Dental caries and diet — nutrient promoting oral bacterial proliferation Consumption of which nutrient most directly promotes the multiplication of oral bacteria and the formation of dental plaque acids?

Introduction / Context:
Dental caries involves demineralization of enamel and dentin due to acids produced by oral bacteria. Diet directly modulates bacterial growth and acid production. Identifying the nutrient category that most strongly drives plaque acidogenesis is crucial in preventive dentistry and nutrition counseling.

Given Data / Assumptions:

• Oral streptococci (e.g., Streptococcus mutans) metabolize fermentable carbohydrates rapidly.
• Frequent sugar exposure lowers plaque pH below the critical threshold for enamel (about pH 5.5).
• Other nutrients have lesser or protective roles (e.g., fluoride strengthens enamel).

Concept / Approach:

Fermentable carbohydrates (sucrose, glucose, fructose, cooked starches) provide substrate for glycolysis in plaque bacteria, producing organic acids (lactic acid). This acid load demineralizes enamel. Therefore, dietary carbohydrates are the primary drivers of bacterial multiplication and cariogenicity, especially when consumed frequently or as sticky, retentive foods.

Step-by-Step Solution:

Verification / Alternative check:

Clinical and epidemiologic studies show reduced caries incidence with decreased sugar intake and with use of non-fermentable sweeteners (xylitol), supporting the carbohydrate mechanism.

Why Other Options Are Wrong:

Fat and protein are not primary substrates for rapid acidogenic plaque metabolism. Fluoride is protective, not cariogenic. Water-only fasting reduces available substrate and bacterial proliferation.

Common Pitfalls:

Focusing only on the amount of sugar rather than frequency and form (liquid vs sticky), both of which greatly influence risk.

Final Answer:

Carbohydrate