Weird Theory Suggests IBS Caused by Body's Inability to Manage Gravity

A weird new theory about the underlying causes of irritable bowel syndrome (IBS) suggests that the condition could result from the body's inability to withstand gravity.

IBS is a gastrointestinal disorder that affects 10 percent of the world's population. People with it display a wide array of symptoms and respond to a range of treatments, but the underlying causes of the condition are still uncertain.

Disparate theories exist to explain the various symptoms of IBS, but Brennan Spiegel, director of Health Services Research at Cedars-Sinai Medical Center in Los Angeles, has told Newsweek that these might be linked by a single unifying factor.

"The abdominal contents are heavy, like a sack of potatoes that we are destined to carry for our entire lives," Spiegel said. "To meet this demand, the body evolved to support the abdominal load using a set of mechanisms that hoist the viscera [large internal organs in the abdominal cavity] in an upright posture.

"It turns out that some people are better designed to carry the abdominal load than others, and differences between bodies can influence [gastrointestinal] health."

Gravity has had a profound effect on our evolution, from how we stand up to how we pump blood around our bodies.

The digestive system is no different: to support our digestive organs, we have evolved an internal suspension system, called the mesentery, that holds up our intestines and prevents them from collapsing into the pelvis.

"Some people inherit a mesentery that is too stretchy, causing the gastrointestinal tract to droop down," Spiegel said.

"The abdominal cavity also keeps its shape because of musculoskeletal supports...[which] act together like a crane to stabilize and suspend the gastrointestinal system.

"If something goes wrong in this system," Spiegel added, "then the crane can sag under the influence of gravity, causing the intestines to droop, leading to slowing of the materials inside, overgrowth of bacteria, and gas formation."

The disruption of these gravity-resisting systems could therefore be responsible for the symptoms of IBS.

"I've been studying IBS for years and published extensively on this topic, but until recently, I never once thought of gravity in relation to this condition," Spiegel said. "That changed when a family member recently began developing [gastrointestinal] distress.

"She has been in an assisted living facility and spending more and more time lying flat in bed. At about the same time she started lying down, her gut issues emerged in lockstep.

"That got me thinking: We're not designed to lie flat. We evolved to be upright," Spiegel said. "I imagined the abdominal contents like a functional stack that is suspended and arrayed in a precise manner that works with and through gravity, and that lying down throws it off.

"As I investigated the literature on this topic, which is vast, I started to see a common thread among all the symptoms of IBS. Not just the [gastrointestinal] symptoms, but also lightheadedness, palpitations, tremors, fatigue, joint pains, backache, and vertigo, among others, could all be traced to difficulty managing gravity."

To support this theory, IBS patients often respond well to physical therapy and exercise, which could potentially result from a strengthening of these internal support systems.

Spiegel said that he had seen potential evidence for this theory in his own patients: "Some people may have bodies evolved for certain pressure levels, or certain altitudes.

"I've had some patients who say their IBS is terrible at sea level, but much better in the mountains. I've always assumed it was because the mountains are peaceful and beautiful, but it might just be because air pressure is different due to gravity itself."

In his paper, published by the American Journal of Gastroenterology, Spiegel wrote that many gastroenterologists had reported seeing unusually twisted intestines in IBS patients during colonoscopies, which could be a result of this inability to resist gravity.

"In circumstances where the gut becomes compressed, kinked, misshapen, or pressurized through gravity misalignment, the intestines may struggle to transit luminal contents efficiently," Spiegel said.

"Dysmotility leads to stasis and microbiome overgrowth, which may cause increased leakiness of the gut, inflammation in the intestines, gas formation, pressure buildup, diarrhea, or constipation."

If gravity really is the underlying cause of the condition, how would IBS patients fare in space?

"We know that many astronauts suffer from [gastrointestinal] issues while in microgravity orbit," Spiegel said. "It may be that we need gravity to thrive, but that too much, or too little, could cause negative effects in certain people."

Further studies will be required to test this hypothesis. "The paper lays out 30 different research studies that could be conducted to test the 'gravity hypothesis' of IBS," Spiegel said.

"Do IBS patients have different physiologic responses to changes in altitudes compared to other patients? Do people with IBS have differences in their connective tissue elasticity in their gut support structures? Do they have differences in their diaphragm attachments, mesentery, colon length, or spinal curvature?... The list goes on and on."

Determining whether IBS really is a result of the body's inability to manage gravity could help inform future treatment options for patients with this often-debilitating condition. Spiegel also hopes that this paper will encourage people to change how they think about IBS.

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References:

Spiegel B, Gravity and the Gut: A Hypothesis of Irritable Bowel Syndrome, Am. J. Gastroenterol., December 1 2022, DOI: http://dx.doi.org/10.14309/ajg.0000000000002066