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.
Groceries
9. “Megavitamin” and High-Potency Multivitamin Formulas
What it is
Supplements 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.
How to protect yourself
Read labels: check % Daily Value and how many times the RDA a dose supplies.
Don’t combine multiple high-potency multivitamins unless advised by a professional.
Periodically monitor liver and kidney function if using high-dose formulas.