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Category: brain

Published on Leave a comment on Main Difference Between Male and Female Brains Is Size

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"

Published on Leave a comment on Avoid Caffeine During Pregnancy

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"

Published on Leave a comment on Link Between Common Parasite and Brain Cancer

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"

Published on Leave a comment on We Need to Discuss the Effects On Humans Of Rising Carbon Dioxide Levels

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.

Published on Leave a comment on Pesticides Linked to Parkinson’s Disease

Study after study finds all sorts of negative health effects from exposure to pesticides, including cancers, endocrine (hormone) disruption, and neurological effects.  Pesticide exposures can occur in the home, at work or school, in the air (drift), and in food and water. A recent study found that higher chronic pesticide exposure, such as occupational exposure (e.g. farm worker), is linked to developing Parkinson's disease.

University of California San Francisco (UCSF) researchers found the higher rates of Parkinson's disease both in people who have genetic susceptibility to developing the disease, and also in those who don't have a genetic susceptibility. Meaning everyone is at risk for developing Parkinson's disease with enough chronic exposure.

Studies find that chronic exposure to some pesticides has a higher risk for Parkinson's disease than others, and especially strong links are with the pesticides 2,4-D, chlorpyrifos, paraquat, glyphosate, and rotenone. Some countries, including in Europe and Canada, ban the use of some of these chemicals due to concerns about links to Parkinson’s, but the U.S. only restricts the use of some of them (e.g. paraquat).

Many pesticides are neurotoxins. Dr. Ray Dorsey (publisher of book: Ending Parkinson's Disease: A Prescription for Action ) said studies show a dose-response effect between chronic pesticide exposure and Parkinson's disease: "an almost perfect correlation between the amount of pesticides used in certain communities and the rates of PD. He points out that Parkinson's disease is the world's fastest growing brain disease with a lifetime risk of about 1 in 15. (That's high!)

Bottom line: Try to minimize your exposure to pesticides. Organic farms don't use the pesticides implicated in neurological harm - because organic standards don't allow it. Also, use organic or least-toxic Integrated Pest Management (IPM) for pest control in your home. Avoid using pesticides in your yard, especially the lawn. Stay away from recently pesticide treated areas. Eat organic foods as much as possible.

In the following article: sporadic Parkinson's disease means it happened spontaneously, which is different from someone having a genetic risk factor. From Beyond Pesticides: Pesticide Exposure Increases the Risk of Developing Gene-Specific and Sporadic Parkinson’s Disease Incidences

Research at the University of California San Francisco (UCSF) finds that pesticide exposure increases the risk of developing Parkinson’s disease (PD), regardless of whether disease onset is idiopathic (spontaneous) or genetic (GBA genetic risk variant). Although the exact etiology [cause] of PD remains unknown, epidemiological and toxicological research repeatedly identifies exposure to pesticides, as well as specific gene-pesticide interactions, as significant adverse risk factors that contribute to PD. Furthermore, this study, “Gene Variants May Affect PD Risk After Pesticide Exposure,” suggests that environmental triggers like occupational exposure to pesticides can prompt PD in individuals with or without the genetic precursor.  ...continue reading "Pesticides Linked to Parkinson’s Disease"

Published on Leave a comment on Vitamin D Levels During Pregnancy Associated With A Child’s IQ

Pregnancy is a time when one should try to eat as well as possible, especially for the health of the developing baby. Included in this is the baby's brain development and later intellectual functioning (neurocognitive development). A recent study found that a mother's vitamin D levels during pregnancy are associated with the IQ of the child - that is, higher levels of vitamin D during the second trimester  of pregnancy were associated with higher IQs at age 4 to 6 in the child.

Just keep in mind that it's an association - it does not mean that lower vitamin D levels cause lower IQ. Vitamin D levels go hand in hand with other things - for example, vitamin D levels are lower when a person has chronic inflammation or an underlying health condition. Other studies have had mixed results - some had similar findings of effects on intellectual development, but others did not. Black women are at higher risk of vitamin D deficiencies due to their skin melanin content (harder to get enough vitamin D from the sun).

However, these results do add support for trying to correct vitamin D deficiencies and keeping vitamin D levels higher during pregnancy - by taking supplements and getting sunlight. Note that it's very hard to get enough vitamin D through food. The researchers said that prenatal supplements typically contain 400–600 IU vitamin D, but this is probably insufficient to correct vitamin D deficiencies, in which case they recommend daily supplementation of 800 to 1000 IU vitamin D.

From Medical Xpress: Vitamin D levels during pregnancy linked with child IQ

Vitamin D is a critical nutrient and has many important functions in the body. A mother's vitamin D supply is passed to her baby in utero and helps regulate processes including brain development. A study published today in The Journal of Nutrition showed that mothers' vitamin D levels during pregnancy were associated with their children's IQ, suggesting that higher vitamin D levels in pregnancy may lead to greater childhood IQ scores. The study also identified significantly lower levels of vitamin D levels among Black pregnant women. ...continue reading "Vitamin D Levels During Pregnancy Associated With A Child’s IQ"

Published on Leave a comment on Some Intense Exercise Is Beneficial For The Brain

Exercise is good for memory and the brain. University of Geneva researchers found that even one short bout of moderate or intense exercise improves memory and acquisition of new motor skills.

In a well-designed study, 15 healthy volunteers exercised intensely for 15 minutes, moderately for 30 minutes, or rested, and were given various tests both before and after exercising. They found that exercise had beneficial effects on the hippocampus of the brain, and that physical exercise improves some types of memory. The hippocampus plays a critical role in learning and memory.

Intense physical exercise improves memory functions by increasing neural plasticity in the hippocampus. [Note: increasing plasticity of the brain is good.] The findings of this study match earlier animal research, in that "a single session of physical exercise has been shown to boost anandamide (AEA), an endocannabinoid known to promote hippocampal plasticity".

The researchers felt that this study provided additional evidence that physical exercise could possibly prevent cognitive decline as people age. Typically some cognitive decline, along with a reduction in brain volume, occurs in the aging brain, so slowing down or preventing cognitive decline is desirable. Bottom line: Get out and move, move, move for brain health! By the way, all physical activity is better than no activity.

From Medical Xpress: Sport and memory go hand in hand

If sport is good for the body, it also seems to be good for the brain. By evaluating memory performance following a sport session, neuroscientists from the University of Geneva (UNIGE) demonstrate that an intensive physical exercise session as short as 15 minutes on a bicycle improves memory, including the acquisition of new motor skills. ...continue reading "Some Intense Exercise Is Beneficial For The Brain"

Published on Leave a comment on Smoking Linked To Hemorrhagic Stroke Deaths

Looking for  a reason to stop smoking? How about brain bleeds? A recent study found that cigarette smoking is linked to death from the extremely serious bleeding stroke called subarachnoid hemorrhage (SAH).

Researchers in Finland followed 16,282 twin pairs for over 40 years. They found that for both men and women smoking was strongly linked to death from a subarachnoid hemorrhage, and was more important than any genetic factors (which had a "modest link" to only a few deaths). They also did not find a link with high blood pressure, or levels of physical activity.

A subarachnoid hemorrhage is a type of stroke that results from bleeding in the space between the brain and the thin membrane that covers it (subarachnoid space). A SAH occurs in about 5 to 6% of all strokes. It is a medical emergency that frequently leads to death.

Excerpts from Science Daily: Smoking linked to bleeding in the brain in large, long-term study of twins

An investigation of the Finnish Twin Cohort reaffirmed a link between smoking and subarachnoid hemorrhage (SAH), a type of bleeding stroke that occurs under the membrane that covers the brain and is frequently fatal. The new study by researchers in Finland is published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.  ...continue reading "Smoking Linked To Hemorrhagic Stroke Deaths"

Published on Leave a comment on Eating More Fruits and Berries Lowers Risk of Dementia

A recent study found that eating higher levels of foods with flavonoids (e.g. berries, apples, and tea) may lower the risk of later development of Alzheimer's disease and other age-related dementias.

Since currently there are no effective drugs that prevent or actual medical treatments for dementia, it is great that what a person eats (the dietary pattern) long-term may be protective. Something we can do to lower our risk for Alzheimer's disease and other dementias!

Tufts University researchers followed 2801 persons (50 years and older) for 20 years and found that those with the lowest intake of flavonoid rich foods (especially 3 flavonoid classes: flavonols, anthocyanins, and flavonoid polymers) had a 20 to 40% higher chance of developing Alzheimer's disease and other dementias, when compared to those eating the most flavonoid rich foods. [Note: The lowest intake group averaged  about 1 1/2 apples, but no berries or tea per month.]

Flavonoids are naturally occurring bioactive pigments, of which there are 7 types, that are found in plant-based foods. Some good sources of different types of flavonoids include berries & red wine (anthocyanin rich), onions & apples, pears (flavonol rich), citrus fruits and juices, teas, dark chocolate, parsley, celery,and soy products.

Eating a variety of fruits and vegetables appears to be best for health benefits. There is no one super-food. Other studies also find that the Mediterranean diet, which emphasizes fruits and vegetables (thus flavonoid rich), may reduce the risk of cognitive decline and dementia, including Alzheimer's disease.

Why are flavonoid containing foods protective, specifically "neuroprotective"? Studies suggest that they do the following: antioxidant effects, protect neurons from neurotoxins and combat neuroinflammation, and favorable changes in brain blood flow,

Excerpts from Science Daily: More berries, apples and tea may have protective benefits against Alzheimer's

Older adults who consumed small amounts of flavonoid-rich foods, such as berries, apples and tea, were two to four times more likely to develop Alzheimer's disease and related dementias over 20 years compared with people whose intake was higher, according to a new study led by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University.  ...continue reading "Eating More Fruits and Berries Lowers Risk of Dementia"

Published on Leave a comment on Flu and Pneumonia Vaccinations Linked To a Lower Alzheimer’s Disease Risk

Could our risk of getting Alzheimer's disease be lowered by something as simple as getting flu and pneumonia vaccines? Two large observational studies suggest just that.

The studies, which were presented at this year's Alzheimer's Association International Conference (AAIC), found that: getting a flu vaccine (with more than one flu shot over the years even better), getting the flu vaccines at a younger age, and additionally getting the pneumonia vaccine between the ages of 65 and 75 years were all associated with a lowered risk of Alzheimer's disease. It's as if they somehow were brain protective.

Excerpts from Medscape: Flu, Pneumonia Vaccination Tied to Lower Dementia Risk

Vaccinations against influenza and pneumonia may help protect against Alzheimer's disease (AD), two large observational studies suggest.

In a cohort study of more than 9000 older adults, receiving a single influenza vaccination was associated with a 17% lower prevalence of AD compared with not receiving the vaccine. In addition, for those who were vaccinated more than once over the years, there was an additional 13% reduction in AD incidence.  ...continue reading "Flu and Pneumonia Vaccinations Linked To a Lower Alzheimer’s Disease Risk"