2024届高三英语一轮复习时文阅读专项训练12

· 保护牙齿可能对大脑有益 Taking good care of your teeth may be linked to better brain health, according to a study published in the July 5, 2023, online issue of Neurology. "Our study found that gum（牙龈） disease and tooth loss were linked to brain shrinkage （萎缩） in the hippocampus, which plays a role in memory and Alzheimer's disease," said study author Satoshi Yamaguchi, Ph.D. of Tohoku University in Sendai, Japan. The study involved 172 people without memory problems. Their average age was 67. Participants had dental exams and took memory tests at the beginning of the study. They also had brain scans to measure the volume of their hippocampus at the beginning of the study. This was measured again four years later. For each participant, researchers counted the number of teeth and checked for amount of gum disease. Researchers found that the number of teeth and amount of gum disease was linked to changes in the left hippocampus of the brain. For people with mild gum disease, having fewer teeth was associated with a faster rate of brain shrinkage, which is the same for people with severe gum disease having more teeth. After adjusting for age, researchers found that for people with mild gum disease, the increase in the rate of brain shrinkage due to one less tooth was equal to nearly one year of brain aging. By contrast, for people with severe gum disease, the increase in brain shrinkage due to one more tooth was equal to 1.3 years of brain aging. "These results highlight the importance of preserving the health of the teeth and not just maintaining the teeth," Yamaguchi said. "The findings suggest that controlling the progression of gum disease through regular dental visits is crucial, and that teeth with severe gum disease may need to be removed and replaced with appropriate false ones." Yamaguchi said future studies are needed with larger groups of people. The limitation of the study is that it was conducted in one region of Japan, so the results may not be applied to