Learning Objectives

• Identify specific dietary patterns that necessitate vitamin and mineral supplementation.
• Explain the biochemical interaction between avidin and biotin.
• Understand the relationship between corn-based diets and Niacin (B3) deficiency.

1. Vegetarian and Vegan Diets

Plant-based diets often lack specific micronutrients found predominantly in animal products. Strict vegans are at the highest risk for several deficiencies.

• Vitamin B12: Found almost exclusively in animal products. Deficiency leads to megaloblastic anemia and neurological symptoms.
• Iron: Plant-based iron (non-heme) is less bioavailable than heme iron from meat.
• Vitamin B2 (Riboflavin): Often found in dairy and eggs.
• Vitamin D: Commonly deficient across many populations, but animal-derived foods are a primary natural source.

2. High Raw Egg White Consumption

Consuming large quantities of raw egg whites can induce a specific vitamin deficiency due to a protein-binding mechanism.

• The Mechanism: Raw egg whites contain avidin, a protein that binds Biotin (Vitamin B7) with extremely high affinity.
• Consequence: This prevents the absorption of Biotin in the gut, leading to dermatitis, alopecia, and enteritis. Note: Cooking the egg whites denatures avidin and removes this risk.

3. Untreated Corn Diets

In regions where corn (maize) is the primary staple and is not properly treated, a specific B-vitamin deficiency is common.

• Vitamin B3 (Niacin) Deficiency: Corn is naturally low in tryptophan (a niacin precursor), and the niacin it does contain is bound and unabsorbable unless treated with alkali (nixtamalization).
• Clinical Outcome: Pellagra, characterized by the “4 Ds”: Dermatitis, Diarrhea, Dementia, and eventually Death.

Activity