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A study by researchers showing troubling effects from certain pesticides (especially a class of fungicides) raises all sorts of questions: What is the long-term effect of chronic low doses of these fungicides in the foods we eat? How much of these chemicals are we getting exposed to? The Univ. of North Carolina researchers studied the effect of 294 chemicals (all common food-use pesticides or other environmental chemicals) on "mouse cortical neurons" (mouse brain cells). They found that one group of chemicals, which they referred to as "cluster 2", "mimics brain disorders" such as autism, advanced age, Alzheimer's, Parkinson's disease, and other neurodegenerative disorders. The chemicals (all pesticides, and mainly fungicides) causing these effects are: fenamidone, pyraclostrobin, famoxadone, trifloxystrobin, fenpyroximate, azoxystrobin, fluoxastrobin pyridaben and rotenone. Even though this study was done on mouse cortical neurons (in vitro), it is meaningful because of the similarities with human brain cells.

Very little is known about human exposure to these chemicals (how much is our exposure?) and their effects on humans, but the data suggest effects similar to that in neurological disorders. The researchers point out that many of the chemical residues in this cluster were found on conventionally raised foods, especially leafy green vegetables, and were detected at relatively high levels, especially pyraclostrobin. Most of these fungicides only came into use after 2000 and usage of these fungicides has been increasing in the U.S, with the exception of pyridaben (decreasing use) and rotenone (very low use). "These data suggest significant human exposure potential to many of the chemicals in cluster 2".

They point out that these fungicide residues have not been detected on organically produced foods (EPA and USDA data), which suggests a way to minimize exposure. None of these chemicals can be used by organic farmers in the U.S. Possible exposure is also from gardens and lawns (if used), contaminated water, and for farm workers in conventional agriculture. From Science Daily:

Could new class of fungicides play a role in autism, neurodegenerative diseases?

Scientists at the UNC School of Medicine have found a class of commonly used fungicides that produce gene expression changes similar to those in people with autism and neurodegenerative conditions, including Alzheimer's disease and Huntington's disease.

Mark Zylka, PhD, senior author of the study and associate professor of cell biology and physiology at UNC, and his team exposed mouse neurons to approximately 300 different chemicals.... "Based on RNA sequencing, we describe six groups of chemicals," Zylka said. "We found that chemicals within each group altered expression in a common manner. One of these groups of chemicals altered the levels of many of the same genes that are altered in the brains of people with autism or Alzheimer's disease." Chemicals in this group included the pesticides rotenone, pyridaben, and fenpyroximate, and a new class of fungicides that includes pyraclostrobin, trifloxystrobin, fenamidone, and famoxadone. Azoxystrobin, fluoxastrobin, and kresoxim-methyl are also in this fungicide class.

"We cannot say that these chemicals cause these conditions in people," Zylka cautioned. "Many additional studies will be needed to determine if any of these chemicals represent real risks to the human brain." Zylka, a member of the UNC Neuroscience Center, and his group found that these chemicals reduced the expression of genes involved in synaptic transmission -- the connections important for communication between neurons. If these genes are not expressed properly, then our brains cannot function normally. Also, these chemicals caused an elevated expression of genes associated with inflammation in the nervous system. This so-called neuroinflammation is commonly seen in autism and neurodegenerative conditions.

The researchers also found that these chemicals stimulated the production of free radicals -- particles that can damage the basic building blocks of cells and that have been implicated in a number of brain diseases. The chemicals also disrupted neuron microtubules. "Disrupting microtubules affects the function of synapses in mature neurons and can impair the movement of cells as the brain develops," Zylka said. "We know that deficits in neuron migration can lead to neurodevelopmental abnormalities. We have not yet evaluated whether these chemicals impair brain development in animal models or people."

Jeannie T. Lee, MD, PhD, professor of genetics at Harvard Medical School and Massachusetts General Hospital, who was not involved in this research, said, "This is a very important study that should serve as a wake-up call to regulatory agencies and the general medical community. The work is timely and has wide-ranging implications not only for diseases like autism, Parkinson's, and cancer, but also for the health of future generations. I suspect that a number of these chemicals will turn out to have effects on transgenerational inheritance."

Zylka's group also analyzed information from the U.S. Geological Survey, which monitors countywide pesticide usage, as well as the Food and Drug Administration and the U.S. Department of Agriculture, which test foodstuffs yearly for pesticide residues. Of the chemicals Zylka's team studied, only the usage of pyridaben has decreased since 2000. Rotenone use has remained the same since 2000. However, the use of all the fungicides in this group has increased dramatically over the past decade.

Indeed, a study from the Environmental Protection Agency found that pyraclostrobin is found on foods at levels that could potentially affect human biology, and another study linked pyraclostrobin usage to honeybee colony collapse disorder. The pesticide rotenone was previously implicated in Parkinson's disease through replicated animal experiments and through human epidemiological studies.....Previous work has also shown that a single dose of the fungicide trifloxystrobin reduced motor activity for several hours in female rats and for days in male rats. Disrupted motor function is a common symptom of Parkinson's disease and other neurological disorders. The related fungicide picoxystrobin impaired motor activity in rats at the lowest dose tested.

Zylka added, "The real tough question is: if you eat fruits, vegetables or cereals that contain these chemicals, do they get into your blood stream and at what concentration? That information doesn't exist." Also, given their presence on a variety of foodstuffs, might long term exposure to these chemicals -- even at low doses -- have a cumulative effect on the brain?

Zylka noted that conventionally grown leafy green vegetables such as lettuce, spinach, and kale have the highest levels of these fungicides. But due to each chemical's effectiveness at reducing fungal blights and rust, crop yields have increased and farmers are expanding their use of these chemicals to include many additional types of food crops.

Zylka's team hopes their research will encourage other scientists and regulatory agencies to take a closer look at these fungicides and follow up with epidemiological studies. "Virtually nothing is known about how these chemicals impact the developing or adult brain," Zylka said. "Yet these chemicals are being used at increasing levels on many of the foods we eat."

Applying fungicide to apple orchard. Credit: Univ. of Kentucky Agriculture Extension

Published on Leave a comment on Health Benefits of Dog Ownership

Another study that found benefits to dog ownership. The study authors concluded that: "Our study provides evidence that dog owners are at a lower risk for ischemic stroke, hemorrhagic stroke and heart failure." This could be to daily exercise, or that dog ownership results in less stress or better psychosocial health, or even some other reason (perhaps dog owners are healthier to start with).   Note: myocardial infarction (MI) is commonly known as a heart attack. From Medscape:

Canine Companions Appear to Help Heart Health: Swedish Study

Middle-aged and older dog owners were less likely to die from cardiovascular heart disease (CVD) or all causes, and those who lived alone were less likely to have an MI (myocardial infarction) or stroke, during a decade of follow-up in a large study based on Swedish national registry data[1]. The findings suggest that "especially for those who live alone, dog ownership makes a significant difference . . . in health status," Dr Mwenya Mubanga (Uppsala University, Sweden) told Heartwire from Medscape.....

Dog owners get daily exercise from walking their dogs, and canine companions can reduce stress, which might explain these findings, the researchers speculate....Similarly, Dr Gang Hu (Pennington Biomedical Research, Baton Rouge, LA).....pointed out that the dog owners do more exercise (by walking their dogs), which may contribute to having a lower body weight, lower blood pressure, and possibly good lipid levels and a lower risk of diabetes—which may all act to lower mortality. Having a dog may also reduce the chances of having depression, which might partly explain the more striking findings in the people who lived alone, he added.

Since 2001, dog owners in Sweden have been required by law to register their dogs, and an estimated 83% of dogs were registered that year with the Swedish Board of Agriculture and/or the Swedish Kennel Club dog registries, Mubanga and colleagues explain. They examined the Swedish national registry data to see how dog ownership was related to new CVD events or mortality.....This included 162,091 dog owners (4.8% of the population) and 3,195,153 people who were not dog owners.

Dog owners who lived alone or with at least one child or adult were less likely to die of CVD or all causes during follow-up compared with those who did not own a dog, but the relationships were stronger for solitary dwellers. Among dog owners, solitary dwellers (but not others) were also significantly less likely to have an MI or stroke than people who did not have a dog.

Published on Leave a comment on Toxoplasmosis Infection Linked to Aggression

 Numerous studies link toxoplasmosis to a number of psychiatric conditions, including bipolar disorder, schizophrenia, and obsessive-compulsive disorder. This infection is also linked to aspects of behavior and personality, from impulsivity to prolonged feelings of guilt and excessive worry, and may even slow a person's reflexes. Now new research has linked latent toxoplasmosis infection to aggression and impulsivity. Those with a psychiatric condition called intermittent explosive disorder (IED) have a greater likelihood of toxoplasmosis infection (when compared to people without IED). People who have IED typically experience recurrent outbursts of extreme, impulsive anger, such as seen in road rage.

Three groups (normal healthy control group, intermittent explosive disorder (IED) group, and non-IED psychiatric disorders group) were studied, and in all 3 groups those who tested positive for the infection had higher levels of aggression within their group. 22% of the IED group had the infection, 17% in the non-IED psychiatric group, and only 9% in the healthy normal control group.This research suggested that toxoplasmosis infection is linked to aggression and impulsivity (with aggression being stronger).

Toxoplasmosis is caused by an infection with Toxoplasma gondii, a protozoan parasite carried by cats. It can also infect humans, through contact with cat feces, poorly cooked meat or contaminated water, and as many as one-third of the world’s population may be infected. The person may not feel sick, but the parasite may form cysts in the brain where it can remain for the rest of a person’s life. In this study they determined that someone had a latent T. gondii infection by the circulating immunoglobulin G (IgG) antibodies to T. gondii in the blood (IgG > 12 IU). And yes, the infection can be successfully treated with medications. From Science Daily:

People with rage disorder twice as likely to have latent toxoplasmosis parasite infection

Individuals with a psychiatric disorder involving recurrent bouts of extreme, impulsive anger--road rage, for example--are more than twice as likely to have been exposed to a common parasite than healthy individuals with no psychiatric diagnosis. In a study involving 358 adult subjects, a team led by researchers from the University of Chicago found that toxoplasmosis, a relatively harmless parasitic infection carried by an estimated 30 percent of all humans, is associated with intermittent explosive disorder and increased aggression.

"Our work suggests that latent infection with the toxoplasma gondii parasite may change brain chemistry in a fashion that increases the risk of aggressive behavior," said senior study author Emil Coccaro, MD, Ellen. C. Manning Professor and Chair of Psychiatry and Behavioral Neuroscience at the University of Chicago. "However, we do not know if this relationship is causal, and not everyone that tests positive for toxoplasmosis will have aggression issues," Coccaro said, adding that additional studies are needed.

Intermittent explosive disorder (IED) is defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, as recurrent, impulsive, problematic outbursts of verbal or physical aggression that are disproportionate to the situations that trigger them. IED is thought to affect as many as 16 million Americans, more than bipolar disorder and schizophrenia combined.....examined possible connections to toxoplasmosis, an extremely common parasitic infection. Transmitted through the feces of infected cats, undercooked meat or contaminated water, toxoplasmosis is typically latent and harmless for healthy adults. However, it is known to reside in brain tissue, and has been linked to several psychiatric diseases, including schizophrenia, bipolar disorder and suicidal behavior.

The research team recruited 358 adult subjects from the U.S., who were evaluated for IED, personality disorder, depression and other psychiatric disorders. Study participants were also scored on traits including anger, aggression and impulsivity. Participants fell into one of three groups. Roughly one third had IED. One third were healthy controls with no psychiatric history. The remaining third were individuals diagnosed with some psychiatric disorder, but not IED. This last group served as a control to distinguish IED from possible confounding psychiatric factors.

The research team found that IED-diagnosed group was more than twice as likely to test positive for toxoplasmosis exposure (22 percent) as measured by a blood test, compared to the healthy control group (9 percent). Around 16 percent of the psychiatric control group tested positive for toxoplasmosis, but had similar aggression and impulsivity scores to the healthy control group. IED-diagnosed subjects scored much higher on both measures than either control group.

Across all study subjects, toxoplasmosis-positive individuals scored significantly higher on scores of anger and aggression. The team noted a link between toxoplasmosis and increased impulsivity, but when adjusted for aggression scores, this link became non-significant. This finding suggests toxoplasmosis and aggression are most strongly correlated. However, the authors caution that the study results do not address whether toxoplasmosis infection may cause increased aggression or IED. "Correlation is not causation, and this is definitely not a sign that people should get rid of their cats," said study co-author Royce Lee, MD.... "We don't yet understand the mechanisms involved..."

 Toxoplasma gondii  tissue cyst in a mouse brain Credit: Jitinder P. Dubey, Wikipedia

Published on Leave a comment on Higher Activity Levels and the Aging Brain

Another study showing that higher physical activity (from a variety of activities) is "related to larger gray matter volume in the elderly, regardless of cognitive status", specifically in gray matter areas of the brain responsible for memory, learning, and cognition. In other words, higher levels of physical activity reduce brain atrophy that occurs with aging and improves cognitive function in elderly individuals.  There is also discussion of higher activity levels improving cerebral (brain) blood flow. Bottom line: get off your butt and move more for better brain health. From Medical Xpress:

Burning more calories linked with greater gray matter volume, reduced Alzheimer's risk

Whether they jog, swim, garden or dance, physically active older persons have larger gray matter volume in key brain areas responsible for memory and cognition, according to a new study by researchers at the University of Pittsburgh School of Medicine and UCLA.The findings, published today in the Journal of Alzheimer's Disease, showed also that people who had Alzheimer's disease or mild cognitive impairment experienced less gray matter volume reduction over time if their exercise-associated calorie burn was high.

A growing number of studies indicate physical activity can help protect the brain from cognitive decline, said investigator James T. Becker, Ph.D., professor of psychiatry, Pitt School of Medicine..... "Our study is one of the largest to examine the relationship between physical activity and cognitive decline, and the results strongly support the notion that staying active maintains brain health."

Led by Cyrus Raji, M.D., Ph.D., formerly a student at Pitt School of Medicine and now a senior radiology resident at UCLA, the team examined data obtained over five years from nearly 876 people 65 or older participating in the multicenter Cardiovascular Health Study. All participants had brain scans and periodic cognitive assessments. They also were surveyed about how frequently they engaged in physical activities, such as walking, tennis, dancing and golfing, to assess their calorie expenditure or energy output per week.

Using mathematical modeling, the researchers found that the individuals who burned the most calories had larger gray matter volumes in the frontal, temporal and parietal lobes of the brain, areas that are associated with memory, learning and performing complex cognitive tasks. In a subset of more than 300 participants at the Pitt site, those with the highest energy expenditure had larger gray matter volumes in key areas on initial brain scans and were half as likely to have developed Alzheimer's disease five years later.

"Gray matter houses all of the neurons in your brain, so its volume can reflect neuronal health," Dr. Raji explained. "We also noted that these volumes increased if people became more active over five years leading up to their brain MRI."

Published on Leave a comment on Microbes and Alzheimer’s Disease?

 Two articles about the link between Alzheimer's disease (AD) and microbes this past week: a study linking periodontal disease and Alzheimer's, and the other a journal editorial (written by an international team of 31 researchers) suggesting that we need to more closely look at the role of microbes in Alzheimer's disease, especially herpes virus, chlamydia and spirochaete bacteria.

This team is suggesting an "infectious cause" for Alzheimer's, an example being the reactivation of herpes simplex virus type 1 (HSV1) in the person. The researchers state that "regarding HSV1, about 100 publications by many groups indicate directly or indirectly that this virus is a major factor in the disease".  The team also mentions the possibility of fungi infection in some cases (see my November 6, 2015 post about a study finding fungal involvement). Both articles mention that treatment of the diseases with some form of antimicrobials or antivirals could possibly treat Alzheimer's disease, and that trails now need to be done.

From Science Daily: Link between gum disease and cognitive decline in Alzheimer’s

A new study has found a link between gum disease and greater rates of cognitive decline in people with early stages of Alzheimer's Disease. Periodontitis or gum disease is common in older people and may become more common in Alzheimer's disease because of a reduced ability to take care of oral hygiene as the disease progresses. Higher levels of antibodies to periodontal bacteria are associated with an increase in levels of inflammatory molecules elsewhere in the body, which in turn has been linked to greater rates of cognitive decline in Alzheimer's disease in previous studies.

The presence of gum disease at baseline was associated with a six-fold increase in the rate of cognitive decline in participants over the six-month follow-up period of the study. Periodontitis at baseline was also associated with a relative increase in the pro-inflammatory state over the six-month follow-up period. The authors conclude that gum disease is associated with an increase in cognitive decline in Alzheimer's Disease, possibly via mechanisms linked to the body's inflammatory response.....However, growing evidence from a number of studies links the body's inflammatory response to increased rates of cognitive decline, suggesting that it would be worth exploring whether the treatment of gum disease might also benefit the treatment of dementia and Alzheimer's Disease.

From Journal of Alzheimer's Disease: Microbes and Alzheimer’s Disease

We are researchers and clinicians working on Alzheimer’s disease (AD) or related topics, and we write to express our concern that one particular aspect of the disease has been neglected, even though treatment based on it might slow or arrest AD progression. We refer to the many studies, mainly on humans, implicating specific microbes in the elderly brain, notably herpes simplex virus type 1 (HSV1), Chlamydia pneumoniae, and several types of spirochaete, in the etiology of AD [1–4]. Fungal infection of AD brain [5, 6] has also been described, as well as abnormal microbiota in AD patient blood [7]. The first observations of HSV1 in AD brain were reported almost three decades ago [8]. The ever-increasing number of these studies (now about 100 on HSV1 alone) warrants re-evaluation of the infection and AD concept.

AD is associated with neuronal loss and progressive synaptic dysfunction, accompanied by the deposition of amyloid-β (Aβ) peptide, a cleavage product of the amyloid-β protein precursor (AβPP), and abnormal forms of tau protein, markers that have been used as diagnostic criteria for the disease [9, 10]. These constitute the hallmarks of AD, but whether they are causes of AD or consequences is unknown. We suggest that these are indicators of an infectious etiology. In the case of AD, it is often not realized that microbes can cause chronic as well as acute diseases; that some microbes can remain latent in the body with the potential for reactivation, the effects of which might occur years after initial infection; and that people can be infected but not necessarily affected, such that ‘controls’, even if infected, are asymptomatic [2].

Regarding HSV1, about 100 publications by many groups indicate directly or indirectly that this virus is a major factor in the disease....The only opposing reports, two not detecting HSV1 DNA in elderly brains and another not finding an HSV1–APOE association, were published over a decade ago [76–78]. However, despite all the supportive evidence, the topic is often dismissed as ‘controversial’. One recalls the widespread opposition initially to data showing that viruses cause some types of cancer, and that a bacterium causes stomach ulcers.

In summary, we propose that infectious agents, including HSV1, Chlamydia pneumonia, and spirochetes, reach the CNS and remain there in latent form. These agents can undergo reactivation in the brain during aging, as the immune system declines, and during different types of stress (which similarly reactivate HSV1 in the periphery). The consequent neuronal damage— caused by direct viral action and by virus-induced inflammation— occurs recurrently, leading to (or acting as a cofactor for) progressive synaptic dysfunction, neuronal loss, and ultimately AD.

AD causes great emotional and physical harm to sufferers and their carers, as well as having enormously damaging economic consequences. Given the failure of the 413 trials of other types of therapy for AD carried out in the period 2002–2012 [79], antiviral/antimicrobial treatment of AD patients, notably those who are APOE ɛ 4 carriers, could rectify the ‘no drug works’ impasse. We propose that further research on the role of infectious agents in AD causation, including prospective trials of antimicrobial therapy, is now justified.

Published on Leave a comment on Education and Climbing Stairs Keep the Brain Younger?

Brain aging can be viewed as having 2 parts: chronological age (normally  the brain grey matter volume slowly shrinks with advancing age) and a lifetime of exposures - which can be negative from unhealthy lifestyle and injuries, and positive from a healthy lifestyle and enriched environments. That's why after a lifetime there can be wide variation in the physiological age of our brains. These differences in the  brain (in the grey matter) can be measured with magnetic resonance imaging (MRIs).

The researchers in this study used the concept of physiological age - the difference between the chronological age and predicted age, as a marker of brain health. They looked at adults of varying ages,and found that the more flights of stairs a person climbs daily, and the more years of school a person had completed, the "younger" their brain physically appears.  This study was a cross-sectional study and so shows an association rather than a definite cause, but interestingly other forms of exercise did not show this link (walking/hiking, jogging, running, bicycling, aerobic exercise, lap swimming, tennis.squash/racquetball, low intensity exercise). From Science Daily:

Want a younger brain? Stay in school -- and take the stairs

Taking the stairs is normally associated with keeping your body strong and healthy. But new research shows that it improves your brain's health too -- and that education also has a positive effect. In a study recently published in the journal Neurobiology of Aging, researchers led by Jason Steffener, a scientist at Concordia University's Montreal-based PERFORM Centre, show that the more flights of stairs a person climbs, and the more years of school a person completes, the "younger" their brain physically appears.

The researchers found that brain age decreases by 0.95 years for each year of education, and by 0.58 years for every daily flight of stairs climbed -- i.e., the stairs between two consecutive floors in a building.

For the study, Steffener and his co-authors used magnetic resonance imaging (MRI) to non-invasively examine the brains of 331 healthy adults who ranged in age from 19 to 79. They measured the volume of grey matter found in participants' brains because its decline, caused by neural shrinkage and neuronal loss, is a very visible part of the chronological aging process. Then, they compared brain volume to the participants' reported number of flights of stairs climbed, and years of schooling completed. 

Results were clear: the more flights of stairs climbed, and the more years of schooling completed, the younger the brain. "This study shows that education and physical activity affect the difference between a physiological prediction of age and chronological age, and that people can actively do something to help their brains stay young," he says.

Published on Leave a comment on Proton Pump Inhibitors Linked to Dementia

A new study has confirmed an association between proton pump inhibitors (PPIs) — drugs that treat heartburn, peptic ulcers, and other acid-related disorders of the upper gastrointestinal tract — and increased risk for dementia in older patients. An earlier study by the same researchers found the same link between PPI use and dementia risk. The drugs work by lowering the amount of acid produced by the stomach. PPIs are among the most frequently prescribed drugs, and include omeprazole (Losec), esomeprazole (Nexium), lansoprazole (Prevacid), and the over-the-counter medication Olex.

The U.S. Food and Drug Administration have warned people to take them for the shortest period possible, namely a few weeks, and only for serious acid reflux, ulcers, or stomach bleeding. Other problems linked to long-term use are: fractures, pneumonia, increased rates of C. difficile, low magnesium levels, and chronic kidney disease. From Science Daily:

Proton pump inhibitors may be associated with increased risk of Dementia

The use of proton pump inhibitors, the popular medications used to treat gastroesophageal reflux and peptic ulcers, may be associated with an increased risk of dementia in a study using data from a large German health insurer, according to an article published online by JAMA Neurology.  The use of proton pump inhibitors (PPIs) has increased among older patients and PPIs are among the most frequently used classes of drugs.

Britta Haenisch, Ph.D., of the German Center for Neurodegenerative Diseases, Bonn, Germany, and coauthors examined the association between the use of PPIs and the risk of dementia using data from 2004 to 2011 on inpatient and outpatient diagnoses and drug prescriptions. Regular PPI use was at least one PPI prescription in each quarter of an 18-month interval.

The study population included 218,493 individuals 75 or older before 144,814 individuals were excluded, leaving 73,679 individuals included in the final analysis. The authors identified 29,510 patients who developed dementia during the study period. Regular users of PPIs (2,950 patients, mostly female and average age nearly 84) had a 44 percent increased risk of dementia compared with those (70,729 patients, mostly female and average age 83) not receiving PPI medication, according to the results.

"The present study can only provide a statistical association between PPI use and risk of dementia. The possible underlying causal biological mechanism has to be explored in future studies. 

Published on Leave a comment on Oral Bacteria Linked to Hemorrhagic Stroke

The finding that the oral bacteria Streptococcus mutans, which is found in 10% of the population, is linked with hemorrhagic strokes is big. S. mutans is found in tooth decay or cavities (dental caries). The researchers found a link with cnm-positive S. mutans with both intracerebral hemorrhage (ICH) and also with cerebral microbleeds.

Some risk factors for strokes have long since been known, such as high blood pressure and advanced age, but then there are those hemorrhagic strikes that don't seem to fit the norm, with no apparent risk factors. Well, apparently the presence of cnm-positive S. mutans is one. My understanding of what cnm-positive S. mutans means is S. mutans bacteria that carries the collagen-binding Cnm gene. This bacteria can be found in a person's saliva and in dental plaque, and swabs of both were taken for this study.

This study builds on other studies that find a link between the bacteria Streptococcus mutans and a number of systemic diseases, including bacteremia, infective endocarditis and hemorrhagic stroke. The researchers of this latest study suggest that infection with cnm-positive S. mutans causes constant inflammation (as shown by 2 inflammatory markers: CRP and fibrinogen), which then causes damage to blood vessels (endothelial damage) in the brain. Bottom line: take care of your teeth and gums.

From Science Daily: Oral bacteria linked to risk of stroke

In a study of patients entering the hospital for acute stroke, researchers have increased their understanding of an association between certain types of stroke and the presence of the oral bacteria (cnm-positive Streptococcus mutans).

In the single hospital study, researchers at the National Cerebral and Cardiovascular Center in Osaka, Japan, observed stroke patients to gain a better understanding of the relationship between hemorrhagic stroke and oral bacteria. Among the patients who experienced intracerebral hemorrhage (ICH), 26 percent were found to have a specific bacterium in their saliva, cnm-positive S. mutans. Among patients with other types of stroke, only 6 percent tested positive for the bacterium.

Strokes are characterized as either ischemic strokes, which involve a blockage of one or more blood vessels supplying the brain, or hemorrhagic strokes, in which blood vessels in the brain rupture, causing bleeding.

The researchers also evaluated MRIs of study subjects for the presence of cerebral microbleeds (CMB), small brain hemorrhages which may cause dementia and also often underlie ICH. They found that the number of CMBs was significantly higher in subjects with cnm-positive S. mutans than in those without. The authors hypothesize that the S. mutans bacteria may bind to blood vessels weakened by age and high blood pressure, causing arterial ruptures in the brain, leading to small or large hemorrhages.

"This study shows that oral health is important for brain health. People need to take care of their teeth because it is good for their brain and their heart as well as their teeth," Friedland said. "The study and related work in our labs have shown that oral bacteria are involved in several kinds of stroke, including brain hemorrhages and strokes that lead to dementia."

Multiple research studies have shown a close association between the presence of gum disease and heart disease, and a 2013 publication by Jan Potempa, Ph.D., D.Sc., of the UofL School of Dentistry, revealed how the bacterium responsible for gum disease worsens rheumatoid arthritis. The cnm-negative S. mutans bacteria is found in approximately 10 percent of the general population, Friedland says, and is known to cause dental cavities (tooth decay). Friedland also is researching the role of oral bacteria in other diseases affecting the brain.  http://www.nature.com/articles/srep20074

Published on Leave a comment on Physical Fitness Now and Brain Size Years Later

Another famous long-running study (Framingham Heart Study) finds more bad news for middle-aged coach-potatoes (that is, those who don't exercise or have poor physical fitness). It's an observational study (thus they found an association), but the finding is pretty damn convincing: that poor physical fitness (basically a sedentary life-style) may be linked to a smaller brain size (brain volume) 20 years later. The reason this is significant is because shrinking brain volume means that accelerated brain aging is occurring.

Researcher Nicole Spartano said: "Brain volume is one marker of brain aging. Our brains shrink as we age, and this atrophy is related to cognitive decline and increased risk for dementia. So, this study suggests that people with poor fitness have accelerated brain aging." Bottom line: if you don't get much exercise or lead a sedentary life-style, then increase your activity levels for hopefully better brain health decades later. Just getting out daily (or several times a week) and walking briskly would improve fitness. From Medical Xpress:

Couch potatoes may have smaller brains later in life

Poor physical fitness in middle age may be linked to a smaller brain size 20 years later, according to a study published in the February 10, 2016, online issue of Neurology, the medical journal of the American Academy of Neurology."We found a direct correlation in our study between poor fitness and brain volume decades later, which indicates accelerated brain aging," said study author Nicole Spartano, PhD, with Boston University School of Medicine in Boston.

For the study, 1,583 people enrolled in the Framingham Heart Study, with an average age of 40 and without dementia or heart disease, took a treadmill test. They took another one two decades later, along with MRI brain scans. The researchers also analyzed the results when they excluded participants who developed heart disease or started taking beta blockers to control blood pressure or heart problems; this group had 1,094 people. 

The participants had an average estimated exercise capacity of 39 mL/kg/min, which is also known as peak VO2, or the maximum amount of oxygen the body is capable of using in one minute. Exercise capacity was estimated using the length of time participants were able to exercise on the treadmill before their heart rate reached a certain level. For every eight units lower a person performed on the treadmill test, their brain volume two decades later was smaller, equivalent to two years of accelerated brain aging. When the people with heart disease or those taking beta blockers were excluded, every eight units of lower physical performance was associated with reductions of brain volume equal to one year of accelerated brain aging.

The study also showed that people whose blood pressure and heart rate went up at a higher rate during exercise also were more likely to have smaller brain volumes two decades later. Spartano said that people with poor physical fitness often have higher blood pressure and heart rate responses to low levels of exercise compared to people with better fitness. Spartano noted that the study is observational. It does not prove that poor physical fitness causes a loss of brain volume; it shows the association. (Link to study in journal Neurology.)

Published on Leave a comment on Traditional Toys and Books Better Than Electronic Toys For Young Children

More evidence that traditional toys and books are superior to electronic toys in both verbal parent-child interactions and non-verbal interactions for young children. Parent-child verbal interactions are so important because they teach young children language, lay the groundwork for literacy skills, teach role-playing, teach emotional and social skills such as turn-taking and accepting others' leads. In other words, put down the electronic gadgets and go spend time talking and interacting with your young child with old style traditional toys and books. From Science Daily:

How does type of toy affect quantity, quality of language in infant playtime?

Electronic toys for infants that produce lights, words and songs were associated with decreased quantity and quality of language compared to playing with books or traditional toys such as a wooden puzzle, a shape-sorter and a set of rubber blocks, according to an article published online by JAMA Pediatrics.

Anna V. Sosa, Ph.D., of Northern Arizona University, Flagstaff, and colleagues conducted a controlled experiment involving 26 parent-infant pairs with children who were 10 to 16 months old. Researchers did not directly observe parent-infant play time because it was conducted in participants' homes. Audio recording equipment was used to pick up sound. Participants were given three sets of toys: electronic toys (a baby laptop, a talking farm and a baby cell phone); traditional toys (chunky wooden puzzle, shape-sorter and rubber blocks with pictures); and five board books with farm animal, shape or color themes.

While playing with electronic toys there were fewer adult words used, fewer conversational turns with verbal back-and-forth, fewer parental responses and less production of content-specific words than when playing with traditional toys or books. Children also vocalized less while playing with electronic toys than with books, according to the results.

Results also indicate that parents produced fewer words during play with traditional toys than while playing with books with infants. Parents also used less content-specific words when playing with traditional toys with their infants than when playing with books. The authors note results showed the largest and most consistent differences between electronic toys and books, followed by electronic toys and traditional toys.

"These results provide a basis for discouraging the purchase of electronic toys that are promoted as educational and are often quite expensive. These results add to the large body of evidence supporting the potential benefits of book reading with very young children. They also expand on this by demonstrating that play with traditional toys may result in communicative interactions that are as rich as those that occur during book reading. ... However, if the emphasis is on activities that promote a rich communicative interaction between parents and infants, both play with traditional toys and book reading can be promoted as language-facilitating activities while play with electronic toys should be discouraged," the study concludes.

EDITORIAL: "Electronic toys that make noises or light up are extremely effective at commanding children's attention by activating their orienting reflex. This primitive reflex compels the mind to focus on novel visual or auditory stimuli. The study by Sosa in this issue of JAMA Pediatrics suggests that they may do more than just command children's attention; they appear to reduce parent-child verbal interactions. Why does this matter? Conversational turns during play do more than teach children language. They lay the groundwork for literacy skills, teach role-playing, give parents a window into their child's developmental stage and struggles, and teach social skills such as turn-taking and accepting others' leads.

Verbal interactions of course are only part of the story. What is missing from this study is a sense of how nonverbal interactions, which are also an important source of social and emotional skills, varied by toy type," write Jenny S. Radesky, M.D., of the University of Michigan Medical School, Ann Arbor, and Dimitri A. Christakis, M.D., M.P.H., of Seattle Children's Hospital and a JAMA Pediatrics associate editor, in a related editorial.