It also tends to occur in less developed areas where people eat maize (corn) as a staple food, as maize is the only grain low in digestible niacin. A cooking technique called nixtamalization i.e., pretreating with alkali ingredients, increases the bioavailability of niacin during maize meal/flour production. For this reason, people who consume corn as tortillas or hominy are at less risk of niacin deficiency. For treating deficiency, the World Health Organization (WHO) recommends administering niacinamide(i.e. nicotinamide) instead of niacin, to avoid the flushing side effect commonly caused by the latter. Guidelines suggest using 300 mg/day for three to four weeks. Dementia and dermatitis show improvement within a week. Because deficiencies of other B-vitamins may be present, the WHO recommends a multi-vitamin in addition to the niacinamide.Hartnup disease is a hereditary nutritional disorder resulting in niacin deficiency. It is named after an English family with a genetic disorder that resulted in a failure to absorb the essential amino acid tryptophan, tryptophan being a precursor for niacin synthesis. The symptoms are similar to pellagra, including red, scaly rash and sensitivity to sunlight. Oral niacin or niacinamide is given as a treatment for this condition in doses ranging from 50 to 100 mg twice a day, with a good prognosis if identified and treated early. Niacin synthesis is also deficient in carcinoid syndrome, because of metabolic diversion of its precursor tryptophan to form serotonin. Measuring vitamin status
Plasma concentrations of niacin and niacin metabolites are not useful markers of niacin status.
People with type I Gaucher have a defect in the enzyme called glucocerebrosidase (also known as acid β-glucosidase). Glucocerebrosidase is an enzyme, and its function is to convert glucocerebroside (also known as glucosylceramide) into ceramide and glucose. When this enzyme doesnt work, glucocerebroside accumulates, which in turn causes liver and spleen enlargement, changes in the bone marrow and blood, and bone disease. It functions as a competitive and reversible inhibitor of the enzyme  glucosylceramide synthase,  the  initial  enzyme  in  a  series  of  reactions  which  results  in  the  synthesis  of  most glycosphingolipids.Earlier treatments on the market (imiglucerase (approved in 1995), velaglucerase (approved in 2010), taliglucerase alfa (Elelyso) (approved in 2012)) are enzyme replacement therapy - they are functioning versions of the enzyme that doesnt work. Miglustat works differently - it prevents the formation of the substance that builds up when the enzyme doesnt work; this is called substrate reduction therapy. Chemistry
Miglustat is an iminosugar, a synthetic analogue of D-glucose and a white to off-white crystalline solid that has a bitter taste. Society and culture
Legal status
Miglustat has been approved in the EU, Canada, and Japan for treating progressive neurological complications in people with Niemann–Pick disease, type C (NPC). Miglustat has not received approval for this indication outside of these countries and use for this disease, including the US, is off-label.