Are Liquid Sugars Different from Solid Sugar in Their Ability to Cause Metabolic Syndrome?

OBJECTIVE Intake of sugary drinks, especially soft drinks, carries increased risk for obesity and diabetes. This article reviews whether sugary drinks carry different risks for metabolic syndrome compared with foods that contain natural or added sugars. METHODS A narrative review was performed to evaluate differences between liquid and solid sugars in their ability to induce metabolic syndrome and to discuss potential mechanisms to account for the differences. RESULTS Epidemiological studies support liquid added sugars, such as soft drinks, as carrying greater risk for development of metabolic syndrome compared with solid sugar. Some studies suggest that fruit juice may also confer relatively higher risk for weight gain and insulin resistance compared with natural fruits. Experimental evidence suggests this may be due to differences in how fructose is metabolized. Fructose induces metabolic disease by reducing the energy levels in liver cells, mediated by the concentration of fructose to which the cells are exposed. The concentration relates to the quantity and speed at which fructose is ingested, absorbed, and metabolized. CONCLUSIONS Although reduced intake of added sugars (sucrose and high-fructose corn syrup) remains a general recommendation, there is evidence that sugary soft drinks may provide greater health risks relative to sugar-containing foods.