Today's edition of Monday Musings is a quick account of two recent studies that highlight actual, literal threats to the fruitfulness and productivity of the human male loin. For years, the average male sperm count has been decreasing, especially in Western industrialized nations, by about 1% to 2% per year. Globally, of course, populations have been increasing, so sperm is successful by playing the numbers game, but we're worried about the individual. We're concerned with per capita sperm count. And it's been dropping.

But why?

For candidate number one, let's look to the bones. Bones, as you know, are active, living organs rather than passive inert structures. They grow (in response to a complex soup of hormonal messaging), they densify (in response to weight-bearing activity), they even atrophy (in response to a lack of weight-bearing activity and/or gravity). The primary regulators of bone growth and function are the sexual organs, which manufacture testosterone and estrogen, the hormones with a big effect on bone structure, but new mouse research is showing that it's a two-way street: osteocalcin, a hormone produced by bone osteoblasts, induces the testicles to produce testosterone (link). Male mice dads with low osteocalcin levels produced smaller, less frequent litters than male mice with normal levels of osteocalcin, who had larger litters and more of them. The tiny mice testicles actually carried a heretofore undiscovered osteocalcin receptor; we human males carry the same receptor in our testicles, so it's likely that osteocalcin plays a similar role in human male fertility. You'd better take your osteocalcin supplements, fellas!

Sodium lauryl sulfate is an effective degreaser used to clean oil stains from the floor of my mechanic's repair shop; what's it doing in my toothpaste and my daughter's bubble bath? And, why is the long-known carcinogen nitrosamine, banned in Canada and the European Union, still a common ingredient in my mascara, concealer, sunless tanning lotion and baby shampoo?

The simple answer is that the U.S. Food and Drug Administration still doesn't bother to regulate anything it dismisses as cosmetics -- any products used topically - despite the growing science showing how easily poisons and pollutants can be absorbed through the skin. Since the 1930s, the only thing the FDA regulates is the accuracy of the labeling on cosmetics.

As long as manufacturers list in gory detail the witches' brew of industrial chemicals, heavy metals, and toxic substances they blend into your eye cream or face wash, they are free to dump whatever they want into your epidermis.

All disease begins in the gut. - Hippocrates

Hippocrates said this more than 2,000 years ago, but we're only now coming to understand just how right he was. Research over the past two decades has revealed that gut health is critical to overall health, and that an unhealthy gut contributes to a wide range of diseases including diabetes, obesity, rheumatoid arthritis, autism spectrum disorder, depression and chronic fatigue syndrome.

In fact, many researchers (including myself) believe that supporting intestinal health and restoring the integrity of the gut barrier will be one of the most important goals of medicine in the 21st century.

There are two closely related variables that determine our gut health: the intestinal microbiota, or "gut flora", and the gut barrier. Let's discuss each of them in turn.

The gut flora: a healthy garden needs healthy soil

Our gut is home to approximately 100,000,000,000,000 (100 trillion) microorganisms. That's such a big number our human brains can't really comprehend it. One trillion dollar bills laid end-to-end would stretch from the earth to the sun - and back - with a lot of miles to spare. Do that 100 times and you start to get at least a vague idea of how much 100 trillion is.

The human gut contains 10 times more bacteria than all the human cells in the entire body, with over 400 known diverse bacterial species. In fact, you could say that we're more bacterial than we are human. Think about that one for a minute.

We've only recently begun to understand the extent of the gut flora's role in human health and disease. Among other things, the gut flora promotes normal gastrointestinal function, provides protection from infection, regulates metabolism and comprises more than 75% of our immune system. Dysregulated gut flora has been linked to diseases ranging from autism and depression to autoimmune conditions like Hashimoto's, inflammatory bowel disease and type 1 diabetes.

Unfortunately, several features of the modern lifestyle directly contribute to unhealthy gut flora:

• Antibiotics and other medications like birth control and NSAIDs
  
• Diets high in refined carbohydrates, sugar and processed foods
  
• Diets low in fermentable fibers
  
• Dietary toxins like wheat and industrial seed oils that cause leaky gut
  
• Chronic stress
  
• Chronic infections

Antibiotics are particularly harmful to the gut flora. Recent studies have shown that antibiotic use causes a profound and rapid loss of diversity and a shift in the composition of the gut flora. This diversity is not recovered after antibiotic use without intervention.

We also know that infants that aren't breast-fed and are born to mothers with bad gut flora are more likely to develop unhealthy gut bacteria, and that these early differences in gut flora may predict overweight, diabetes, eczema/psoriasis, depression and other health problems in the future.

If an individual with heart disease takes cocaine, their chance of having a heart attack increases 26-fold.

If a person with heart disease is exposed to heavy traffic fumes, their chance of having one increases by five per cent.

But because most people are exposed to traffic fumes, and only a small number take cocaine, on a population-wide basis traffic pollution triggers more heart attacks, concluded the Belgian researchers.

Applied to Britain, where there are around 124,000 heart attacks each year, traffic fumes could trigger 9,200 heart attacks, and cocaine around 1,100.

Scientists at Hasselt University and the Catholic University of Leuven, both in Belgium, came to their conclusions after looking at 36 studies.

New York - A groundbreaking study published today by one of the world's leading neuroscientists challenges the longstanding conviction that radiation emitted from cellphones is too weak to have an effect on the brain.

You can think of cellphone saturation as one giant, uncontrolled human experiment. There are now 293 million wireless connections in use in the United States, according to the trade group CTIA-The Wireless Association. And Americans log a staggering 2.26 trillion minutes yakking on those mobile devices every year - all at a time when the biological effects of cellphones remain controversial and the research on those effects often of dubious quality.

A study published today by leading researchers in the premiere medical journal JAMA hasn't found a smoking gun, but it does challenge the longstanding conviction that radiation emitted from cellphones is too weak to have an effect on the brain. It is notable not only for that finding and for appearing in a top journal - it is also turning heads because the lead researcher is Nora Volkow, director of the National Institute on Drug Abuse and one of the world's leading brain scientists.

Are cosmetics hazardous to your health?

Are girls increasing their risk of breast cancer by wearing blush, or their chances of reproductive abnormalities by applying lip gloss? It sounds crazy, but critics of the cosmetic industry say the concern is in the ingredients.

And it's not just environmental health groups sounding the alarm. Right now, new legislation is being introduced to close what legislators call "major loopholes" in a federal law. The bill's sponsors say the current law leaves Americans unknowingly exposed to potentially harmful mystery ingredients. That's why Eyewitness News is taking a hard look at the debate over whether cosmetics are truly hazardous to your health, especially for teenage girls.

Breakfast cereals, including corn flakes, bread and snacks are under threat after the US authorities approved the growing of a new GM maize.

The warning is significant because it comes from the North American Millers' Association, a food industry trade body, rather than green campaigners.

The new maize or corn has been genetically modified to be used to create ethanol, which is being promoted as a substitute for petrol.

However, wheat growers, food companies and millers in America, fear that food crops will become contaminated with the GM maize, which has been developed by biotech company Syngenta.

While the health risks of tobacco are well known, several studies have shown that people with a history of cigarette smoking have lower rates of neurodegenerative diseases like Parkinson's and Alzheimer's disease. However, the explanations for nicotine's neuroprotective effects continue to be debated.

Now a team of neuroscientists at the University of South Florida College of Medicine presents new evidence of an anti-inflammatory mechanism in the brain by which nicotine may protect against nerve cell death. Their study was published today in the Journal of Neurochemistry.

In laboratory experiments, the researchers demonstrated that nicotine inhibits activation of brain immune cells known as microglia. Chronic microglial activation is a sign of brain inflammation that is a key step in nerve cell death. The researchers also identified the specific site, the alpha-7 acetylcholine receptor subtype, to which nicotine binds to block microglial activation.

"We propose that nicotine's ability to prevent overactivation of microglia may be additional mechanism underlying nicotine's neuroprotective properties in the brain," said USF neuroscientist R. Douglas Shytle, PhD, lead author of the study.

"This finding lets us explore a new way of looking at neurodegenerative diseases like Alzheimer's," said Jun Tan, PhD, MD, principal investigator for the study. "A better understanding of the therapeutic aspects of nicotine may also help us develop drugs that mimic the beneficial action of nicotine without its unwanted side effects."

Speaking directly into a cellphone while holding it against your ear can alter brain activity in those areas closest to the device's antenna, claims a new study published Tuesday in the Journal of the American Medical Association (JAMA).

Researchers at the National Institutes of Health (NIH) and the Brookhaven National Laboratory in New York studied 47 adults over the course of a year, using positron emission tomography (PET) to measure their glucose metabolism, or the amount of sugar it takes a cell to fuel activity, according to Shirley S. Wang of the Wall Street Journal.

"They conducted scans after subjects had cellphones held to their left and right sides for 50 minutes on two different days," she said. "The first day neither cellphone was turned on. The second day the right phone was activated but muted so the participants wouldn't hear any noise. Because the participants didn't know which phone was active, their expectations couldn't skew the results."

They discovered that areas of the brain that were closest to the antenna became "significantly more active" when an operational cellphone was held next to the ear, even when it wasn't used to conduct a conversation, according to Wang.

In fact, their glucose metabolism levels spiked an average of 8% to 10%, which is said to be comparable to the increase in metabolism in the visual cortex when speaking to someone, study author Dr. Nora Volkow told the Wall Street Journal.

What remains unclear is whether or not that alteration of brain activity can cause harm to the orbitofrontal cortex, which is the region affected by the cellphone activity.

Students are using laptop computers more in the classroom and in their free time to stay connected, but this jump doesn't come without consequences: Kids, teens and young adults are consequently complaining of musculoskeletal discomfort - including neck, back and shoulder pain.

According to a new study conducted by researchers at Boston University about laptop use and discomfort levels published in the journal Ergonomics earlier this month, more than 50 percent of university students said they already experience pain attributed to the computer. Meanwhile, one in seven said they experienced pain after working on a computer for just one hour.