Nutrition: impact on oral and systemic health.

Good dietary practices and optimal nutritional status promote growth and tissue development, as well as feature prominently in the prevention of diseases. Malnutrition (particularly protein-energy malnutrition, which invariably involves concurrent deficiencies of the antioxidant micronutrients) promotes salivary gland hypofunction, impaired immunity, and an early shift in the oral microbial ecology toward a preponderance of anaerobic organisms. The immune suppression, which includes impaired cytokine function as well as diminished acute-phase response to infections, impacts negatively on the natural history of inflammatory periodontal diseases. The pathogenesis of oral cancer is influenced by deficiencies of antioxidant nutrients, and there is evidence for diminished DNA methylation, disruption of DNA integrity, and increased DNA damage in folate deficiency.