Want To Know If You Have Good Gut Health? Try Turning Your Poop Blue.

This experiment tests your gut microbiome, which plays a role in your digestion, mood and more. Here's why and how to do it.
Will you take part in the blue poop challenge?
Will you take part in the blue poop challenge?

Staring down in the toilet bowl, Tim Spector had momentarily forgotten he’d eaten a muffin filled with food coloring. Poking from the well of water was the contents of his bowel, in a shocking shade of electric blue.

Spector, a professor of genetic epidemiology at King’s College London and author of “The Diet Myth,” is calling for members of the public to follow suit and eat blue-colored muffins to monitor their gut transit times. This is the time it takes for food to travel from your mouth to the other end.

The aim is to educate people about their biology, specifically their gut health, and to get people talking about the glamorous topic of poop.

Spector was involved in a study, published in the medical journal Gut, which saw 863 healthy individuals eat food with blue dye to monitor gut transit times. It found longer gut transit times were generally linked with more undesirable bacteria, while shorter transit times indicated a healthier gut.

The gut microbiome is crucial for our health, Spector said. Think of it a bit like a community of microbes made up of things like microorganisms, bacteria, viruses and fungi.

“There are trillions of these guys and they are crucial for many bits of our body running well,” Spector said. “This includes things like how well we digest food, how we deposit fat, our mental state, whether we’re hungry or full, and it’s really important for our immune system as well.”

He wants people to eat blue-colored food ― specifically two blue muffins ― and then time how long it takes for them to have blue-green poop. It’s one of the “easiest ways” to get an idea of what’s happening in your gut, he said, as you can monitor exactly how quickly your body processes it.

How To Take Part

1. Bake your own muffins (with food coloring) at home. Eat two for breakfast and start your timer.

2. Look out for blue-green poop when you go to the toilet. Jot down the time you spot it.

3. Get your results and discover your “poo personality” on the Blue Poop Challenge website.

We know from Spector’s research that shorter gut transit times of around 20 hours are indicative of a healthier and happier gut, while longer transit times (30+ hours) suggest a more unhealthy microbiome.

People who are constipated have a slow gut transit time. “They are generally more likely to have bad gut health and bad microbes,” Spector said. “This study showed there was ... a clear link between having a speedy transit time and having a healthy range of diverse microbes that are good for your health.”

His study suggests gut transit times are a more informative marker of your gut microbiome function than traditional measures used currently, such as the Bristol stool chart. (You might remember this from your doctor’s office. The poster shows you different poop types, from hard, rabbit-like rocks to runny sludge. Patients are asked to pick which one of these seven types they are.)

Ultimately, Spector hopes the Blue Poop Campaign will get people talking about their bowel movements a bit more.

“We want to educate people so they start talking about gut health without embarrassment,” said Spector, who admits he’s done this experiment himself a couple of times. “It’s always a shock because I forget until I look in the toilet,” he laughed. “It’s a shocking blue!” His gut transit time is around 18 hours, which is pretty healthy.

What if my gut transit time is too slow?

It you take part and notice your transit time is on the slow side, there are four changes you can make to improve your gut microbiome (and speed things up).

1. Eat more diverse type of plants. Ideally you should be eating 30 plants a week, Spector said, which includes fruits, vegetables, nuts, seeds and herbs. This helps improve the diversity of your gut microbiome while also giving you plenty of fiber to move things along.

2. Pick brightly colored plants to eat. Spector said foods with polyphenols in them are great. Think: brightly colored berries, apples, nuts, green lettuce and apricots.

3. Eat more fermented foods. This includes yogurt as well as the four Ks: kefir, kombucha, kimchi and kraut (or sauerkraut).

4. Avoid ultra processed foods as these are bad for gut health. Ultra processed foods are not “modified foods” – like frozen or canned products – but foods that have undergone multiple processes which result “in little, if any, intact whole foods being present,” Spector said. Examples include sweets, packaged snacks like biscuits and crisps, ready meals and soft drinks.

This post originally appeared in HuffPost UK.

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