雅思阅读 · The Hidden World of Gut Bacteria

生物主题。题型：填空 + T/F/NG。难度：中等（P2）。

正文 Passage

The human body is home to trillions of bacteria, most of which live in the digestive system. Collectively known as the gut microbiome, these microscopic organisms weigh about two kilograms and outnumber human cells by at least three to one. Far from being unwelcome guests, they play a central role in keeping us healthy.

The microbiome helps us digest food that the human body cannot break down on its own, particularly fibre from plants. It produces vitamins, trains the immune system, and even influences our mood and behaviour through a chemical pathway known as the gut-brain axis. A growing body of research suggests that the composition of gut bacteria is linked to conditions as diverse as obesity, depression, allergies and autoimmune diseases.

This has led to the idea that manipulating the microbiome could treat illness. The most extreme example is faecal microbiota transplantation (FMT), in which beneficial bacteria from a healthy donor are introduced into a patient's gut. FMT has proved remarkably effective against recurrent infections by the bacterium Clostridioides difficile, a hospital-acquired infection that kills thousands each year. Trials are now under way to test FMT against obesity, diabetes and even depression.

But the microbiome is not simply a good-to-have accessory. It is shaped by everything we eat, by the antibiotics we take, and by the way we were born — babies delivered by caesarean section, for instance, miss out on the bacteria they would have picked up during a vaginal birth. Modern living, with its sterilised environments, highly processed food and overuse of antibiotics, may be depriving us of the microbial diversity our bodies evolved to expect.

Some researchers worry that we are oversimplifying a complex system. The microbiome is not a single organ to be fixed; it is an ecosystem of hundreds of species that interact with each other and with the human body in ways we barely understand. A treatment that works for one person may do nothing for another. Probiotic yoghurts and drinks, widely marketed as health boosters, have so far failed to produce consistent results in rigorous trials.

Still, the gut microbiome remains one of the most promising frontiers in medicine. The day may come when a simple stool test tells doctors not just what is wrong, but which combination of bacteria, fibres and foods will put it right.

题目 Questions

Questions 1-5: Complete the notes. NO MORE THAN TWO WORDS.

• The gut microbiome weighs about (1) ____________.
• Gut bacteria help digest (2) ____________ from plants.
• The chemical link between the gut and the brain is called the (3) ____________.
• FMT has been very effective against infections by (4) ____________.
• Babies born by (5) ____________ miss out on certain bacteria.

Questions 6-10: T/F/NG

6. Gut bacteria outnumber human cells by at least three to one.

7. FMT has already been proven to cure depression.

8. Antibiotics can affect the composition of gut bacteria.

9. Probiotic yoghurts consistently improve health in rigorous trials.

10. All scientists agree that the microbiome is fully understood.

答案 Answers

核心词汇

microbiome / bacteria / digestive / fibre / vitamin / immune system / gut-brain axis / obesity / depression / FMT / transplant / antibiotic / caesarean / probiotic / ecosystem