Provided are: a Maillard reaction inhibitor which can inhibit the progress of a Maillard reaction in a living body effectively, does not cause any adverse side effect, can be applied safely, and can be produced without requiring any complicated process and an anti-aging agent for skin, an anti-diabetic complication agent, a food and a beverage, in each of which the Maillard reaction inhibitor is used. The Maillard reaction inhibitor according to the present invention contains 50 to 90 mass pcnt of a polyphenol as an active ingredient. The Maillard reaction inhibitor according to the present invention has a potent inhibitory activity on a Maillard reaction, and therefore can inhibit a Maillard reaction in a living body efficiently and can prevent and improve various functional disorders of proteins occurring in a living body. Due to this activity, the Maillard reaction inhibitor can prevent aging and is useful for the prevention and treatment of diabetic complications. When the tannin is added to a collagen-containing food or beverage, the occurrence of a Maillard reaction in the food or beverage can be prevented to thereby prevent the deterioration of the food or beverage, and the occurrence of a Maillard reaction in a living body can also be prevented.
