Vitamin A

SeriousSmokersGrade A

Retinyl palmitate combined with beta carotene was associated with increased risk of lung cancer among smokers in the CARET trial.

SeriousChronic high vitamin A intake for acne vulgarisGrade D

A 17-year-old developed benign intracranial hypertension with bilateral papilledema and bilateral transverse sinus obstruction following chronic vitamin A intake of 150,000 units daily for acne vulgaris.

SeriousElderly with long-term vitamin A supplement useGrade D

In elderly people, greater fasting plasma retinyl esters were associated with long-term vitamin A supplement use (more than 5 years) and biochemical evidence of liver damage.

SeriousHigh liver vitamin A concentrationsGrade D

High concentrations of vitamin A in the liver were reported as toxic in the context of a study of cystic fibrosis patients, while normal liver concentrations were described as potentially protective against liver damage.

SeriousHuman alcoholicsGrade D

Depleted hepatic vitamin A content was reported in human alcoholics, with altered hepatic retinoid metabolism considered in the context of alcoholic liver disease.

SeriousHypervitaminosis AGrade D

Hypervitaminosis A was reported to have a number of remarkable negative consequences, with some cases described as potentially fatal.

SeriousLong-term high intakeGrade D

Liver biopsy in a patient with chronic high vitamin A intake showed characteristic signs of hypervitaminosis A without fibrosis.

SeriousLong-term retinoid useGrade D

Long-term use of retinoids is associated with risks including teratogenicity, reported in the context of first- and second-generation retinoids applied therapeutically for skin cell function and oncological diseases.

SeriousPediatric chronic high vitamin A intakeGrade D

A nine-year-old female with vitamin A intoxication had demineralized bones and retarded skeletal maturation identified on radiographic studies.

SeriousPreadolescent children with cystic fibrosis and pancreatic insufficiencyGrade D

High vitamin A intakes and elevated serum retinol in children with CF and PI were associated with possible toxicity reported to increase the risk of CF-associated liver and bone complications.

SeriousPregnancyGrade D

Oral vitamin A was reported to carry teratogenicity, identified as a property of the compound alongside its potential for toxicity and long half-life.

SeriousRetinol supplementationGrade D

Retinol has intrinsic hepatotoxicity, which complicates its use in correcting vitamin A deficiency through supplementation, particularly in people who also consume alcohol.

SeriousVLBW infants receiving therapeutic vitamin A amountsGrade D

Vitamin A hepatotoxicity was described in a cohort of 41 VLBW patients receiving therapeutic amounts of vitamin A.

ModerateAdequately nourished childrenGrade A

High-intake Vitamin A supplementation was associated with adverse outcomes related to respiratory infection, diarrhea, and growth in children who were predominantly adequately nourished.

ModerateChildren in developed regions with higher baseline serum retinolGrade A

Children in developed regions have higher baseline serum retinol levels, which may predispose them to immunosuppressive effects associated with high-amount vitamin A supplementation.

ModerateChronic high intake (oil-based preparations)Grade A

A meta-analysis of case reports found that chronic hypervitaminosis A was induced after daily intakes of 2 mg retinol/kg in oil-based preparations sustained for many months or years.

ModerateChronic intake (water-miscible, emulsified, and solid preparations)Grade A

Chronic hypervitaminosis A was induced at intakes as low as 0.2 mg retinol/kg/day in water-miscible, emulsified, and solid preparations sustained for only a few weeks.

ModerateNeonatesGrade A

Minimal acute adverse effects were reported in apparently healthy neonates following high-intake oral vitamin A supplementation.

ModerateResected stage I lung cancer patientsGrade B

Among treated patients receiving high-intake retinol palmitate, skin dryness and desquamation were the most frequently reported adverse symptoms, occurring in 60% of all treated participants.

ModerateCystic fibrosisGrade C

In nine adult cystic fibrosis patients, one had a raised fasting plasma retinyl ester concentration suggestive of chronic hypervitaminosis A, though no symptoms of toxicity were observed.

ModerateHead and neck cancer patients receiving TAR therapy (TS-1, Vitamin A, and radiation)Grade C

In one patient at level 3 of the TAR therapy regimen (TS-1 combined with Vitamin A intramuscularly and radiation), Grade 4 toxicity of anorexia was observed.

ModerateAcne patientsGrade D

In the studies reviewed, side effects associated with oral vitamin A intake were mainly mucocutaneous in nature.

ModerateChildren (large vitamin A intake from candy-like chewable supplements)Grade D

Serum retinol concentrations took 1 to 3 weeks to peak and many months to normalize following large vitamin A intake in 3 children, indicating a prolonged elevation of circulating retinol.

ModerateChildren with high serum vitamin A levelsGrade D

In healthy Swedish children, the observed pattern of RBP levels relative to vitamin A levels suggested the existence of a toxicity threshold in the interaction between vitamins A and E and RBP.

ModerateElderly people / excess intakeGrade D

Retinol can be toxic when taken in excess, and elderly people may be at particular risk for hypervitaminosis A.

ModerateEnd-stage renal failure patients on regular dialysisGrade D

Patients with end-stage renal failure on regular dialysis had significantly raised plasma vitamin A concentrations compared to normal controls, and these raised levels were reported to contribute to hypervitaminosis A toxicity.

ModerateOral Vitamin A use for acneGrade D

In clinical studies of oral Vitamin A for acne, mucocutaneous side effects and headaches were the most commonly reported adverse effects; both resolved with continued treatment or cessation.

MinorPostmenopausal patients with advanced breast cancerGrade C

In postmenopausal patients receiving retinyl acetate combined with tamoxifen, the most frequent side effects were hot flushes, nausea (and/or vomiting), headache, and cutaneous itching; overall toxicity was generally mild.