Vitamin Deficiency

Vitamin Deficiency is a topic covered in the 5-Minute Clinical Consult.

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  • Vitamins are essential micronutrients required for normal metabolism, growth, and development.
  • Deficiencies are less common in the Western world, but certain populations are at increased risk.
  • Regulations mandating vitamin supplementation in food products, adequate food security, and availability of vitamin supplements make vitamin deficiencies less common in developed countries.
  • Toxicity is rare for water-soluble vitamins; toxicity is possible with fat-soluble vitamins (A, D, E, K).


  • Predominant age
    • Geriatric patients, pregnant women, exclusively breastfed infants, and individuals with certain chronic disease states
  • Individuals from Africa and Southeast Asia are at increased risk.
  • True incidence is unknown because most vitamin deficiencies are asymptomatic.

  • Varies by age groups, comorbid conditions, geography, and setting (i.e., urban, rural)
  • The prevalence of vitamin B12 deficiency is ∼6% in patients <60 years of age and increases to around 20% after age 60 years (1).
  • Vitamin D deficiency has become increasingly recognized and its prevalence is increased in individuals with darker skin pigmentation, obesity, low dietary intake of vitamin D, or low sunlight exposure.

Etiology and Pathophysiology

  • Disease-related deficiency can develop under healthy conditions, generally due to one of five mechanisms:
    • Reduced intake
    • Diminished absorption
    • Increased use
    • Increased demand
    • Increased excretion
  • Chronic disease states: HIV, malabsorption (such as celiac sprue and short bowel syndrome), chronic liver and kidney disease, alcoholism, malignancies, pernicious anemia, and inborn errors of metabolism
  • Bariatric surgeries: gastric bypass, gastrectomy, small or large bowel resection
  • Related to certain drugs: prednisone, phenytoin, isoniazid, protease inhibitors, methotrexate, phenobarbital, alcohol, nitrous oxide, H2 receptor antagonists, metformin, colchicine, cholestyramine, 5-fluorouracil, 6-mercaptopurine, azathioprine, chloramphenicol, proton pump inhibitors, chronically used antibiotics, penicillamine, and hydralazine
  • Malnutrition, imbalanced nutrition, obesity, fad diets, extreme vegetarianism, total parenteral nutrition, bulimia/anorexia, and other eating disorders
  • Dialysis
  • Parasitic infestation

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

Risk Factors

Poverty, malnutrition, chronic disease states, advanced age, dietary restrictions, bariatric surgery, and exclusively breastfed infants

General Prevention

  • Ingesting large and varied amounts of vitamin supplements increases risk of toxicity and drug–drug interactions.
  • Antioxidant supplement use has not been shown to impact cancer incidence and has increased mortality risk in some studies (2).
  • Avoiding restrictive diets decreases the likelihood of vitamin deficiency.
  • In particular age groups or with certain risk factors, vitamin supplementation may be recommended.
  • USPSTF recommends against low-dose supplementation with vitamin D (<400 IU) and calcium (<1,000 mg) to reduce fracture risk in community-dwelling postmenopausal women (3).
  • USPSTF recommends that all women planning or capable of pregnancy take a daily supplement containing 0.4 to 0.8 mg of folic acid (4)[A].
  • USPSTF recommends against the use of β-carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer (2).
  • All infants should receive 400 IU/day of vitamin D soon after birth whether breast- or formula fed (5).

Commonly Associated Conditions

Anemia, neuropathies, dermatitis, visual disturbances

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