The human body, it turns out, is surprisingly good at making stone.
Authors
- Katie Edwards
Commissioning Editor, Health + Medicine and Host of Strange Health podcast, The Conversation
- Dan Baumgardt
Senior Lecturer, School of Psychology and Neuroscience, University of Bristol
Give it enough time and the right conditions and it will go about crystallising minerals, hardening secretions and, in rare cases, turning tragedy into rock. Gallstones. Kidney stones. Tonsil stones. Salivary stones. And, in one of the strangest and saddest corners of medical history, stone babies.
In the second episode of The Conversation's Strange Health podcast, we take a tour through the stony side of human anatomy and ask why this keeps happening, where these stones form and which ones you actually need to worry about.
Strange Health explores the weird, surprising and sometimes alarming things our bodies do. Each episode takes a bodily mystery or viral health claim and traces it back to anatomy, chemistry and evidence, drawing on researchers with first-hand experience of these processes. Some discoveries are not ideal mealtime material.
This episode's guide is Adam Taylor , professor of anatomy at Lancaster University and long-time contributor to The Conversation. Taylor has spent years studying stones in both everyday and extraordinary contexts, including a rare genetic condition called alkaptonuria. In people with this condition, the body cannot properly break down certain proteins, leading to blackened cartilage, dark urine and an unusually high risk of stone formation throughout the body. It is exactly as unsettling as it sounds.
Stones, Taylor explains, form when substances that normally stay dissolved stop behaving themselves. Calcium, phosphate, uric acid and one of the building blocks of protein called cysteine can all crystallise if conditions are right. Once a few molecules stick, more follow. The process snowballs. Over time, a stone appears.
Kidney stones and gallstones are the most familiar examples, and among the most painful. Their jagged crystal edges scrape delicate tissues, trigger spasms and cause bleeding as the body desperately tries to force them through narrow ducts never designed for sharp objects. Larger stones can block urine flow entirely, damaging the kidneys and, if left untreated, causing serious harm.
Smaller stones can form elsewhere. Tonsil stones develop when food debris, bacteria and dead cells collect in the crevices of the tonsils and harden. Salivary stones can form when ducts become blocked by bacteria or foreign material, sometimes something as mundane as a stray toothbrush bristle. These stones are rarely dangerous, but they are often unpleasant, painful and, judging by social media , irresistibly watchable when removed.
Then there are stone babies, or lithopedions. In extremely rare cases, a pregnancy that cannot continue is not expelled from the body. Instead, the immune system encases the remains in calcium, effectively mummifying them to prevent infection. Some have been discovered decades later, only after death.
What unites all of these stones is not toxins or detoxing , but chemistry and fluid balance, and sometimes bad luck. Taylor stresses that dehydration is one of the biggest risk factors. When fluids slow down, materials that are normally carried in fluid begin to solidify. Stones follow.
Listen to Strange Health to understanding why solid things form inside something that is mostly water, and why some stones are medical emergencies while others are just deeply, memorably gross. You have been warned about watching while eating.
Strange Health is hosted by Katie Edwards and Dan Baumgardt. The executive producer is Gemma Ware, with video and sound editing for this episode by Sikander Khan. Artwork by Alice Mason.
In this episode, Dan and Katie talk about a social media clip from tonsilstonessss on TikTok.
Listen to Strange Health via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here . A transcript is available via the Apple Podcasts or Spotify apps.
Katie Edwards works for The Conversation.
Adam Taylor and Dan Baumgart do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
