(Sep. 6, 2010) — Plaque-causing bacteria can jailbreak from the mouth into the bloodstream and increase your risk of heart attack, says a scientist at the Society for General Microbiology's autumn meeting in Nottingham.
Professor Howard Jenkinson, from the University of Bristol explains how oral bacteria can wreak havoc if they are not kept in check by regular brushing and flossing. "Poor dental hygiene can lead to bleeding gums, providing bacteria with an escape route into the bloodstream, where they can initiate blood clots leading to heart disease," he said.
Streptococcus bacteria commonly live in the mouth, confined within communities termed biofilms and are responsible for causing tooth plaque and gum disease. The University of Bristol researchers, in collaboration with scientists at the Royal College of Surgeons in Ireland (RCSI), have shown that once let loose in the bloodstream, Streptococcus bacteria can use a protein on their surface, called PadA, as a weapon to force platelets in the blood to bind together and form clots.
Inducing blood clots is a selfish trick used by bacteria, as Professor Jenkinson points out. "When the platelets clump together they completely encase the bacteria. This provides a protective cover not only from the immune system, but also from antibiotics that might be used to treat infection," he said. "Unfortunately, as well as helping out the bacteria, platelet clumping can cause small blood clots, growths on the heart valves (endocarditis), or inflammation of blood vessels that can block the blood supply to the heart and brain."
Professor Jenkinson said the research highlights a very important public health message. "People need to be aware that as well keeping a check on their diet, blood pressure, cholesterol and fitness levels, they also need to maintain good dental hygiene to minimise their risk of heart problems."
The team is using a brand-new blood flow model, developed by Dr Steve Kerrigan at the RCSI, School of Pharmacy, Dublin, that mimics conditions in the human circulatory system. "We are currently investigating how the platelet-activating function of PadA can be blocked. This could eventually lead to new treatments for cardiovascular disease which is the biggest killer in the developed world," said Professor Jenkinson.
ScienceDaily
(July 14, 2010) — Black tea, a Southern staple and the world's most consumed beverage, may contain higher concentrations of fluoride than previously thought, which could pose problems for the heaviest tea drinkers, Medical College of Georgia researchers say.
"The additional fluoride from drinking two to four cups of tea a day won't harm anyone; it's the very heavy tea drinkers who could get in trouble," said Dr. Gary Whitford, Regents Professor of oral biology in the School of Dentistry. He presented his findings at the 2010 International Association of Dental Research Conference in Barcelona, Spain.
Most published reports show 1 to 5 milligrams of fluoride per liter of black tea, but a new study shows that number could be as high as 9 milligrams.
Fluoride is known to help prevent dental cavities, but long-term ingestion of excessive amounts could cause bone problems. The average person ingests a very safe amount, 2 to 3 milligrams, daily through fluoridated drinking water, toothpaste and food. It would take ingesting about 20 milligrams a day over 10 or more years before posing a significant risk to bone health.
Whitford discovered that the fluoride concentration in black tea had long been underestimated when he began analyzing data from four patients with advanced skeletal fluorosis, a disease caused by excessive fluoride consumption and characterized by joint and bone pain and damage. While it is extremely rare in the United States, the common link between these four patients was their tea consumption -- each person drank 1 to 2 gallons of tea daily for the past 10 to 30 years.
"When we tested the patients' tea brands using a traditional method, we found the fluoride concentrations to be very low, so we wondered if that method was detecting all of the fluoride," Whitford said, noting that the tea plant, Camellia sinensis, creates a quandary when measuring fluoride. Unique among other plants, it accumulates huge concentrations of fluoride and aluminum in its leaves -- each mineral ranges from 600 to more than 1,000 milligrams per kilogram of leaves. When the leaves are brewed for tea, some of the minerals leach into the beverage.
Most published studies about black tea traditionally have used a method of measuring fluoride that doesn't account for the amount that combines with aluminum to form insoluble aluminum fluoride, which is not detected by the fluoride electrode. Whitford compared that method with a diffusion method, which breaks the aluminum-fluoride bond so that all fluoride in the tea samples can be extracted and measured.
He tested seven brands of store-bought black tea, steeping each for five minutes in deionized water, which contains no fluoride. The amount of fluoride in each sample was 1.4 to 3.3 times higher using the diffusion method than the traditional method.
The new information shouldn't deter tea drinkers, as the beverage is safe and some teas even have health benefits, Whitford said. "The bottom line is to enjoy your favorite tea, but like everything else, drink it in moderation."
(Sep. 6, 2010) — Plaque-causing bacteria can jailbreak from the mouth into the bloodstream and increase your risk of heart attack, says a scientist at the Society for General Microbiology's autumn meeting in Nottingham.
(July 14, 2010) — Black tea, a Southern staple and the world's most consumed beverage, may contain higher concentrations of fluoride than previously thought, which could pose problems for the heaviest tea drinkers, Medical College of Georgia researchers say.
