Nutrition and Environmental Medicine Quiz

Pantothenic Acid (Vitamin B5)

• Diagnosis involves evaluating blood, plasma, serum, or urine levels; urine levels preferred for dietary intake assessment.
• Management includes a daily oral dosage of 5 mg of pantothenic acid.

Biotin

• Key sources: Liver, egg yolk, soybean products, yeast.
• Essential cofactor for carboxylase enzymes in carbohydrate, amino acid, and lipid metabolism.
• Recommended daily allowance (RDA): 8-12 µg daily for children, 30 µg daily for adults.

Vitamin B3 (Niacin)

• Sources include yeast, meats (especially liver), grains, legumes, corn, and seeds.
• Tryptophan can be converted to niacin; requires 60 mg tryptophan for 1 mg niacin along with vitamin B6.
• NAD/NADP function as cofactors in enzymatic redox reactions.
• RDA is measured as niacin equivalents (NE): 6-12 mg for children, 16 mg for adult males, and 14 mg for nonpregnant females.

Pellagra

• Caused by niacin deficiency, resulting in a metabolic encephalopathy.
• Common in regions where corn is a major dietary staple, such as parts of China, Africa, and India.
• Four D's of Pellagra: Dermatitis, Diarrhea, Dementia, Death, although not always observed.
• Skin manifestations include Casal's necklace, with rashes developing from sun exposure.

Causes of Pellagra

• Inadequate intake from maize or jowar diets, malnutrition, chronic alcoholism.
• Rare generalized malabsorption.
• Drug-induced causes (e.g., prolonged isoniazid therapy, certain chemotherapeutics).
• Other disorders, such as Hartnup's disease or carcinoid syndrome, divert tryptophan away from niacin production.

Vitamin C (Ascorbic Acid)

• Toxicity can be acute or chronic; acute toxicity linked to doses over 2g, causing abdominal issues.
• Chronic effects may include kidney stones, iron overload, hemolysis in G6PD deficiency, and interference with drug efficacy.
• Recommended dietary intake: 120 mg daily for adults, with 60 mg required to prevent scurvy.
• High Vitamin C intake may lower the incidence of gastric and esophageal cancers.

Clinical Features of Pellagra

• Chronic deficiency can lead to skin, gastrointestinal, and neurological symptoms.
• Dermatological symptoms include hyperpigmentation and skin lesions.
• Gastrointestinal issues can manifest as diarrhea, glossitis, and dysphagia.
• Neurological symptoms range from depression to hallucinations and confusion.

Diagnosis and Management

• Diagnosis reliant on clinical features; rapid improvement with niacin treatment is notable.
• Niacin status is assessed through urinary metabolites or erythrocyte NAD:NADP ratios.
• Treatment for niacin deficiency typically includes nicotinamide at 100-200 mg, with dietary changes recommended.

Vitamin B12 and Folic Acid

• Further details addressed in Chapter 8.

Biotin Deficiency

• Rare but can arise from long-term parenteral nutrition or excessive raw egg white consumption.
• Clinical symptoms may include dermatitis, conjunctivitis, and neurological changes.
• Diagnosis involves measuring urine biotin concentrations and enzyme activity.

Vitamin C Deficiency (Scurvy)

• Scurvy is primarily due to insufficient Vitamin C intake.
• High-risk groups include infants on inadequate diets, individuals with chronic diseases, and those lacking vegetable intake.
• Symptoms of scurvy comprise malaise, weakness, hemorrhages, and emotional changes.

Scurvy Types and Symptoms

• Adult scurvy: Symptoms include fatigue, pain, easy bruising, and bleeding gums.
• Infantile scurvy (Barlow's disease): Notable for subperiosteal hemorrhages and skeletal changes.

Test your knowledge on pantothenic acid and biotin, two essential vitamins crucial for metabolic functions. This quiz covers their diagnostic methods, management, and dietary sources. Perfect for students and professionals in nutrition and health sciences.