Ever had questions about how exercise might affect your gut health, or, vice versa? You're not alone. We put the frequently asked questions to consultant gastroenterologist Dr Sarmed Sami as part of our 'Ask the Expert' series.
And, with features editor David Bradford suffering a bout of bothersome gut symptoms, we sent his sample off for a microbiome test, to find out just how useful the results can be.
Gut health FAQ
Is exercise such as cycling good for the gut?
It is excellent for gut microbiome diversity. Regular exercise improves the good bacteria in the gut and reduces the bad bacteria, which is associated with better health outcomes. Exercise improves the motility of the gut, meaning you’ll feel less bloated. It also improves digestion and helps ensure regular bowel movements, as well as reducing the risk of liver and bowel cancer. The list goes on.
Can long bouts of high-intensity exercise cause gut problems?
Yes, strenuous exercise can cause gut symptoms such as acid reflux and may upset the digestive system. This is because, during strenuous exercise, blood supply to the muscles is prioritised, taking blood away from the gut. As a result, the gut effectively goes to sleep and food takes much longer to digest. Cyclists are especially prone to reflux and heartburn because of being in a leant-forward position.
How long before riding should a cyclist eat?
Ideally three to four hours, as that’s how long it takes to digest a meal. Obviously you may need to refuel during a ride by consuming low-volume, high-calorie foods. After exercise, you need a cool- down period of half an hour to an hour, to allow blood supply to the gut to normalise.
Are high-sugar energy products bad for the gut?
There is no evidence of any serious harm to gut health from these products, provided their use is limited to during exercise. It is better for gut health to take on some food, rather than none, during prolonged exercise.
What are the key markers of poor gut health?
Symptoms such as persistent diarrhoea, blood in the stool, nausea, vomiting, food getting stuck when you eat or recurring stomach pains may indicate an underlying medical condition and should be investigated by a doctor. Milder symptoms such as heartburn, indigestion, bloating, inconsistent stool, etc, may indicate poor gut health rather than disease, and tests may be needed.
Is there any value in paying for a microbiome test?
At this stage, there is no practical value. I have not tested my own microbiome, and I’m a gut doctor. If someone has an unhealthy lifestyle, their microbiome is likely to be in a poor state, but the solution is to change their lifestyle.
Are probiotic products beneficial?
In patients with symptoms, I recommend probiotics for three months to see if they help. In people with no symptoms and who have a healthy lifestyle, no, there is little evidence of any benefit.
What about fermented foods, are they worth the cash?
There is evidence that the prebiotics in fermented foods may be beneficial by improving microbiome diversity. Even better is a Mediterranean diet, which is excellent for the gut microbiome.
What are your top diet tips for good gut health?
Everyone needs a healthy source of protein every day, ideally from fish or plant sources. Minimise your intake of red meat. Olive oil has many health benefits. Include wholegrain, healthy carbs: wild rice, wholegrain bread, oats, etc. Then you need your fibre: plentiful fruit and veg, as well as nuts and seeds.
What is the gut-brain axis all about?
If you are stressed or nervous in your life, your body releases stress hormones and neurotransmitters that can make the gut more sensitive, such as in IBS, which is now referred to as a disorder or gut-brain interaction. The worry can exacerbate the symptoms and it becomes a vicious cycle. Meditation, yoga and CBT can help in these circumstances.
CW takes the biome test
Late last year, I started experiencing some bothersome gut symptoms, writes features editor David Bradford.
Nothing alarming, but a level of gassiness, gurgling and discomfort that just wasn’t normal for me. My GP ran blood and stool tests, which found nought untoward. So when I noticed that gut health brand Chuckling Goat was offering a microbiome test (£295), I decided to post off some poo, hoping for helpful insight.
About four weeks later, my results were in. Overall, my microbiome wellness was rated 8/10, with good microbial diversity and no nasty pathogens detected, but my pro-, pre- and post-biotics were rated only 6/10. So what now? Chuckling Goat’s “action plan” recommended that I start eating fermented foods alongside taking their Complete Prebiotic, as well as their Tummy Tea to help settle my stomach. But did my (apparently inconclusive) results really explain my symptoms, and would the proposed solutions actually help? I turned to NHS gut specialist Dr Andrew Goddard.
“Your scores are a bit arbitrary, as scoring microbial health isn’t simple,” said Goddard. “Having said that, you do have a reasonably diverse microbiome with lots of ‘good’ bacteria. You must be eating a reasonably balanced diet.”
What about the action plan? “It is mostly reasonable,” replied Goddard. “There is good evidence that fermented foods can change your microbiome and reduce some markers of inflammation, provided you keep eating them long-term.
“There is some sense in the advice,” he concluded, “but little evidence for the expensive supplements recommended. You’d have to repeat the microbiome test after making the changes, and even then, no one knows what those results really mean.”