Recommended Oral Vitamin A Supplementation for Adults

For healthy adults, take 6,000 IU of vitamin A daily as part of a routine multivitamin supplement for prophylaxis. 1, 2

Standard Prophylactic Dosing

Healthy adults should receive 6,000 IU vitamin A daily, typically provided through a standard multivitamin supplement 1, 2
This prophylactic dose is recommended by the American College of Nutrition and represents the optimal amount for disease prevention in the general population 1
Most adults do not consume optimal amounts of vitamins through diet alone, making supplementation prudent 3

Adults who have undergone bariatric surgery require 10,000 IU vitamin A daily due to malabsorption risk 4, 1, 2
After RYGB (Roux-en-Y gastric bypass), additional supplementation is especially important if symptoms like deteriorating night vision or dry eyes develop 4
Following malabsorptive procedures (BPD/DS), start with 10,000 IU (3,000 μg) oral vitamin A daily and adjust based on monitoring 4

The upper safe limit is 10,000 IU daily for women who may become pregnant 1, 2
Beta-carotene form is strongly preferred over retinol for prophylaxis in pregnant women or those planning conception to avoid teratogenic risks 1, 2

When vitamin A deficiency is diagnosed (not prophylaxis):

Treat with 10,000-25,000 IU oral vitamin A daily for 1-2 weeks until clinical improvement occurs 4, 1, 2
Recheck vitamin A levels at 3 months after initiating treatment 4
If deficiency does not respond to oral treatment, refer to specialist for assessment and consideration of intramuscular vitamin A injections 4

Requires aggressive treatment: 50,000-100,000 IU intramuscularly for 3 days, followed by 50,000 IU daily for 2 weeks intramuscularly 1, 2

Understanding toxicity limits is critical:

The Institute of Medicine upper limit (UL) is 10,000 IU daily for women of childbearing age 1, 2
Chronic toxicity can develop from daily amounts exceeding 25,000 IU for more than 6 years or 100,000 IU for more than 6 months 1, 2, 5
Acute toxicity may occur when quantities above 300,000 IU are ingested within hours or days 1
Long-term supplementation with doses below 7,500 RE (25,000 IU) daily has been shown safe in adults aged 18-54 years over 12 years of monitoring 6

Vitamin A supplements should be given with lipid emulsion whenever possible to minimize losses from adsorption and photo-degradation 1, 2
Water-miscible forms may improve absorption, especially after malabsorptive procedures 4
Avoid water-soluble solutions which can lead to substantial losses 1

Use light-protecting material during administration as vitamin A is light-sensitive and undergoes photo-degradation 1

Normal serum vitamin A levels for adults range from 300-800 μg/L 1
In patients with risk factors for deficiency, periodic monitoring of vitamin A levels is recommended 1
Annual monitoring of serum retinol levels once normal values are achieved 2
Check serum retinol levels 3-6 months after any dosage change 2
Serum retinol and retinyl esters measurements should be considered in patients being investigated for malabsorption 1

Do not exceed 10,000 IU daily in women of childbearing age due to teratogenic risk 1, 2
Excessive vitamin A supplementation can exacerbate vitamin K deficiency and affect blood coagulation 1
Failing to account for dietary vitamin A intake when prescribing supplements can lead to toxicity 2
Do not confuse preformed retinol with beta-carotene when calculating total vitamin A intake 2
In patients with chronic kidney disease, exercise caution as they may have high retinol serum levels despite potential deficiency in total body stores 1
Plasma vitamin A levels are homeostatically controlled and are not good indicators of vitamin A status except in cases of deficiency or excess 7