USMLE Step 1 Question
TOPIC: Vitamin Deficiencies
A 22-year-old female presents to your clinic with recurrent bloating, abdominal pain, and diarrhea after consuming dairy products. Her symptoms have been worsening over the past three months months. Vital signs are within normal limits. Laboratory studies show a normal complete blood count, metabolic panel, and thyroid function tests. The patient reports a significant improvement in her symptoms after following a lactose-free diet for two weeks. If her lactose intolerance is left untreated, which of the following nutritional consequences is most likely to occur in this patient?
A) Iron deficiency anemia
B) Vitamin D deficiency
C) Vitamin B12 deficiency
D) Vitamin A deficiency
E) Folate deficiency
F) Vitamin K deficiency
Let’s dissect the essential details of this question…
Nutritional deficiencies are commonly tested USMLE concepts, so let’s take a closer look at all of our answer choices; then, we’ll discuss the correct answer and why it is, in fact, most correct.
A) Iron deficiency anemia
While not directly linked to lactose intolerance, iron deficiency anemia can occur due to similar dietary restrictions that limit the intake of iron-rich foods. Some individuals might avoid dairy and mistakenly reduce other essential nutrient-rich foods, leading to iron deficiency.
B) Vitamin D deficiency
Dairy products are a significant source of Vitamin D, and individuals avoiding these products due to lactose intolerance may not compensate with other Vitamin D sources, leading to deficiency. Vitamin D is crucial for calcium and phosphorus absorption, impacting bone health.
C) Vitamin B12 deficiency
Vitamin B12 deficiency is less directly related to lactose intolerance and more associated with overall dietary patterns. It's primarily found in animal products, and while dairy is included, other sources like meat, fish, and eggs can provide B12.
D) Vitamin A deficiency
Dairy products can be a source of Vitamin A, especially when fortified. Avoiding dairy due to lactose intolerance might reduce Vitamin A intake, but deficiency would likely result from broader dietary inadequacies.
E) Folate deficiency
Folate deficiency is generally not directly linked to lactose intolerance. Folate is abundant in fruits, vegetables, and fortified grains, which are not restricted by lactose intolerance.
F) Vitamin K deficiency
Dairy products are not a primary source of Vitamin K, which is found in green leafy vegetables, meat, and eggs. Vitamin K deficiency in the context of lactose intolerance would likely stem from a broader dietary limitation.
Physiologically, lactose intolerance is due to the body's inability to produce enough lactase enzyme, leading to undigested lactose fermenting in the colon, causing symptoms. This condition prompts individuals to avoid lactose-containing foods, potentially leading to deficiencies if not properly managed with a balanced diet or supplements. Understanding the sources of these nutrients and the role of lactase in digestion helps connect the dots between lactose intolerance and its potential nutritional implications.
In the context of untreated lactose intolerance, the most likely nutritional consequence in this patient would be B) Vitamin D deficiency.
Lactose intolerance leads to the avoidance of dairy products, which are primary dietary sources of Vitamin D. When individuals with lactose intolerance eliminate or significantly reduce dairy intake without substituting other Vitamin D-rich foods or supplements, they risk developing a deficiency.
Dairy products are often fortified with Vitamin D. It is crucial for bone health, as it facilitates the intestinal absorption of calcium and phosphorus. Without adequate Vitamin D, the risk for bone demineralization conditions, such as osteopenia and osteoporosis, increases, especially in a patient who avoids dairy products due to lactose intolerance.
Thanks for reading!