Downstream from that, kidney function may suffer because liver dysfunction affects fluid, electrolytes, and toxin removal.
Key risk factors
Taking several multivitamins + individual fat-soluble vitamin pills.
Using “megavitamin” formulas that deliver many times the Recommended Dietary Allowance (RDA).
How to protect yourself
Check the total intake of each fat‐soluble vitamin (from diet + supplements).
Avoid using multiple products that provide overlapping fat-soluble vitamins unless supervised.
Monitor liver enzymes if you routinely use high-dose fat‐soluble vitamins.
6. Herbal Supplements With Documented Hepato- and Nephro-toxicity (e.g., Kava, Comfrey, Black Cohosh, concentrated Green Tea Extract)
What they areHerbal “natural” supplements often marketed for stress relief, weight loss, menopause support, etc.
How they harm
Kava: has been linked to liver enzyme abnormalities, liver injury; may reduce kidney blood flow and increase harmful metabolites in kidneys.
Comfrey: contains pyrrolizidine alkaloids, strongly hepatotoxic.
Black Cohosh: associated with liver damage in some cases. Concentrated green tea extract (high catechin doses): linked to acute liver injury.
Key risk factors
Use of high‐dose extracts rather than customary food/herbal doses.
Poorly regulated products with contaminants.
Existing liver or kidney disease.
How to protect yourself
Use herbal supplements cautiously; check for reliable third-party testing.
Avoid high doses unless under supervision.
Monitor liver/kidney function if using such products.
Be especially cautious if also taking other liver- or kidney-stressors (alcohol, medications, etc).
7. High-dose Protein / “Protein Powders” in Overuse
What it is
Protein powders (whey, casein, plant‐based) used by athletes or fitness enthusiasts.
How it harms
Kidneys filter nitrogenous waste from protein metabolism. If you consume very large amounts of protein (well beyond needs) AND have dehydration or borderline kidney function, kidneys must work harder.
Liver processes amino acids; excessive protein may increase liver workload (though the liver is more resilient than kidney in this respect).
Key risk factors
Chronic very high protein intake (e.g., >2.5 g/kg body-weight daily) especially with insufficient hydration.
Dehydration, pre-existing kidney impairment.
How to protect yourself
Calculate protein needs (often ~1.2-2 g/kg for active adults) and avoid far exceeding it.
Stay well hydrated.
If you have kidney disease, get guidance from a dietitian/nephrologist.
8. Overuse of Iron or Other Minerals (Selenium, Calcium, Zinc)
What it is
Minerals are essential but in excess can cause organ damage.
How it harms
Iron: described above (see section 3).
Calcium: excess may cause kidney stones, nephrocalcinosis, and burden kidneys.
Selenium & Zinc: in excess can lead to toxicity, which may secondarily stress liver/kidneys (though less directly documented).
Key risk factors
Taking high‐dose mineral supplements without checking levels or needs.
Combining many supplements/mineral fortifications that unintentionally sum to high doses.
How to protect yourself
Test mineral levels (serum ferritin, calcium, etc) before supplementing.
Avoid self-diagnosis and mega dosing minerals.
Consider nutrient intake from food when calculating total mineral intake.
9. “Megavitamin” and High-Potency Multivitamin Formulas
What it isSupplements that deliver multiple vitamins/minerals at very high doses (10×, 50×, 100× the Recommended Daily Allowance) often marketed as “health boosters.”
How it harms
The body may handle typical nutrient amounts well, but when doses are extremely high, vitamins/minerals may act like drugs (not just nutrients). The liver and kidneys must metabolise and excrete the excess.
A fact sheet: “Severe side effects such as kidney stones, liver or nerve damage… can occur from 10 to over 100 times the DRI.”
Key risk factors
Taking multiple high-potency multivitamins or stacking them with other supplements.
Assuming “more is better” and ignoring upper intake limits.
