Vitamin D and Kidney Stones
Vitamin D, a fat-soluble vitamin, is essential for normal growth of bone and teeth structures in humans, and is produced within our body by activation of various solid steroid alcohols such as cholesterol. This is possible, though, only with the body’s exposure to sunlight. This vitamin is also found in fish-liver oils, egg yolk, and milk. Vitamin D is vital for absorption of calcium by the human bone structures thereby playing an important role in development and maintenance of good bone health. Thus, adults who are on calcium supplements necessarily take vitamin D for its effective absorption by their bones.
A high potassium and magnesium diet along with plenty of fluid intake naturally protect humans from producing kidney stones. Now, certain studies have found that people who follow a regular diet low in potassium and magnesium but have a high intake of refined, processed food products, carbonated beverages, consume foods with a high acidic residue and are on calcium and vitamin D supplements, they have a higher risk of developing kidney stones. Modern diet is composed mainly of high animal protein and processed foods with more consumption of carbonated and caffeinated beverages. The result is reduced alkalinity of the blood and body tissues, and vitamin D does not function well in such a body state. Thus, when this vitamin does not facilitate proper absorption of calcium by the bones, it leads to increased intestinal absorption of calcium. While mostly calcium is excreted in stools, when the amount is in excess, it can settle in urine increasing the chance of developing calcium-based stones.
To get a clearer picture, it is essential to know how kidney stones are formed. Kidneys are organs that filter unwanted byproducts from blood after the body’s metabolic process is complete and passed into urine. Kidney stones are made when minerals found in urine begin to crystallize instead of getting dissolved completely in the urinary tract. This happens when substances that normally inhibit crystal formation are absent or do not function as they should, or when the urine is highly concentrated due to poor fluid intake. Under normal conditions, calcium binds with oxalates and phosphates in the intestines and gets excreted in stools. But in a situation where vitamin D is more it leads to increased intestinal absorption of calcium causing excessive calcium to enter the urine. So, when vitamin D and calcium put in their combined effort to promote bone health, similarly they work together to increase the risk of calcium deposits in urine.
It is impossible for the human body to derive excess vitamin D from sunlight or from food sources. Individuals who are deficient in vitamin D; either due to staying indoors most of their waking hours or have an aversion towards its food sources like fish, eggs, and milk, need to get this vitamin from fortified food products and supplements. When the dose of vitamin D is high, it can give rise to the development of kidney stones. Most adults require only daily intake of 600 International Units of vitamin D with a slight increase in the dosage in older adults. A dosage above this can be dangerous for those individuals who are more prone to producing kidney stones. Most cases of vitamin D toxicity arise from overuse of vitamin D supplements. Always consult a medical physician before taking vitamin D supplements.