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How Strong Is the Acid in the Human Stomach?

The acid in the human stomach, primarily hydrochloric acid, is impressively potent, capable of breaking down food and warding off pathogens. Its pH can be as low as 1.5, similar to car battery acid. Intrigued by how our bodies handle such corrosive substances? Discover the fascinating mechanisms that protect us from our own digestive power. What safeguards are in place? Continue reading to uncover the secrets of our stomach's resilience.

The human stomach is a hostile place where hydrochloric acid, potassium chloride, and sodium chloride combine to create a highly acidic brew that breaks down food into easy-to-digest particles. It also defends against pathogens and microbes that could make you ill. On a scale of zero to 14 (from very acidic to alkaline), the stomach’s pH is between 1 and 2. It's just slightly less acidic than battery acid, which can dissolve metal and bone.

Compare that to a vulture that dines on animal carcasses, many of which have been dead for quite a long time. A vulture’s stomach is even more acidic than a human's, with a pH just above 0. There are also two types of bacteria in the bird's stomach – Clostridia and Fusobacteria – to keep vultures from getting sick from the rotting meat.

The strange world of the stomach:

  • The cells lining the human stomach also release several enzymes and mucus, the latter of which protects the stomach lining from the highly acidic gastric juices and keeps them from damaging the stomach.

  • The pH level of a human stomach can fluctuate. Some medications and high levels of stress can prevent the body from producing hydrochloric acid. When that happens, the stomach's reactions can range from burping and bloating to heartburn, diarrhea, and nausea.

  • Vultures will eat “virtually any dead vertebrate – mammal, bird, snake, fish. They prefer recently deceased organisms rather than extremely putrid carcasses,” explains ornithologist Gary Graves of the Smithsonian Institution, adding that “day-old road-killed deer are perfect.”

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    • On the pH scale, ranging from 0 (most acidic) to 14 (least acidic), human stomach acid is around 2; a vulture’s is just above 0.
      By: GraphicCompressor
      On the pH scale, ranging from 0 (most acidic) to 14 (least acidic), human stomach acid is around 2; a vulture’s is just above 0.