During fasting, glycan foraging significantly changes pH.

• A. Not specified
• B. Depends on organism
• C. True
• D. False

Answer: (D)

Glycan foraging is the use of host-derived glycans, like mucins, by oral bacteria as an energy source. However, the rate and extent of acid production from breaking down these complex glycans are much lower than the rapid lactic acid production seen when fermentable dietary carbohydrates are consumed. During fasting, there are fewer readily fermentable substrates, and the saliva and plaque buffering system helps maintain pH. Therefore, even though glycan foraging occurs, it does not drive a significant shift in pH; the overall pH remains relatively stable rather than dropping or rising dramatically. In this context, glycan foraging can influence which microbes thrive, but it does not cause a major pH change.