe that a mixture of pesticides—not just one particular pesticide—is responsible for the link. The strongest variable in their analysis were the proportion of fruits and vegetables consumed that use three or more pesticides. “The more pesticides are applied on any particular crop, that seems to be having a bigger impact,” Chavarro says...But for people who are concerned about their dietary exposure to pesticides, there are ways to lower it, he says, like eating organic and choosing produce not listed on the Environmental Working Group’s dirty dozen list.

From Science  Daily: Pesticides in fruit and vegetables linked to semen quality

Assistant Professor of Nutrition and Epidemiology at the Harvard T.H. Chan School of Public Health in Boston (USA), Jorge Chavarro, said: "These findings should not discourage the consumption of fruit and vegetables in general. In fact, we found that total intake of fruit and vegetables was completely unrelated to semen quality. This suggests that implementing strategies specifically targeted at avoiding pesticide residues, such as consuming organically-grown produce or avoiding produce known to have large amounts of residues, may be the way to go."

There were no differences seen between men in the four groups who consumed fruit and vegetables with low-to-moderate pesticide residues. In fact, there was a significant trend towards having a higher percentage of normally shaped sperm among men who consumed the most fruit and vegetables with low pesticide residues -- a relative increase of 37% from 5.7% to 7.8%...Note:Pesticide use varies from country to country, but in the USA those used on fruit and vegetables include Atrazine, Malathion, Chlorpyrifos and Carbendazim. 

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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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Research is accumulating that the microbial exposure from a vaginal birth, breastfeeding, and pets in the first year of life are all good for a baby's developing immune system and the gut microbiome.

From Science Daily: Breastfeeding, other factors help shape immune system early in life

Researchers say that breastfeeding and other factors influence a baby's immune system development and susceptibility to allergies and asthma by what's in their gut. The striking findings from a series of studies further advance the so-called hygiene hypothesis theory that early childhood exposure to microorganisms affects the immune system's development and onset of allergies, says Christine Cole Johnson, Ph.D., MPH, chair of Henry Ford's Department of Public Health Sciences and principal research investigator.

The gut microbiome is the collection of microorganisms in the gastrointestional, or GI, tract, and the human body has billions of these microbes... The gut microbiome is known to play an important role in immune system development, and is thought to contribute to a host of diseases like obesity, autoimmune diseases, circulating disorders and pediatric allergies and infection.

"For years now, we've always thought that a sterile environment was not good for babies. Our research shows why. Exposure to these microorganisms, or bacteria, in the first few months after birth actually help stimulate the immune system," Dr. Johnson says."The immune system is designed to be exposed to bacteria on a grand scale. If you minimize those exposures, the immune system won't develop optimally."

In six separate studies, researchers sought to evaluate whether breastfeeding and maternal and birth factors had any effect on a baby's gut microbiome and allergic and asthma outcomes. Using data collected from the WHEALS birth cohort, researchers analyzed stool samples from infants taken at one month and six months after birth. They also looked at whether the gut microbiome impacted the development of regulatory T-cells, or Treg, which are known to regulate the immune system. Highlights:

• Breastfed babies at one month and six months had distinct microbiome compositions compared to non-breastfed babies. These distinct compositions may influence immune system development. • Breastfed babies at one month were at decreased risk of developing allergies to pets. • Asthmatic children who had nighttime coughing or flare-ups had a distinct microbiome composition during the first year of life. • For the first time, gut microbiome composition was shown to be associated with increasing Treg cells.

Researchers found that a baby's gut microbiome patterns vary by: • A mother's race/ethnicity. • A baby's gestational age at birth. • Prenatal and postnatal exposure to tobacco smoke. • Caesarean section versus vaginal delivery.• Presence of pets in the home.

Henry Ford's landmark 2002 study found exposure to dogs or cats in the first year of a baby's life reduced their risk for allergies.

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More than a year after California revised its flame retardant standards so that new furniture (the polyurethane foam in upholstered sofas, sofa beds, and chairs) does not have to use flame retardants, it is still hard to find out whether the furniture is flame retardant free. This is what I have experienced in the last few months - the store doesn't know and the manufacturer won't respond to emails.

The new furniture label should say TB 117-2013 , and then you still need to ask the retailer if there are flame retardants in the upholstered furniture. The new label means that the manufacturer does NOT have to use flame retardant chemicals anymore, but it does NOT mean they are chemical free. And flame retardants are still found in many baby products (car seats, bumpers, crib mattresses, strollers, nursing pillows, etc), some personal care products, and electronics. It's a buyer beware situation.

More and more research is finding health problems with flame retardants because they are "not chemically bound" to the products in which they are used - thus they escape over time, and get into us via the skin (dermal), inhalation (from dust), and ingestion (from certain foods and dust on our fingers). And because flame retardants are persistant, they bioaccumulate (they build up over time). They can be measured in our urine and blood.

Evidence suggests that flame retardants may be endocrine disruptors, carcinogenic, alter hormone levels, decrease semen quality in men, thyoid disruptors, and act as developmental neurotoxicants (when developing fetus is exposed during pregnancy)  so that children have lowered IQ and more hyperactivity behaviors.

How does one know if the foam in your furniture has flame retardants in it? Duke University will test it for free if you send them a small piece of the furniture's foam. http://sites.nicholas.duke.edu/superfund/whats-in-my-foam/ I originally read about this service a few months ago in The Atlantic,

From The Atlantic: How to Test a Couch for Toxins

It began with a smell. Kerri Duntley had just bought a pair of large, cream-colored couches....As the scent continued to fill her living room, Duntley asked herself a troubling question: What was causing the couches to smell like industrial chemicals? The answers weren’t easy to find. Duntley searched in web forums and even tried contacting the couches’ manufacturer. “I called and called and called,” she said. “They just would not give me the information.” She grew frustrated and began looking for new couches. It was then that she discovered an unusual service run by a Duke University lab.

The lab’s offer was simple. First, the lab instructed, wield a pair of scissors. Grab something made with polyurethane foam—say, a mattress or the innards of a couch cushion. Cut a small chunk from the foam. Wrap the surgical work in tinfoil, ziplock seal it and mail the crime-scene-looking evidence off to Durham, North Carolina. Wait up to 45 days, the lab said, and it’ll arrive: a report detailing toxic flame retardants embedded in the foam.

Duntley complied. When the results came back, she learned that her couch sample had tested positive for two flame retardants, including one that has proven harmful in animal studies, a finding that she called heartbreaking. Her experience points to a vast gap in safety information about consumer goods. With the U.S. government’s limited power to regulate chemicals, many consumers, like Duntley, are left to piece together their own crude health-risk assessments. That fabric softener? It may smell like the Elysian Fields, but what if its unlisted ingredients cause cancer? 

Government officials , academic researchers, the chemical industry and environmentalists agree: The U.S. system of chemical regulation is broken. But while the fight over reform continues in Washington, consumers remain blind to many of the chemicals that enter their homes.

Duke’s service is looking in its small way to change that. The lab—which offers anyone a free chemical analysis of polyurethane foam—has informed hundreds of Americans about their furniture’s toxicity. At the same time, the foam samples have given Duke’s team a large bank of crowdsourced research. By offering a free service to an anxious public, Duke’s scientists are gaining a clearer view of chemical manufacturing. And they’re learning just how much we don’t know about the chemicals that enter our homes.

Stapleton was part of a scientific cohort that found ingesting dust—say, getting our dusty hands on a burger—is by far our largest source of exposure to flame retardants; flame retardants aren’t chemically bound to their products, and so they attach themselves to airborne dust.

But what began in California soon became a de facto national standard, since furniture companies didn’t want to manufacture separate lines. Stapleton was interested to see how chemically saturated our furniture really is. So she and her colleagues asked families for samples of their baby products’ foam. After reviewing 101 samples from across thirteen states, Stapleton’s 2011 study reached a startling conclusion: Flame retardants accounted for about 5 percent of the products’ weight, and the chemicals were found in 80 percent of the samples.

Some of the chemicals were carcinogens. Others were from a chemical class known as polybrominated diphenyl ethers, or PBDEs, which have been linked to lower IQ scores, attention deficit hyperactivity disorder, and thyroid disorders. The most common flame retardant among the samples was tris (1,3-dichloroisopropyl)phosphate, or TDCPP, which researchers say is likely to harm the neurological development of infants. TDCPP, in fact, was used throughout the 1970s in children’s pajamas, until critical health research led manufacturers in 1977 to stop using it. Yet the chemical had reemerged in products like strollers and baby mattresses.

The lab offered to test some of these strangers’ furniture for free. But the requests kept coming. That’s when Stapleton and her colleagues decided to expand the scope of the testing and conceived of a free service for the public. They’d test anyone’s polyurethane foam for a suite of seven common flame retardants as something of a public service, since it would be funded by a federal grant (itself funded by taxpayer dollars). The service would also aid Stapleton’s research, offering a valuable stream of crowdsourced data about the chemicals used in furniture.

By crowdsourcing her research, Stapleton has also uncovered a flame retardant that academic literature has yet to identify. The flame retardant is a chlorinated organophosphate, like TDCPP, and its health effects are unknown, she said. Stapleton said that this recent discovery-by-accident followed the same pattern as her research on Firemaster 550, a popular flame retardant that replaced two widespread PBDEs after they were withdrawn from the market... But emerging research has raised concerns about Firemaster 550, too. One study from Boston University and Duke researchers found that the chemical mixture may cause obesity in humans. Stapleton found the same effect in rats.

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U.S. government agencies (such as FDA) say phthalates are OK, but evidence is mounting that they definitely are not OK. It's impossible to totally avoid phthalates, but one can lower exposure amounts by eating whole unprocessed foods, not microwaving or storing food in plastic containers (best is glass), and read ingredient lists on labels, including personal care products. From Medical Xpress:

Plastics chemical tied to changes in boys' reproductive development

When expectant mothers are exposed to plastics chemicals called phthalates during the first trimester, their male offspring may have a greater risk of infertility later in life, a new study suggests.Boys exposed to the chemical diethylhexyl phthalate (DEHP) may be born with a significantly shorter anogenital distance than those not exposed to these chemicals. Anogenital distance is the distance between the anus and the genitals. A shorter anogenital distance has been linked to infertility and low sperm count, the researchers explained.

"We saw these changes even though moms' exposure to DEHP has dropped 50 percent in the past 10 years," said lead researcher Shanna Swan, a professor of preventive medicine and obstetrics, gynecology and reproductive medicine at the Icahn School of Medicine at Mount Sinai in New York City. "Therefore, we have not found a safe level of phthalate exposure for pregnant women," she contended.

Swan said that this study cannot prove that these boys will have fertility problems as adults or that DEHP causes these problems. However, animal studies have implicated the chemical in male reproductive problems. Based on the data from this study, Swan believes there is a strong association between exposure to DEHP and fertility in human males.

DEHP is used to soften plastics. Most exposure results from eating foods that pick up the chemical during processing, Swan said. "Since food is the largest source of DEHP for consumers, it is difficult for pregnant women to minimize exposure," she said. "Eating unprocessed food will likely help. However, eliminating DEHP from food really has to be done by food producers."The chemical is also found in medical tubing and in a variety of products, including flooring, wallpaper, lacquers and personal care products, Swan said.

For the study, Swan's team collected data on almost 800 pregnant women and their infants.Specifically, the researchers found that exposure in the womb to three types of DEHP was associated with a significantly shorter anogenital distance in boys, but not in girls.

A group representing the chemical industry took issue with the study, however. In a statement, the American Chemistry Council (ACC) stressed that the study only examined one type of phthalate, not all versions of the chemical... The ACC added that DEHP "is known to break down into its metabolites within minutes after it enters the body. 

But another expert says phthalate exposure may not be benign. Dr. Kenneth Spaeth, director of the Occupational and Environmental Medicine Center at North Shore University Hospital in Manhasset, N.Y., said, "virtually everyone in the U.S. experiences continual exposure to phthalates."And, a number of studies have tied the chemicals with changes in developing fetuses. "Phthalates, in particular, have been shown in both human and animal studies to interfere with normal fetal development," he said.

This study supports what has been demonstrated before, that phthalate exposure in the first trimester is linked to male reproductive development, Spaeth said. "This study is an important step forward in establishing this effect because the study included a much larger number of individuals than prior studies and helps identify one particular agent, DEHP, as an important contributor to this effect," he said.Additionally, this study shows the importance of exposure in the first trimester as a critical window for the effect of phthalates on the male reproductive system. 

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Since people have abandoned using iodized salt and started using kosher salt or sea  salts, iodine deficiency has increased (especially during pregnancy when iodine needs are greater). The medical journal The Lancet noted in 2008: "According to World Health Organization, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age. ... Thus iodine deficiency, as the single greatest preventable cause of mental retardation, is an important public-health problem." From Wikipedia : Iodine deficiency is the leading cause of preventable mental retardation, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations. The article states that iodine deficiency typically lowers IQ by 10 to 15 points. So it's a big deal, a really big deal.  But don't overdo the iodine! Excess iodine also has serious problems.From Medscape:

New Recommendations Call for Iodine in All Prenatal Vitamins

Endocrinology groups are applauding a new recommendation from a dietary-supplement trade association that calls for iodine supplementation in all prenatal vitamins prescribed for pregnant and breastfeeding women.

In addition, the public health committee of the American Thyroid Association (ATA) recently published a statement reiterating the ATA recommendation that women take a daily multivitamin containing 150 μg of iodine during prepregnancy, pregnancy, and lactation. The statement also warns of the potential risks of excess iodine consumption and exposure, particularly through the use of unregulated kelp supplements.

The US Council for Responsible Medicine's new guidelines call for all dietary-supplement manufacturers and marketers to begin including at least 150 μg of iodine in all daily multivitamin/mineral supplements intended for pregnant and lactating women in the United States within the next 12 months.

In the past several years, removal of iodized salt from commercial products such as bread and milk, along with increased use of kosher salt and sea salt, which don't contain iodine, and the adoption of vegetarian and vegan diets have led to a reduction in dietary iodine consumption. "There never was a coherent US policy about iodization," Dr Stagnaro-Green noted.

Worldwide, about two billion people are iodine-deficient. While most of the US population has adequate iodine levels, data from the National Health and Nutrition Examination Survey suggest that more than half of pregnant women have urinary iodine concentrations below 150 mg/dL (Thyroid. 2011;21:419-427). 

Pregnant women actually need more iodine than other people because of increased thyroid-hormone production, renal losses, and fetal iodine requirements. Iodine deficiency during pregnancy can result in maternal and fetal goiter, cretinism, intellectual impairment, neonatal hypothyroidism, and increased pregnancy loss and mortality, Dr Stagnaro-Green and colleagues explained in a 2012 editorial (JAMA2012;308:2463-2464).

"So, women of childbearing age are the subpopulation of Americans with the lowest iodine levels yet have the greatest need during pregnancy and breastfeeding, for the neurodevelopment of the fetal and neonatal brain," he told Medscape Medical News. 

In 2009, a study found that only 51% of US prenatal multivitamin brands contained any iodine and, in a number of randomly selected brands, the actual dose of iodine contained in the supplements did not match values on the labeling.

However, the American College of Obstetricians and Gynecologists (ACOG) has not joined in these efforts. While the group does recommend the 150-μg dose for pregnant and lactating women, it does not currently endorse the prenatal-supplement recommendation, advising instead that women get their iodine through dietary sources.

In the ATA's public health committee statement, Angela M Leung, MD, from the University of California Los Angeles David Geffen School of Medicine, and colleagues, including Dr Stagnaro-Green, note that iodine is a micronutrient required for normal thyroid function. The US recommended daily allowances (RDA) for iodine intake are 150 μg in adults, 220 to 250 μg in pregnant women, and 250 to 290 μg in breastfeeding women. Dietary sources such as iodized salt, dairy products, some breads, and seafood usually contain enough to meet the RDA for most people who aren't pregnant or lactating.

However, there is an upper safety limit, with ingestion of more than 1100 μg/day not recommended due to the risk for thyroid dysfunction. In particular, infants, the elderly, pregnant and lactating women, and people with preexisting thyroid disease are at risk for adverse effects of excess iodine on the thyroid.

Many iodine, potassium iodide, and kelp supplements contain hundredfold greater amounts of iodine than the recommended upper limit, Leung and colleagues caution."Given the increasing popularity of iodine and kelp supplements, recommendations cautioning against excess iodine were indicated. The potential result of iodine-induced thyroid dysfunction, which may be particularly harmful during pregnancy and breastfeeding and in the elderly, may not be well-known," she told Medscape Medical News.

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Yes, this finding is important , but what should be also noted is this sentence in the article: "He also noted that it may not be a disease itself, but the treatment for the disease, that's actually responsible for reproductive malfunction." It has been known for decades that men's sperm is affected by environmental chemicals (such as pesticides), alcohol, smoking, and medications. So it's important to figure out if it's the medicine or the health condition that's causing the problem - or perhaps it's both. From Science Daily:

Infertility is a warning: Poor semen quality linked to hypertension, other health problems

A study of men who were evaluated for the cause of their infertility finds previously unknown relationships between deficiencies in their semen and other, seemingly unrelated health problems. A study of more than 9,000 men with fertility problems has revealed a correlation between the number of different defects in a man's semen and the likelihood that the man has other health problems.

The study, conducted by investigators at the Stanford University School of Medicine, also links poor semen quality to a higher chance of having various specific health conditions, such as hypertension, and more generally to skin and endocrine disorders....A study Eisenberg co-authored a few years ago showed that infertile men had higher rates of overall mortality, as well as mortality linked to heart problems, in the years following an infertility evaluation. 

In the new study, Eisenberg and his colleagues analyzed the medical records of 9,387 men, mostly between 30 and 50 years old, who had been evaluated at Stanford Hospital & Clinics (now Stanford Health Care) between 1994 and 2011 to determine the cause of their infertility. ...So, using the database, the investigators were able to compare the overall health status of men who had semen defects to that of the men who didn't.

With a median age of 38, this was a fairly young group of men. However, 44 percent of all the men had some additional health problem besides the fertility problem that brought them to the clinic. In particular, the investigators found a substantial link between poor semen quality and specific diseases of the circulatory system, notably hypertension, vascular disease and heart disease. 

In addition, as the number of different kinds of defects in a man's semen rose, so did his likelihood of having a skin disease or endocrine disorder. When looking at the severity of all health problems, the scientists observed a statistically significant connection between the number of different ways in which a man's semen was deficient and the likelihood of his having a substantial health problem.... He also noted that it may not be a disease itself, but the treatment for the disease, that's actually responsible for reproductive malfunction. He said he is exploring this possibility now.

This article mentions a few of the other issues that are linked with male infertility.While incomplete, at least it mentions smoking, BPA exposure, binge drinking, obesity, and lack of sleep.From Medical Daily:

Your Sperm And Your Health: What Your Semen Can Tell You About Your Health

The following article focused on other links to male infertility. It also discussed an interesting 2012 study that looked at the effects of wearing tight briefs (which heats the genitals) versus boxers on sperm production (hint: briefs had very negative effect). From Five Thirty Eight Science:

Men, Those Tightie Whities Really Are Killing Your Sperm Count

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Another study that shows that differences in the gut microbiota appear early in life, and appear to be based on length of gestation (pregnancy) and type of delivery (vaginal vs C-section). From Science Daily:

Birth method, gestation duration may alter infants' gut microbiota

Environmental factors like mode of delivery and duration of gestation may affect how infants' gut bacteria mature, and that rate could help predict later body fat, international researchers have found.

Among a group of 75 infants, those who were vaginally delivered and had a longer gestation before birth tended to more quickly develop a more mature gut microbiota, and had typical body fat at 18 months. By contract, babies who were delivered via Caesarean section and had shorter gestations took longer to acquire a more mature gut microbiota and had lower body fat at 18 months.

"It seems like the early environment, for instance mode of delivery, mode of feeding, the duration of gestation and living environment may be influencing the rate at which babies acquire their gut microbiota," said senior study author Joanna Holbrook, a senior principal investigator at the Singapore Institute for Clinical Sciences, "and that in turn has an association with how babies grow and put on body fat."

At birth, human infants start accumulating intestinal microbiota until a relatively stable state is reached, Holbrook said. The rate at which babies acquire gut microbiota is believed to have a considerable impact on later health outcomes.

For the study, Holbrook and colleagues used a laboratory technique called 16s rRNA sequencing to analyze stool samples that had been collected from 75 infants participating in the GUSTO (Growing Up in Singapore Toward Healthy Outcomes) study, which includes members of the three main ethnic groups in Singapore: Chinese, Indian and Malay. The samples were taken when the infants were three days old, three weeks old, three months old and six months old. 

Their work found that the samples could be classified into three distinct clusters based on when infants' gut microbiota matured. Of 17 infants who had a more mature, six month-like microbiota profile high in the bacteria Bifidobacterium and Collinsella by day three, 16 were delivered vaginally. Other babies took up to six months to reach that stage.

Most infants acquired a similar microbiota by the age of six months. Infants that acquired a profile high in Bifidobacterium and Collinsella at an earlier age had typical body fat at age 18 months, while those that acquired this profile later had relatively low body fat.