A 41-year-old woman comes to the office due to a 6-month history of increasingly severe fatigue and malaise. For the past 5 years, she has lived on a small farm and eats only vegetables, fruits, and grains that she grows herself. Medical history is unremarkable. The patient takes no medications or nutritional supplements. She does not use tobacco or alcohol. This patient is at increased risk for deficiencies of which of the following nutrients?

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11ec160b_3ae9_e0eb_9249_832c304e106c_MD0001_00 A vegan diet is characterized by abstinence from all animal-sourced products. It differs from a simple vegetarian diet in that most vegetarians consume some nonmeat animal products (eg, milk, eggs). A vegan diet is typically plentiful in most vitamins (eg, A, B complex [except B₁₂], C), minerals (eg, potassium, magnesium), and soluble fiber. Although most single plant-based protein sources (except soy) are deficient in certain essential amino acids, requirements can be met with a mixed (eg, legumes plus grains) vegan diet. However, individuals on a vegan diet are at increased risk for the following: Cobalamin (vitamin B₁₂) deficiency: It may take years to develop in those with large baseline B₁₂ stores; manifestations include megaloblastic anemia and subacute combined degeneration of the dorsal columns of the spinal cord. Iron deficiency: Many plant products (eg, leafy green vegetables) provide iron, but the quantity is often inadequate for those with increased iron requirements (eg, growing children, menstruating women) (Choice A). Calcium and vitamin D deficiency: Most people obtain a significant amount of calcium and vitamin D from dairy and other animal-sourced products; individuals on a vegan diet often consume less of these nutrients than nonvegans, so supplementation may be necessary to prevent osteoporosis, especially in those without significant sunlight exposure (sunlight typically accounts for approximately 200-400 IU/day of a requirement of 600 IU/day). This patient developed fatigue and malaise following years on a limited vegan diet. Although many commercially prepared vegan products are fortified with additional vitamins and minerals, this patient is consuming unprocessed foods only. She likely has anemia due to deficiency of iron and/or vitamin B₁₂. (Choices B, D, E, and F) Folic acid and thiamine (vitamin B₁) are abundant in plant-based foods. Deficiency may occur in individuals with abnormal dietary habits (eg, alcohol use disorder) but is uncommon in those consuming a variety of fruits, vegetables, and grains. Educational objective: A vegan diet is characterized by abstinence from all animal-sourced products. Individuals on a vegan diet are commonly deficient in calcium, vitamin D, vitamin B₁₂, and iron and may require supplementation.

A 41-Year-Old Woman Comes to the Office Due to a 6-Month