What vitamins are most likely to deplete in the first 6 months of taking Ozempic (semaglutide) with inadequate supplementation and very low food intake?

Vitamin Deficiencies Most Likely to Occur in First 6 Months of Ozempic with Inadequate Food Intake

Thiamine (vitamin B1) is the most critical deficiency risk in the first 6 months when taking Ozempic with severely restricted food intake, as it can develop rapidly and cause life-threatening Wernicke's encephalopathy, followed by vitamin B12, iron, folate, and fat-soluble vitamins (A, D, E, K).

Highest Priority: Thiamine (Vitamin B1)

• Thiamine deficiency develops most rapidly with poor nutritional intake and prolonged vomiting or dysphagia, which are common with GLP-1 agonists like Ozempic 1.
• The complete multivitamin containing thiamine may not be sufficient to prevent deficiency when food intake is severely restricted 1.
• Immediate thiamine supplementation (50 mg once or twice daily from a B-complex supplement) should be considered for the first 3-4 months, particularly if there is prolonged vomiting, dysphagia, or poor nutritional intake 1.
• If Wernicke's encephalopathy is suspected, parenteral thiamine replacement is required immediately 1.

High-Risk Deficiencies in First 6 Months

Vitamin B12

• Vitamin B12 deficiency develops when consumption of animal protein and medical foods is inadequate 1.
• Severe megaloblastic anemia has been reported in individuals with inadequate protein intake 1.
• B12 deficiency can cause neurological deficits including memory loss, which could be erroneously attributed to other causes 1.
• Supplementation with 250-350 μg daily or 1000 μg weekly sublingual is recommended when dietary intake is insufficient 1.
• Acid suppression (if taking PPIs or H2 blockers concurrently) can impair absorption of protein-bound dietary B12, increasing deficiency risk with prolonged use beyond 4 years 2.

Iron

• Iron deficiency without anemia is commonly reported with inadequate food intake 1.
• Iron deficiency anemia may be dietary in origin when oral diet is insufficient 1.
• Supplementation with 45-60 mg elemental iron daily from multivitamin and supplements is recommended 1.
• Serum ferritin less than 15 μg/L confirms iron deficiency anemia 1.

Folate (Vitamin B9)

• Folate deficiency occurs with inadequate consumption of medical foods or dietary sources 1.
• Check and treat vitamin B12 deficiency before initiating folic acid treatment to avoid precipitation of subacute combined degeneration of the spinal cord 1.
• 400 μg daily should be included in routine multivitamin supplementation 1.

Moderate-Risk Deficiencies

Fat-Soluble Vitamins (A, D, E, K)

• Both excessive and inadequate intakes of vitamins A and D are possible with inappropriate supplementation when food intake is very low 1.
• Vitamin A deficiency can present with disturbances in night vision and xerophthalmia 1.
• Vitamin D supplementation of 3000 IU daily is recommended, with titration to reach normal concentrations of 30 ng/mL 1.
• Vitamin E deficiency should be treated with 100-400 IU daily 1.
• Vitamin K deficiency requires 1-2 mg oral vitamin K daily 1.

Copper and Zinc

• Zinc and copper have an inverse relationship for absorption, requiring careful monitoring when supplementing 1.
• A ratio of 8-15 mg zinc to 1 mg copper should be maintained 1.
• Two adult multivitamin-mineral supplements daily containing zinc (15 mg) and copper (2 mg) are recommended 1.

Vitamin C

• Vitamin C deficiency can present with gingival swelling, bleeding, and mucosal changes 3.
• The routine daily multivitamin should follow recommended intake for vitamin C 1.
• For deficiency, 100 mg three times daily or 500 mg daily for 1 month is recommended 1.

Critical Clinical Pitfalls

• Never supplement folic acid before checking and treating B12 deficiency, as this can precipitate subacute combined degeneration of the spinal cord 1.
• Prolonged vomiting, dysphagia, or inability to tolerate supplements requires immediate evaluation for thiamine deficiency 1.
• Patients should be educated about the severe consequences of untreated thiamine deficiency and instructed to seek early medical advice 1.
• Protein malnutrition can develop with severely restricted intake, requiring monitoring beyond just vitamin supplementation 1.

Recommended Supplementation Strategy

• Start with two adult multivitamin-mineral supplements daily containing iron, folic acid, zinc, copper, selenium, and thiamine (200% of RDA) 1.
• Add thiamine 50 mg once or twice daily from B-complex supplement for first 3-4 months 1.
• Add calcium citrate 600 mg daily 1.
• Add vitamin D 3000 IU daily 1.
• Add vitamin B12 250-350 μg daily or 1000 μg weekly sublingual 1.
• Monitor for clinical signs of deficiency and adjust supplementation accordingly 1.