Kidney stones represent a potentially painful disorder, characterized by the formation of salt crystals within the kidney tubules. Many dietary factors -- such as vitamin C intake, oxalate consumption and hydration -- all contribute to your risk of kidney stones. Taking high doses of vitamin D-3 can also increase your risk of developing the stones.
Vitamin D-3 Function
Your body utilizes vitamin D-3 -- as well as other forms of vitamin D -- to regulate calcium in your body. Proper vitamin D-3 levels ensure that sufficient calcium remains in your bone tissue, to prevent bone weakening, while small amounts of calcium support muscle, heart and nerve function. Too much or too little vitamin D-3 can disrupt this calcium balance, affecting your bones and a number of other tissues throughout your body.
Effect on Kidneys
One of the possible effects of excessive vitamin D-3 intake is an increased risk of kidney stones. Excessive vitamin D-3 increases calcium levels in your blood, which in turn increases the calcium exposure of cells in your kidneys. At such high levels, the calcium can react with other molecules in your bloodstream to form calcium salt crystals, which can grow into noticeable kidney stones. As a result, individuals overconsuming vitamin D might develop lower back or abdominal pain, blood in their urine, or might even develop a blocked kidney or urinary tract due to the kidney stones.
Upper Intake Levels
Consuming vitamin D-3 above your upper tolerable limit can increase your risk of kidney stones, while keeping your vitamin intake below the tolerable limit generally proves safe. The Linus Pauling Institute at Oregon State University indicates that adults' vitamin D consumption should not exceed 100 mcg, or 4,000 IU daily. If you take vitamin megadoses, such supplements often contain more than your upper tolerable intake and might therefore pose health risks to your kidneys.
Recommendations and Considerations
You can prevent the risk of kidney stones due to vitamin D-3 consumption by taking vitamin supplements only as required. Individuals who receive sun exposure on a regular basis may not require additional vitamin D consumption, because your skin can synthesize vitamin D when exposed to UV light. In addition, several foods, such as milk, fortified juice, egg yolks and fatty fish all contain vitamin D. If you require vitamin D-3 supplements, talk to your doctor about a safe supplement level to prevent kidney stones.
