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Humans (slightly) perk up their ears when listening intently to sounds! A recent study found that muscles around the human ear make tiny subtle movements (ear 'perking' movements) when focusing on novel, unusual, or specific sounds. These movements of muscles around the ears also indicate the direction of sounds a person is paying attention to.

It's not the obvious pointing of the ears that dogs and cats do - it's much more subtle and can be seen in the "electrical activity of muscles around the ear". Thus the researchers write: "Our species may nevertheless have retained a vestigial pinna-orienting system that has persisted as a 'neural fossil’ within in the brain for about 25 million years. Consistent with this hypothesis, we demonstrate that the direction of auditory attention is reflected in sustained electrical activity of muscles within the vestigial auriculomotor system. "

From Science Daily: Our animal inheritance: Humans perk up their ears, too, when they hear interesting sounds

Many animals, including dogs, cats and various species of monkeys, will move their ears to better focus their attention on a novel sound.  ...continue reading "Humans Slightly Perk Up Their Ears To Sounds"

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Great news for those who enjoy a glass of wine or beer every day! A large study found that light to moderate drinking among middle-aged to older adults may preserve brain function as they age. Over a 10 year period, those who drank a drink or two a day tended to have better test scores in a series of tests that measured cognitive functioning.

Normally there is some cognitive decline as people age. But researchers found that low to moderate drinking (less than 8 drinks per week for women and less than 15 drinks for men) was associated with consistently higher mental functioning and slower rates of cognitive decline (when compared to those who never drank or drank more). They found that these associations were similar for both men and women, but stronger among white participants than black participants.

Just keep in mind that while this and other studies find cognitive benefits from drinking alcohol (in humans and mice), other studies find harms from drinking alcohol, specifically increased risk of many cancers.

From Science Daily: Light drinking may protect brain function

Light to moderate drinking may preserve brain function in older age, according to a new study from the University of Georgia.  ...continue reading "Is A Daily Glass Of Alcohol Good For The Brain?"

There have been concerns for years about the food additive titanium dioxide. This is because it may be in nanoparticle form, and recent studies have raised concerns that nanoparticles can travel to other organs in the body (because they are so small), and are inflammatory. Nanoparticles are so small that they are measured in nanometers or billionths of one meter.

It is added to food and medicines (e.g. Allegra) to make colors whiter and brighter, so it's not needed at all. It is in many processed foods, including candy and baked goods, so children actually consume more of it than adults. In Europe titanium dioxide nanoparticles (particles less than 100nm) are mainly found in the food additive called E171. Nanoparticles make up about 36% of the particles in E171.

Now a new study, even though done with mice, has raised more health concerns about titanium dioxide. Mice consuming titanium dioxide in their diet had significantly altered composition of their gut microbes, inflammation of their colon (the intestines), and changes in function of the liver. The effect was bigger in obese mice.

From Science Daily: Common food additive causes adverse health effects in mice

A common food additive, recently banned in France but allowed in the U.S. and many other countries, was found to significantly alter gut microbiota in mice, causing inflammation in the colon and changes in protein expression in the liver, according to research led by a University of Massachusetts Amherst food scientist.  ...continue reading "Titanium Dioxide Doesn’t Belong In Food"

High heat is not good for a developing baby during pregnancy. And neither is air pollution. A just published large study concluded that higher temperatures from climate change and increased air pollution (from ozone and fine particulates PM2.5) increases the risk of giving birth to premature, underweight, or stillborn children.

The researchers analyzed 68 studies, for a total of 32,798,152 births in the United States. Almost 33 million births! Another important finding was that those at highest risk were persons with asthma and minority groups, especially black mothers.

The researchers point out that animal studies find the same things: "that both air pollutant and heat exposure may contribute to adverse obstetrical outcomes". So there is lots of support for these findings of harmful effects.

Another recent study (by Univ. of California researchers) drew similar conclusions: that exposure to heatwaves during the week before birth was strongly linked to an increased risk of preterm delivery. And the hotter the temperature or the longer the heatwave, the greater the risk.

Since the long-term forecast is for increasing temperatures and longer duration heat waves throughout the world, these findings are very worrisome.

The study published in the JAMA Network Open (a Journal of the American Medical Association): Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the USA: Systematic Review

A NY Times discussion of the findings: Climate Change Tied to Pregnancy Risks, Affecting Black Mothers Most

Discussion of earlier study (Feb. 2020) from Science Daily: Heatwave exposure linked to increased risk of preterm birth in California

Will 2020 be the warmest year on record? Early signs are suggesting that it might be - e.g. May was the warmest May globally, and the forecast is for a hotter than average summer. As month after month breaks temperature records, the question is - at what point will certain areas of the US (and other parts of the world) become unbearable? What can humans tolerate?

Temperatures are inching towards 120 degrees F in the summer in southwest United States, and higher elsewhere in the world. This is incredibly high! [For comparison, at 133 degrees Fahrenheit the coronavirus Covid-19 is killed off after 15 minutes.] While it varies for each species, the general rule for organisms is: "Above a certain temperature, a cell will collapse and die."

A Scientific American article wrote about humans: "So how does heat kill? When core body temperature rises too high, everything breaks down: The gut leaks toxins into the body, cells begin to die, and a devastating inflammatory response can occur."

There are stages to how the body responds: First heat exhaustion occurs. This can be reversed by moving the person to a cool location, loosening clothing, and applying cool, wet wash clothes to the body. But if the person does't get cooled off, then it advances to heat stroke. This is where their core body temperature rises above 104 degrees F (40 degrees C). Heat stroke can trigger seizures, convulsions, coma, and even death.

Another important point: humans can tolerate higher heat if the humidity is low. People cool off by sweating, and if the humidity is high, they can't. So keep all these things in mind when contemplating rising summer heat spells. What will humans eventually do as temperatures keep going up year after year? Mass migrations? Try to cope somehow?

Excerpts from Science News For Students: Explainer: How heat kills

The human body can’t handle excessive heat. The processes that keep us alive work best within a certain temperature window. That’s generally between about 36° and 37° Celsius (96.8° to 98.6° Fahrenheit), depending on the person.  ...continue reading "How Hot Is Too Hot For Humans?"

Eat dinner earlier, not later. A small study looked at the time dinner was eaten and the interval to bedtime. They found that eating a late dinner affects the metabolism negatively: blood sugar levels were higher, and the amount of ingested fat burned was lower, when compared to those eating an earlier dinner. Dinner was the same foods, just eaten at 2 different times.

The 20 young, healthy participants ate dinner at either 6 pm or 10 pm, and bedtime was at 11 pm. According to the results of the study, eating a late dinner alters metabolic markers during sleep in a way that could lead to obesity or diabetes. "The peak glucose level after late dinner was about 18% higher, and the amount of fat burned overnight decreased by about 10% compared to eating an earlier dinner."

This adds to evidence suggesting that the time meals are eaten can influence the development of obesity and metabolic syndrome. Sleep lowers the metabolic rate. Other studies have also found that eating earlier is better than later: for example, weight loss is greater in those eating the main meal of the day earlier rather than later.

The weird thing was, these effects were found even though the early dinner group was given a 200 calorie snack at 10 pm. So it's not like they had zero calories after their 6 pm dinner. (The late dinner group ate the same snack at 6 pm.) Based on these findings, I wonder how much better the metabolic markers would have been if zero calories were eaten after the 6 pm dinner?

From Science Daily: People who eat a late dinner may gain weight

Eating a late dinner may contribute to weight gain and high blood sugar, according to a small study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.  ...continue reading "Try Not To Eat Dinner Close To Bedtime"

It turns out that it rains tons and tons of tiny pieces of plastic each year! These tiny pieces of plastic, called microplastics, are carried like dust in the wind and  air currents around the earth, and eventually come down like dust. Or particles from nearby urban areas can come down in rain, storms, and snow.

Researchers from a study looking at dust and rainwater samples in 11 western United States parks estimate that more than 1000 tons of this stuff fall each year just on this area alone. They estimate that 4% of the dust deposited on the land had microplastics in them, and nearly all samples had microplastics in them. The researchers found that an average of "132 plastics per square meter" was deposited each day. Yikes!

Where does it come from? Most of the microparticles were microfibers that came from synthetic textiles used for clothing (shed when worn or from washing, drying) and carpeting. But also industrial processes, outdoor equipment, industrial paints and coatings). Since plastics are persistant, they break up into little pieces over time and become microplastics.

Which means tons and tons more of these microplastics are falling on the rest of the United States and world, including us. How much are we breathing in? And what, if anything, is it doing to us?

So far studies have found microplastics in foods, drinking water, estimates of humans ingesting more than 74,000 microplastics each year, that we are breathing them in, and that they are found in human stool . Also, it is known that microplastics can accumulate and harm wildlife, and can move up the food chain.

It doesn't look good for us as plastic production (348 million metric tons of plastic produced worldwide in 2017) and plastics in the environment keep increasing. We need to address this problem. Now.

Excerpts from a good article on this study: A threat from above: Plastic rains down on US National Parks and Wilderness areas

Last August, scientists delivered the chilling news that microplastics suspended in the Earth's atmosphere were being deposited in remote areas of the Arctic and Europe. Now researchers report similar microplastic accumulation in iconic American protected areas including the Grand Canyon and Joshua Tree.  ...continue reading "It’s Raining Microplastics"

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Normal aging. We all wonder what happens in normal aging, and now a large study confirms what many already thought: kidney function deteriorates as a normal part of aging. It's not an illness, it's normal.

The international study found that whether a person is healthy or has some existing problems doesn't matter - the kidneys normally deteriorate as we age. Just quicker and with more loss in some people, and more so in those with illnesses such as diabetes. Yup, normal aging is tough.

From Medical Xpress: Kidneys deteriorate with age, regardless of health

An international study carried out on nearly 3000 people in Norway, Germany and Iceland shows that human kidney function deteriorates with age regardless of the presence of other diseases. The results from the study have recently been published in the Journal of the American Society of Nephrology (JASN). To discover how kidney function progresses, the researchers examined the kidney function of a group of people between the ages of 50 and 70, and two groups of people between the ages of 70 to 95.  ...continue reading "Kidney Function Normally Deteriorates As We Age"

Does exposure to common PFAS chemicals contribute to an earlier age for menopause? A recent University of Michigan study found an association between blood levels of PFAS (per-and polyfluoroalkyl substances) in women and age at menopause. Women with the highest levels of PFAS in their blood had menopause 2 years earlier than those with lower levels.

PFAS are commonly known as "forever chemicals" because they persist in the environment and in humans. These chemicals have been widely used in many industrial and consumer products, such as non-stick cookware and food packaging, including microwave popcorn bags. They are also endocrine (hormone) disruptors and are thought to have an effect on ovarian aging.

What you can do: Don't microwave food, including popcorn, in the packaging it came in. Use microwave safe dishes instead.  Also, avoid nonstick cookware, and instead use plain stainless steel cookware.

From Science Daily: PFAS exposure may cause early menopause in women

Per- and polyfluoroalkyl substance (PFAS) exposure may cause menopause to occur two years earlier in women, according to a new study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism.  ...continue reading "Common PFAS Chemical Exposure and Age At Menopause"

Dogs exposed to lawn pesticides develop similar cancers as humans exposed to lawn pesticides, but in dogs the cancers appear with a much shorter time lag - only a few years. In contrast, human cancers can take decades to appear. This is why dogs can be viewed as "sentinel species" - they show risks or dangers due to chemical exposures in the environment earlier than humans.

This is why this study having both humans and dogs wear silicone monitoring devices to measure chemicals (pesticides, flame retardants, and phthalates) they are exposed to in the environment is so interesting. Both dogs and humans showed similar exposure levels to the chemicals. Think of it - whatever our pet dogs are exposed to in the environment, we also are exposed to it. And if something causes harm, we probably also are being harmed by it.

From Science Daily: Monitoring environmental exposures in dogs could be early warning system for human health

Man's best friend may also be man's best bet for figuring out how environmental chemicals could impact our health. Researchers from North Carolina State University and Duke University's Nicholas School of the Environment used silicone dog tags as passive environmental samplers to collect information about everyday chemical exposures, and found that dogs could be an important sentinel species for the long term effects of environmental chemicals ...continue reading "Are Our Dogs Early Warning Systems For Harmful Chemical Exposures?"