Synthesis of fatty acids in myelin is function of which vitamin?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Applied Nutrition & Dietetics

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Explanation

Vitamin B12 is essential for the synthesis of the fatty acids that form the myelin sheath around nerve cells.
It functions as a coenzyme for the enzyme methylmalonyl-CoA mutase, which is critical for proper fatty acid metabolism.
A deficiency in Vitamin B12 leads to the accumulation of methylmalonyl-CoA.
This substance is then used to create abnormal fatty acids, which destabilize the myelin sheath and cause demyelination and neurological damage.

Option B: Vitamin B6 (Pyridoxine) is primarily involved in amino acid metabolism and the synthesis of neurotransmitters. While it plays a role in sphingolipid synthesis (a component of myelin), its function is not as central to the synthesis of myelin fatty acids as Vitamin B12.
Option C: Vitamin B1 (Thiamine) is crucial for carbohydrate metabolism and energy production (ATP) in the nervous system. Its deficiency impairs nerve function due to an energy deficit, not because of a defect in myelin structure.
Option D: Vitamin B2 (Riboflavin) is a precursor for FAD and FMN, coenzymes that are essential for cellular respiration and energy production through oxidation-reduction reactions.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemical role of B-complex vitamins in the nervous system as background academic context rather than a clinical decision trigger.
Nurses must recognize neurological symptoms like paresthesia (tingling), ataxia (unsteady gait), and memory changes as potential signs of Vitamin B12 deficiency, especially in high-risk groups like older adults, vegans, and patients with a history of gastric surgery.
Early detection and treatment of B12 deficiency are critical because the associated neurological damage can become irreversible if left untreated.
What if? If a patient with megaloblastic anemia is treated only with folic acid without first ruling out B12 deficiency, the anemia may resolve, but the neurological damage will continue to progress. This is a critical patient safety consideration.

How to Approach the Question

First, identify the key physiological process in the question stem, which is the 'synthesis of fatty acids in myelin'.
Next, systematically review the primary functions of each B vitamin listed in the options.
Recall that Vitamin B1 (Thiamine) is for carbohydrate/energy metabolism.
Recall that Vitamin B2 (Riboflavin) is for redox reactions/energy metabolism (FAD/FMN).
Recall that Vitamin B6 (Pyridoxine) is mainly for amino acid metabolism.
Remember that Vitamin B12 (Cobalamin) has a specific role in fatty acid metabolism via the methylmalonyl-CoA mutase reaction, which directly impacts myelin integrity.

Concept Tested & Keywords

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