Are mannose and galactose diastereoisomers? consider only d-sugars.

Yes, mannose and galactose diastereoisomers consider only d-sugars because mannose is bundled as the nourishing supplement "d-mannose", is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. Mannose is significant in human absorption, particularly in the glycosylation of certain proteins. Numerous congenital conditions of glycosylation are related with transformations in enzymes involved in mannose absorption.