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

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

请帮忙给出正确答案和分析，谢谢！