NEW YORK (NYTIMES) - Every few months, like clockwork, hundreds of videos promising tips and tricks to "hack" your gut flood TikTok.

In March, influencers pushed shots of aloe vera juice.

"My digestive system, like my gut health? Never been better," one gushed in a video with one million likes while tapping on a purple bottle of the drink.

Another, with the username "oliveoilqueen," advocated drinking extra-virgin olive oil every day in a video viewed more than 3.5 million times, claiming that doing so cleared her skin, made her periods less painful and fixed her frequent bloating.

Videos tagged with #guttok have garnered nearly 400 million views. They are crammed with suggestions for cucumber-ginger juices and boiled apples, bone broth in the morning and sludgy sweet potato soups at night.

There is not enough data to prove whether any of these supposed fixes improve digestive functions, gastrointestinal experts said.

Some purported gut-health helpers, like coconut oil, have high fat content that can loosen stool and irritate your stomach, said Dr Beth Czerwony, a registered dietitian with the Cleveland Clinic's Center for Human Nutrition.

Others, such as aloe vera juice, may cause diarrhoea in some people.

And since the Food and Drug Administration largely does not regulate supplements, gastroenterologists are reluctant to recommend the pills, powders and products promoted by influencers.

"If somebody is claiming to have something that will immediately turn gut health around, you should be sceptical of that," said Dr Justin Sonnenburg, a professor of microbiology and immunology at Stanford University.

Instead, his research points to long-term lifestyle habits that can benefit the gut - ones that rarely go viral or make their way to social media acclaim.

The online obsession with gut health is just one example of self-transformation content, said Dr Stephanie Alice Baker, a senior lecturer in sociology at the City, University of London who studies online wellness culture. "What you see is this trend of self-optimisation," she said.

The most popular #guttok videos tend to feature before and after pictures - the swell of bloating under a crop top becomes toned abs. In a culture that sometimes bristles at mentions of dieting or weight loss, framing these changes around a topic like gut health might be more palatable to an influencer's audience, she said.

There is also an inherent intimacy that comes with talking about the gut, Dr Baker said. Authenticity attracts an audience - and it is hard to get more personal than talking about bowel movements.

"That's what people are referring to when they say gut health," said Dr Rabia De Latour, a gastroenterologist at NYU Langone Health. "They want to stamp a nice, pretty name on it, but it's about pooping."

Signs of poor gut health

There is evidence to suggest that gut-related health conditions, particularly irritable bowel syndrome, have spiked over the past few decades, said Dr Sonnenburg, a surge he attributes to the rise of processed and packaged foods.

A global survey published in 2021 of more than 73,000 adults from 33 countries found that more than 40 per cent of respondents had gastrointestinal disorders, like irritable bowel syndrome or constipation.

Chronic, unexplained abdominal pain, constipation and diarrhoea are all signs of poor gut health, experts said. People may also feel sluggish or "blah".

If you are concerned about your gut, pay attention to the consistency of your stool, said Dr De Latour. You want them to be soft, smooth and sausage-shaped.

The Bristol Stool Chart, a medical classification of seven groups of poop, can help determine whether your stool is healthy.

Gut health can have long-term health consequences, doctors said. The gut is linked to the immune system and heart health, and emerging research is examining the link between gut flora and neurological disorders like Parkinson's disease, said Dr Reezwana Chowdhury, an assistant professor at Johns Hopkins Medicine.

Issues with your gut could point to a larger health problem, she added, and people experiencing gastrointestinal symptoms like abdominal pain or chronic diarrhoea should consult a doctor.

Tips for improvement

- Eat more fibre: Two kinds of fibre can aid your gut: soluble fibre - the gummy fibres from foods like oatmeal and apple skins - and insoluble fibre, which serves as a laxative that helps push food through the digestive system. Nuts, whole grains, beans and legumes can be good sources of insoluble fibre, Dr Czerwony said.

Be careful not to introduce a lot of fibre too quickly, though. You want to ease into any dietary changes, experts said, and steadily increase the amount of fibre-rich foods you add to your meals over a period of weeks.

- Limit processed foods: Emulsifiers that help keep packaged foods shelf-stabilised can erode the mucus barrier in your gut, Dr Sonnenburg said, and artificial sweeteners found in many processed foods can lead to unhealthy gut microbes.

Bacteria in the gut may quickly convert simple sugars and starches into gas, he said, causing bloating. This means that fast foods and processed foods - which Dr Sonnenburg defines as foods with ingredients "your grandmother wouldn't recognise as food", like additive chemicals - can contribute to poor gut health.

But the gut microbiome is fairly resilient, he said. The occasional ice cream binge or petrol station snack will not wreak havoc on your gut health.

- Opt for fermented foods: Dr Sonnenburg published a study in August showing that fermented foods such as yogurt, kimchi, kefir, sauerkraut and kombucha can increase the diversity of bacteria in the gut.

His research found that people who ate six servings of fermented foods each day saw these benefits - the equivalent of consuming one cup of yogurt, about 480ml bottle of kombucha and one cup of kimchi in a day.

Past research has linked high levels of diversity in your gut microbiome to lower rates of obesity, diabetes and other health conditions.

- Lower your stress levels: There is a strong connection between the gut and the brain, Dr Czerwony said. "If you're stressed, if you're not sleeping well, you might have gastrointestinal symptoms and think it's from your diet. It could be from your lifestyle," she said.

Adequate levels of sleep, hydration and exercise are also linked to gut health, she said.

Even a small amount of physical activity can help with digestion. "If you're feeling sluggish and bloated, go for a walk," she said.