Did you know that the speed at which your body digests food not only affects how full you feel, but can also provide clues about your overall health?
It may come as a surprise, but actual research (including my own) shows that intestinal transit time (the time it takes for food to be eaten, digested, and excreted as waste) is associated with health problems. It has been shown that there is a possibility that
Think of your bowel transit time like a train journey. If the train runs slowly or stops for a long time at the station, everything will move backwards, causing delays and discomfort. However, if the train passes through the station too quickly, it will miss important stops where passengers need to get off.
For example, a 2004 study in the British Journal of Cancer found that slow intestinal transit time increases the risk of colon cancer. This is probably because the intestinal wall is exposed to potential carcinogens in the stool for a longer period of time.
Slow transit times can also affect the gut microbiome, the community of bacteria and other microorganisms that live there and play important roles in our health.
In my own research published in the journal Gut in 2021, my colleagues and I showed that slow transit times of 59 hours or more are associated with “bad” gut bacteria, which have previously been associated with markers of poor heart health. found that it was associated with increased levels. and inflammation.
Similarly, a recent study published in the journal Cell showed that people with slower transit times tend to have higher microbial loads (the total number of bacteria in their gut).
Although this is not inherently harmful, it can have negative effects under certain conditions. Normally, microorganisms in the intestine are excreted in the stool. However, if the transit time is slow, they will not be removed and will continue to proliferate.
Dietitian Dr. Emily Leeming explains that intestinal transit time (the time it takes for food to be eaten, digested, and excreted as waste) can be linked to health issues. .
This produces more microorganisms to feed on, but it takes longer to reach the microorganisms, leaving them with less food sources, primarily fiber. The microorganisms can then produce harmful byproducts associated with inflammation, which are often precursors to illness and disease.
(This is one of the reasons why I advise people to eat more fiber. 90 per cent of the UK population don’t meet the recommended 30g of fiber per day. Don’t forget to drink plenty of water.)
However, rapid intestinal transit times can also cause problems. When food moves through the intestines too quickly, nutrient absorption is reduced, resulting in an energy crash and can leave you hungry soon after eating.
It can also reduce the total number of microorganisms living in your gut (some of which play an important role in protecting you from infections and are related to mood). This is because by moving rapidly, bacteria have limited time to interact with the food you eat, creating molecules that support your health.
Occasional high-speed movements, such as when you’re nervous (because your body’s fight-or-flight response kicks in and digestion is stimulated), do not cause harm, but frequent high-speed movements can cause fatigue, moodiness, or It may cause you to feel unwell. .
The optimal time for digestion is believed to be approximately 14 to 58 hours. This is long enough for nutrients to be absorbed, but not so long that gut microbes use up 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 not only gut health but also the immune system.
So how do you measure intestinal transit time?
Certain gut bacteria are associated with positive emotions, allowing you to better self-regulate your emotions
A clear sign of slow intestinal transit time is constipation. This means straining, hard stools, or fewer than three stools per week for at least three months.
A 2019 study published in the American Journal of Gastroenterology found that one in three Brits who think they are not constipated actually meet the medical definition of constipation.
You may also have slow intestinal transit times without meeting the full definition of constipation. Although you may have regular bowel movements, they take longer to defecate, causing discomfort and bloating.
Scientific research tends to use expensive, high-tech tools. For example, an ingestible capsule with a sensor that tracks the time it takes for food to pass through the intestines and sends precise data to an external device. However, there are some free ways to measure your intestinal transit time at home (note, however, that these are not diagnostic tests).
In our study, we used bright blue muffins dyed with food coloring and measured the time from when participants ate them to when they noticed a change in the color of their stool.
You can try this by making blue muffins at home, or you can eat sweet corn (easier to find in your stool) or beets (which can make your poop red) instead.
The good news is that your diet can help you achieve optimal digestion speed, keep you feeling full and energized for longer, and reduce bloating and digestive discomfort. Here are my tips for effective foods.
Blue Muffin is useful for measuring a person’s intestinal transit time. You can easily make them by adapting the muffin recipe and adding blue food coloring.
A small but powerful kiwi fruit
Kiwifruit’s water-retaining fiber increases water and volume in the intestines, softening stools and improving bowel movements.
A large study published in The American Journal of Gastroenterology in 2023 found that eating two kiwifruits a day for one month improved constipation and digestive discomfort, and reduced bowel movements for one week. It was found that the number increases by approximately 1.5 times.
A 2010 study published in the Asia Pacific Journal of Clinical Nutrition found that consuming two kiwis a day shortened intestinal transit time by an average of 8 hours in people with constipation.
natural fiber supplements
Psyllium husk is a fiber supplement that can be easily found at most pharmacies and is widely available in powder or capsule form (follow the manufacturer’s guidelines for dosage).
Made from the seeds of the shrub-like herb Plantago ovata, it is rich in a type of fiber that absorbs water in the intestines and regulates bowel movements.
Even if you suffer from constipation or loose stools, psyllium can help soften your stools to make them easier to pass, or make them larger and slow them down.
A large study published in The American Journal of Gastroenterology in 2023 found that eating two kiwifruits a day for a month can help reduce constipation.
Rye bread is richer in fiber than other grains, which reduces intestinal transit time.
Let’s darken the bread
Rye is rich in dietary fiber than other grains, and rye bread reduces slow intestinal transit time by 23 percent compared to white bread, increases the number of bowel movements by an additional 1.4 times per week, and increases the impact of gut bacteria. It has been shown to reduce the levels of compounds that can cause A 2010 study published in the Journal of Nutrition linked it to colon cancer.
100g of Pumpernickel rye bread contains 7g of fiber, which is a significant amount compared to the recommended intake of 30g.
Dried fruit with a punch
You’re probably familiar with the idea that dried fruits are a concentrated source of dietary fiber that can help you stay on track. And some dried fruits have been particularly proven to be effective.
A 2016 study published in the Asia Pacific Journal of Clinical Nutrition found that eating 300g of fig paste (if you don’t have this available, try the same amount of dried or fresh figs) every day for two months , it was found that there was a small but positive effect on health. Constipation (of course, there are a lot of figs, so you may want to try other methods first).
Raisins may also be helpful. A small study published in the British Journal of Nutrition in 2013 found that consuming 120g of raisins per day not only improved intestinal transit times by 14 hours in participants, but also lowered levels of short-chain fatty acids. I found out it was expensive. , beneficial molecules produced by the gut microbiome.
…and don’t forget to stay hydrated (including tea and coffee)
This softens your stool and makes it easier for your intestinal muscles to move food at a healthy rate.
A good rule of thumb is eight glasses of water a day, but your hydration needs will vary depending on your exercise and weather.
An easy way to check is to look at the color of your urine. The color of your urine should be a light lemonade color.
