Having clean teeth and gums may do more than add sparkle to your smile. It might also reduce your risk of a heart attack or stroke.
In recent years, a growing body of medical evidence has suggested that poor oral health contributes to cardiovascular disease. According to one theory, oral bacteria enter the bloodstream and then damage blood vessels, setting the stage for strokes and heart attacks.
Now, an international team of scientists has taken the research a big step further by seeing what happened when they dramatically improved the oral hygiene of a group of volunteers.
The study involved 120 patients suffering from periodontal disease, or chronically inflamed gums resulting from a buildup of bacterial plaque.
About half the volunteers received regular dental care and instructions on proper cleaning. The others got intensive dental therapy, including deep cleaning and removal of bad teeth, to reverse the periodontal disease.
As part of the study, the researchers also did a series of tests to measure the condition of volunteers' blood vessels, including checks for signs of inflammation.
After six months, those who received the intensive dental therapy showed significant improvement in their blood vessels, compared with those in the control group.
The results, published in the New England Journal of Medicine, clearly establish "a causal link between periodontal disease and blood vessel function," the lead researcher, Maurizio Tonetti, said in an e-mail from Switzerland.
Of course, heart disease is a complex illness involving many different risk factors. And a lot more research is needed before scientists can say conclusively that better oral hygiene can reduce the risk of heart attacks and strokes.
Still, periodontal disease is extremely common, Dr. Tonetti noted. It's a research trail worth following.
Garlic folk tales
Garlic might be able to drive away vampires, but it won't drive down your cholesterol levels, according to the most rigorous study ever done on the pungent bulb.
Previous studies conducted in test tubes and on animals indicated that garlic might be useful in controlling low-density lipoprotein (LDL), the so-called "bad" cholesterol. But human trials seemed to produce inconsistent results.
So researchers at the Stanford University School of Medicine, with $1.5-million from the U.S. National Institutes of Health, set out to do a definitive study.
They recruited 192 patients with moderately elevated cholesterol levels. The volunteers were randomly slotted into one of four groups. Some ate a clove of raw garlic a day in a specially prepared sandwich; another group got a powdered garlic supplement sold under the brand name Garlicin; others took a commercial garlic extract, Kyolic; and the fourth group received an inactive placebo.
After six months of treatment, there was no difference among the groups, according to the findings published in Archives of Internal Medicine.
"It didn't budge," said the lead researcher, Christopher Gardner. "The average LDL cholesterol was virtually unchanged from month to month to month across the three different types of garlic."
Dr. Gardner said it is possible that garlic, which is steeped in ancient folklore, might have other medicinal properties. But "if you are taking it for cholesterol lowering, then you are not using your money wisely."
Grey power
Aging Canadians, take heart: Your career isn't necessarily over just because you're older.
A study of airplane pilots showed that years of deeply ingrained expertise can compensate for the loss of certain skills that happen through the natural aging process.
The U.S. researchers tested 118 pilots, aged 40 to 69, in flight simulators to measure their performance. They were tested once a year for a period of three years.
Not surprisingly, younger pilots scored higher at certain tasks, such as those measuring reaction time. But experienced senior pilots still performed at a very high level, said Joy Taylor, the lead researcher at the Aging Clinical Research Center in Palo Alto, Calif.
Some pilots who stay active can maintain their performance over time "due to a mechanism of preserved task-specific knowledge known as crystallized intelligence," according to the study published in the journal Neurology. Older pilots might be a few milliseconds slower, but they can rely on their years of experience to help them do the right thing.
"This study underscores the importance of looking at factors other than age alone," Dr. Taylor said. "More important factors are expert knowledge, mental agility and health status."
As more people approach the traditional retirement age, job simulations and other objective tests "could help in fairly testing for competence in the workplace," she said.