There are nutrients that are considered essential for maintaining immunity. One of them is vitamin D. Some experts point to vitamin D as a necessary supplement that modern people, who spend a lot of time indoors, should take. In fact, vitamin D is necessary for maintaining immunity and bone health. However, taking high doses of vitamin D every day for a long time can actually be toxic.
Vitamin D is a fat-soluble vitamin. Unlike water-soluble vitamins like vitamin C, this means that the remaining vitamins are not excreted in urine but accumulate in the body. If the concentration of vitamin D in the blood is too high, one can experience 'hypercalcemia'. This is because vitamin D promotes calcium absorption.
Mild symptoms of hypercalcemia include nausea, constipation, frequent urination, and fatigue. If it worsens, kidney stones can form, and kidney function can decline. Once the kidneys are damaged, recovery is difficult, so care should be taken in daily management. Additionally, calcium can accumulate in organs such as blood vessels or the heart, leading to calcification, which hardens like stones.
Of course, if taken in appropriate amounts, there is no need to worry too much. The recommended daily intake of vitamin D for adults is around 400-800 IU. The upper limit known to be safe is within 4000 IU per day. However, older adults, postmenopausal women, and those at risk for osteoporosis can safely take the recommended amount prescribed by their doctor every day.
It is not advisable to take 4000 IU of vitamin D daily just because it is considered good for you, even if your vitamin D levels are normal in a blood test. Additionally, taking a multivitamin and vitamin D together every day can lead to unintentional excessive intake. If you currently have kidney disease or have experienced kidney stones, be sure to consult a specialist before deciding on the intake and dosage.
