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A7.0
Vitamin A – Forschung
Gemischte Evidenz
553 begutachtete Studien
Was die Evidenz sagt
Gemischte Evidenz
Die Studien sind gespalten: Vitamin A half in 8 von 17 Fällen, der Rest war ergebnislos oder zeigte keinen Nutzen.
Die meiste Evidenz stammt aus hochwertigen Meta-Analysen und randomisierten Studien, veröffentlicht 1976–2026 mit einer typischen Studiengröße von 773 Teilnehmenden.
Basierend auf 553 Studien · 69 Meta-Analysen · 445 RCTs · 768,235 Teilnehmende insgesamt
Konfidenz
Hohe Konfidenz
Was die Studien gefunden haben
8geholfen5unklar4nicht geholfen· 536 weitere ohne bewertete Effektdaten
Nach Outcome
Therapeutic & clinical
Gemischte Evidenz529 Studien
Women's health
Gemischte Evidenz65 Studien
Vision & xerophthalmiaEntscheidend für die Rhodopsin-Synthese und das Nachtsehen; ein Mangel verursacht Erblindung · 2-4 weeks
Begrenzte Belege63 Studien
Anemia & hematology
Überwiegend Mechanismus / Beobachtung26 Studien
Safety profile & toxicity
Überwiegend Mechanismus / Beobachtung19 Studien
Immune supportVerbesserte Immunzellfunktion und Barriereintegrität · 2-4 weeks
Überwiegend Mechanismus / Beobachtung16 Studien
Skin healthEssenziell für die Erneuerung der Hautzellen und die Barrierefunktion · 4-8 weeks
Überwiegend Mechanismus / Beobachtung7 Studien
Heart & blood pressure
Überwiegend Mechanismus / Beobachtung4 Studien
Bone health
Überwiegend Mechanismus / Beobachtung4 Studien
Inflammation
Überwiegend Mechanismus / Beobachtung3 Studien
Cholesterol & lipids
Zu wenige bewertete Studien1 Studie
Glucose & metabolic
Zu wenige bewertete Studien1 Studie
Cognitive function
Zu wenige bewertete Studien1 Studie
In Zahlen
Aus 38 Studien mit messbaren Effekten gezogen
Wahrscheinlich echte Effekte
64%
über Studien hinweg
Untersuchte Personen
768k
typische Studie: 773 Personen
Stärkste Designs
514
69 gepoolt, 445 randomisiert
Zeigte Nutzen
47%
8/17 Studien
Wie lange Studien liefen
Unter einer Woche
1
1–3 Monate
1
3+ Monate
1
Untersuchte Populationen
General population5
Adults2
Adults at risk for UTI1
Adults and children1
Stetige Forschung
64 Studien in den letzten 5 Jahren · Neueste Meta-Analyse: 2026
197620012026
1Urinary tract infection preventionMeta-Analysen=10,495 · very large study2025
Einfach gesagt: D-mannose, triple therapy, vaccine, probiotics, and cranberry serve as potential nonantibiotic intervention options for clinical UTI prevention.
Han Z et al. · Infection (2025)
Nearly 80% of the RCTs utilized double-blind or triple-blind designs.
D-mannose, triple therapy, vaccine, probiotics, and cranberry serve as potential nonantibiotic intervention options for clinical UTI prevention.
2Inflammatory biomarkersMeta-Analysen=1,834 · large study2022
Einfach gesagt: The result of this study demonstrates that supplementation of vitamin A at low and high dosages for short and long durations increases the CRP plasma concentrations on adults and vitamin A supplementation decreases the TNF-α concentrations in chronic hepatitis B on adults.
Gholizadeh M et al. · Scientific Reports (2022)
Among 13,219 articles, 13 studies were included for analysis of CRP and TNF-α, and 9 studies were included for IL-6.
Vitamin A supplementation significantly increased CRP concentration (WMD: 0.84 mg/L; 95% CI 0.29-1.39).
Subgroup analysis showed a negative significant association between 50,000 IU/day retinyl palmitate and IL-6, and between vitamin A and TNF-α in chronic hepatitis B.
Einfach gesagt: Based on moderate certainty of evidence, vitamin A had no effect on mortality in the individually randomised trials.
Bjelakovic G et al. · BMJ open (2024)
Kein klarer Effekt
← SchlechterKein EffektBesser →
Could be chance
Vitamin A did not reduce mortality in individually randomised trials (RR 0.99, 95% CI 0.93 to 1.05; I²=32%; p=0.19; 105 trials; moderate certainty), and this effect was not affected by the risk of bias.
In individually randomised trials, vitamin A had no effect on mortality in children (RR 0.96, 95% CI 0.88 to 1.04; I²=24%; p=0.28; 78 trials, 178 094 participants) nor in adults (RR 1.04, 95% CI 0.97 to 1.13; I²=24%; p=0.27; 27 trials, 61 880 participants).
Vitamin A reduced mortality in the cluster randomised trials (0.84, 95% CI 0.76 to 0.93; I²=66%; p=0.0008; 15 trials, 14 in children and 1 in adults; 364 343 participants; very low certainty).
4Iron deficiencyMeta-Analysen=443 · medium study2024
Einfach gesagt: Overnutrition is associated with increased risk of ID, but not zinc or VA deficiencies, with an inverted U-shaped relationship observed between iron status and bodyweight.
Tan X et al. · BMJ global health (2024)
Sehr groß Schaden
← SchlechterKein EffektBesser →
Likely real
Synthesising 16 records of OR from seven eligible studies, overnutrition (overweight and obesity) increased odds of iron deficiency (ID) (OR (95% CI): 1.51 (1.20 to 1.82), p<0.0001, I2=40.7%).
Odds appeared to be higher for children living with obesity (1.88 (1.33 to 2.43), p<0.0001, I2=20.6%) in comparison to those with overweight (1.31 (0.98 to 1.64), p<0.0001, I2=40.5%), although between group differences were not significant (p=0.08).
Overnutrition is associated with increased risk of ID, but not zinc or VA deficiencies, with an inverted U-shaped relationship observed between iron status and bodyweight.
5Subclinical vitamin A deficiencySystematische Übersichtn=4,455 · very large study2019
Einfach gesagt: Fortifying staple foods with vitamin A alone may make little or no difference to serum retinol concentrations or the risk of subclinical vitamin A deficiency.
Hombali AS et al. · The Cochrane database of systematic reviews (2019)
Kein klarer Effekt
← SchlechterKein EffektBesser →
It is uncertain whether vitamin A alone reduces the risk of subclinical vitamin A deficiency (risk ratio (RR) 0.45, 95% CI 0.19 to 1.05; 2 studies; 993 participants; I² = 33%, very low-certainty evidence).
The certainty of the evidence was mainly affected by risk of bias, imprecision and inconsistency.It is uncertain whether vitamin A fortification reduces clinical vitamin A deficiency, defined as night blindness (RR 0.11, 95% CI 0.01 to 1.98; 1 study, 581 participants, very low-certainty evidence).
When compared to no intervention, it is uncertain whether the intervention reduces the risk of subclinical vitamin A deficiency (RR 0.71, 95% CI 0.52 to 0.98; 2 studies; 318 participants; I² = 0%; very low-certainty evidence) .
6Miscarriage preventionMeta-Analysen=276,820 · very large study2016
Einfach gesagt: Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage.
Balogun OO et al. · The Cochrane database of systematic reviews (2016)
Kaum spürbar Nutzen
← SchlechterKein EffektBesser →
Multivitamin supplementation There was evidence of a decrease in the risk for stillbirth among women receiving multivitamins plus iron and folic acid compared iron and folate only groups (RR 0.92, 95% CI 0.85 to 0.99, 10 trials, 79,851 women; high-quality evidence).
Antioxidant vitamins supplementation There was no evidence of differences in early or late miscarriage between women given antioxidant compared with the low antioxidant group (RR 1.12, 95% CI 0.24 to 5.29, one trial, 110 women).
Taking any vitamin supplements prior to pregnancy or in early pregnancy does not prevent women experiencing miscarriage.
7Maternal and infant mortality and morbidityMeta-Analysen=8,577 · very large study2016
Einfach gesagt: There was no evidence of benefit from different doses of vitamin A supplementation for postpartum women on maternal and infant mortality and morbidity, compared with other doses or placebo.
Oliveira JM et al. · The Cochrane database of systematic reviews (2016)
Kein klarer Effekt
← SchlechterKein EffektBesser →
Effects were less certain at six months (risk ratio (RR) 0.50, 95% CI 0.09 to 2.71; 564 participants; 1 RCT; low-quality evidence).
We found insufficient evidence that vitamin A increases abdominal pain (RR 1.28, 95% CI 0.95 to 1.73; 786 participants; 1 RCT; low-quality evidence).
We found low-quality evidence that vitamin A supplementation increased breast milk retinol concentrations by 0.20 µmol/L at three to three and a half months (mean difference (MD) 0.20 µmol/L, 95% CI 0.08 to 0.31; 837 participants; 6 RCTs).
8Maternal, birth, child health and development outcomesMeta-Analysen=451,723 · very large study2020
Einfach gesagt: In addition, they further contribute to the ongoing discourse of choosing antenatal MMN over IFA as the standard of care in LMICs.
Oh C et al. · Nutrients (2020)
IFA supplementation showed notable improvement in maternal anemia and the reduction in low birthweight, whereas LNS supplementation had no apparent effect on outcomes; further research that compares LNS and MMN supplementation could help understand differences with these commodities.
For single micronutrient supplementation, improvements were noted in only a few outcomes, mainly pre-eclampsia/eclampsia (calcium), maternal anemia (iron), preterm births (vitamin D), and maternal serum zinc concentration (zinc).
These findings highlight that micronutrient-specific supplementation should be tailored to specific groups or needs for maximum benefit.
9Mother-to-child HIV transmissionMeta-Analysen=6,601 · very large study2017
Einfach gesagt: Antepartum or postpartum vitamin A supplementation, or both, probably has little or no effect on mother-to-child transmission of HIV in women living with HIV infection and not on antiretroviral drugs.
Wiysonge CS et al. · The Cochrane database of systematic reviews (2017)
Antepartum or postpartum vitamin A supplementation, or both, probably has little or no effect on mother-to-child transmission of HIV in women living with HIV infection and not on antiretroviral drugs.
The intervention has largely been superseded by ART which is widely available and effective in preventing vertical transmission.