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].
However, increasing vitamin D levels with supplements may suppress melatonin generation, leading to sleep disturbances. For this reason, people should take vitamin D supplements in the morning to replicate how the body synthesizes them from sunlight rather than taking them at night.
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.
Results showed that after a year of daily treatment of MS patients, high doses of vitamin D significantly suppressed the nighttime melatonin and that there is a negative correlation between vitamin D and melatonin.
There's been some buzz suggesting a link between supplementing with vitamin D before bedtime and the ability to drift off to dreamland. Some studies have shown that vitamin D is connected to the production of melatonin, which regulates circadian rhythm and drives sleep.
Safety and side effects
However, taking too much vitamin D in the form of supplements can be harmful. Children age 9 years and older, adults, and pregnant and breastfeeding women who take more than 4,000 IU a day of vitamin D might experience: Nausea and vomiting. Poor appetite and weight loss.
Phenobarbital, phenytoin, and other anticonvulsant medications -- These medications may accelerate the body's use of vitamin D. Mineral oil -- Mineral oil also interferes with absorption. In addition, Vitamin D may enhance the effects of doxorubicin , a medicine used to treat a variety of cancers.
Is too much vitamin D3 (cholecalciferol) harmful? Yes, having vitamin D levels that are too high in your body can lead to high blood levels of calcium. This can be harmful to your kidneys and cause side effects, such as nausea, constipation, loss of appetite, muscle weakness, and kidney stones.
Can you take vitamin D and magnesium together? Yes. In fact, it's probably best to take both together. Because so many people have low magnesium levels, vitamin D supplements on their own aren't very helpful for a large portion of the population.
Excess Vitamin D
You may also develop kidney stones or kidney damage. Other symptoms of vitamin D toxicity include weakness, fatigue or tiredness, vomiting, weight loss, itchy skin, constipation and muscle control issues.
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.
Magnesium. Magnesium was the featured nutrient in a study published in the Journal of Research of Medical Science, which found that adding a supplement in elderly participants improved the symptoms of insomnia and sleep quality. Nuts, beans, seeds, tofu, bananas and whole grains are all good sources of magnesium.
Therefore, conditions that affect the gut and digestion, like celiac disease, chronic pancreatitis, Crohn's disease, and cystic fibrosis, can reduce vitamin D absorption.
But vitamin D is a 'fat-soluble' vitamin, so your body can store it for months and you don't need it every day. That means you could equally safely take a vitamin D supplement of 20 micrograms a day or 500 micrograms once a month.
For adults, if you're taking a loading dose for severe vitamin D deficiency you'll usually take it daily or weekly for 6 to 10 weeks. To maintain your vitamin D levels or prevent deficiency you'll usually take colecalciferol long term.
Two forms of vitamin D are available in supplements: vitamin D3 and vitamin D2. Both can help correct vitamin D deficiency, but most doctors recommend D3 because it is slightly more active and therefore slightly more effective.
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.
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.
Vitamin D deficiency has been linked to a number of illnesses and chronic conditions, including high blood pressure, diabetes, metabolic syndrome, pulmonary disease, and chronic pain. We've seen evidence that Vitamin D deficiency is associated with sleep problems, particularly with daytime sleepiness.
"Adequate levels of magnesium in the body are essential for the absorption and metabolism not only of vitamin D but of calcium as well," Dean states. "Magnesium converts vitamin D into its active form so that it can help calcium absorption.
How to use Vitamin D3. Take vitamin D by mouth as directed. Vitamin D is best absorbed when taken after a meal but may be taken with or without food. Alfacalcidol is usually taken with food.