Your kidneys function like filters to help preserve the health of your blood. Healthy kidneys retain nutrients in your bloodstream, while removing toxins and other harmful chemicals from your body via your urine. While a healthy diet, rich in vitamins, can promote kidney function, consuming excessively high levels of some vitamins can harm your kidneys.
VItamin C
One vitamin that can potentially harm your kidneys is vitamin C, or ascorbic acid. This vitamin has a number of beneficial functions: it helps nourish your blood vessels, maintains bone tissue and healthy connective tissue. However, too much vitamin C can also raise the levels of oxalate in your blood, and can therefore promote the formation of oxalate-containing kidney stones. Left untreated, these stones can potentially grow to a sufficient size to block your kidney tubules, harming your kidney function. To prevent kidney stones, the University of Maryland Medical Center recommends you not exceed 1,000mg of vitamin C daily.
Vitamin D
Another vitamin that can potentially harm your kidneys--if consumed in high doses--is vitamin D. Too much vitamin D increases calcium levels in your blood, and in turn increases the amount of calcium that flows through your kidney tubules. This excess calcium can trigger the formation of calcium-containing kidney stones, harming the health of the kidneys. If you take vitamin D supplements, consult your doctor to determine a safe dosage unlikely to cause kidney stones.
Vitamin A
Excessive consumption of vitamin A can also potentially damage your kidneys. Retinol, a biologically active form of vitamin A, interacts with calcium-regulating hormones in your body. Excessive vitamin A consumption increases your blood calcium levels, which in turn affects your kidneys. As a result, hypervitaminosis A--a condition caused by vitamin A toxicity--can cause kidney damage, along with other symptoms including bone pain, nausea, headache and an increased risk of brain damage.
Other Factors
Though not a vitamin, the levels of calcium in your body can also contribute to kidney stones and damage. The majority of kidney stones contain calcium, so excessive calcium consumption can potentially increase your risk of kidney stone development. The UMMC indicates that consuming calcium supplements at a level of more than 2,000mg daily can potentially harm your kidneys. In addition, low fluid intake, high salt intakes and high meat consumption all contribute to kidney stones and damage.
