Raisins and Cereals Containing Raisins on Plaque Acidogenicity in Children

Raisins are traditionally perceived as sweet and sticky. However, their sweetness is contributed by fructose and not sucrose. We have identified antimicrobial phytochemicals in raisins against oral pathogens. Hypothesis: The addition of raisins to bran flakes does not increase the acidogenicity of dental plaque. Objective: To investigate the effect of raisins and raisin-containing cereals on dental plaque pH in young children. Methods: Twenty children (7-11 years) participated in this randomized controlled study. The four test food groups were raisins, bran flakes, commercial raisin bran cereal (cRB) and experimental raisin bran cereal (eRB). Sucrose and sorbitol (10%) were used as positive and negative controls. Subjects refrained from oral hygiene for 24 hrs prior to each test. The in vivo plaque pH of two predetermined interproximal surfaces of teeth in the upper jaw was measured with a touch microelectrode (Beetrode®) prior to (baseline) and at 2, 5, 10, 15, 20 and 30 min after consumption of 10g of a test food or rinsing with a solution. Results: All test foods, except sorbitol solution reduced plaque pH over the 30 min period (e.g., ΔpH: Sucrose 0.91; cRB 0.70), with the largest reduction noted between 10-15 min. Consumption of cRB produced the highest plaque pH drop compared to the other food groups at 10 min (p<0.05). Addition of raisins to bran flakes (eRB) promoted a less pronounced pH drop beyond 10 min when compared to bran flakes alone (p<0.05). Consumption of raisins or adding raisins to bran flakes (eRB) did not reduce plaque pH below pH 6 over the 30 min test period. Conclusions: The addition of raisins to bran flakes without extrinsic sugars does not promote any further drop in plaque pH. Raisins may not be as acidogenic as commonly perceived.

(Study supported by the California Raisin Marketing Board, Fresno, CA)