Vegan diet

Associated deficiencies

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• Common: vitamin B12, vitamin D, calcium
  • Vitamin B12 and Vitamin D are animal-source only
  • Vitamin B12 deficiency takes years
• Possible: iron, zinc
  • Increased risk: children (rapid growth requires higher zinc/iron) & young women (menstrual blood loss requires higher iron).

• Vitamin B12 (Cobalamin):
  • Source: Found almost exclusively in animal products. Deficiency is a major concern. But it takes years.
    • Instead folate is rich in many vegetables, hence it’s called 叶酸
  • Presentation: Megaloblastic anemia, peripheral neuropathy (paresthesias), subacute combined degeneration of the spinal cord (loss of proprioception/vibration sense), glossitis, dementia.
  • Mgmt: Must supplement with oral B12 or consume fortified foods (e.g., fortified cereals, plant milks).
• Iron:
  • Source: Plant-based iron is non-heme iron, which has lower bioavailability than heme iron from meat.
  • Presentation: Microcytic anemia (fatigue, pallor, koilonychia).
  • Mgmt: Consume iron-rich plant foods (lentils, tofu, spinach, fortified cereals) with a source of vitamin C to enhance absorption. Menstruating women are at higher risk.
• Calcium & Vitamin D:
  • Source: Dairy is a major source of both. Plant sources of calcium include fortified plant milks, tofu, and leafy greens (e.g., kale). Vitamin D is primarily from sun exposure and fortified foods.
  • Presentation: ↑ risk of osteopenia, osteoporosis, and fractures.
  • Mgmt: Ensure adequate intake of calcium-rich/fortified foods. Vitamin D supplementation is often necessary, especially in regions with limited sun.
• Omega-3 Fatty Acids (DHA/EPA):
  • Source: Primarily from fatty fish. Plant sources (flaxseed, walnuts, chia seeds) provide ALA, but conversion to DHA/EPA is inefficient.
  • Relevance: Important for brain and cardiovascular health.
  • Mgmt: Consider algal oil supplements for a direct source of DHA/EPA.
• Protein:
  • Source: Plant proteins can be less digestible and may be “incomplete” (lacking one or more essential amino acids).
  • Mgmt: Requires eating a variety of protein sources (e.g., legumes, grains, soy products, nuts, seeds) to ensure a complete amino acid profile.