Vitamine a

[datenshi]

Ik las dat een teveel aan Vitamine A schadelijke gevolgen kan hebben voor ongeboren baby's, weet iemand hier misschien wat voor schade dat in houd? ik kan zo snel niet vinden wat voor schade het is, alleen maar dat er schade kan komen

[Mrtn]

Klik

[Wouter_Masselink]

De bronnen waar wikipedia naar verwijst zijn niet meer terug te vinden. Derhalve is dus ook niet te zien welke afwijkingen er ontstaan.

[datenshi]

het enige wat ik daar ook heb zien staan is "These defects may be severe, even life-threatening.", en ik vraag me af wat voor "defects" ze dan over praten, want er zijn honderden, al dan niet meer, delen van het lichaam die een afwijking kunnen krijgen.

[anusthesist]

Hoe heb je gezocht? Neem anders een keertje onze zoekhandleiding door. Als ik zoek op 'hypervitaminosis A birth defects' krijg ik oa deze link: http://www.fetal-exposure.org/resources/in...-and-pregnancy/

[peterbill]

Neem de volgende full text eens door van de volgende studie:

Teratogenicity of high vitamin A intake.

Abstract

BACKGROUND:

Studies in animals indicate that natural forms of vitamin A are teratogenic. Synthetic retinoids chemically similar to vitamin A cause birth defects in humans; as in animals, the defects appear to affect tissues derived from the cranial neural crest.

METHODS:

Between October 1984 and June 1987, we identified 22,748 pregnant women when they underwent screening either by measurement of maternal serum alpha-fetoprotein or by amniocentesis. Nurse interviewers obtained information on the women's diet, medications, and illnesses during the first trimester of pregnancy, as well as information on their family and medical history and exposure to environmental agents. We obtained information on the outcomes of pregnancy from the obstetricians who delivered the babies or from the women themselves. Of the 22,748 women, 339 had babies with birth defects; 121 of these babies had defects occurring in sites that originated in the cranial neural crest.

RESULTS:

For defects associated with cranial-neural-crest tissue, the ratio of the prevalence among the babies born to women who consumed more than 15,000 IU of preformed vitamin A per day from food and supplements to the prevalence among the babies whose mothers consumed 5000 IU or less per day was 3.5 (95 percent confidence interval, 1.7 to 7.3). For vitamin A from supplements alone, the ratio of the prevalence among the babies born to women who consumed more than 10,000 IU per day to that among the babies whose mothers consumed 5000 IU or less per day was 4.8 (95 percent confidence interval, 2.2 to 10.5). Using a smoothed regression curve, we found an apparent threshold near 10,000 IU per day of supplemental vitamin A. The increased frequency of defects was concentrated among the babies born to women who had consumed high levels of vitamin A before the seventh week of gestation.

CONCLUSIONS:

High dietary intake of preformed vitamin A appears to be teratogenic. Among the babies born to women who took more than 10,000 IU of preformed vitamin A per day in the form of supplements, we estimate that about 1 infant in 57 had a malformation attributable to the supplement.

[datenshi]

ik had op een soortgelijke manier gezocht, maar het woord "hypervitaminosis" had ik er niet bij gezet. had die website dus niet gevonden, maar in ieder geval bedankt