Dietary Carbohydrates

Carbohydrates, which include sugars, starches, and fibers, are macronutrients (i.e., nutrients consumed in large quantities – fat, protein, carbohydrates, and water), provide 4kcal/gram, and are naturally present in fruits, vegetables, grains, and dairy foods. The term fermentable carbohydrates refer to sugars and starches that are metabolized by oral bacteria to produce acid. From a chemical perspective, fermentable sugars are categorized as mono- (i.e., fructose, glucose, and galactose) or di-saccharides (i.e., sucrose, maltose, and lactose). Starches are composed of long chains of glucose. The food industry hydrolyzes starches to produce short glucose chains for functional and/or sensory properties; the resulting modified starches are more cariogenic than the original starches. More complete hydrolyzation followed by isomerization results in high fructose corn syrup (HFCS) which is used as a sweetener in processed foods. Finally, the term ‘added sugars’ refers to sugars that are added to foods during production, by the home cook, or at the point of consumption. Similarly, ‘free sugars’ refers to sugars added to foods and beverages as well as those naturally present in honey and fruit juices. Both the United States Department of Agriculture’s Dietary Guidelines for Americans and the World Health Organization recommend limiting added and free sugars, respectively, to less than 10% of total energy intake.^9,10