Description

• Vitamins are essential micronutrients required for normal metabolism, growth, and development.
• Specific vitamin deficiencies can lead to medical conditions and health complications.
• Deficiencies are rarely diagnosed or documented in the Western world. Regulations mandating vitamin supplementation in food products, adequate food supply, availability of vitamin supplements, and lack of physician awareness all play a role.
• Fat-soluble vitamins (A, D, E, K) and water-soluble vitamins (B)

Epidemiology

• Predominant age:
  • Affects mainly geriatric population
  • Occurs in select adult demographics: Pregnant women, chronic disease states (see “Etiology”)
• Travelers spending extended time in developing nations
• Very low for isolated vitamin deficiencies in Western world; true incidence unknown
• Vitamin levels are rarely measured (exceptions include vitamin B₁₂ [risk increases >50] and folate [risk increases with specific states: Pregnancy, antiepileptic drugs, neoplastic processes, alcoholism])

Prevalence
Varies by age groups, comorbid conditions, geography, and setting (i.e., urban, rural)

Risk Factors

Poverty, malnutrition, chronic disease states, advanced age, dietary restrictions, bariatric surgery, and exclusively breast-fed infants

• Cystic fibrosis
• Rare genetic predisposition:
  • Autoimmune disease (e.g., pernicious anemia)
  • Congenital enzyme deficiencies (e.g., biotinidase deficiency)
  • Transcobalamin II deficiency
  • Ataxia and vitamin E deficiency (AVED)
• A-β-lipoproteinemia

General Prevention

• No data exist that demonstrate that use of a multivitamin decreases risk of any disease.
• Ingesting large and varied amounts of vitamins increases risk of toxicity and drug–drug interactions.
• Use of antioxidants to prevent cancer has had no beneficial effect on cancer incidence, and, in some studies, has increased risk of death (1)[A].
• Adequate intake of a balanced diet containing carbohydrates, proteins, and fats
• Avoidance of fad diets
• Vitamin or nutrition supplementation, when appropriate

ALERT
Use of multivitamins has not resulted in decreased risk of cancer, heart disease, stroke, or all-cause mortality (2)[A].

Geriatric Considerations
US Preventive Services Task Force recommends at least 800 IU/d of vitamin D to lower risk of falls, fractures, and cancer (3)[A].

Pathophysiology

Deficiencies usually related to disease can develop under healthy conditions and generally occur by 1 of 5 mechanisms:

• Reduced intake
• Diminished absorption
• Increased utilization
• Increased demand
• Increased excretion

Etiology

• Chronic disease states: HIV, malabsorption, chronic liver and kidney disease, alcoholism, pernicious anemia, etc.
• Gastric surgeries: Gastric bypass, gastrectomy, small or large bowel resection, etc.
• Predisposition related to certain medicines: Prednisone, phenytoin, isoniazid, protease inhibitors, proton pump inhibitors, chronic antibiotic use, penicillamine, hydralazine, etc. (4)
• Malnutrition, imbalanced nutrition, eating disorders: Obesity, bulimia/anorexia, fad diets, extreme vegetarianism
• Dialysis
• Parasitic infestation

Commonly Associated Conditions

Osteoporosis, anemia, neuropathies, Hartnup disease