- Etiology
- Pathogenesis, Pathology & Pathophysiology
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- Study Questions
| DEFICIENCY | TOXICITY |
|---|---|
| Pellagra (dementia, dermatitis, diarrhea, death), stomatitis | Flushing, vasodilation, pruritus, hepatotoxicity |
A lack of niacin can cause digestive issues, such as nausea and abdominal cramps. Severe deficiency may also cause mental confusion.
These Thai chicken tacos with peanut sauce are a great way to get niacin in your diet.
Niacin deficiency may result from inadequate dietary intake of vitamin B3 (niacin) and/or ‘tryptophan’, a dietary amino acid from which NAD can also be synthesized (3).
Niacin deficiency leads to pellagra, a disorder that produces skin rash (dermatitis), weight loss, and neurologic changes including depression and dementia.
[ Riboflavin deficiency leads to mouth ulcers (stomatitis), cheilosis (dry, scaly lips), scaly skin (seborrhea), and photophobia. Because biotin is widely distributed in foods and is synthesized by intestinal bacteria, biotin deficiency is rare. However, the heat-labile molecule avidin, found in raw egg whites, binds biotin tightly and blocks its absorption, causing dermatitis, dehydration, and lethargy. Lactic acidosis results as a buildup of lactate due to the lack of functional pyruvate carboxylase when biotin is missing. Vitamin C deficiency leads to scurvy, which causes bleeding gums and bone disease].
Other nutrient deficiencies (e.g., vitamin B2, B6, and iron) may also contribute to the development of niacin deficiency.
Symptoms
The most common symptoms of niacin deficiency involve the skin, digestive system, and nervous system (2).
The symptoms of the late stage of severe vitamin B3 (niacin) deficiency ─ a disease called ‘pellagra’ ─ include inflammation of the skin (dermatitis), vomiting, diarrhea, headache, fatigue, and memory loss. If untreated, pellagra is ultimately fatal (3).
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A 52 year old alcoholic man complains of painful lesions on his tongue and inside his mouth. He also has hyper-pigmented scales on his face and both hands. He is weak, forgetful and suffers of burning sensation in several parts of his body. He mentions that he has diarrhea for the last two months.
Deficiency of which of these vitamins is responsible for this patient’s condition?
A-Vitamin A
B-Vitamin B3 (niacin)
C-Vitamin C
D-Vitamin D
E-Folic acid
Answer