Sugarless yoghurt could help beat bad breath, tooth decay and gum disease, say scientists.

Japanese researchers found eating the yoghurt(1)_____ levels of hydrogen sulphide—a major(2)_____ of bad breath—in 80% of volunteers. The keys are active bacteria in yoghurt. (3)_____ were presented at a meeting of the International Association for Dental Research. A total of 24 volunteers who(4)_____ in the study were given strict instructions(5)_____ oral hygiene, diet and medication intake. They spent two weeks (6)_____ yoghurts and similar foods, like cheese. Researchers then(7)_____ bacteria levels and odour-causing(8)_____, including hydrogen sulphide. The volunteers then ate 90 grams of yoghurt a day for six weeks. At the end of the study, researchers took(9)_____ again. They found hydrogen sulphide levels decreased in 80% of participants. Dr. Nigel Carter,(10)_____ executive of the British Dental Health Foundation, said: "The foundation has long been(11)_____ peoples attention to sugar-free yoghurts as a(12)_____ snack, so it is pleasing to hear that it may have oral health benefits we were previously(13)_____ of. "Although this research is still in the early stages there is no(14)_____ that sugar-free yoghurts provide a much healthier(15)_____ to sweets and chocolate, and we would encourage snackers to incorporate them into their(16)_____." However, Dr. Carter stressed that the best way to beat bad breath was by(17)_____ a good oral health routine. This(18)_____ brushing twice-a-day with fluoride(氟化物)toothpaste, cutting(19)_____ on the frequency of sugary snacks and drinks and visiting a dentist(20)_____.

(1)

A．increased

B．disturbed

C．averaged

D．reduced