Yes, getting too much vitamin D can be harmful. Very high levels of vitamin D in your blood (greater than 375 nmol/L or 150 ng/mL) can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, excessive urination and thirst, and kidney stones.
Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day.
Adults aged up to 70 years old should be getting at least 600 IU. Adults older than 70 should be getting at least 800 IU of vitamin D. However, some sources say you should consume up to 1000 IU of vitamin D past the age of 70.
Unless your doctor recommends it, avoid taking more than 4,000 IU per day, which is considered the safe upper limit.
Vitamin D Levels
Healthy Bones Australia recommends a vitamin D level of at least 50 nmol/L at the end of winter and during summer higher levels are common in the range of 60-70 nmol/L. Your doctor will only test your vitamin D level (with a blood test) if you are at risk of vitamin D deficiency.
But how do you flush vitamin D out of your system – and can you even do that? Yes, by ensuring you consume plenty of water. This will encourage urination, allowing your body to shed the excess vitamin D and calcium more quickly. Prescription diuretics like furosemide can also be helpful.
There's no set time of day that's best to take vitamin D supplements. Some people say taking vitamin D supplements at night is an insomnia risk. There's no research to confirm this, but you might want to take your supplement earlier in the day if you think it's screwing with your sleep.
Some side effects of taking too much vitamin D include weakness, dry mouth, nausea, vomiting, and others. Taking vitamin D for long periods of time in doses higher than 4000 IU (100 mcg) daily is possibly unsafe and may cause very high levels of calcium in the blood.
There are quite a few differences between vitamin D and vitamin D3, but the main difference between them is that vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous levels in the body, whereas the vitamin D3 is the natural form of vitamin D produced by the body from sunlight.
Too much vitamin D can cause harmful high calcium levels. Tell your doctor right away if any of these signs of high vitamin D/calcium levels occur: nausea/vomiting, constipation, loss of appetite, increased thirst, increased urination, mental/mood changes, unusual tiredness.
In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs/day appears to be safe.
Optimum intake
The National Academy of Medicine recommend a daily intake of 600 international units (IU) for adults aged 19–70 years and 800 IU per day for individuals aged 70+ years.
Conclusion: Oral vitamin D 3 has no significant effect on blood pressure in people with vitamin D deficiency. It reduces systolic blood pressure in people with vitamin D deficiency that was older than 50 years old or obese.
Vitamin D and sleep: The surprising connection
Early research suggests it is inversely related to melatonin, your sleep hormone. Increasing vitamin D levels may suppress melatonin levels. So, it makes sense that taking it at night could disrupt your sleep.
Growing evidence has demonstrated that vitamin D has a role in sleep regulation [12]. Specifically, vitamin D deficiency (VDD) can increase risk of sleep disorders and is associated with sleep difficulties, shorter sleep duration, and nocturnal awakenings in children and adults [13,14,15].
Symptoms of too much vitamin D
The symptoms include: Increased thirst. Frequent urination.
Extremely high vitamin D levels are harmful and can cause nausea, vomiting, confusion, excessive thirst and kidney stones. Vitamin D supplements can interact with certain medications, so check with your doctor before starting one.
Excess levels of vitamin D in your system can lead to an array of complications and symptoms, including weakness and fatigue.
High doses of vitamin D supplements over time can cause vitamin D toxicity. A condition called hypercalcaemia (where there is too much calcium in your blood) is the most common result of taking too much vitamin D. Signs of this condition include nausea, dehydration and constipation.
Use the CVS Health At Home Vitamin D Test Kit to get accurate and comprehensive results in the privacy and comfort of your own home. Simply collect your blood sample using this convenient kit, mail it to the lab, and receive your results through a secure online portal in just a few days.
Vitamin D (from food, sunshine and supplements) changes to calcidiol in the liver, which is measured from blood to check the level of vitamin D. The half-life of calcidiol of D3 (we get from supplements and e.g. fish) is 15–30 days. Half-life is the period during which vitamin D stores decrease by half.