雅思阅读 023 · The Hype behind Probiotics

改编自 Scientific American（Lydia Denworth, 2026）。题型：选择题 + T/F/NG + 填空。难度：中等偏上（Passage 2，约 900 词）。

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🎧 课文朗读音频（约 1 分钟）

正文 Passage

There are microbes living in medicine cabinets across the U.S., next to the aspirin and the Band-Aids. And people want them there.

Probiotics are capsules or pills with live microorganisms — almost always bacteria or yeast — that are supposed to confer health benefits once people swallow them. Some people bought the pills at the recommendation of doctors. Others, aware of new evidence about the ways microbes in our guts influence physical functioning, bought them on their own.

But despite this popularity, evidence that probiotics help people is surprisingly limited. Medical organisations such as the American Gastroenterological Association recommend only a few specific bacterial strains for a few well-defined conditions. "The average person likely doesn't need probiotics and is unlikely to benefit from them for day-to-day use," says gastroenterologist Omeed Alipour.

"That cautious perspective is widely shared across the medical and scientific community," says Yosra Helmy, a microbiologist at the University of Kentucky. "It's not because probiotics lack promise but because the science remains uneven, highly strain-specific and difficult to generalise."

Probiotics are attractive because our gastrointestinal systems naturally contain trillions of microbes, collectively called the gut microbiome. Much of this microbiota is beneficial. It keeps the gut's microbial community in balance and supports protective intestine and stomach linings. It also produces metabolites such as short-chain fatty acids that nourish cells, regulate the immune system and metabolic balance, and help to produce vitamins.

We regularly replenish our helpful gut bacteria when we eat yogurt, kefir, kimchi, kombucha and miso. Fiber-rich diets provide fuel for the beneficial bugs once they are in our systems.

In a few situations, diet alone is not enough. Some of the strongest evidence in favour of added probiotics is for two rare conditions. One is necrotising enterocolitis, which kills intestinal tissue in premature infants. The other is pouchitis, inflammation of the small pouch created as part of surgery for ulcerative colitis.

For the wider population, a prevalent evidence-based reason to take probiotics is to prevent or minimise diarrhoea brought on by antibiotics. That is because antibiotics do not target just the bad bacteria; they tend to wipe out entire colonies of helpful bacteria as well. Studies show that some Lactobacillus and Bifidobacterium species, as well as a yeast called Saccharomyces boulardii, can help with antibiotic-induced problems.

Studies have also found that probiotics reduce infections from the bacterium Clostridioides difficile, which can damage the colon. But the effect is small. Gastroenterologists recommend probiotics only for those at high risk of infection: the elderly, those who have had previous infections, or those taking multiple antibiotics for long periods.

Sufferers of irritable bowel syndrome (IBS) would love to find a probiotic that reduces symptoms such as bloating, constipation and diarrhoea. Recent studies have found that some strains bring improvement for some people, but gastroenterologists cannot predict who will benefit.

Until newer products are available, experts recommend that anyone looking to improve gut health begin with nutrition. A diet rich in fiber and fermented foods is a better solution than buying a bottle of pills. For those who still want to try probiotics, the good news is that the risks are low overall. But their use should always be targeted and limited: try one for four to eight weeks and then reassess your symptoms. "They are not a universal solution," Helmy says.

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题目 Questions

Questions 1-4: Choose the correct letter.

1. What are probiotics?

• A. painkillers
• B. capsules with live microorganisms
• C. herbal teas
• D. vitamins

2. According to Alipour, the average person:

• A. needs probiotics every day
• B. is unlikely to benefit from day-to-day probiotic use
• C. should take probiotics only when sick
• D. should avoid all probiotics

3. Which condition has strong evidence for probiotic use?

• A. the common cold
• B. necrotising enterocolitis in premature infants
• C. obesity
• D. diabetes

4. Why do antibiotics cause diarrhoea?

• A. they kill helpful bacteria as well as bad ones
• B. they strengthen the immune system
• C. they increase fiber intake
• D. they have no side effects

Questions 5-8: T/F/NG

5. Probiotics are rigorously evaluated as medicines in the U.S.

6. The gut microbiome helps produce vitamins.

7. Probiotics work for everyone with IBS.

8. Experts recommend a diet rich in fiber and fermented foods.

Questions 9-13: Complete the notes. Choose NO MORE THAN TWO WORDS.

• Probiotics are capsules with live (9) ____________.
• The gut microbiome produces short-chain (10) ____________ that nourish cells.
• Antibiotics tend to wipe out entire colonies of (11) ____________ bacteria.
• Probiotics reduce infections from (12) ____________ difficile.
• Experts recommend trying a probiotic for four to eight weeks and then (13) ____________ symptoms.

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答案 Answers

题号	答案
1	B
2	B
3	B
4	A
5	FALSE（dietary supplements, not rigorously evaluated）
6	TRUE
7	FALSE（some strains help some people）
8	TRUE
9	microorganisms
10	fatty acids
11	helpful
12	Clostridioides
13	reassess

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核心词汇

probiotic / gut microbiome / bacteria / yeast / microorganism / strain / diarrhoea / antibiotic / inflammation / ulcerative colitis / IBS / fermented food / fiber / immune system / supplement