Is Your Gut Microbiome the Key to Health and Happiness? - Unit 7

C1 Advanced · Multiple Choice Reading · Ready for C1 Advanced 4th Edition Workbook, Macmillan Education

You are going to read an article about the gut microbiome. For questions 1–6, choose the answer (A, B, C or D) which you think fits best according to the text.

The gut microbiome is a vast ecosystem of organisms such as bacteria, yeasts, fungi, viruses and protozoans that live in our digestive pipes, which collectively weigh up to 2 kg (heavier than the average brain). It is increasingly treated by scientists as an organ in its own right. Each gut contains about 100 trillion bacteria, many of which are vital, breaking down food and toxins, making vitamins and training our immune systems. Over the past decade, research has suggested the gut microbiome might potentially be as complex and influential as our genes when it comes to our health and happiness. As well as being implicated in mental health issues, it’s also thought the gut microbiome may influence our athleticism, weight, immune function, inflammation, allergies, metabolism and appetite. The hope is that it may one day be possible to diagnose some diseases and health problems by analysing gut bacteria and to treat them with specific bacteria. An understanding of the gut’s importance to our well-being now fuels a global probiotic market projected to grow to $64 billion within a few years. Probiotics are bacteria associated with healthy gut flora – such as the Lactobacillus acidophilus and Bifidobacterium lactis we see advertised in ‘live’ yoghurt. The challenge lies in pinpointing the cause and effect of specific bacteria and translating the results into treatments. This isn’t easy. Giulia Enders, who wrote the international bestseller Gut, says, ‘We have no idea what all the seemingly normal bugs are doing. We don’t really know which bacteria does what in who, so it is a big experiment.’ Philip WJ Burnet, an associate professor at the University of Oxford, has had promising results testing the effects of prebiotics on mood. Essentially, prebiotics ‘are dietary fibres that feed bacteria already in our gut,’ he says. ‘If you eat these fibres, you grow lots of species of good bacteria.’ His trial tested a commercially sold prebiotic and suggested it might have the potential to reduce anxiety. In his study, people without the supplement paid more attention to negative imagery, but those on the prebiotic paid more attention to the positive. He is cautious to point out, however, that when people take antidepressants, these early changes don’t necessarily lead to their symptoms improving. He also stresses, ‘Prebiotics, or indeed any dietary supplements, are unlikely to replace the drugs used for the treatment of psychiatric illnesses. But they might be useful in helping medication work better in people who do not respond very well to them.’ This year, the health journalist Michael Mosley tested the sleep-enhancing effects of prebiotics for his documentary The Truth About Sleep, and Burnet oversaw the five-day experiment. At the start of the trial, Mosley spent 21% of his time in bed awake – by the end, that had shrunk to 8%. Of all the strategies Mosley tested to treat his insomnia, he found prebiotics the most effective. So should we all be hitting the prebiotics? People hate hearing it, says Burnet, but supplements can’t replace a healthy, varied diet. Lentils, asparagus and artichokes are examples of natural prebiotic sources. ‘But who wants to eat a bowl of artichokes when you can just pour some prebiotic powder on your cornflakes?’ Enders thinks it’s only a matter of time before bacteria supplements are available to support weight loss. Bacteria associated with leanness and obesity have already been identified (if you give mice bacteria from an obese human, the mice will become obese too, and if you give mice bacteria from a lean human, they will stay lean). And the common Lactobacillus reuteri has been shown to increase levels of leptin, a hormone that makes you feel full up, while lowering the hunger hormone ghrelin. That is not to say, she warns, that ‘other aspects of weight gain should be put aside, but it could be a great additional help’. All the gut experts are keen to point out that no matter how repetitive the advice, a varied diet rich in fresh vegetables and fermented foods, such as sauerkraut, along with exercise and stress management, is the route to sustained gut (and general) health. John Cryan, an expert in the gut microbiome, believes we are five years off cracking the human gut microbiome, but of course, there’s no way of knowing. Could it be a similar case to that of the human genome – another great hope in personalised preventative medicine, but which becomes more complex the more we learn about it? ‘It could be,’ he admits. ‘The only difference is that, unlike your genome, which you can’t do an awful lot with, your microbiome is potentially modifiable.’ Enders agrees. ‘I think the belief that many or even all diseases are rooted in only the gut bacteria will have to turn out as wrong,’ she says. ‘Humans are wonderfully complex animals with multiple connections to mind, food, life and the environment. The cool thing is that it is far easier to change the gut compared with our genes.’

contains organisms that we couldn’t survive without.

is just as important as any other organ in the body.

can cause a range of physical and mental health problems.

has a greater impact on our well-being than our genes.

The writer claims that the gut microbiome

they have been successfully used to treat health problems.

nobody knows whether they are as good for us as the adverts claim.

they are the probiotics that the reader is most likely to have heard of.

they are at the heart of a multi-billion-dollar industry.

The writer mentions Lactobacillus acidophilus and Bifidobacterium lactis because

might one day be used instead of conventional medication.

seem to be more effective than some antidepressants.

appear to make people think less negatively.

are naturally produced by our digestive systems.

Burnet’s research into prebiotics and mood suggests that certain prebiotics

the prebiotics in some natural foods are more effective than prebiotic powder.

some people would prefer to take a supplement instead of changing their diet.

Available as a free printable PDF worksheet with an optional answer key.

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