Disclosed is a crystalline or amorphous compound which is a folate or a reduced folate of D-glucosamine, D-galactosamine, folate, -dihydrofolate, -tetrahydrofolate, unsubstituted or substituted with a 5-methyl-, 5-formyl-, 10-formyl-, 5,10-methylene-, 5,10-methenyl- moiety, the compound, whenever contemplated, being in a (6R,S), (6S) or a (6R) configuration. Use of this crystalline or amorphous compound for the preparation of a medicament, a food additive or a nutritional supplement, for the prevention and/ or the treatment of either deficiencies or diseases positively affected by the administration of both folates and reduced folates is also disclosed, wherein the deficiencies or diseases is selected from neurological affection (such as subacute encephalitis associated with dementia and vacuolar myelopathies)； pathopsychological, vascular and cardiovascular conditions (such as premature occlusive arterial disease, severe vascular disease in infancy and childhood, progressive arterial stenosis, intermittent claudication, renovascular hypertension, ischemic cerebrovascular disease, premature retinal artery and retinal vein occlusion, cerebral occlusive arterial disease, occlusive peripheral arterial disease, premature death due to thromboembolic disease and ischemic heart disease)； autoimmune diseases (such as psoriasis, celiac disease, arthritic and inflammation conditions)； megaloblastic anaemia due to folate deficiency, intestinal malabsorption, for reducing a female's risk of having a miscarriage and/ or of having a fetus with a neural tube defect, a cleft lip defect, and/or a cleft palate defect, for maintaining and/or normalizing the homocysteine level and/or metabolism； alterations of the synthesis and/or the functioning and/or the changes of DNA and RNA and the alterations of cell synthesis； depressive illnesses.
