Niacin deficiency
| Pellagra | |
|---|---|
 |
|
| Person with pellagra with typical skin lesions | |
| Classification and external resources | |
| Specialty | Dermatology |
| ICD-10 | E52 |
| ICD-9-CM | 265.2 |
| DiseasesDB | 9730 |
| MedlinePlus | 000342 |
| eMedicine | ped/1755 |
| Patient UK | Pellagra |
| MeSH | C18.654.521.500.133.699.529 |
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
|
8.8 g
|
|
| Tryptophan | 0.062 g |
| Vitamins | |
| Niacin (B3) |
(8%)
1.2 mg |
|
|
| Percentages are roughly approximated using US recommendations for adults. | |
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
|
25 g
|
|
| Tryptophan | 0.2445 g |
| Vitamins | |
| Niacin (B3) |
(86%)
12.9 mg |
|
|
| Percentages are roughly approximated using US recommendations for adults. | |
Pellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin (vitamin B3 or vitamin PP, from pellagra-preventing factor) in the diet. It can be caused by decreased intake of niacin or tryptophan, and possibly by excessive intake of leucine. It may also result from alterations in protein metabolism in disorders such as carcinoid syndrome or Hartnup disease. A deficiency of the amino acid lysine can lead to a deficiency of niacin, as well.
Pellagra is classically described by "the three Ds": diarrhea, dermatitis, dementia. A more comprehensive list of symptoms includes:
J. Frostig and Tom Spies (acc. to Cleary and Cleary) described more specific psychological symptoms of pellagra as:
Despite clinical symptoms, blood level of tryptophan or urinary metabolites such as 2-pyridone/N-methylniacinamide ratio <2 or NAD/NADP ratio in red blood cells could be used to diagnose pellagra. Diagnosis could be confirmed after rapid improvements in the symptoms in patients using high doses of niacin (50–500 mg/day) or niacin enriched food.
Pellagra can develop according to several mechanisms, classically as a result of niacin (vitamin B3) deficiency, which results in decreased NAD production leading to most of the pathology (since NAD and its phosphorylated NADP form are cofactors required in many body processes, the pathological impact of pellagra is broad and results in death if not treated).
The first mechanism is simple dietary lack of niacin. Second, it may result from deficiency of tryptophan, an essential amino acid found in meat, poultry, fish, eggs, and peanuts that the body converts into niacin. Third, it may be caused by excess leucine, as it inhibits quinolinate phosphoribosyl transferase (QPRT) and inhibits the formation of Niacin or Nicotinic acid to Nicotinamide mononucleotide (NMN) causing pellegra like symptoms to occur.
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Wikipedia