The invention provides a compound of formula (I)wherein:A, B, C, D, W, X, Y and Z are each independently selected from H and OH；or a salt thereof；for use in the treatment and/or prophylaxis of a condition, disease or disorder in a subject, wherein the compound or salt is orally administered to a subject in a daily amount of from 2.8 to 6.6 mmol per day, over a period of at least 21 days. Also are provided are the compound of formula (I) for use in increasing mitophagy and/or autophagy, maintaining and/or improving muscle function and administration as a dietary, nutritional and/or health supplement.
