Here’s a detailed breakdown of nine vitamins, supplements and supplement-practices that can damage your liver and/or kidneys — how they do it, the risks, how to spot the problem, and how to protect yourself. This is general info, not personalized medical advice: if you have liver or kidney disease (or are pregnant, taking meds, etc.), you should talk to a doctor before using supplements.
1. Excessive Vitamin A (Preformed Retinol)
Vitamin A comes in two general forms: preformed vitamin A (retinol/retinyl esters) found in animal-derived foods and supplements, and provitamin A carotenoids (e.g., beta-carotene). The toxic risk is mostly from the preformed kind.
How it harms
The liver stores vitamin A and plays a major role in metabolising/clearing it. In high doses the liver can get overloaded, leading to inflammation, liver enzyme elevation and even cirrhosis.
Accumulation of retinol/retinyl esters in liver and other organs causes oxidative stress, fibrosis risk.
With kidneys: the damage is less direct, but because liver dysfunction affects whole-body metabolism, and vitamin A excess can disturb fluid/electrolyte balance, kidneys can get secondarily stressed.
Examples & evidence
One case report: a person habitually ingesting ~13,000 µg vitamin A supplement daily developed cirrhosis; improvement after stopping. Guidance: “Fat-soluble vitamins such as vitamins A, D… may lead to liver or kidney damage when taken in very high amounts.”
Key risk factors
Taking mega-doses in supplement form (many times the RDA/upper limit).
Multiple supplements stacking preformed vitamin A plus foods high in retinol.
Existing liver disease, or taking other hepatotoxic drugs.
How to protect yourself
Prefer getting vitamin A from a balanced diet rather than high-dose pills unless prescribed.
If you take vitamin A supplements, check the form (retinol vs beta-carotene) and dose.
Monitor liver enzymes if high doses are used.
Avoid “stacking” many supplements that each have vitamin A.
