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The incredibly high use of pesticides in this country, especially when routinely applied to crops, lawns, and residence interiors, is worrisome. Over 1 billion pounds used in the US annually! Not only are there all sorts of environmental effects, including contamination of water, air, soil, but pesticides also have health effects on humans and wildlife. It seems that with each new study, more concerns are raised.

A recent large study found a link with amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, and exposure to pesticides. The Dartmouth College researchers found the link with about two dozen neurotoxic pesticides, including 2,4-D, chlorpyrifos, glyphosate, permethrin, MCPB, carbaryl, and paraquat.

Note that 2,4-D is a herbicide (weed-killer) that is used in crops, and also in feed and weed products for lawns. Glyphosate is the most commonly used herbicide in the world, and used extensively on crops in the US.

The study has limitations, but it should definitely get people investigating this possibility more. For a while now, pesticide exposure has been hypothesized to be a risk factor for ALS. This is a progressive and fatal disease that affects nerve cells in the brain and spinal cord, causing loss of muscle control.

Excerpts from Environmental Health News: Higher estimated pesticide exposures linked to ALS risk

Every year, approximately 5,000 people in the U.S. are diagnosed with amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease.  ...continue reading "Pesticides and Lou Gehrig’s Disease"

Something to ponder: Are tiny plastic particles (microplastics) that enter the human body traveling to the brain and causing harm? An article by the science writer Erica Cirino examines that question by looking at existing research and comes to the disturbing conclusion of: Yes, they are.

Yes, that plastic particles are inhaled or ingested (in food, water, and air), that many are excreted, but some travel to organs in the body, are absorbed in the bloodstream, and some eventually cross into the brain. Research in fish shows that this ultimately results in abnormal (dysfunctional) behavior. [Note: she is the author of the book Thicker Than Water, which addresses the plastics pollution problem.]

One problem is that plastic particles contain all the chemicals in the original plastic, which includes endocrine (hormone) disruptors.  Another is that the plastic particles accumulate once they are in the organs. Yes, studies find plastic particles in humans (e.g., the placenta, the lungs, and other tissues) and also that many microparticles are excreted in feces. But much is still unknown.

A study by Canadian researchers estimated that the consumption of microplastics by Americans ranges from 39,000 to 52,000 particles (depending on age and sex) each year. When they added in inhalation of microplastic particles, the numbers increased to 74,000 to 121,000. And those who only drink bottled water may be getting an additional 90,000 microplastics (versus about 4000 microplastics from tap water). Yikes!

Since more and more plastics are entering the environment each year, then this does not bode well for humans. We need to deal with plastic pollution!

Excerpts from an article by Erica Cirino in The Scientist: Opinion: Plastic Pollution May Endanger Brains

In 1950, 2 million metric tons of plastic were produced globally; in 2015, petro-chemical companies churned out 381 million metric tons. Most plastic waste—more than 6.3 billion metric tons of it has been generated by humans over the last 80 years—is never recycled. And to scientists’ best knowledge, petroleum-based plastic will never biodegrade. Instead, it breaks up into ever-smaller particles that always remain plastic.  ...continue reading "Microplastics Are Entering Our Bodies"

Some mental abilities actually improve with age! This is great news, because the general view is that our brain volume shrinks and mental abilities decline with age (especially after age 70).

A large Georgetown Univ. Medical Center study of 702 participants (58 to 98 years old) found that two important brain functions actually improve with age, probably due to lifelong experience using them. They were attention and executive functions - which allow us to attend to new information and to focus on what's important in a situation. They underlie  memory, decision making, self-control, navigation, language, and reading.

Is this why there is a saying that wisdom comes with age?

From Science Daily: Key mental abilities can actually improve during aging

It's long been believed that advancing age leads to broad declines in our mental abilities. Now new research from Georgetown University Medical Center offers surprisingly good news by countering this view.  ...continue reading "Some Thought Processes Improve With Age"

Recently there have been studies with conflicting results about the health benefits or harms from coffee consumption. Overall, it seems like moderate intake is OK and beneficial for adults, but too much may cause harm. And avoid caffeinated coffee if pregnant. Yesterday I posted about several recent studies finding health benefits from daily coffee consumption.

Coffee has anti-inflammatory effects, and contains more than a thousand chemical compounds. Over the years many studies found health benefits with regular and decaffeinated coffee, especially when a filter is used in the brewing process (e.g. drip coffee). But when the coffee is made by methods that don't filter the coffee (e.g. French press) the results may show harm, especially if large quantities are consumed daily.

The following are two recent studies finding that coffee consumption is associated with health benefits, and two studies finding potential harm from coffee consumption of over 6 cups a day. Note that whether the coffee is filtered or not may make a difference in results (the last 2 studies).

From (Jan. 11, 2021) Science Daily: Higher coffee intake may be linked to lower prostate cancer risk ...continue reading "Coffee Can Have Health Benefits, But Perhaps Harmful In Large Amounts"

There is another great reason to try to lose weight if you are overweight or obese - being overweight or obese lowers blood flow to the brain in older adults. Yikes! However, one bit of good news from a study of 495 adults (average age 69) was that increased physical activity (brisk walks count!) can reduce or eliminate this association.

This could help explain why obesity increases the risk for a number of conditions as a person gets older, such as heart disease, dementia, and Alzheimer's disease.

The study was part of the Irish Longitudinal Study on Ageing. The average BMI (body mass index) was 28, which is considered overweight. One finding was that each 1 cm increase in waist circumference was associated with the same reduction of brain (cerebral) blood flow as 1 year of advancing age. (Yes, brain volume and blood flow typically diminish with age in older adults. So you want to prevent it as much as possible.)

The study found that higher levels of physical activity can reduce or remove this association of overweight & obesity and reduced brain blood flow. So if it's not possible to lose weight - then get really physically active!

How much exercise is beneficial? The researchers recommend at least 1.5 to 2 hours per day of "being active", that is, doing activities that require "moderate" effort - this means breathing somewhat harder than normal (e.g. brisk walking, cycling at a regular pace, carrying light loads). Equally beneficial is to get some "vigorous activity" which results in breathing much higher than normal (e.g., digging, aerobics, fast cycling, carrying heavy loads). But any and all movement is good!

Medical Xpress: Researchers find obesity linked to reduced blood flow to the brain

A new study from scientists at The Irish Longitudinal Study on Aging (TILDA) at Trinity College Dublin reveals important findings, indicating that being overweight or obese significantly reduces blood flow in the brain. The study also shows that increased physical activity can positively modify, or even negate, this reduction in brain blood flow. ...continue reading "Overweight and Obesity Is Associated With Reduced Blood Flow In the Brain"

The possibility of a vaccine for helping the body fight cancer just got one step closer. A vaccine that targets a specific type of usually incurable brain cancer called "diffuse glioma" has had very good results in a trial of the vaccine. This is great news for a brain cancer that, even with treatment, keeps spreading throughout the brain, and only has a general 5-year survival rate of 48.9%.

The most important findings of the vaccine trial: the 3 year survival rate after being fully vaccinated was 84%, and in this group of 30 patients - 63% did not have any progression in tumor growth. And 82% of one subgroup of patients whose immune system showed a specific response to the vaccines had no tumor progression within the 3 year study period. This is amazing news for a cancer that typically has such a bleak prognosis.

brain cancer, diffuse glioma
Diffuse glioma in the brain. Credit: NCI

In a follow-up to this trial the researchers are combining the vaccine with checkpoint inhibitor immunotherapy (which give the immune system a boost), and which they think (are hoping) may produce even better results. Think of it this way - these treatments have the potential for you (your body's immune system) to effectively fight a cancer. The future is looking bright!

From Medical Xpress: First-ever vaccine for malignant brain tumors reported safe, effective in early trial

Tumor vaccines can help the body fight cancer. Mutations in the tumor genome often lead to protein changes that are typical of cancer. A vaccine can alert the patient's immune system to these mutated proteins. For the first time, physicians and cancer researchers from Heidelberg and Mannheim have now carried out a clinical trial to test a mutation-specific vaccine against malignant brain tumors. The vaccine proved to be safe and triggered the desired immune response in the tumor tissue, as the team now reports in the journal Nature.  ...continue reading "Encouraging Results For A Vaccine Targeting Brain Tumors"

Finally, a huge review of decades of studies answers the question of whether there are actual structural differences between male and female brains. And the answer is...(drumroll)... No - they are very similar. There aren't male brains and female brains with 2 different brain shapes or features. The main difference is a size difference in brain volume.

Women tend to have a little smaller brain (about 11% in adults) because they are smaller than men. (Similarly, smaller men also have smaller brains.) The Chicago Medical School researchers found that any sex/gender differences in the human brain are extremely subtle and inconsistent, and maybe account for 1% of variation between males and females. Note: Brain size is not correlated with or indicative of intelligence! 

They found that the size of the structures in the brain (e.g cerebellum, hippocampus) change along with the volume - it's a matter of proportion. The researchers summarized it: "Males’ brains are larger than females’ from birth, stabilizing around 11% in adults. This size difference accounts for other reproducible findings: higher white/gray matter ratio, intra- versus interhemispheric connectivity, and regional cortical and subcortical volumes in males."

By the way, the researchers also point out that large studies find that human males and females are far more similar than different in most measures of cognition, personality and attitudes.

From Medical Xpress: Massive study reveals few differences between men and women's brains

How different are men and women's brains? The question has been explored for decades, but a new study led by Rosalind Franklin University neuroscientist Lise Eliot is the first to coalesce this wide-ranging research into a single mega-synthesis. And the answer is: hardly at all. ...continue reading "Main Difference Between Male and Female Brains Is Size"

Evidence is building that caffeine should be avoided during pregnancy because it harms the developing baby. A recent study found when caffeine (coffee!) is consumed during pregnancy, then structural changes occur in the brain of the developing baby. These changes can be seen years later in brain scans, and these appear to result in behavioral changes in the children. The minimal, but noticeable behavioral changes were behavioral issues, attention difficulties, and hyperactivity.

The Univ. of Rochester School of Medicine and Dentistry researchers  found subtle changes in brain pathways ("alteration of the microstructure of critical fiber tracts") between brain regions that could be seen in the children at age 9 to 10 years. They analyzed brain scans (from MRIs) of 9157 children, of which 4,135 had mothers that reported consuming caffeine more than once a week.

Other studies find that health problems associated with caffeine (coffee) intake during pregnancy are miscarriage, stillbirth, low birth weight and/or small for gestational age, and childhood leukemia. There is a dose-response effect - the more caffeine is ingested, the more negative health effects.

Other human studies looking at this issue are observational, but negative health effects are supported by animal research going back more than four decades. Caffeine crosses the placenta and goes to the baby. Negative health effects occur because the fetus can not clear the caffeine well because it lacks an enzyme that metabolizes caffeine.

Unfortunately, medical guidelines in both the US and Europe are that moderate (up to 200 mg) ingestion of caffeine during pregnancy is OK, which means about 2 cups of regular coffee a day. Since studies show it's not OK, it's time to revise the guidelines!

From Science Daily: Brain changed by caffeine in utero

New research finds caffeine consumed during pregnancy can change important brain pathways that could lead to behavioral problems later in life. Researchers in the Del Monte Institute for Neuroscience at the University of Rochester Medical Center (URMC) analyzed thousands of brain scans of nine and ten-year-olds, and revealed changes in the brain structure in children who were exposed to caffeine in utero.  ...continue reading "Avoid Caffeine During Pregnancy"

The common parasite Toxoplasmosa gondii is associated with an increased risk of a rare form of aggressive brain cancer called glioma, according to a recent study. Toxoplasmosis is a disease that results from infection with the microscopic Toxoplasma gondii parasite.

People can be exposed to this parasite from infected cat feces, drinking  contaminated water, eating infected undercooked meat (especially pork, lamb, venison). Mother-to-child transmission during pregnancy can also occur. [CDC toxoplasmosis page] Most healthy people recover from toxoplasmosis without treatment, but it can be dangerous for certain groups (e.g. the fetus during pregnancy)

Toxoplasma gondii Credit: CDC

The study found that persons with gliomas are more likely to have antibodies to T. gondii (which means they've had a prior infection), than a similar group that was cancer free. The researchers thought the parasite can sometimes form cysts in the brain, and the inflammation associated with the cysts might be responsible.

The study looked at 2 groups of people, both in the US and in Norway. Another finding was that "some people with glioma have no T. gondii antibodies, and vice versa". (Whew...) The study showed an association, and does not prove cause and effect. However, other studies found similar results.

Gliomas make up the majority of malignant brain tumors, and glioblastomas (with a 5 year survival rate of 5%) are the most common type. Gliomas occur in approximately 6.6 per 100,000 individuals each year. In comparison, it is estimated that 11% of the US population to 60% in some areas of the world have been infected with the T. gondii parasite. And yet the brain cancer is very rare.

From Science Daily: Study identifies exposure to common food-borne pathogen linked to rare brain cancer

A new study suggests a link between toxoplasma gondii (T. gondii) infection and the risk of glioma, a type of brain cancer, in adults. 

...continue reading "Link Between Common Parasite and Brain Cancer"

Carbon dioxide levels in the atmosphere reached a new high in 2020 - and this in spite of the COVID-19 world-wide lockdowns. Yikes!

In May 2020 the carbon dioxide levels in our atmosphere reached a peak of 417.1 ppm (parts per million)! The carbon dioxide levels slightly fluctuate daily (on November 30, 2020 they were at 413.81 ppm at the Mauna Loa Observatory). But over the years they have been rising (an average of 2.37 ppm per year in the last decade), and are now at levels not experienced in several million years!

This is of concern not just because the earth is warming (resulting in more extreme weather), but also what higher and higher carbon dioxide levels might do to our thinking processes. Think of a "stuffy room" where it is harder to think - this can already occur starting at about 600 ppm of CO2, and known to occur at 945 ppm and higher (in rooms with many people in them). While current CO2 levels are below that, we are faced with the possibility that if they keep rising we will get there eventually - and there will be no escape from the "stuffy room" feeling!

Yes, there is research on this topic - studies suggest that at high levels of carbon dioxide our thinking gets worse. A University of Colorado study reports that a growing body of evidence finds that as CO2 levels increase, there are effects on thinking (cognitive functioning), including decision making, planning, and complex strategic thinking. As carbon dioxide levels rise to 945 ppm and higher, the effects are even more significant, especially with mentally demanding tasks.

There are also physical effects of rising carbon dioxide exposure in humans: increased CO2 in the lungs, in the blood, and in the brain (which is associated with reduced oxygen and brain activity), increased sleepiness and anxiety (both of which harm cognitive function), and acidosis (lowered blood pH - which leads to symptoms such as restlessness and a rise in blood pressure). One study in juvenile rats found "reduced levels of neuroprotective growth factor", which harmed brain development and impaired learning and memory.

What about babies and children? Developing fetuses? The elderly? The sick?  All unknown. Also, studies looking at effects are short term, but our future (if not changed) will have us exposed to higher and higher levels of CO2 all the time.

Further information: Scientists from NOAA and Scripps Institution of Oceanography monitor the values at the Mauna Loa Observatory and found that monthly carbon dioxide (CO2) values at Mauna Loa first breached the 400 ppm threshold in 2014. Go look at the graph and click on all the links. Yes, it's scary unless we all make a huge effort to cut global CO2 emissions.

World Meteorological Association: Carbon dioxide levels continue at record levels, despite COVID-19 lockdown

NOTE: The atmosphere  is the air and gases in it that surround the earth.