Skip to content

The following article in a popular magazine follows up on research that came out last year about the alarming steep decline in male sperm counts and sperm concentration over the past few decades. This is true for the U.S., Europe, Australia, New Zealand, and it is thought world wide. The article discusses the causes: environmental chemicals and plastics, especially those that are endocrine disruptors (they disrupt a person's hormones!). These chemicals are all around us, and we all have some in our bodies (but the amounts and types vary from person to person). Some examples of such chemicals are parabens, phthalates, BPA and BPA substitutes.

Even though there are effects from these chemicals throughout life, some of the worst effects from these chemicals seem to be during pregnancy - with a big effect on the developing male fetus. Testosterone levels in men are also droppingBottom line: males are becoming "less male", especially due to their exposure to all these chemicals when they are developing before birth (fetal exposure). Since it is getting worse with every generation of males, the concern is that soon males may be unable to father children because their sperm count will be too low - infertility.

Why isn't there more concern over this? What can we do? We all use and need plastic products, but we need to use safer chemicals in products, ones that won't mimic hormones and have endocrine disrupting effects. Remember, these chemicals have more effects on humans than just sperm quality (here and here). While you can't totally avoid plastics and endocrine disrupting chemicals, you can definitely lower your exposure. And it's most important before conception (levels of these chemicals in both parents), during pregnancy, and during childhood.

Do go read the whole article. Excerpts from Daniel Noah Halpern's article in GQ: Sperm Count Zero

A strange thing has happened to men over the past few decades: We’ve become increasingly infertile, so much so that within a generation we may lose the ability to reproduce entirely. What’s causing this mysterious drop in sperm counts—and is there any way to reverse it before it’s too late? 

Last summer a group of researchers from Hebrew University and Mount Sinai medical school published a study showing that sperm counts in the U.S., Europe, Australia, and New Zealand have fallen by more than 50 percent over the past four decades. (They judged data from the rest of the world to be insufficient to draw conclusions from, but there are studies suggesting that the trend could be worldwide.) That is to say: We are producing half the sperm our grandfathers did. We are half as fertile.

The Hebrew University/Mount Sinai paper was a meta-analysis by a team of epidemiologists, clinicians, and researchers that culled data from 185 studies, which examined semen from almost 43,000 men. It showed that the human race is apparently on a trend line toward becoming unable to reproduce itself. Sperm counts went from 99 million sperm per milliliter of semen in 1973 to 47 million per milliliter in 2011, and the decline has been accelerating. Would 40 more years—or fewer—bring us all the way to zero? 

I called Shanna H. Swan, a reproductive epidemiologist at Mount Sinai and one of the lead authors of the study, to ask if there was any good news hiding behind those brutal numbers. Were we really at risk of extinction? She failed to comfort me. “The What Does It Mean question means extrapolating beyond your data,” Swan said, “which is always a tricky thing. But you can ask, ‘What does it take? When is a species in danger? When is a species threatened?’ And we are definitely on that path.” That path, in its darkest reaches, leads to no more naturally conceived babies and potentially to no babies at all—and the final generation of Homo sapiens will roam the earth knowing they will be the last of their kind.

...continue reading "Will All Men Eventually Be Infertile?"

Two recent studies caught my eye – both reviews of scientific research that looked at the issue of diet and whether it contributes to the development of Intestinal Bowel Disease (IBD), specifically Crohn’s disease and ulcerative colitis. These are chronic inflammatory disorders of the gastrointestinal tract, and which are rapidly increasing in developed countries (over 1 million individuals in the US). The main question is: Does a person’s diet contribute to the development of IBD?

Both articles (one in the journal Nature Reviews and one in Immunology) said: YES, there is growing evidence that a person’s diet has a role in the development of IBD. Both articles stated that the current view is that some individuals may be genetically susceptible, and their diet (which feeds the microbes in the gut) then makes them more prone to the disease due to the mucosal lining becoming permeable and inflamed. Studies have shown that people with IBD have gut microbial communities that are imbalanced or out of whack (dysbiosis).

What does this mean? A person’s diet has a key role in what microbes live in the gut (human gut microbiome) – what one eats feeds the microbes in the gut, and a person’s general dietary pattern feeds some types of microbes and not others. So what one eats determines what lives in the gut microbial community. Unfortunately a fiber-deficient diet (typical Western diet) is both linked to increased mucosal inflammation (the mucus layer of the intestines) and it makes it leaky. In other words, a fiber deficient diet impairs the mucus layer of the intestines. Animal studies also support this (that the diet regulates mucosal barrier function).

People in developed countries such as the US typically eat a Western style diet. A Western diet is characterized by high amounts of red meat, processed food, high-fat foods, refined grains, sugary desserts, and low intakes of dietary fiber. However, the Western style diet has been linked to increased mucosal inflammation of the intestines, and to a higher incidence of a number of diseases, including ulcerative colitis and Crohn’s disease.

What diet is best? A diet rich in fruits and vegetables, whole grains, nuts, seeds, legumes (beans), and fish. Low in red meat, but moderate amounts of poultry. High in vitamin D, and high in omega-3 fatty acids. High in dietary potassium and zinc. Eat the foods, not supplements. One good example to follow is the Mediterranean diet. Think of it this way: high fiber diets lower inflammation in the gut, low fiber diets increase inflammation.

Both articles had similar diagrams showing that diet has an effect on the microbes in the gut (the microbiome), which results in either 1) a healthy mucosal lining of the intestines, or 2) a disturbed mucosal lining, disturbed permeability, and inflammation. The one article calls it the “mucinous layer” and the other calls it the gut “barrier” in the diagrams, but both are talking about the mucosal lining of the intestines.

The following image contrasts the effects on the intestines of the two types of diet - the intestines on the left have "homeostasis" (balance) from a healthy dietary pattern (lots of fiber, fruits& vegetables, etc) , and the one on the right has inflammation from a Western dietary pattern.  To see it more clearly, go to the original Figure 1. in the article by L. Celiberto et al: Inflammatory bowel disease and immunonutrition: novel therapeutic approaches through modulation of diet and the gut microbiome

The other review:  The role of diet in the aetiopathogenesis of inflammatory bowel disease

The reality is that we are exposed to thousands of industrial chemicals in our daily lives - in our foods, products, even in dust. Chemicals can get into us through ingestion (food and contaminated water), through inhalation (in dust and contaminated air), and can even be absorbed through the skin. Blood and urine tests can measure the chemicals that we have been exposed to - this is called biomonitoring. Of course, each of us has different levels of these unwanted chemicals - but yes, even those living off the grid and eating all organic foods will have some unwanted chemicals in their bodies. Studies are finding that these chemicals have negative health effects - some effects we know about, but many, many are still unknown.

Of big concern is a pregnant woman's exposure to chemicals because they can have health effects on the developing baby, including life-long effects (e.g. neurological effects, endocrine disrupting effects, immunological effects). Yes, this is scary stuff, especially because we know so little about their effects.

A group of University of California researchers figured out a new way to measure these chemicals in the blood (it's called liquid chromatography-quadrupole time-of-flight mass spectrometry), and looked for the presence of 696 chemicals in a group of 75 pregnant women in California. They found an average of 56 chemicals in each woman (the number of chemicals ranged from 32 to 73 chemicals per woman), and also found a number of chemicals never monitored before. Yikes.

What to do? We can't totally avoid unwanted chemical exposure, but we can lower our exposure to some chemicals. Look at the last post for ideas on how to minimize exposures in our foods. Try to avoid pesticides - both in your home, yard, and in food (eat organic food as much as possible). Avoid fragrances and products containing fragrances. Avoid dryer sheets, air fresheners, and scented candles. Read labels and avoid products with fragrances, parabens, stain protectors, flame retardants, and antibacterials , anti-odor, or anti-mildew products.  Avoid non-stick or Teflon cookware. Avoid BPA and also the replacement chemicals (yes, they're as bad). Don't microwave plastic containers (glass dishes are OK). Glass & stainless steel for foods is fine. Wash hands before eating. Yes, it's a lifestyle change, but one worth doing.

From Medical Xpress: Study finds 56 suspect chemicals in average pregnant woman

Each year, tens of thousands of chemicals are manufactured in or imported into the United States—more than 30,000 pounds of industrial chemicals for every American—yet experts know very little about which chemicals may enter people's bodies, or how these substances affect human health. Now, scientists at UC San Francisco have found a way to screen people's blood for hundreds of chemicals at once, a method that will improve our ability to better assess chemical exposures in pregnant women, and to identify those exposures that may pose a health risk. 

...continue reading "Study Finds An Average of 56 Suspect Chemicals In Pregnant Women"

The American Academy of Pediatrics (representing 67,000 pediatricians) has come out with a statement expressing serious health concerns about the Food and Drug Administration's  (FDA) lax regulation of chemicals added to food and food packaging - such as additives, BPA, colors, flavors, nitrates, nitrites, etc. They also list ways that this problem could be fixed (Congress needs to pass legislation!), and also give some steps on how people can lower their exposure to these chemicals.

A panel of experts representing the group issued both a technical report and a statement which talked about the scientific evidence (which grows yearly) against such compounds such as bisphenol A (BPA), phthalates, perfluoroalkyl chemicals (PFCs) used in grease-proof paper, certain colors (dyes), and preservatives. These chemicals can enter into the body and cause harm or health problems, for example  by disrupting crucial biological processes such as the endocrine (hormone) system and immune system. A number of these chemicals are thought to mimic or suppress natural hormones - they are endocrine disruptors. Children and developing fetuses are especially vulnerable to long-term effects. They also expressed concern with nonpersistent pesticides.

Many of the chemicals currently in the food supply "have not been tested at all, while others have not been tested for endocrine disruption or their impact on brain development, and their effect on children's health is still unknown," said Trasande, the paper's lead author and an associate professor of pediatrics at New York University School of Medicine in New York. This is because the old required tests are too simplistic, too crude, using old out-dated technology and knowledge.

The American Academy of pediatrics points out in the statement that currently: "more than 10 000 chemicals are allowed to be added to food and food contact materials in the United States, either directly or indirectly, under the 1958 Food Additives Amendment to the 1938 Federal Food, Drug, and Cosmetic Act (FFDCA)". Many of these were grandfathered in for use by the federal government before the 1958 amendment, and an estimated 1000 chemicals are used under a “generally recognized as safe” (GRAS) designation process..."  Whew.... so many chemicals...

Is there a problem with GRAS? Of the approximate 1,000 GRAS compounds added to food and food packaging, the large majority were designated as such by either the company that manufactures them or a paid consultant. (Do you see a problem here? The conflicts of interest are huge - the fox is guarding the chickens.)

How can you personally lower your exposure to all these chemicals? 1) Eat as many fresh fruits and vegetables as possible, and avoid eating canned foods (the can lining has BPA or other just as worrisome chemicals - bisphenols), 2) Avoid processed meat, especially during pregnancy (nitrates, nitrites, etc), 3) Avoid microwaving food or liquids in plastic containers (chemicals leach out) - including infant formula and breastmilk, 4) Avoid putting plastics in the dishwasher (chemicals leach out), 5) Use alternatives to plastic such as glass and stainless steel, 6) Avoid plastics with recycling codes 3 (phthalates), 6 (styrene), and 7 (bisphenols) unless plastics are labeled as “biobased” or “greenware,” indicating that they are made from corn and do not contain bisphenols, 7) Wash  hands before eating, and wash fruits and vegetables that cannot be peeled. 8) Also - read the ingredients on all labels, and look for "real" ingredients ...continue reading "Pediatricians Have Health Concerns About All the Additives In Food"

A recent study of pregnant women found new health problems with the pesticide glyphosate, which is the active ingredient in the weedkiller Roundup (made by Monsanto). The researchers found that women  with higher levels of glyphosate are more likely to have shorter pregnancies. Another major finding was that almost all the pregnant women (93%) in this study had detectable levels of glyphosate in their urine. I posted about this study earlier, but now it has been published in the journal Environmental Health.

All the pregnant women were living in central Indiana (in the cornbelt) in a mix of areas (suburban, urban, and rural), and whether they had well or public drinking water. In case you don't know, it is not good for a baby to be born early, and there can be lifelong health consequences - so every extra week (till full term) is good during pregnancy. The researchers found higher levels of glyphosate in women living in rural areas (farm areas) and those drinking greater than 24 ounces a day of caffeinated beverages. The researchers thought that diet (food) and inhalation of contaminated dust were the major ways that the glyphosate got into the pregnant women.

Glyphosate is the most heavily used herbicide (a type of pesticide) in the world. Nearly 300 million pounds were applied in the U.S. in 2015, with much of the application in the Midwest. Scroll down to see a USGS map of glyphosate (Roundup) use in 2015 in the US. You can see that incredibly huge amounts of glyphosate are used in the midwest on farmland - greater than 88.6 pounds per square mile! (it's the dark brown areas on the map). Top crops it's used on are corn, soybeans, and canola, especially genetically modified Roundup Ready crops. It is also used as a dessicant right before harvest ("preharvest") on many crops. This is why crops have glyphosate residues on them, and why so many streams and lakes are contaminated (due to agricultural runoff). About 90% of corn and soybean crops grown in the United States are Roundup Ready, and then these grains are used in most processed foods. Note: glyphosate (Roundup) can not be used on organic crops.

The herbicide has been linked to a number of health problems, including cancer, birth defects, endocrine disruption, and reproductive problems. (Posts on glyphosate.)  There are currently hundreds of lawsuits from farmers and others claiming that Roundup gave them cancer.

...continue reading "Popular Weedkiller Found In Pregnant Women"

As many (most?) people know nowadays - drinking alcohol during pregnancy can have negative effects on the developing baby. Drinking a lot of alcohol can result in fetal alcohol syndrome, but drinking smaller amounts (frequently or binge drinking now and then) can also have negative effects, even though not as severe. The effects from alcohol are called fetal alcohol spectrum disorders - because the effects are along the spectrum from major to minor effects. Currently they're called  fetal alcohol syndrome, partial fetal alcohol syndrome, or alcohol related neurodevelopmental disorder. Effects are generally determined by the child's facial features, physical growth, neurobehavioral development, and prenatal alcohol exposure (esp. by interviewing the mother).

A recent study tried to determine how common are fetal alcohol spectrum disorders in the United States. The researchers screened 6639 first grade children in 4 communities from different areas of the US, and fully evaluated about 3000 children for fetal alcohol spectrum disorders. They found that the disorders ranged from 1.1% to 5% in the communities studied - and they felt that this is a conservative estimate. Interestingly, almost all of these newly diagnosed children had not been diagnosed with fetal alcohol spectrum disorders before the study. So it's easy to miss, and to misdiagnose- thus a "hidden problem".

How to avoid this problem? Don't drink alcohol during pregnancy. But unfortunately many women don't realize that they are pregnant in the first trimester, especially if the pregnancy is unplanned. The Centers for Disease Control (CDC) says on its site (official advice) that women should: "Stop drinking alcohol if they are trying to get pregnant or could get pregnant." What about men who drink alcohol and then conceive a child? There is also some research (mainly animal research) that alcohol can have negative effects on the father's sperm and the resulting fetus. Not fetal alcohol spectrum disorders, but perhaps other health effects which are still being determined.

From  journalist Pam Belluck's article at the NY Times: Far More U.S. Children Than Previously Thought May Have Fetal Alcohol Disorders

More American children than previously thought may be suffering from neurological damage because their mothers drank alcohol during pregnancy, according to a new study. The study, published Tuesday in the journal JAMA, estimates that fetal alcohol syndrome and other alcohol-related disorders among American children are at least as common as autism. The disorders can cause cognitive, behavioral and physical problems that hurt children’s development and learning ability.

The researchers evaluated about 3,000 children in schools in four communities across the United States and interviewed many of their mothers. Based on their findings, they estimated conservatively that fetal alcohol spectrum disorders affect 1.1 to 5 percent of children in the country, up to five times previous estimates. About 1.5 percent of children are currently diagnosed with autism.

The range of fetal alcohol spectrum disorders (also called FASDs) can cause cognitive, behavioral and physical difficulties. The most severe is fetal alcohol syndrome, in which children have smaller-than-typical heads and bodies, as well as eyes unusually short in width, thin upper lips, and smoother-than-usual skin between the nose and mouth, Dr. Chambers said. A moderate form is partial fetal alcohol syndrome. Less severe is alcohol-related neurodevelopmental disorder, in which children have neurological but not physical characteristics and it is known that their mothers drank during pregnancy.

Then there is the stigma that often makes mothers reluctant to acknowledge alcohol consumption. “When you identify a kid with FASD, you’ve just identified a mom who drank during pregnancy and harmed her child,” said Susan Astley, director of the Fetal Alcohol Syndrome Diagnostic and Prevention Network at the University of Washington, who was not involved in the study. While Dr. Astley, a longtime expert in the field, said she admired the researchers’ hard work, she said the reliability of the study’s numbers was hampered by several factors. For example, only 60 percent of eligible families in the schools allowed their children to be evaluated and more than a third of those children’s mothers declined to answer questions about drinking during pregnancy.

The authors of the study, which was funded by the National Institute on Alcohol Abuse and Alcoholism, acknowledged the study’s limitations and tried to partly compensate by providing a conservative estimate (of 1.1 percent to 5 percent) that is likely low and another estimate (of 3.1 percent to 9.9 percent) that is likely high. Dr. Chambers also said the results might not generalize across the country because although the four communities were diverse, they did not include a large, high-poverty urban area or certain rural or indigenous communities that struggle with high rates of alcoholism. The locations, which are not named in the publication, include small-to-midsize cities in the Midwest and Rocky Mountains, a Southeast county and a Pacific Coast city the authors identified in interviews as San Diego. [Original study.]

Vitamin D supplements are incredibly popular, but whether vitamin D supplements should be taken during pregnancy and at what dose is still debated, and studies have had conflicting results. Now a review by Canadian researchers of 43 studies of vitamin D supplementation during pregnancy found that there is "insufficient evidence to guide recommendations during pregnancy". They said that overall the studies were small or of low quality -  and the "available data did not provide evidence of benefit" from vitamin D supplementation during pregnancy.

They found that vitamin D supplementation slightly increased the mean (average) birth weight by 2 ounces (58.33 g), reduced the risk of small for gestational age births, and reduced the risk of the child wheezing at age 3. There was no effect on preterm birth, and there was a lack of evidence of benefits of prenatal vitamin D supplementation for maternal health conditions (e.g. gestational diabetes) during pregnancy.

Currently recommendations regarding vitamin D supplementation vary widely among medical and professional organizations, and WHO (World Health Organization) currently recommends against routine prenatal vitamin D supplementation. Luckily there are a number of studies going on right now on this issue that may help answer this question - how much vitamin D, if any, should be taken during pregnancy? From Medical Xpress:

Insufficient evidence to guide recommendations on vitamin D in pregnancy

There is currently insufficient evidence to guide recommendations on the use of vitamin D supplements in pregnancy, conclude researchers in The BMJ today. A team led by Dr Daniel Roth at The Hospital for Sick Children in Toronto, say some of the most critical questions about the effectiveness of taking vitamin D supplements during pregnancy "will probably remain unanswered in the foreseeable future."

Vitamin D helps maintain calcium levels in the body to keep bones, teeth and muscles healthy. Numerous studies suggest that taking vitamin D supplements may also help protect against heart disease, cancer, respiratory infections and asthma - as well as conditions related to pregnancy, such as preeclampsia and gestational diabetes. But results are conflicting and recommendations vary widely among medical and professional organisations.

So Dr Roth and his team set out to assess the current and future state of the evidence on vitamin D supplements during pregnancy. They analysed results from 43 randomised controlled trials involving 8,406 women, to estimate the effects of taking vitamin D supplements during pregnancy on 11 maternal and 27 child outcomes.... The results show that taking supplements during pregnancy increased vitamin D levels in both the mother's bloodstream and umbilical cord blood, but the researchers did not consistently find that higher doses of vitamin D led to healthier women and babies.

Overall, vitamin D increased average birth weight by 58 g and reduced the risk of having a small baby, but more detailed analyses weakened the authors' confidence in these findings. There was a lack of evidence of benefits of vitamin D supplements for maternal health conditions related to pregnancy, no effect on other birth outcomes of public health importance, such as premature birth, and scant evidence on safety outcomes.  [Original study.]

A while ago I posted the results of studies showing differences in infant  microbiomes (community of microbes) depending on whether the babies were delivered vaginally or by C-section, and also that "vaginal seeding" may eliminate some of these differences. [C-section babies also have a higher incidence of some health issues, such as allergies, asthma, etc.] Well....that research generated a lot of controversy both for and against, and resulted in many women requesting that "vaginal seeding" be done to their babies after they were delivered by C-section. Even the noted microbiome researcher Rob Knight publicly admitted that the procedure was done to his baby after his partner received a C-section.

Vaginal seeding is the process of swabbing the bodies of C-section babies (including the mouth and nose) with a gauze pad containing the vaginal fluids from their mothers in the minutes after birth - so that the baby is exposed to the same maternal microbes as a baby born vaginally (because mothers transmit microbes to the baby as it moves through the birth canal). Initial research showed this made the microbiomes of the C-section babies look a lot like vaginally born babies, especially their skin and oral microbiomes, but whether these differences persist after a few months is unclear.

Now the American College of Obstetrics and Gynecology (ACOG) has come out with a position paper that vaginal seeding should not be done to babies, except as part of an official clinical trial. Their main opposition to the procedure is fear of transmitting pathogenic bacteria or viruses (e.g. group B streptococci, and STDs). The main reasons in support of doing the  vaginal seeding procedure is the body of research finding differences among C-section and vaginally delivered babies (allergies, asthma, etc.), and the concern that at least some of this may be due to lack of  exposure to maternal vaginal microbes during delivery. Instead, ACOG suggests breastfeeding the baby to transmit maternal microbes to the baby to "seed the gut". And if "a patient insists on performing the procedure herself, ACOG recommends ob-gyns have a documented discussion of the potential risks".

As can be expected, there is an outcry and rejection by some (many?) of the ACOG position paper. At least the ACOG paper acknowledges that every woman can make her own decision regarding this issue, even though they may not support it. And absolutely everyone agrees that more research is needed. From Ars Technica:

Doctors warn new parents: Step away from the vaginal fluid swabs

To slather, or not to slather—that is the question that has been roiling doctors, scientists, and new parents recently. And a new ruling by a doctor’s group stands to muck up the debate further. Amid the birth of microbiome research, some scientists have advocated for smearing bacteria-laden vaginal secretions on any newborns who missed out—namely those born via Caesarian section. Scientists keenly hypothesize that such a gooey glaze can “seed” a more-or-less sterile infant with life-long microbial companions. These wee chums may help train an infant's immune system and dodge issues like allergies and asthma later in life. Several studies have indeed found correlations between C-section deliveries and higher risks of those conditions.

In the latest turn to the controversy, the American College of Obstetricians and Gynecologists’ (ACOG) Committee on Obstetric Practice issued a November opinion firmly wiping up the slimy idea. In its opinion, the committee said it: “…does not recommend or encourage vaginal seeding outside of the context of an institutional review board-approved research protocol, and it is recommended that vaginal seeding otherwise not be performed until adequate data regarding the safety and benefit of the process become available.”

The few studies we do have on infant microbiomes provide no clear answers on the significance of an early “seeding” for health. A 2016 review looking at the patterns of microbial communities in the guts of infants in their first year found that C-section babies did show differences in the first three months. However, those differences disappeared by six months. Similarly, a small study of 18 babies also published last year found that vaginal seeding could eliminate microbial differences between vaginally and C-section delivered babies. But the study only looked at the infants' microbiomes in that first month, and the health effects—if any—are unknown.

The most concerning thing about vaginal seeding, the committee argues, is the potential for transmitting pathogens, such as herpes simplex virus, human papilloma virus (HPV), group B streptococci, and Neisseria gonorrhea. .... If a woman insists on the seeding, the committee recommended she be thoroughly tested and informed of the risks—as well as discouraged.

Once again a study finds that pesticide exposure is linked to an adverse health effect - that pesticide exposure in the home during pregnancy and early childhood is linked to an elevated risk of brain tumor in the child. Other studies have also found that pesticides used in the home are associated with a higher risk of childhood cancers.

This is because pesticides do cross the placental barrier, as the study researchers point out: "There is evidence that pesticides cross the fetal-placental barrier since residues of some insecticides have been found in umbilical cord blood, neonatal hair, and meconium following maternal exposure during pregnancy." Also, the International Agency for Research on Cancer (IARC) has classified "more than twenty pesticide chemical compounds as potential human carcinogens".

The following are examples (but there are more) of other studies finding pesticide and childhood cancer links: A meta-analysis published in 2015 in Pediatrics by researchers at Harvard University found that children exposed to indoor insecticides (also herbicides) have a higher risk of certain childhood cancers, specifically leukemia, lymphomas, and brain tumors. A 2013 study published in Cancer Causes and Control found that professional pest control applications in the home within a year of conception and during pregnancy was associated with a higher risk of childhood brain tumors. A review of studies published in 2010 found that pesticide exposure during pregnancy and childhood increased the risk of childhood leukemia.

The good news is that there are alternatives to exposing fetuses and children to toxic pesticides at home - by using alternative ways of dealing with pests, such as least toxic Integrated Pest Management (IPM) or organic methods. That means doing other things (such as sealing or caulking holes, putting out traps and baits, vacuuming), a focus on least toxic methods and on prevention (here and here), rather than routinely applying toxic pesticides. If needed, least toxic pesticides include boric acid and vinegar. Other sources of pesticide exposure for pregnant women and children are foods and exposure in settings outside the home - perhaps even a friend's yard. By the way, pesticide exposure for everyone is linked to a higher risk of health problems, not just pregnant women and children.

From Science Daily: Pesticide use during pregnancy linked to increased risk of childhood brain tumors

Previous epidemiological studies have suggested that exposure to pesticides during pregnancy may have a possible role in the development of childhood brain tumors. In a new International Journal of Cancer analysis, researchers found a link between maternal residential pesticide use -- particularly insecticides -- and the risk of childhood brain tumorsThe analysis included 437 malignant childhood brain tumor cases and 3102 controls from two French studies. Pesticide use was associated with a 1.4-times increased risk of childhood brain tumors.

The investigators noted that many pesticide compounds are classified as probable carcinogens, and there is evidence that some insecticides can pass through the feto-placental barrier. "Although such retrospective studies cannot identify specific chemicals used or quantify the exposure, our findings add another reason to advise mothers to limit their exposure to pesticides around the time of pregnancy," said Nicolas Vidart d'Egurbide Bagazgoïtia, lead author of the study. [Original study.]

Another problem for overweight or obese men: an increased risk of poor sperm quality. Researchers in India found that compared to normal weight men, obesity was associated with lower sperm count, lower volume of semen, lower sperm concentration, poor sperm motility (the movement of sperm), as well as sperm defects. There is some evidence (from other studies and the researchers own work) that there is improvement in sperm quality with weight loss.

The researchers pointed out that other studies have shown that "paternal obesity at conception had deleterious effects on embryo health, implantation, pregnancy, and live birth rates." And that poor sperm quality is a cause of infertility. So.... what do the researchers recommend? Weight loss and exercise, and perhaps bariatric surgery, for obese men having fertility problems due to poor sperm quality. From Medical Xpress: 

As men's weight rises, sperm health may fall

A widening waistline may make for shrinking numbers of sperm, new research suggests. Indian scientists studied more than 1,200 men and found that too much extra weight was linked to a lower volume of semen, a lower sperm count and lower sperm concentration. In addition, sperm motility (the ability to move quickly through the female reproductive tract) was poor. The sperm had other defects as well, the researchers added. Poor sperm quality can lower fertility and the chances of conception.

"It's known that obese women take longer to conceive," said lead researcher Dr. Gottumukkala Achyuta Rama Raju, from the Center for Assisted Reproduction at the Krishna IVF Clinic, in Visakhapatnam. "This study proves that obese men are also a cause for delay in conception," he added.

But in continuing research, the study team is looking to see if losing weight will improve the quality of sperm. Although that study is still in progress, early signs look good that sperm quality improves as men lose weight, Rama Raju said. Recent reports have found that extreme weight loss after bariatric surgery reversed some of the sperm decline, he said.

For the study, Rama Raju and his colleagues used computer-aided sperm analysis to assess the sperm of 1,285 men. Obese men, they found, had fewer sperm, a lower concentration of sperm and inability of the sperm to move at a normal speed, compared with the sperm of men of normal weight. Moreover, the sperm of obese men had more defects than other sperm. These defects included defects in the head of the sperm, such as thin heads and pear-shaped heads.  [Original study.]

 Human sperm. Credit: Wikipedia