The Healthspan Map · Nutrient

Vitamin A (RAE)

Linked to getting too little

Where a shortfall of Vitamin A (RAE) is linked — 9 sources.In the order the Map holds them: strongest evidence first. That is a statement about the evidence, not about what matters most.
Nutrient or lever	Direction	Strength	Evidence type	What was found	Source
Vitamin A (RAE)	Eat enough of	Moderate	Review / narrative	Vitamin A deficiency impairs iron mobilisation and contributes to anemia.	Vitamin A & anemia (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Emerging	Cohort / observational	Vitamin A supports retinal light-sensing that entrains circadian rhythm; inadequacy is associated with short sleep.	NHANES 2005-2016 (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Moderate	Mechanistic	Retinoic acid from vitamin A is essential for spermatogenesis; deficiency halts sperm production and higher serum retinol tracks with normal sperm parameters.	Nutrition & male fertility (Transl Androl Urol 2020) (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Strong	Established clinical	Vitamin A deficiency impairs mucosal/epithelial immunity and raises respiratory-infection risk and severity; deficient children benefit clearly from correction.	Vitamin A & pneumonia in children (WHO ELENA) (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Moderate	Review / narrative	Vitamin A deficiency causes follicular hyperkeratosis (phrynoderma), dry skin and impaired epithelial repair.	Vitamin A & epithelium (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Emerging	Review / narrative	Vitamin A participates in thyroid hormone metabolism and TSH regulation; low status is one micronutrient contributor to dysfunction.	Nutrition & thyroid review (PMC11314468) (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Strong	Established clinical	Vitamin A builds rhodopsin and keeps the cornea moist; deficiency causes night blindness and xerophthalmia — the leading preventable cause of childhood blindness worldwide.	Xerophthalmia (Cleveland Clinic) (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Moderate	Review / narrative	Vitamin A maintains mucosal/epithelial barriers and NK/T-cell function.	Vitamin A & mucosal immunity (opens in a new tab)
Vitamin A (RAE)	Eat enough of	Moderate	Mechanistic	Vitamin A is required for normal growth, reproduction and fetal development; deficiency impairs growth in children.	NIH ODS – Vitamin A & Carotenoids (opens in a new tab)

Linked to getting too much

Where an excess of Vitamin A (RAE) is linked — 8 sources.In the order the Map holds them: strongest evidence first. That is a statement about the evidence, not about what matters most.
Nutrient or lever	Direction	Strength	Evidence type	What was found	Source
Vitamin A (RAE)	Don't overdo	Strong	Established clinical	Acute hypervitaminosis A (preformed retinol, >100x RDA) causes severe headache, dizziness and raised intracranial pressure.	NIH ODS – Vitamin A & Carotenoids (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Moderate	Cohort / observational	Excess preformed vitamin A (retinol) stimulates bone resorption and antagonizes vitamin D; high intake links to lower BMD and higher hip-fracture risk, strongest when vitamin D is low.	Vitamin A/retinol & fracture (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Moderate	Established clinical	High-dose vitamin A is teratogenic (>10,000 IU/day risk in pregnancy; isotretinoin is a potent teratogen), and chronic excess also impairs sperm production, morphology and motility.	Vitamin A-mediated birth defects review (PMC10788247) (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Moderate	Systematic review	In non-deficient people, high-dose vitamin A supplementation increased acute respiratory-infection incidence (RR 1.08) via temporary immune-regulation malfunction.	Excessive vitamin A supplementation & ARTI meta-analysis (Nutrients 2021) (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Moderate	Established clinical	Vitamin A toxicity causes dry, cracked skin, cheilitis, hair loss and brittle nails.	Hypervitaminosis A & skin (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Strong	Established clinical	Preformed vitamin A is a potent teratogen; excess in pregnancy causes severe fetal malformations.	StatPearls – Vitamin A Toxicity (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Strong	Established clinical	Chronic high-dose vitamin A activates hepatic stellate cells, causing fibrosis, portal hypertension and cirrhosis.	Vitamin A (NIH LiverTox) (opens in a new tab)
Vitamin A (RAE)	Don't overdo	Emerging	Established clinical	Prolonged high-dose vitamin A can cause hypercalcemia.	Case series (PMC10185110) (opens in a new tab)