High-dose fat-soluble vitamins (A, E)

Tier 4 — risky / avoid · Excess toxicity

Unlike water-soluble vitamins you excrete, vitamins A, D, E, and K accumulate in body fat and the liver. Cochrane found vitamin E above 400 IU per day increases all-cause death risk. NIH warns vitamin A above 10,000 IU per day causes liver damage and severe birth defects in pregnancy. Mega-dose supplements sold online can easily push you past these limits without you realising.

Dose: Safe upper limits: Vitamin A ≤3,000 mcg RAE/day; Vitamin E ≤400 IU/day; never exceed without medical supervision