High provitamin A carotenoid serum concentrations, elevated retinyl esters, and saturated retinol-binding protein in Zambian preschool children are consistent with the presence of high liver vitamin A stores.

BACKGROUND: Biomarkers of micronutrient status are needed to best define deficiencies and excesses of essential nutrients. OBJECTIVE: We evaluated several supporting biomarkers of vitamin A status in Zambian children to determine whether any of the biomarkers were consistent with high liver retinol stores determined by using retinol isotope dilution (RID). DESIGN: A randomized, placebo-controlled, biofortified maize efficacy trial was conducted in 140 rural Zambian children from 4 villages. A series of biomarkers were investigated to better define the vitamin A status of these children. In addition to the assessment of total-body retinol stores (TBSs) by using RID, tests included analyses of serum carotenoids, retinyl esters, and pyridoxal-5'-phosphate (PLP) by using high-pressure liquid chromatography, retinol-binding protein by using ELISA, and alanine aminotransferase (ALT) activity by using a colorimetric assay. RESULTS: Children (n = 133) were analyzed quantitatively for TBSs by using RID. TBSs, retinyl esters, some carotenoids, and PLP differed by village site. Serum carotenoids were elevated above most nonintervened reference values for children. α-Carotene, ß-carotene, and lutein values were >95th percentile from children in the US NHANES III, and 13% of children had hypercarotenemia (defined as total carotenoid concentration >3.7 µmol/L). Although only 2% of children had serum retinyl esters >10% of total retinol plus retinyl esters, 16% of children had >5% as esters, which was consistent with high liver retinol stores. Ratios of serum retinol to retinol-binding protein did not deviate from 1.0, which indicated full saturation. ALT activity was low, which was likely due to underlying vitamin B-6 deficiency, which was confirmed by very low serum PLP concentrations. CONCLUSIONS: The finding of hypervitaminosis A in Zambian children was supported by high circulating concentrations of carotenoids and mildly elevated serum retinyl esters. ALT-activity assays may be compromised with co-existing vitamin B-6 deficiency. Nutrition education to improve intakes of whole grains and animal-source foods may enhance vitamin B-6 status in Zambians.

Acute vitamin A toxicity: a report of three paediatric cases.

The following report describes three paediatric cases of vitamin A toxicity secondary to carnivorous fish liver ingestion. Further discussion of vitamin A toxicity and management of toxicity is included.

Polar hysteria: an expression of hypervitaminosis A.

Isotretinoin (Accutane) is a drug closely related to the chemical structure of Vitamin A. The pharmacology and toxicology of these two retinoids is similar enough to warrant comparison. Accutane is a powerful drug which its manufacturer, Roche, indicates is limited for severe recalcitrant nodular acne. This potency is also reflected in Accutane's well-known ability to produce severe birth defects if taken during pregnancy. Less well-known is the risk of this lipid soluble chemical to affect the Central Nervous System. Reports of intracranial hypertension, depression, and suicidal indeation with Accutane use have prompted an examination of this serious and life threatening potential. Though Roche has added a warning to its product label for signs of depression and suicidal ideation, this product is being overprescribed for all forms of acne, including mild cases and moderate acne that have not been treated with alternative medications, which have a lesser risk of depression and suicide. There is no contesting that this drug is effective at clearing up the most severe forms of acne, but the public must be informed of its proper, limited indication for use; depression and suicide can follow in patients with no prior history of psychiatric symptoms or suicide attempts.