If supplementing, ensure periodic check of liver function.
4. High doses of Vitamin C (Especially in certain forms)
What it is
Vitamin C (ascorbic acid) is water‐soluble and generally lower risk than fat‐soluble vitamins. But very large doses may cause kidney issues.
How it harms
Excess vitamin C is metabolised to oxalate; high urinary oxalate may lead to calcium-oxalate kidney stones.
Kidneys bear the burden of excreting excess; in people with reduced kidney function the risk is greater.
Key risk factors
Very high supplementation (e.g., >1 g/day, especially chronically).
History of kidney stones or reduced kidney function.
How to protect yourself
Stay within safe limits (e.g., ~ 200-500 mg/day unless directed otherwise).
Hydrate well (water helps flush oxalate).
Avoid combining large doses of vitamin C with other stone‐risk nutrients (e.g., high calcium).
5. Fat-soluble vitamin “stacking” (Vitamins A, D, E, K)
What it is
When you take multiple supplements that contain fat-soluble vitamins, you might unintentionally exceed safe limits collectively.
How it harms
As these vitamins accumulate in tissues and liver, excess burdens liver metabolism and storage capacity.
The liver is the central processing organ for fat‐soluble vitamins; increments in storage can lead to hepatotoxicity or liver dysfunction
