Final answer:
In lactose intolerance, the stool pH is typically less than 5.5, indicating an acidic environment. This is due to the fermentation of undigested lactose by intestinal bacteria. The correct answer for stool pH in lactose intolerance is option A) pH < 5.5.
Step-by-step explanation:
The stool pH in lactose intolerance is typically pH < 5.5, which indicates an acidic environment. This occurs because individuals with lactose intolerance cannot fully digest lactose, the sugar found in milk and dairy products. As undigested lactose enters the colon, it is fermented by bacteria, resulting in the production of lactic acid and other short-chain fatty acids, leading to a lower stool pH.
Using the pH scale as a reference, where a pH less than 7 is acidic and a pH greater than 7 is basic, we can determine that a stool pH of less than 5.5 is significantly acidic. This is in contrast to more alkaline or basic conditions which would result in a pH above 7. Therefore, in the context of lactose intolerance, option A) pH < 5.5 is the correct answer.
Stool acidity tests are useful for diagnosing lactose intolerance in small infants, where other diagnostic tests might be risky or impractical. It's a non-invasive way to assess whether undigested lactose is fermenting in the intestines and producing acids.