Elderly People Smell Different
In a 2000 study, scientists found that people's concentration of the compound 2-nonenal increased with age beginning at around age 40. They theorized that 2-nonenal was produced by the breakdown of fatty acid chains in the skin. Somewhat surprisingly, subjects who smelled the age-related odor (and were unaware of its source) rated it as less intense and less unpleasant than odors from younger people.
Key Facts In This Video
Trimethylamine, a chemical produced by gut bacteria, can smell like rotting fish or urine. (0:33)
Researchers think that elderly people develop a distinct smell because of changes in the skin's glands and secretions. (1:16)
Diabetic ketoacidosis occurs when the body lacks insulin and breaks down fat for fuel, causing a sickeningly sweet aroma. (2:18)