According to a new theory, irritable bowel syndrome, the most common gastrointestinal disorder, may be caused by gravity.
Researchers believe the body’s inability to manage gravity could be the root cause of irritable bowel syndrome and many other conditions. The hypothesis is part of a study from the Cedars-Sinai Medical Center, which has been published in the American Journal of Gastroenterology.
“As long as there’s been life on Earth, from the earliest organisms to Homo sapiens, gravity has relentlessly shaped everything on the planet,” explained Brennan Spiegel, director of Health Services Research at Cedars-Sinai and author of the hypothesis explained.
“Our bodies are affected by gravity from the moment we’re born to the day we die. It’s a force so fundamental that we rarely note its constant influence on our health,” said Spiegel, who is also a professor of Medicine.
The debate around irritable bowel syndrome
The underlying mechanism of irritable bowel syndrome has caused a great deal of debate amongst researchers since it was first described over a century ago. Irritable bowel syndrome affects around 10% of the worlds population and experts still do not fully understand how or why it develops.
There are several contrasting theories that may explain the clinical features of irritable bowel syndrome. One of these theories speculates that the condition is a gut-brain interaction disorder. There is evidence to suggest that the condition can be treated with neuromodulators and behavioural therapies.
Another theory suggests that irritable bowel syndrome is caused by abnormalities in the gut microbiome, which can be treated with antibiotics or low fermentable diets. Other theories suggest that abnormalities in motility, gut hypersensitivity, abnormal serotonin levels or a dysregulated autonomic nervous system are causes of the condition.
“There’s such a variety of explanations that I wondered if they could all be simultaneously true,” said Spiegel.
“As I thought about each theory, from those involving motility to bacteria, to the neuropsychology of irritable bowel syndrome, I realised they might all point back to gravity as a unifying factor. It seemed pretty strange at first, no doubt, but as I developed the idea and ran it by colleagues, it started to make sense.”
Gravity can damage the body
According to Spiegel gravity can compress the spine and impact people’s flexibility, it can also cause organs to shift downward, deviating from their natural position.
“The body evolved to hoist this load with a set of support structures. If these systems fail, then symptoms can occur along with musculoskeletal problems,” he explained.
Certain people’s bodies are more capable of carrying this load than others. Some people have “stretchy” suspension systems that can cause the intestines to droop. Others have spinal issues that cause the diaphragm to sag and the belly to protrude, which can lead to a compressed abdomen.
The researchers believe these factors may trigger motility problems or bacterial overgrowth in the gut. This could also explain why physical therapy and exercise work as effective treatments for irritable bowel syndrome, as these interventions strengthen the support systems. However, the gravity theory goes beyond the intestines.
“Our nervous system also evolved in a world of gravity, and that might explain why many people feel abdominal ‘butterflies’ when anxious. It’s curious that these ‘gut feelings’ also occur when falling toward Earth, like when dropping on a roller coaster or in a turbulent aeroplane,” said Spiegel.
“The nerves in the gut are like an ancient G-force detector that warns us when we’re experiencing—or about to experience—a dangerous fall. It’s just a hypothesis, but people with irritable bowel syndrome might be prone to over-predicting G-force threats that never occur.”
Researchers have also hypothesised that serotonin may play a role in the development of irritable bowel syndrome. Serotonin is a neurotransmitter that may have evolved in part to manage gravity across body systems. Without serotonin, people would not be able to stand up, maintain balance, circulate blood, or pump intestinal contents against gravity.
“Dysregulated serotonin may be a form of gravity failure. When serotonin biology is abnormal, people can develop irritable bowel syndrome, anxiety, depression, fibromyalgia, and chronic fatigue. These may be forms of gravity intolerance,” explained Spiegel.
