It is almost impossible to get too much vitamin D from sunlight or food. Excessive thirst, an altered level of consciousness, high blood pressure, calcification in the kidney tubes, kidney failure or hearing loss may also develop (4, 27). For decades, experts have recommended calcium supplements to prevent osteoporosis which is responsible for fractures that cause many elderly men and women to lose their independence — and sometimes their lives.How too much can hurt: “More and more stu… All rights reserved. You can find more info about vitamin D on this page: Vitamin D 101 – A Detailed Beginner’s Guide, Vitamin D is very important for your health, but it is possible to get too much of it. The main consequence of vitamin D toxicity is a buildup of calcium in the blood, called hypercalcemia (25). Nearly all vitamin D overdoses result from taking high amounts of vitamin D supplements. Can you take too much vitamin D if you know that you’re already deficient? High calcium levels can cause various symptoms, and the calcium can also bind to other tissues and damage them. People over 70 were most likely to take more than 4,000 IUs daily. This article lets you know what dosage of vitamin D is best. Treatment involves limiting all vitamin D intake and sun exposure. Keep in mind that these are just hypotheses, but it may be wise to make sure you are getting enough of these nutrients if you are going to supplement with vitamin D. If you are supplementing with vitamin D, then it may be important to also ensure sufficient intake of vitamin A, vitamin K and magnesium. This can weaken the bones and damage the kidneys and the heart. These may reduce the risk of adverse effects from a higher vitamin D intake. Bear in mind high-dose vitamin D will be more expensive too. Registered dietitian Samantha Heller is a senior clinical nutritionist at NYU Langone Medical Center in New York City. For normal, healthy adults, Health Canada recommends a total daily intake of 600 international units (IU) up to age 70, and 800 IU after age 70. However, we know that the active form of vitamin D functions in a similar way as a steroid hormone. Vitamin D is very unlikely to cause severe symptoms of toxicity right away, and symptoms may take months or years to show up. It travels inside cells, telling them to turn genes on or off. Can you overdose on vitamin D? The Best Supplements for Healthy Digestion, How to Get the Protective Power of Vitamin K. In 2007-2008, 0.2 percent of Americans took 4,000 IUs or more daily. Symptoms of high calcium levels include weight loss, bone loss, kidney stones and heart irregularities. Vitamin D integration was stopped and, in a week, hypercalcemia normalized. Heller said that appropriate vitamin D levels have been linked to lower risks of certain cancers, early death, depression in adolescents, type 2 diabetes, and improved heart health and immune system regulation. Since relatively little is known about how vitamin D toxicity works, it is hard to define an exact threshold for safe or toxic vitamin D intake (5). There are four fat-soluble vitamins in the human diet: A, D, E and K. This guide examines their health benefits, functions and main dietary sources. On the other hand, vitamin D toxicity (too much vitamin D in the blood) is considered anything above 200–240 ng/mL of blood. You’re most likely to experience symptoms of too much vitamin D when taking supplements in high doses for a long period of time. Why it matters: Calcium plays a critical role in building and maintaining healthy bones. The study was published as a research letter in the June 20 issue of the Journal of the American Medical Association. According to the latest NHS guidance, adults and children over the age of one need 10mcg (micrograms) of Vitamin D per day. Clearly, vitamin D is beneficial, regardless of how it is obtained. Those who are between 7 months and a year old can only tolerate 1500 IU of vitamin D. Toddlers from age 1 to 3 years shouldn’t exceed 2500 IU, whereas children from 4 to 8 years should have a maximum of 3000 IU of vitamin D. From 9 years onwards into adulthood, the highest tolerated intake of vitamin D is 4000 IU. Taking high doses of vitamin D causes your liver to produce a chemical called 25(OH)D, which makes calcium accumulate in your bloodstream. It's also found in fortified foods such as milk, and naturally in fatty fish such as salmon, Rooney said. Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). One reason people may be taking so much extra vitamin D is concern about getting too little of the vitamin. When using Vitamin D at dosages higher than 4000 IU per day, it’s recommended that … Another nutrient that may be important is magnesium. Vitamin D toxicity is generally caused by excessive doses of vitamin D supplements, not by diet or sun exposure (16, 17). Nutrient deficiencies may occur with almost every nutrient, but some are more likely than others. Taking too much supplemental vitamin D can be toxic in rare cases. This is the equivalent of 4,000 IU a day. There are several forms, including two that are important to humans: D2 and D3. It is produced in the skin when it is exposed to sun. Most kids and adults spend lots of time indoors at school and work. Getting too much vitamin D may cause a loss of appetite and weight, increased urination or heart arrhythmia. Vitamin D is important for optimal health, but 42% of Americans are deficient. But Rooney and her colleagues are concerned that the pendulum may have swung too far in the other direction, and that some people may be taking too much vitamin D. The researchers looked at information from national surveys that included nearly 40,000 people. Vitamin K helps regulate where calcium ends up in the body, and high amounts of vitamin D may deplete the body’s stores of vitamin K (29, 30). Here's what you need to know. The exact mechanism behind vitamin D toxicity is complicated and isn’t fully understood at this point. Large doses may cause damage, despite a lack of noticeable symptoms. Vitamin D is essential for good health. Early symptoms of hypercalcemia include nausea, vomiting, diarrhea, constipation and weakness (26). Some studies have used dietary supplements containing the 25(OH)D 3 form of vitamin D. Per equivalent microgram dose, 25(OH)D 3 is three to five times as potent as vitamin D 3 [35,36]. It usually develops over time, since extra vitamin D can build up in the body. Vitamin D toxicity is usually reversible, but severe cases may eventually cause kidney failure and calcification of the arteries (23, 24). Vitamin D2 (ergocalciferol) is synthesized by plants, and vitamin D3 (cholecalciferol) is synthesized by humans when skin is exposed to ultraviolet-B (UVB) rays from sunlight. This is because vitamin D accumulates in body fat, and is released into the blood slowly (4). "The surplus can build up in the body … Biotin plays an important role in the health of your hair, skin, and nails, but can it really help with hair growth? It's hard to get enough vitamin D from the sun, though. Guidelines for blood levels of vitamin D are as follows (9, 10, 11, 12, 13, 14): A daily vitamin D intake of 1000–4000 IU (25–100 micrograms) should be enough to ensure optimal blood levels for most people. In 2007-2008, only 0.2 percent did that. "Our bodies are designed to get the bulk of our vitamin D from the sun," said Heller, who wasn't involved with the study. High doses of vitamin D can cause hypercalcemia without toxicity symptoms, but can also cause toxicity symptoms without hypercalcemia (29). People respond very differently to high doses of vitamin D. Therefore, it is hard to evaluate which doses are safe and which are not. Because vitamin A is stored in your body fat, it can build up to dangerous levels over time. Because vitamin D assists in calcium absorption from the intestine, very high vitamin D levels can cause high calcium levels as well. © 2005-2021 Healthline Media a Red Ventures Company. Vitamin D, often referred to as the sunshine vitamin, is actually a fat-soluble hormone that the body can synthesize naturally. All rights reserved. For perspective, the recommended daily amount of vitamin D is only 600 IUs for adults aged 70 and younger. It has been hypothesized that two other fat-soluble vitamins, vitamin K and vitamin A, may play important roles in vitamin D toxicity. This includes the kidneys. Larger doses have not been linked with any additional health benefits, and may therefore be completely unnecessary. "There's not much research on longer-term health outcomes on high-dose supplements," she said. Although vitamin D toxicity is a very rare condition, recent increases in supplement use may lead to an increase in reported cases. Large doses of vitamin D can be harmful, even though there may not be immediate symptoms of toxicity. On admission, hypercalcemia (3.23 mmol/L) and acute kidney injury (eGFR 20 mL/min) were detected, associated with high concentrations of 25OH-vitamin D (920 nmol/L), confirming the suspicion of vitamin D intoxication. So when a person has too much, it can lead to dangerously high levels of blood calcium, a condition called hypercalcemia. Excessive vitamin D intake frequently results in kidney injury. Healthline Media does not provide medical advice, diagnosis, or treatment. The active form of the vitamin is calcitriol, synthesized from … To be safe, you should not exceed the 4,000 IU (100 mcg) upper limit without consulting with a doctor or dietitian. Study finds more people are exceeding the upper daily limit of what is considered safe. Unless you think you’re likely to be severely deficient, there’s no need to go to these upper limits. Kidney failure. Taking vitamin A, vitamin K and magnesium with vitamin D may therefore improve bone function and reduce the chances of other tissues becoming calcified (33, 34, 35). It took about 6 months for renal function and 18 months for vitamin D values to go back to normal. By 2013-2014, that number was 3.2 percent, the study found. Large doses of vitamin D (such as more than 4,000 IU a day) should be taken only under the advice of your health care provider. However, a new study has found that too much can have a negative effect on some members of the population. Intake in the range of 40,000–100,000 IU/day (10-25 times the recommended upper limit) has been linked with toxicity in humans. Poor appetite. Blood Levels of Vitamin D: Optimal vs. Vitamin D toxicity is extremely rare, but does occur with extreme doses. This article explores 6 side effects of taking too much vitamin…, Vitamins D and K are crucial for your health, but some say vitamin D is harmful to those low in vitamin K. Here's a look at the science behind this…. Because we are not in the sun as much as our forefathers were, Vitamin D deficiency is a big problem but taking too much vitamin D in supplement form can be unhealthy at high doses. Vitamin D toxicity implies that vitamin D levels in the body are so high that they cause harm. In one case study, a … An occasional high dose of vitamin D is sometimes used to treat a deficiency, but always consult with your doctor or dietitian before taking a large dose. Usually, most of the body’s vitamin D is in storage, bound to either vitamin D receptors or carrier proteins. 1 You may think that is a good thing, but withOUT the hormones in place to deposit the calcium and phosphate into the bones, the calcium and phosphate deposit into soft tissues. Treating vitamin D intoxication includes avoiding sun exposure and eliminating all dietary and supplemental vitamin D. Your doctor may also correct your calcium levels with increased salt and fluids, often by an intravenous saline. For those over 70, the recommendation is 800 IUs … As a result, the main symptom of vitamin D toxicity is hypercalcemia – elevated levels of calcium in the blood (4, 5). In contrast to water-soluble vitamins, the body has no easy way of getting rid of fat-soluble vitamins. This is 10-25 times the recommended upper limit, in repeated doses. But she noted that vitamin D deficiencies are common worldwide, and said many people may need to take vitamin D supplements to get sufficient amounts. WebMD does not provide medical advice, diagnosis or treatment. Vitamin D toxicity is, thankfully, quite rare but can lead to hypercalcemia and together the symptoms can include: Nausea. You can get too much vitamin D if you overdo the supplements. However, there is a risk of serious health issues from getting too much vitamin A. So, how much of Vitamin D is too much or too less for the body? Some vitamin D can also protect against some sun damage. As with many other things in nutrition, more does not always equal better. Very little “free” vitamin D is available (1, 2). However, doses up to 10,000 IU have not been shown to cause toxicity in healthy individuals (10, 15). This is one reason why vitamin D toxicity is so difficult to detect. The main dietary sources of vitamin D are fish liver oils and fatty fish. The US Department of Health and Human Services (HHS) lists the ideal daily amount of Vitamin D for adults as 600 IU with an upper limit as 4,000 IU. This article explores the relationship between vitamin D and body…. The FDA recommends that adult women get 700 mcg of vitamin A per day, while men should get at least 900 mcg. The main consequence of vitamin D toxicity is hypercalcemia, with symptoms including nausea, vomiting, weakness and kidney failure. According to the Institute of Medicine, 4000 IU is the safe upper level of daily vitamin D intake. High-dose vitamin D supplements. The surveys were taken beginning in 1999 and continued through 2014. Additionally, vitamin D supports bone growth and remodeling and the neuromuscular and immune functions. The blood levels in these cases of toxicity ranged from 257–620 ng/ml, or 644–1549 nmol/L. TUESDAY, June 20, 2017 (HealthDay News) -- When it comes to vitamin D supplements, it's possible that Americans may be getting too much of a good thing, new research suggests. Vitamin D toxicity, also known as hypervitaminosis D, is a rare condition that occurs when a person has consumed too much vitamin D. Vitamin D is a nutrient that helps the body absorb and regulate calcium in the blood. Vitamin D forces our bodies to absorb calcium and phosphorous. The researchers said the trends of increasing use of supplemental vitamin D were found across most age groups, genders, races and ethnicities. This may lead to elevated levels of “free” vitamin D in the body, which may travel inside cells and overwhelm the signalling processes affected by vitamin D. One of the main signalling processes has to do with increasing the absorption of calcium from the digestive system (3). 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