The perception that raisins are thought to be a "sticky" sweet fruit, detrimental to oral health, has been rebutted by research conducted by the Illinois College of Dentistry.

The research, entitled Phytochemicals in raisins inhibit growth and adherence of plaque bacteria, demonstrates that raisins contain phenolic compounds and other antioxidants that help prevent the production of acid by mouth bacteria.

Dr Christine Wu and her colleagues from the University of Illinois at Chicago dental school have also shown that various compounds present within raisins inhibit the growth of streptococcus mutans and porphyromonas gingivallis, which cause gum disease.

Raisins contain polyphenolic compounds such as catechins, epicatechins and flavanols, which contain enamel preserving properties. Catechins have been shown to have a direct effect against streptococcus mutans and streptococcus sobrinus to prevent bacteria sticking to the teeth.

Diets that help produce strong enamel are critical to ensure teeth are resistant to dental caries. Dental professionals have commonly recommended that healthy snacks, such as raisins and other dried fruit, be eaten as part of a meal as opposed to a between-meal snack because they were thought of as a sweet fruit.

The new research, however, points to the fact that raisins, eaten as a snack, not only satisfy the need for a healthy diet by containing essential nutrients and energy, but do not promote the development of dental caries.