Gut expert reveals surprising blue muffin trick that can show if your bowel movements are healthy – as sluggish toilet habits are linked to colon cancer

Did you know that the rate at which your body digests food not only affects how full you feel, but can also provide clues about your overall health?

This may surprise you, but research (including my own) shows that intestinal transit time – the time it takes from eating food until it is digested and excreted as waste – may be linked to health problems.

Think of your transit time like a train journey: if the train creeps or stalls at a station for too long, everything backs up, causing delays and inconvenience. But if the train rushes through the stations too quickly, it misses important stops where passengers need to get off.

For example, slow intestinal transit time is associated with a greater risk of colon cancer, according to a 2004 study in the British Journal of Cancer — possibly because it prolongs the intestinal lining’s exposure to potential carcinogens in feces.

A slow transit time can also affect the gut microbiome – the community of bacteria and other microbes that live there and play a key role in our health.

In my own research, published in the journal Gut in 2021, my colleagues and I found that a slow transit time of more than 59 hours was associated with higher levels of ‘bad’ gut bacteria previously linked to markers of poor heart health. and inflammation.

Similarly, a recent study in the journal Cell found that people with slow transit times tend to have higher microbial loads (the total number of bacteria in the intestines).

While this is not inherently harmful, it can have negative consequences under certain circumstances. Normally, microbes in the intestines are excreted through the feces. But if the transit time is slow, they are not eliminated and continue to multiply.

This creates more microbes to feed on, while their food source, mainly fiber, becomes scarcer the longer it takes to reach them. The microbes can then eventually produce harmful byproducts related to inflammation, which is often a harbinger of disease and illness.

(This is one reason why I advise people to eat more fiber – as 90 per cent of the UK population don’t meet the recommended 30 grams of fiber per day – don’t forget to drink plenty of fluids too.)

But rapid intestinal transit can also cause problems. Food that moves through the intestines too quickly can lead to poorer nutrient absorption, resulting in energy crashes and leaving you feeling hungry soon after eating.

It can also reduce the overall number of microbes in your gut (some of which play a crucial role in protecting against infections, or are linked to your mood) – that’s because rapid transit limits the time in which bacteria interact with the food you eat . and create the molecules that support your well-being.

Although occasional bouts of rapid transit, such as when you’re nervous (when your body’s fight-or-flight response kicks in and digestion speeds up), don’t cause any harm, frequent occurrences can leave you feeling tired, moody or unwell . .

The sweet spot for digestion is believed to be about 14 to 58 hours. This is long enough for the nutrients to be absorbed, but not so long that the gut microbes deplete their preferred food source.

This balance supports a ‘healthy’ gut microbiome, allowing the production of healthy molecules such as short-chain fatty acids, which support both your immune system and the health of your gut.

So, how do you measure transit time in your intestines?

An obvious sign of slow intestinal transit is constipation: straining, hard stools or less than three times a week for at least three months.

As many as one in three people in Britain who don’t think they are constipated actually meet the medical definition of constipation, according to a 2019 study in The American Journal of Gastroenterology.

And you can have slow intestinal transit without meeting the full definition of constipation; you may have regular bowel movements, but they take longer, leading to discomfort or bloating.

Scientific studies often use expensive high-tech instruments; Ingestible capsules with sensors that track how long it takes for food to travel through the intestines, then transmit accurate data to an external device. But there are a few ways you can measure intestinal transit time for free at home (note: these are not diagnostic tests).

In our study, we used bright blue muffins – dyed with food coloring – and measured the time between the time participants ate them and the time they noticed their stool changing color.

You can try this at home by making your own blue muffins, or instead you can eat sweetcorn (easy to spot in stool) or beetroot (which can turn your poop red).

The good news is that your diet can help you achieve optimal digestion so you feel full and energetic longer, limiting bloating and digestive problems. Here are my tips for the best foods that can help.

SMALL BUT MIGHTY KIWI FRUIT

Kiwi fruit increases the water content and volume in the intestines thanks to its water-retaining fibers that soften the stool and improve bowel movements.

A large study published in 2023 in The American Journal of Gastroenterology found that eating two kiwis a day for a month helped improve constipation and digestive discomfort, producing about 1.5 times more bowel movements per week.

A 2010 study published in the Asia Pacific Journal of Clinical Nutrition found that eating two kiwis a day shortened intestinal transit time in people with constipation by an average of eight hours.

THE NATURAL FIBER SUPPLEMENT

Psyllium husk is a fiber supplement that you can easily find at most pharmacies and is widely available in powder or capsule form (follow the manufacturer’s guidelines for dosage).

It is made from the seeds of the shrubby herb Plantago ovata and is packed with a type of fiber that absorbs water in the intestines and helps regulate bowel movements.

Whether you suffer from constipation or loose stools, psyllium can help by softening stools for easier passage, or bulking them up to slow down the stool.

GO DARK WITH YOUR BREAD

Rye is richer in dietary fiber than other grains, and rye bread has been shown to speed up slow intestinal transit by 23 percent compared to white bread, providing 1.4 extra bowel movements per week – and lowering levels of compounds possibly linked to colon cancer , according to a 2010 study in the Journal of Nutrition.

Just 100 grams of pumpernickel rye bread contains 7 grams of fiber, which makes a significant contribution to the recommended 30 grams.

DRIED FRUIT WITH ADDED PUNCH

You’re probably familiar with the idea that dried fruit helps you ‘stay regular’ as a concentrated source of fiber. And some dried fruits have been specifically shown to help.

A 2016 study in the Asia Pacific Journal of Clinical Nutrition found that eating 300 grams of fig paste (if you can’t get your hands on this, try a similar amount of dried or fresh figs) every day for two months had a small but positive effect on health. constipation (although that’s obviously a lot of figs, so you might want to try other strategies first).

Raisins can also be helpful: A small 2013 study published in the British Journal of Nutrition found that 120 grams of raisins per day not only improved participants’ intestinal transit time by 14 hours, but they also had higher levels of fatty acids with a had a short chain. , beneficial molecules produced by your gut microbiome.

…AND REMEMBER TO STAY HYDRATED WATER (including tea and coffee)

This softens the stool, making it easier for your intestinal muscles to move food at a healthy pace.

Although eight glasses of water per day can be a useful guideline, your hydration needs may vary depending on exercise and weather.

An easy way to check this is to look at the color of your urine; it should be a pale lemonade color.