Effect of Rice Hulls and Other Seed Hulls on Dental Caries Production in the Cotton Rat

Abstract

While studying natural diets which were cariogenic to the cotton rat, Constant, Sievert, Phillips, and Elvehjem1 found that the degree of dental caries produced by an oatmeal diet was sharply decreased by the inclusion of finely ground oat hulls in the diet. The protective effect was greater at the 25 per cent level than at the 12.5 per cent level. Later work by Taketa and Phillips2 demonstrated that oat hulls were also protective in a semipurified diet at both 25 and 10 per cent levels. These workers furnished evidence suggesting that the protective effect was due neither to a brushing or abrasive action by the hulls nor to a dilution of the cariogenic diet by the hulls. They also verified an earlier observation by Constant et al.1 that the ash portion of the hulls was not anticariogenic. Jenkins and Phillips3 showed that the crude fiber, hemicellulose, and lignin fractions of the hulls were devoid of anticariogenic activity. Taketa and Phillips2 found that the greatest activity was located in an ethanol-soluble fraction of the hulls, which comprised less than 5 per cent of their weight. Some activity remained in the residue; however, later studies4 showed that extraction with ammoniacal ethanol removed activity that was not removed by ethanol alone.The activity in the ethanol extract not only was effective in the inhibition of dental caries but was also capable of inhibiting the growth of organisms isolated from the carious cotton rat tooth.5 This observation, coupled with the fact that a pure culture of Lactobacillus acidophilus var. Farr was inhibited by the extracted solids, indicated that the anticariogenic activity of oat hulls was related to an alteration in the oral flora of the cotton rat. Using L. acidophilus as an assay organism for oat-hull anticariogenic factors, Taketa and Phillips5 found the active factors to be acidic in nature and perhaps to be certain phenolic acids and palmitic acid.Madsen4 assayed other seed hulls for their anticariogenic activity by feeding them in an oatmeal diet at the 25 per cent level. It was found that, in addition to oat hulls, the hulls of rice and peanuts were also effective and reduced the incidence of caries by about 75 per cent; the hulls of cottonseed and barley reduced the incidence by about 35 per cent. Madsen also demonstrated that the acidic fraction prepared from ethanol extracts of these hulls was effective as a growth inhibitor of L. acidophilus var. Farr.Subsequent studies demonstrated that oat hulls were also anticariogenic in the diet of the albino rat. Madsen4 found them to be anticariogenic when fed in a semipurified diet to the Harvard strain of caries-susceptible rats. Buttner and Muhler6 demonstrated

Phytic Acid: Properties and Potential Applications in Dentistry

“…These studies revealed an increased caries incidence with decreased intake of IP6 following changes in dietary habits and food processing and refinement (Jenkins et al, 1959a;Jenkins et al, 1959b;Jenkins, 1966). Several early studies showed a reduction of experimental caries in animals fed dietary IP6 (Taketa and Phillips, 1957;Buttner and Muhler, 1959;McClure, 1960;Madsen and Edmonds, 1962;Vogel et al, 1962;McClure, 1963;McClure, 1964;Dawes and Shaw, 1965;Englander and Keyes, 1970;Cole et al, 1980); however, these findings were not corroborated by other researchers, where IP6 had limited or no protective influence (Limbasuta et al, 1961;König and Grenby, 1965;Grenby, 1966;Lllienthal et al, 1966). The cariostatic mechanism of IP6 is not fully understood, although several pathways have been suggested.…”

From the mouths of babes: Dental caries in infants and children and the intensification of agriculture in mainland Southeast Asia

“…It is generally accepted that carbohydrates with low molecular weights, such as sucrose, are easily fermentable and therefore highly cariogenic (Newburn, 1982; Leach et al, 1983). Of particular relevance to the study of dental health in Southeast Asian populations is the relatively cariostatic nature of rice (Madsen and Edmonds, 1962). A clinical study has shown that parboiled rice resulted in one of the smallest increases in acidity when compared with sucrose and carbohydrate rich foods like potatoes and wheat bread (Lingström et al, 1993).…”

Nutrition and dental decay

“…The anticaries effect of oat hulls was coniirmed by Madsen (1958), Taketa McDonald (I 974) using rodent models given cariogenic diets comprising moderate and high percentages of mono-and disaccharides. Other seed hulls including those of barley, cocoa, cottonseed, peanut, pecan, soya bean and s d o w e r have also been shown to confer an anticaries effect on cariogenic diets in the cotton-rat model (Madsen & Edmonds, 1962). It is suggested that the anticaries effect is induced by the polyphenols present in the hulls exerting an antibacterial or an antidemineralization role.…”