VOA慢速英语--研究表明细菌可能导致焦虑和抑郁

Study Suggests Possible Bacteria Link to Nervousness, Depression

A new study of mice suggests bacteria may help to cause anxiety and depression in overweight people.

The research raises questions about whether changing organisms living inside our bodies or changes in diet could help treat these conditions.

A 2017 study found that one-third of the world’s population is overweight or considered obese¹.

When people become obese, this changes the processes by which the body uses food to make energy, build tissue and remove waste material. Left untreated, these changes can lead to diabetes².

Diabetes is a serious condition. It affects how your body uses blood sugar. Obese people also have higher rates of anxiety and depression than other individuals.

Ronald Kahn studies diabetes at Harvard Medical School in Massachusetts. He says researchers have wondered if people suffer from depression because they are obese or because of their metabolism³.

"And we asked the question, 'Maybe the metabolic⁴ link is at least partly fueled by the microbiome,'" Kahn said.

The microbiome is the community of bacteria, fungi⁵ and other microorganisms living in your stomach. It changes with your diet. And Kahn says those changes may affect both body and mind.

To test the theory, he and his research team fed mice a high-fat diet and studied their behavior as the animals became obese.

In one test, they put mice in a box divided into a darkened area on one side and a light area on the other side. They found that the more nervous, anxious mice liked to spend time on the dark side.

"And a mouse on a high fat diet will spend more time in the dark than a mouse on a normal… diet will. So, they have more sign of anxiety," Khan said.

The anxiety went away when the mice were given antibiotic⁶ drugs.

The researchers said this suggests that the bacteria were helping⁷ make the mice nervous.

The researchers then wanted to see if they could produce the same effect by giving the same bacteria to animals raised in a bacteria-free environment, with no microbes of their own.

They found that it did. Microbes from obese mice made the bacteria-free mice anxious. Microbes from obese mice given antibiotics⁸ did not.

"It was actually quite a surprise,” Khan said. “Even though we had seen some effects on metabolism in the rest of the body, I was very surprised how dramatic and how clear the effects were also on the brain and on behavior."

A report on the study appears in the journal Molecular⁹ Psychiatry¹⁰.

Kahn noted¹¹, however, that the new study does not mean antibiotics are the cure for depression. The drug kills both good and bad microbes. Also, drug misuse¹² is making these powerful medicines less effective.

Another important point, he said, is that what happens in mice does not necessarily happen in humans, or it may only happen for some people.

Gregory Simon is a mental health specialist at the Kaiser Permanente Washington Heath Research Institute. He said that it is also important to remember there is much more going on with people than just their microbes.

"The difficulty is, both of these things, depression and obesity¹³, are complicated things that have multiple, multiple factors influencing them," Simon said.

He says genetics, environment, social influences and our microbes all help shape people and their behavior.

I’m Phil Dierking.

Words in This Story

antibiotic - n. a drug that is used to kill harmful bacteria and to cure infection?

anxiety - n. fear or nervousness about what might happen?

dramatic - adj. sudden and extreme?

factor - n. something that helps produce or influence a result?

fungi - n. any one of a group of living things (such as molds, mushrooms, or yeasts) that often look like plants but have no flowers and that live on dead or decaying things?

obese - adj. fat in a way that is unhealthy?

journal - n. a magazine that reports on things of special interest to a particular group of people?

metabolism - n. the chemical processes by which a plant or an animal uses food, water, etc., to grow and heal and to make energy?

multiple - adj. more than on

1 obese   

adj.过度肥胖的，肥大的

参考例句：

• The old man is really obese,it can't be healthy.那位老人确实过于肥胖了，不能算是健康。
• Being obese and lazy is dangerous to health.又胖又懒危害健康。

2 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

3 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

4 metabolic   

adj.新陈代谢的

参考例句：

• Impressive metabolic alternations have been undergone during embryogenesis.在胚胎发生期间经历了深刻的代谢变化。
• A number of intoxicants are associated with metabolic acidosis.许多毒性物质可引起代谢性酸中毒。

5 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

6 antibiotic   

adj.抗菌的；n.抗生素

参考例句：

• The doctor said that I should take some antibiotic.医生说我应该服些用抗生素。
• Antibiotic can be used against infection.抗菌素可以用来防止感染。

7 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

8 antibiotics   

n.（用作复数）抗生素；（用作单数）抗生物质的研究；抗生素，抗菌素( antibiotic的名词复数 )

参考例句：

• the discovery of antibiotics in the 20th century 20世纪抗生素的发现
• The doctor gave me a prescription for antibiotics. 医生给我开了抗生素。

9 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

10 psychiatry   

n.精神病学，精神病疗法

参考例句：

• The study appeared in the Amercian science Journal of Psychiatry.这个研究发表在美国精神病学的杂志上。
• A physician is someone who specializes in psychiatry.精神病专家是专门从事精神病治疗的人。

11 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

12 misuse   

n.误用，滥用；vt.误用，滥用

参考例句：

• It disturbs me profoundly that you so misuse your talents.你如此滥用自己的才能，使我深感不安。
• He was sacked for computer misuse.他因滥用计算机而被解雇了。

13 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。