What nutrient do vegans have a high deficiency in?

Vitamin B12 Deficiency is the Most Common Nutritional Deficiency in Vegans

Vegans have the highest risk of vitamin B12 deficiency among all dietary patterns, with deficiency rates ranging from 11-90% depending on age group and supplementation status. 1, 2

Primary Nutrient Deficiencies in Vegan Diets

Vegan diets, which exclude all animal products, commonly lead to several nutrient deficiencies, with vitamin B12 being the most significant:

• Vitamin B12 (cobalamin) deficiency is virtually inevitable in vegans without supplementation as this vitamin is found almost exclusively in animal-based foods 3
• Other common deficiencies in vegans include:
  • Iodine 3
  • Iron 3
  • Selenium 3
  • Zinc 3
  • Long-chain omega-3 fatty acids (EPA and DHA) 3
  • Creatine 3
  • Carnosine 3
  • Taurine 3

Vitamin B12 Deficiency: Prevalence and Risk

The prevalence of vitamin B12 deficiency among vegans is particularly concerning:

• Studies across multiple countries (Denmark, Finland, Sweden, Switzerland) consistently show high rates of B12 deficiency in vegans 3
• Deficiency rates vary by demographic group:
  • Up to 45% among infants 1
  • 0-33.3% among children and adolescents 1
  • 17-39% among pregnant women 1
  • 0-86.5% among adults and elderly individuals 1
• Vegans have significantly higher deficiency rates than other vegetarians 1, 2
• Those who have been vegan since birth show higher deficiency rates than those who adopted the diet later in life 2

Clinical Consequences of B12 Deficiency

Untreated vitamin B12 deficiency can lead to severe and sometimes irreversible health consequences:

• Neurological manifestations:

  • Peripheral neuropathy (pins and needles, numbness) 3
  • Cognitive difficulties (concentration problems, memory loss, "brain fog") 3
  • Balance issues and impaired gait 3
  • Spinal cord degeneration (can become permanent if deficiency persists beyond 3 months) 4
  • Cerebral atrophy 3

• Hematological manifestations:

  • Macrocytic anemia 3
  • Abnormal blood counts 3

• Other manifestations:

  • Glossitis 3
  • Optic nerve dysfunction (blurred vision, visual field loss) 3
  • Unexplained fatigue 3
  • Failure to thrive (in infants and children) 3

Supplementation Recommendations

Given the high risk of deficiency, supplementation is essential for vegans:

• Regular B12 supplementation is mandatory for all vegans 4, 5
• Dosage options:
  • Daily supplementation: 50-100 mcg per day is recommended 6
  • Weekly supplementation: 350 mcg weekly appears as effective as 2000 mcg weekly in correcting marginal deficiency 7
• Small, frequent doses are more effective than infrequent large doses 5
• Pregnant and lactating vegan women require particular attention to ensure adequate B12 for their developing babies 5
• Monitoring B12 status is essential even with supplementation 5

Pitfalls and Caveats

Important considerations when addressing B12 deficiency in vegans:

• Folic acid supplementation may mask B12 deficiency by correcting the anemia while allowing neurological damage to progress 4
• B12 deficiency can be present even without anemia 5
• Many vegans are not diligent about supplementation despite being aware of the need 3
• B12 deficiency is particularly dangerous during pregnancy, childhood, and adolescence 3
• Fortified foods alone may not provide sufficient B12 for many vegans 5
• Regular assessment of B12 status is necessary for all vegans through a combination of diet history and appropriate laboratory testing 5