How much vitamin D can I take before it damages my organs?

Research suggests that serious vitamin D toxicity, including damage to the heart, blood vessels and kidneys, is most likely to occur if you take doses exceeding 10,000 international units (IUs) of vitamin D per day. High doses of vitamin D can raise the level of calcium in the blood so high that these tissues calcify -- that is, they harden.

Taking vitamin D supplements at doses above the tolerable upper intake level (UL) can raise the risk of less severe adverse effects, including weight loss, nausea and vomiting, nervousness, heart arrhythmias, extreme thirst and excessive urination. The UL for vitamin D is 4,000 IUs per day for adults and children ages 9 and older, 3,000 IUs for children ages 4 to 8 and 2,500 IUs for children ages 1 to 3. For babies, the safe limits are 1,000 IU from birth to 6 months, and 1,500 IU from 7 to 12 months.

The current Recommended Dietary Allowance (RDA) for vitamin D is 600 IUs per day for people ages 1 to 70 and 800 IUs per day for people ages 71 and older.

Use caution. Talk to your doctor about whether you need to take vitamin D supplements and, if you do, what the best dose would be for you.
It is pretty common practice to use a loading regimen of Vitamin D such as yours so that it does not take months to correct your vitamin D levels. These larger loading doses are typically administered for a short time (8 weeks) and do not cause toxicity. In general, the body can handle large doses of vitamin D, especially when there is a deficiency. The average dose for poor absorption of vitamin D is 10,000-50,000 IU daily, or this may be given as once per week dose.

If you are concerned about your vitamin D dose, you should follow up with your doctor. You can also monitor for signs of too much Vitamin D, which include unexplained nausea, vomiting, poor appetite, constipation, weakness, weight loss, mental status changes such as confusion and abnormal heart beats, if any of these symptoms occur, follow up with your doctor as soon as possible. Vitamin D does not interact with your Coumadin. Your INR level (blood thinning level) may be affected by many different things, including the amount of vitamin K in your diet or multivitamins. Vitamin K is found in green leafy vegetables such as spinach or kale, and also can be found in some daily multivitamins. Be sure to choose a daily vitamin that does NOT contain vitamin K. It can be hard to find the right dose of Coumadin, sometimes the INR (blood thinning level) will change without any explanation and the dose of Coumadin will need to be adjusted and monitored more closely. It is best to work closely with your doctor and keep him or her informed of any changes in your diet or medications, and always talk to your doctor before adding a new over-the-counter medication, vitamin, or herbal supplement.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.