送交者: Latino2 于 2005-6-16, 11:01:15:
科学家发现葡萄干中所含有的几种植物化学物质 (Phytochemicals)可以有效抑制口腔中特定细菌的成长，这几株细菌则是造成蛀牙和牙周病的祸首之一。
以前一般认为甜度高的葡萄干可能对牙齿健康不好，研究发现，蔗糖才是容易造成蛀牙和牙周病的首祸，葡萄干甜味高，主要是因为葡萄糖和果糖所致，并不一定会造成蛀牙。
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Raisins As A Functional Food For Oral Health
Compounds found in raisins fight bacteria in the mouth that cause cavities and gum disease, according to researchers at the University of Illinois at Chicago, College of Dentistry.
"Our laboratory analyses showed that phytochemicals in this popular snack food suppress the growth of several species of oral bacteria associated with caries and gum disease," said Christine D. Wu, Professor and Associate Dean for Research at the UIC College of Dentistry and lead author of the study.
The data will be presented at the annual meeting of the American Society for Microbiology beginning June 5, 2005.
Routine chemical analyses identified five compounds in Thompson seedless raisins: oleanolic acid, oleanolic aldehyde, betulin, betulinic acid, and 5-(hydroxymethyl)-2-furfural. All of these are known phytochemicals - antioxidants found in plants.
Oleanolic acid inhibited the growth of two species of oral bacteria: Streptococcus mutans, which causes cavities, and Porphyromonas gingivalis, which causes periodontal disease.
The compound was effective against the bacteria at concentrations ranging from about 4 to 1,000 µg/ml. At a concentration of 31 µg/ml, oleanolic acid also blocked S. mutans adherence to surfaces. Adherence is crucial for the bacteria to form dental plaque, the sticky biofilm consisting of oral bacteria that accumulates on teeth. After a sugary meal, these bacteria release acids that erode the tooth enamel.
Wu said that the data counter a longstanding public perception that raisins promote cavities.
"Raisins are perceived as sweet and sticky, and any food that contains sugar and is sticky is assumed to cause cavities," Wu said. "But our study suggests the contrary. Phytochemicals in raisins may benefit oral health by fighting bacteria that cause cavities and gum disease."
In an earlier unpublished study, Wu’s collaborator Dr. Shahrbanoo Fadavi (Pediatric Dentistry, UIC College of Dentistry) found that adding raisins to bran cereal did not increase the acidity of dental plaque. However, the commercial raisin-bran cereal with added sugar was most acidogenic compared with raisins or bran cereal alone.
"Foods that are sticky do not necessarily cause tooth decay; it is mainly the added sugar (sucrose) that contributes to the problem" Wu said.
The present study was funded by the California Raisin Marketing Board.
Besides collaborator Dr. A. Douglas Kinghorn, Adjunct Professor at the UIC College of Pharmacy, other scientists involved in the study were Dr. Jose F. Rivero-Cruz and Dr. Min Zhu (both, UIC College of Dentistry) and Dr. Baoning Su (UIC College of Pharmacy).