News

You are never really alone.

That's because your body is home to 100 trillion microbes. A typical adult will harbour more than a pound of bacteria in the gut – not to mention the microscopic residents that dwell within virtually every other cavity and surface of the human form.

But don't feel grossed out or the least bit violated. They are mostly friendly inhabitants that aid digestion and help protect you from malevolent pathogens.

And now, for the first time, researchers have produced an atlas of bacterial diversity across the human body. The study, conducted at the University of Coloradois being published Friday in the journal Science.

“Within the human body there is a very large range of different bacterial communities,” said Rob Knight, the senior scientist on the project. What's more, the team found surprisingly wide variability in bacterial communities from person to person. In other words, we don't all carry the same species of microbes, although they may perform similar functions.

This latest study was made possible by recent advances in genetic technology that allow researchers to identify vast amounts of microbial DNA relatively quickly and cheaply.

The team collected microbes from nine healthy adults. The subjects were analyzed from head to toe – and almost every place in between – on several different occasions. Samples were taken from ear canals, nostrils, mouth, lower intestine and 18 different skin sites, ranging from the armpits to the back of the knees.

So why is it so important to document our unseen companions? Dr. Knight says they are thought to play a pivotal role in our overall health. For instance, some research suggests bacteria in the vagina help guard against yeast infections. Other studies indicate gut bacteria can influence how our bodies react to certain medications. There is even reason to believe microbes affect our ability to lose weight on certain diets.

And that means the health differences between people may be partly explained by the variety of different bacteria that make up our own personal microbial communities.

Tobacco moratorium

Despite government restrictions on tobacco advertising and promotion, the industry is always coming up with fresh ways to hook new customers or convince existing smokers not to quit.

For instance, the launch of flavoured cigarillos and slim cigarettes seemed especially alluring to youth. And the introduction of “activated carbon filter cigarettes” created the impression these new products aren't as harmful as previous brands – even though all tobacco is bad for your health.

It can often take years for governments to legislate specific product bans. So, several public-interest groups are now calling for a moratorium on all new tobacco products.

“The introducing of new products is a back-door way to evade public health measures and promote tobacco products and smoking,” Flory Doucas, co-director of the Quebec Coalition for Tobacco Control, said in a statement released at a conference in Montreal this week.

She added that “a moratorium on new tobacco products would be more effective and make more sense” than the government trying to play catch-up with each and every marketing ploy.

Manufacturers might challenge a moratorium in court, arguing that it violates free-trade agreements or infringes on their freedom of expression. But Ms. Doucas believes legislation could be crafted to withstand a counteroffensive.

Cynthia Callard, executive director of Physicians for a Smoke-Free Canada, agrees. “We see a moratorium as a complementary strategy that would reinforce other [anti-smoking] measures.”

Java jolt

Middle-aged shift workers should resist the temptation to use caffeine as “a pick-me-upper” late at night, says University of Montreal researcher Julie Carrier. A jolt of java will only make it harder for them to get the restorative sleep they need to face another night shift.

Most people know that caffeinated drinks can disrupt sleep, said Dr. Carrier. But few realize that “the older you get, the more affected your sleep will be by coffee,” she added.

“As you age, you have less slow-wave sleep – or deep sleep – and that means your sleep is already vulnerable to challenges,” she said. Caffeine also results in a reduction of slow-wave sleep.

In a new study, published in the journal Sleep Medicine, she showed that the combined effects of age and caffeine produced extremely fragmented sleep among middle-aged subjects. She recommends that everyone over 40 cut back on caffeine – particularly those who frequently work nights shifts and must slumber during the day just as their biological clock sends a strong wake-up signal.