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Exciting research! From Science Daily:

Home is where the microbes are

A person's home is their castle, and they populate it with their own subjects: millions and millions of bacteria. Scientists have detailed the microbes that live in houses and apartments. The study was conducted by researchers from the U.S. Department of Energy's Argonne National Laboratory and the University of Chicago. 

The results shed light on the complicated interaction between humans and the microbes that live on and around us. Mounting evidence suggests that these microscopic, teeming communities play a role in human health and disease treatment and transmission.

"We know that certain bacteria can make it easier for mice to put on weight, for example, and that others influence brain development in young mice," said Argonne microbiologist Jack Gilbert, who led the study. "We want to know where these bacteria come from, and as people spend more and more time indoors, we wanted to map out the microbes that live in our homes and the likelihood that they will settle on us.

The Home Microbiome Project followed seven families, which included eighteen people, three dogs and one cat, over the course of six weeks. The participants in the study swabbed their hands, feet and noses daily to collect a sample of the microbial populations living in and on them. They also sampled surfaces in the house, including doorknobs, light switches, floors and countertops. Then the samples came to Argonne, where researchers performed DNA analysis to characterize the different species of microbes in each sample.

They found that people substantially affected the microbial communities in a house -- when three of the families moved, it took less than a day for the new house to look just like the old one, microbially speaking.

Regular physical contact between individuals also mattered -- in one home where two of the three occupants were in a relationship with one another, the couple shared many more microbes. Married couples and their young children also shared most of their microbial community.

Within a household, hands were the most likely to have similar microbes, while noses showed more individual variation. Adding pets changed the makeup as well, Gilbert said -- they found more plant and soil bacteria in houses with indoor-outdoor dogs or cats.

In at least one case, the researchers tracked a potentially pathogenic strain of bacteria called Enterobacter, which first appeared on one person's hands, then the kitchen counter, and then another person's hands. "It's also quite possible that we are routinely exposed to harmful bacteria -- living on us and in our environment -- but it only causes disease when our immune systems are otherwise disrupted."

Home microbiome studies also could potentially serve as a forensic tool, Gilbert said. Given an unidentified sample from a floor in this study, he said, "we could easily predict which family it came from."

The research also suggests that when a person (and their microbes) leaves a house, the microbial community shifts noticeably in a matter of days."You could theoretically predict whether a person has lived in this location, and how recently, with very good accuracy," he said.

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An interesting article that discusses research that finds advantages to being dyslexic. Perhaps think in terms of cognitive diversity. From Scientific American:

The Advantages of Dyslexia

With reading difficulties can come other cognitive strengths.

In our laboratory at the Harvard-Smithsonian Center for Astrophysics we have carried out studies funded by the National Science Foundation to investigate talents for science among those with dyslexia. The dyslexic scientist Christopher Tonkin described to me his sense of this as a sensitivity to “things out of place.”  He’s easily bothered by the weeds among the flowers in his garden, and he felt that this sensitivity for visual anomalies was something he built on in his career as a professional scientist.  Such differences in sensitivity for causal perception may explain why people like Carole Greider and Baruj Benacerraf have been able to perform Nobel prize-winning science despite lifelong challenges with dyslexia.

Why are there advantages in dyslexia?  Is it something about the brains of people with dyslexia that predisposes them to causal thinking? Or, is it a form of compensation, differences in the brain that occur because people with dyslexia read less? Unfortunately, the answer to these questions is unknown.

One thing we do know for sure is that reading changes the structure of the brain. An avid reader might read for an hour or more a day, day in and day out for years on end. This highly specialized repetitive training, requiring an unnaturally precise, split-second control over eye movements, can quickly restructure the visual system so as to make some pathways more efficient than the others.

My colleagues and I suggested that one reason people with dyslexia may exhibit visual talents is that they have difficulty managing visual attention⁠. It may at first seem ironic that a difficulty can lead to an advantage, but it makes sense when you realize that what we call “advantages” and “disadvantages” have meaning only in the context of the task that needs to be performed.

For example, imagine you’re looking to hire a talented security guard. This person’s job will be to spot things that look odd and out of place, and call the police when something suspicious —say, an unexpected footprint in a flowerbed— is spotted. If this is the person’s task, would you rather hire a person who is an excellent reader, who has the ability to focus deeply and get lost in the text, or would you rather hire a person who is sensitive to changes in their visual environment, who is less apt to focus and block out the world?

Tasks such as reading require an ability to focus your attention on the words as your eyes scan a sentence, to quickly and accurately shift your attention in sequence from one word to the next.  But, to be a good security guard you need an opposite skill; you need to be able to be alert to everything all at once, and though this isn’t helpful for reading, this can lead to talents in other areas.

A series of studies by an Italian team led by Andrea Facoetti have shown that children with dyslexia often exhibit impairments in visual attention. In one study,Facoetti’s team measured visual attention in 82 preschool children who had not yet been taught to read. The researchers then waited a few years until these children finished second grade, and then examined how well each child had learned reading. They found that those who had difficulty focusing their visual attention in preschool had more difficulty learning to read.

These studies raise the possibility that visual attention deficits, present from a very early age, are responsible for the reading challenges that are characteristic of dyslexia. If this theory is upheld, it would also suggest that the observed advantages are not an incidental byproduct of experience with reading, but are instead the result of differences in the brain that were likely present from birth.

If this is indeed the case, given that attention affects perception in very general ways, any number of advantages should emerge.  While people with dyslexia may tend to miss details in their environment that require an attentional focus, they would be expected to be better at noticing things that are distributed more broadly.  To put this another way, while typical readers may tend to miss the forest because its view is blocked by all the trees, people with dyslexia may see things more holistically, and miss the trees, but see the forest.

Among other advantages observed, Gadi Geiger and his colleagues at MIT found that people with dyslexia can distribute their attention far more broadly than do typical readers, successfully identifying letters flashed simultaneously in the center and the periphery for spacings that were much further apart. They also showed that such advantages are not just for things that are visual, but that they apply to sounds as well. In one study, simulating the sounds of a cocktail party, they found that people with dyslexia were able to pick out more words spoken by voices widely-distributed in the room, compared with people who were proficient readers.

Whether or not observations of such advantages —measured in the laboratory— have applications to talents in real life remains an open question. But, whatever the reason, a clear trend is beginning to emerge: People with dyslexia may exhibit strengths for seeing the big picture (both literally and figuratively) others tend to miss.  Thomas G. West has long-argued that out-of-the-box thinking is historically part and parcel of dyslexia, and more recently physicians Brock and Fernette Eide have advanced similar arguments. Sociologists, such as Julie Logan of the Cass Business School in London agree.  Logan found that dyslexia is relatively common among business entrepreneurs; people who tend to think differently and see the big picture in thinking creatively about a business.

Whatever the mechanism, one thing is clear: dyslexia is associated with differences in visual abilities, and these differences can be an advantage in many circumstances, such as those that occur in science, technology, engineering and mathematics. It’s only when everything is all the same that nothing productive can get done. Neurological differences similarly drive the engine of society, to create the contrasts between hot and cold that lead to productive work. Impairments in one area can lead to advantages in others, and it is these differences that drive progress in many fields, including science and math.

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Eating more tomatoes is doable, tastes delicious, and reduces prostate cancer risk! From Science Daily:

Fighting prostate cancer with tomato-rich diet

Men who eat over 10 portions a week of tomatoes have an 18 percent lower risk of developing prostate cancer, new research suggests. With 35,000 new cases every year in the UK, and around 10,000 deaths, prostate cancer is the second most common cancer in men worldwide. Rates are higher in developed countries, which some experts believe is linked to a Westernised diet and lifestyle.

To assess if following dietary and lifestyle recommendations reduces risk of prostate cancer, researchers at the Universities of Bristol, Cambridge and Oxford looked at the diets and lifestyle of 1,806 men aged between 50 and 69 with prostate cancer and compared with 12,005 cancer-free men.

The NIHR-funded study, published in the medical journal Cancer Epidemiology, Biomarkers and Prevention, is the first study of its kind to develop a prostate cancer 'dietary index' which consists of dietary components -- selenium, calcium and foods rich in lycopene -- that have been linked to prostate cancer. Men who had optimal intake of these three dietary components had a lower risk of prostate cancer.

Tomatoes and its products -- such as tomato juice and baked beans -- were shown to be most beneficial, with an 18 per cent reduction in risk found in men eating over 10 portions a week. This is thought to be due to lycopene, an antioxidant which fights off toxins that can cause DNA and cell damage. 

The researchers also looked at the recommendations on physical activity, diet and body weight for cancer prevention published by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR). Only the recommendation on plant foods -- high intake of fruits, vegetables and dietary fibre -- was found to be associated with a reduced risk of prostate cancer. 

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If taking Clostridia as a probiotic for food allergies works, it would be amazing for food allergy sufferers. Very exciting research. From Time:

The Bacteria That May One Day Cure Food Allergies

Every round of antibiotics a person takes will wipe out strains of bacteria inside the body, some of which are eliminated forever. Considering how early and how often antibiotics are administered to kids—coupled with our increasingly antimicrobial lifestyles—we’ve become more prone to allergies and other ailments, the hygiene hypothesis goes. There’s no cure for food allergies, just lifestyle adjustments and abstention. But Nagler and her team may have the germ of an idea for treatment using gut bacteria, according to a new mice study published in the Proceedings of the National Academy of Sciences.

The team dosed two groups of mice with peanut allergens. One group of mice had been bred to be entirely without gut germs; the other group had sparsely populated gut bacteria due to treatment with antibiotics. Both groups of mice had higher levels of the allergen in their bloodstream compared to mice with healthy gut-bacteria populations.

After giving those same mice a mix that contained the bacteria strain Clostridia, their allergen levels plummeted. Infusing the mice with another group of intestinal bacteria, Bacteroides, didn’t help—so the researchers think the effect is special to Clostridia. “These bacteria are very abundant and they reside very close to the epithelial lining, so they’re in intimate contact with the immune system,” Nagler says.

Next, they’ll transfer gut bacteria from food-allergic infants and healthy infants into germ-free mice, Nagler says. “If we give back Clostridia to a mouse that has the bacteria of an allergic child, can we now reverse susceptibility in that mouse?”

This is a more in-depth article of the research. From Science Daily:

Gut bacteria that protect against food allergies identified

The presence of Clostridia, a common class of gut bacteria, protects against food allergies, a new study in mice finds. The discovery points toward probiotic therapies for this so-far untreatable condition. Food allergies affect 15 million Americans, including one in 13 children, who live with this potentially life-threatening disease that currently has no cure, researchers note.

Although the causes of food allergy -- a sometimes deadly immune response to certain foods -- are unknown, studies have hinted that modern hygienic or dietary practices may play a role by disturbing the body's natural bacterial composition. In recent years, food allergy rates among children have risen sharply -- increasing approximately 50 percent between 1997 and 2011 -- and studies have shown a correlation to antibiotic and antimicrobial use.

"Environmental stimuli such as antibiotic overuse, high fat diets, caesarean birth, removal of common pathogens and even formula feeding have affected the microbiota with which we've co-evolved," said study senior author Cathryn Nagler, PhD, Bunning Food Allergy Professor at the University of Chicago. "Our results suggest this could contribute to the increasing susceptibility to food allergies."

To test how gut bacteria affect food allergies, Nagler and her team investigated the response to food allergens in mice. ...This sensitization to food allergens could be reversed, however, by reintroducing a mix of Clostridia bacteria back into the mice. Reintroduction of another major group of intestinal bacteria, Bacteroides, failed to alleviate sensitization, indicating that Clostridia have a unique, protective role against food allergens.

To identify this protective mechanism, Nagler and her team studied cellular and molecular immune responses to bacteria in the gut. Genetic analysis revealed that Clostridia caused innate immune cells to produce high levels of interleukin-22 (IL-22), a signaling molecule known to decrease the permeability of the intestinal lining.

While complex and largely undetermined factors such as genetics greatly affect whether individuals develop food allergies and how they manifest, the identification of a bacteria-induced barrier-protective response represents a new paradigm for preventing sensitization to food. Clostridia bacteria are common in humans and represent a clear target for potential therapeutics that prevent or treat food allergies. 

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Interesting study that definitely needs follow-up to see if it also applies to women. Nice news for coffee drinkers - that coffee consumption may have protective effects against gum disease. From Medical Xpress:

Coffee drinkers—your gums may thank you

Coffee contains antioxidants. Antioxidants fight gum disease. Does coffee, then, help fight gum disease?  Lead author and 2014 DMD graduate Nathan Ng said, "We found that coffee consumption did not have an adverse effect on periodontal health, and, instead, may have protective effects against periodontal disease."

Coffee consumption was associated with a small but statistically significant reduction in number of teeth with periodontal bone loss. Researchers concluded that coffee consumption may be protective against periodontal bone loss in adult males—the group examined in the study.

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Several more articles on the benefits of exercise. From Science Daily:

Train your heart to protect your mind

Exercising to improve our cardiovascular strength may protect us from cognitive impairment as we age, according to a new study. "Our body's arteries stiffen with age, and the vessel hardening is believed to begin in the aorta, the main vessel coming out of the heart, before reaching the brain. Indeed, the hardening may contribute to cognitive changes that occur during a similar time frame," explained the first author of the study. "We found that older adults whose aortas were in a better condition and who had greater aerobic fitness performed better on a cognitive test. We therefore think that the preservation of vessel elasticity may be one of the mechanisms that enables exercise to slow cognitive aging."

The researchers worked with 31 young people between the ages of 18 and 30 and 54 older participants aged between 55 and 75. This enabled the team to compare the older participants within their peer group and against the younger group who obviously have not begun the aging processes in question. None of the participants had physical or mental health issues that might influence the study outcome.

The results demonstrated age-related declines in executive function, aortic elasticity and cardiorespiratory fitness, a link between vascular health and brain function, and a positive association between aerobic fitness and brain function. "Although the impact of fitness on cerebral vasculature may however involve other, more complex mechanisms, overall these results support the hypothesis that lifestyle helps maintain the elasticity of arteries, thereby preventing downstream cerebrovascular damage and resulting in preserved cognitive abilities in later life."

From Science Daily:

Physically fit kids have beefier brain white matter than their less-fit peers

A new study of 9- and 10-year-olds finds that those who are more aerobically fit have more fibrous and compact white-matter tracts in the brain than their peers who are less fit. 'White matter' describes the bundles of axons that carry nerve signals from one brain region to another. More compact white matter is associated with faster and more efficient nerve activity.

The analysis revealed significant fitness-related differences in the integrity of several white-matter tracts in the brain: the corpus callosum, which connects the brain's left and right hemispheres; the superior longitudinal fasciculus, a pair of structures that connect the frontal and parietal lobes; and the superior corona radiata, which connect the cerebral cortex to the brain stem."All of these tracts have been found to play a role in attention and memory," Chaddock-Heyman said. 

From Science Daily:

Exercise may protect older women from irregular heartbeat

Increasing the amount or intensity of physical activity can cut the chances of older women developing a life-threatening irregular heartbeat, according to new research. Researchers found that post-menopausal women who were the most physically active had a 10 percent lower risk of developing atrial fibrillation (AF), compared to women with low levels of physical activity, even if they were obese. Obesity is an important risk factor for atrial fibrillation.

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Reading this article, I kept thinking of vampires and Transylvania. But the million dollar question is - will it work? From New Scientist:

Young blood to be used in ultimate rejuvenation trial

 In October, people with Alzheimer's disease will be injected with the blood of young people in the hope that it will reverse some of the damage caused by the condition.

The scientists behind the experiment have evidence on their side. Work in animals has shown that a transfusion of young mouse blood can improve cognition and the health of several organs in older mice. It could even make those animals look younger. The ramifications for the cosmetics and pharmaceutical industries could be huge if the same thing happens in people.

Disregarding vampire legends, the idea of refreshing old blood with new harks back to the 1950s, when Clive McCay of Cornell University in Ithaca, New York, stitched together the circulatory systems of an old and young mouse – a technique called heterochronic parabiosis. He found that the cartilage of the old mice soon appeared younger than would be expected.

It wasn't until recently, however, that the mechanisms behind this experiment were more clearly understood. In 2005, Thomas Rando at Stanford University in California and his team found that young blood returned the liver and skeletal stem cells of old mice to a more youthful state during heterochronic parabiosis. The old mice were also able to repair injured muscles as well as young mice (Nature, doi.org/d4fkt5). Spooky things seemed to happen in the opposite direction, too: young mice that received old blood appeared to age prematurely. In some cases, injured muscles did not heal as fast as would be expected.

Several other experiments have shown similar effects. In 2012, Amy Wagers at Harvard University showed that young blood can reverse heart decline in old mice.

Once the researchers had ruled out the effect of reduced blood pressure on the older mice, they identified a protein in the blood plasma called growth differentiation factor 11 (GDF11) that appeared to fall with age. To see if it was linked to the rejuvenating effects, the team gave old mice with enlarged hearts daily injections of GDF11 for 30 days. Their hearts decreased in size almost as much as they had in the parabiosis experiments (Cell, doi.org/q2f).

In both mice and humans, GDF11 falls with age. We don't know why it declines, but we know it is involved in several mechanisms that control growth. It is also thought to mediate some age-related effects on the brain, in part by activation of another protein that is involved in neuronal growth and long-term memory.

So the billion-dollar question is: would a GDF11 boost have the same effect in humans? Wyss-Coray thinks it will, having taken the next step of injecting young human blood plasma into old mice. His preliminary results suggest that human blood has similar rejuvenating benefits for old mice as young mouse blood does.

"We saw these astounding effects," he says. "The human blood had beneficial effects on every organ we've studied so far."

Now, the final step – giving young human blood plasma to older people with a medical condition – is about to begin. Getting approval to perform the experiment in humans has been relatively simple, says Wyss-Coray, thanks to the long safety record of blood transfusions. So in early October, a team at Stanford School of Medicine will give a transfusion of blood plasma donated by people under 30 to older volunteers with mild to moderate Alzheimer's.

Following the impressive results in animal experiments, the team hopes to see immediate improvements in cognition, but Wyss-Coray cautions that it is still very experimental. All researchers involved in the work agree that GDF11 is unlikely to be the only factor that keeps organs youthful. "It's too optimistic to think there would be just one factor," says Francesco Loffredo, who studies the effects of young blood in old animals at Harvard University. "It's much more likely to be several factors that exert these effects in combination."

Alessandro Laviano at the Sapienza University of Rome in Italy says that the research on diseases of ageing certainly holds promise, but he is more interested in the potential use of young blood in chronic disease. ...Before moving to clinical trials in people with cancer we need to learn more about the dynamics of the beneficial factors in blood, says Laviano, such as when they are at their peak. Do we reach a peak at 5 or 35 years? "We just don't know," he says.

An earlier related exciting study (from May 2014) in which it was found that "the blood of young mice has the ability to restore mental capabilities in old mice". From Science Daily:

Infusion of young blood recharges brains of old mice

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An interesting small study of the human armpit bacterial community. From Real Clear Science:

Antiperspirants Alter Your Armpit Bacteria and Could Actually Make You Smell Worse

In modern society, antiperspirants are widely hailed as a godsend, dispelling the inconvenient odors wafting from armpits everywhere. But a new study casts doubts on their vaunted position. As it turns out, antiperspirants may actually make you smell worse in the long run.

For 90% of all Americans, slathering on deodorants and antiperspirants is a daily occurrence, a precautionary measure against foul odors and unsightly sweat stains. The odors arise when bacteria living in our armpits break down lipids and amino acids excreted in sweat into more smelly substances. Deodorants employ antimicrobial agents that kill off bacteria, as well as chemicals that replace noxious odors with pleasant aromas. Deodorants that double as antiperspirants, like Degree, Old Spice, and Dove, take the process one step further by physically plugging sweat glands with aluminum-based compounds.

While most of us might only concern ourselves with the dry, aromatic benefits of antiperspirants and deodorants, researchers at the Laboratory of Microbial Ecology and Technology at the University of Ghent in Belgium are more interested in the effects on bacteria. Billions of bacteria dwell in the "rain forests" under our arms, and the substances we don are mucking with their habitats!

To uncover how deodorants and antiperspirants affect armpit bacteria, Chris Callewaert, a Ph.D student specializing in microbial ecology, and a team of researchers recruited eight subjects for a task a great many people (and especially their friends) might deem unbearable: Six males and two females pledged not to use deodorant or antiperspirant for an entire month. Specifically, four subjects stopped using their deodorants and another four stopped using their antiperspirant deodorant. (Most antiperspirants are also deodorants. See image below for an example.) Another control subject who did not regularly use either was asked to use deodorant for a month. The duration was chosen because it takes approximately 28 days for a new layer of skin cells to form.

The researchers analyzed the diversity and abundance of subjects' armpit bacteria at various timepoints before they stopped using antiperspirant, during the period of abstaining from antiperspirant, and for a few weeks after resuming the use of antiperspirant. Switching hygiene habits plainly altered the armpit bacterial communities of every subject. Since no two armpits and their resident bacteria are identical, it was difficult to pinpoint precise changes brought about by deodorants or antiperspirants, but one clear trend did materialize: antiperspirants resulted in a clear increase of Actinobacteria.

You might not recognize the name of Actinobacteria, but chances are, you've smelled them. Dominated by Corynebacterium, they are the major instigators of noxious armpit odor. Other microbes that inhabit the armpit, like Firmicutes and Staphylococcus, don't produce odors as quickly, nor are those odors nearly as pungent.

Callewaert believes the aluminum compounds in antiperspirants may be to blame, killing off "good," less smelly bacteria and allowing "bad" bacteria to dominate. His study found that deodorants which lack these sweat-blocking antiperspirant compounds are actually linked to a slight decrease of stinky Actinobacteria.

Though antiperspirants and deodorants are widely used, they are only a temporary fix."The measures we utilize today do not take away the initial source: the odor causing bacteria," Callewaert told RealClearScience. "Deodorants only mask unpleasant odors. We can do better than that. The follow up of this research is finding better solutions."

And Callewaert is already working on one: "armpit bacterial transplantation"."We take away the bad bacteria from the armpit of somebody with a body odor, and replace it with the good bacteria of a relative who doesn't have a body odor," he explained."So far we have helped over 15 people. For most subjects it brings immediate improvements. Most of them on a permanent time scale, although there are also people who suffer again from a body odor after some months."

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The bottom line is to read the ingredients list on products, and avoid all products labeled "antimicrobial" or "antibacterial" (because those are the ones typically containing triclosan and triclorocarban). Over 2000 products contain antibacterial compounds. I've even seen them in pillows, pillow protectors, mattress pads, dish racks, toys, and blankets! As we know from the latest microbiology research, we need to cultivate a healthy microbiome, and not throw it out of whack by continuously trying to kill off all bacteria. From The Atlantic:

It's Probably Best to Avoid Antibacterial Soaps

Antimicrobial chemicals are so ubiquitous that a recent study found them in pregnant mothers' urine and newborns' cord blood. Research shows that their risks may outweigh their benefits.

Antimicrobial chemicals, intended to kill bacteria and other microorganisms, are commonly found in not just soaps, but all kinds of products—toothpaste, cosmetics, and plastics among them. There is evidence that the chemicals aren’t always effective, and may even be harmful, and their ubiquity means people are often continually exposed to them. One such chemical, triclosan, has previously been found in many human bodily fluids. New research found traces of triclosan, triclocarban, and butyl paraben in the urine of pregnant women, and the cord blood of newborn infants. 

The research looked at the same population of 180 expectant mothers living in Brooklyn, New York, most of Puerto Rican descent. In a study published last week in Environmental Science and Technology, researchers from Arizona State University and State University of New York’s Downstate School of Public Health found triclosan in 100 percent of the women’s urine samples, and triclocarban in 87 percent of the samples. Of the 33 cord blood samples they looked at, 46 percent contained triclosan and 23 percent contained triclocarban.

In another, still-unpublished study, the researchers found that all of the cord blood samples contained “at least one paraben,” according to Dr. Rolf Halden, director of ASU’s Center for Environmental Security. 

Triclosan and triclocarban are endocrine disruptors, Halden explains. The risk there is that the chemicals can mimic thyroid hormones, potentially disrupting the metabolism and causing weight gain or weight loss. Previous research has also shown a connection between higher levels of triclosan in urine, and allergy diagnoses in children.

In the study looking at butyl paraben, the researchers found an association between higher exposure to the chemical, and a smaller head circumference and length of babies after they were born. Butyl paraben is used as a preservative, so it’s found in a wider breadth of products, according to Halden.

From Science News: Pregnant women, fetuses exposed to antibacterial compounds face potential health risks 


As the Food and Drug Administration mulls over whether to rein in the use of common antibacterial compounds that are causing growing concern among environmental health experts, scientists are reporting that many pregnant women and their fetuses are being exposed to these substances. The compounds are used in more than 2,000 everyday products marketed as antimicrobial, including toothpastes, soaps, detergents, carpets, paints, school supplies and toys, the researchers say.

The problem with this, explains Pycke, a research scientist at Arizona State University (ASU), is that there is a growing body of evidence showing that the compounds can lead to developmental and reproductive problems in animals and potentially in humans. Also, some research suggests that the additives could contribute to antibiotic resistance, a growing public health problem.

Although the human body is efficient at flushing out triclosan and triclocarban, a person's exposure to them can potentially be constant. "If you cut off the source of exposure, eventually triclosan and triclocarban would quickly be diluted out, but the truth is that we have universal use of these chemicals, and therefore also universal exposure," says Rolf Halden, Ph.D., the lead investigator of the study at ASU.

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Here it is, a list of 17 cancers linked to being overweight or obese. From Science Daily:

Overweight and obesity linked to 10 common cancers, over 12,000 cases every year in UK

A higher body mass index (BMI) increases the risk of developing 10 of the most common cancers, the largest study of its kind on BMI and cancer, involving more than 5 million adults in the UK, shows. Each 5 kg/m² increase in BMI was clearly linked with higher risk of cancers of the uterus (62% increase), gallbladder (31%), kidney (25%), cervix (10%), thyroid (9%), and leukemia (9%). Higher BMI also increased the overall risk of liver, colon, ovarian, and breast cancers.

Using data from general practitioner records in the UK's Clinical Practice Research Datalink (CPRD), the researchers identified 5·24 million individuals aged 16 and older who were cancer-free and had been followed for an average of 7·5 years. The risk of developing 22 of the most common cancers, which represent 90% of the cancers diagnosed in the UK, was measured according to BMI after adjusting for individual factors such as age, sex, smoking status, and socioeconomic status. A total of 166 955 people developed one of the 22 cancers studied over the follow-up period. BMI was associated with 17 out of the 22 specific types of cancer examined.

Each 5 kg/m² increase in BMI was clearly linked with higher risk of cancers of the uterus (62% increase), gallbladder (31%), kidney (25%), cervix (10%), thyroid (9%), and leukemia (9%). Higher BMI also increased the overall risk of liver (19% increase), colon (10%), ovarian (9%), and breast cancers (5%), but the effects on these cancers varied by underlying BMI and by individual-level factors such as sex and menopausal status. Even within normal BMI ranges, higher BMI was associated with increased risk of some cancers.

There was some evidence that those with high BMI were at a slightly reduced risk of prostate cancer and premenopausal breast cancer. Based on the results, the researchers estimate that excess weight could account for 41% of uterine and 10% or more of gallbladder, kidney, liver, and colon cancers in the UK.