How Much Vitamin D Is Necessary?
Almost all research today suggests that the 400 IU recommended daily intake is simply not enough. Exactly how much people need is highly dependent on a number of external factors, such as sun exposure, skin tone, and diet, but a safe level for most individuals, absent a blood test, is 2000 IU per day. Having your healthcare practitioner perform a 25-hydroxyvitamin D test will allow you to work with them to optimize your daily intake in order to reach appropriate levels of vitamin D in your blood. For some individuals, especially during winter months, 5000 to 10,000 IU may be necessary.
What is the proper level? There is still some debate about this, but experts agree that the government’s recommended levels of 20 ng/mL or above are just too low. For bone health, a minimum level of 28-32 ng/mL is recommended, but this is just the minimum. Reviewing the evidence from the studies, overall health begins to benefit at 30 ng/mL and optimal levels are between 36 and 48 ng/mL. Dr. Fuhrman recommends you get between 35 and 55 ng/mL, which is a clean, easy to remember range that will guarantee you get the most benefit out of the vitamin D without needless over-supplementing.
Vitamin D toxicity is exceedingly rare and only reported in cases of supplementation above 40,000 IU a day. The main adverse effect, short of toxicity, is hypercalcemia, or too much calcium in the blood. This, too, is rare, and suspected to only occur when blood levels of vitamin D reach 280 ng/mL or more.
This is five times the maximum blood level Dr. Fuhrman and other experts recommend! You would need to take excessive amounts of vitamin D supplements to reach 280 mg/mL, making hypercalcemia (or any other vitamin D related toxicity) an extremely unlikely occurrence. Getting a 25-hydroxyvitamin D test and working with your doctor will ensure you never reach this range. If you can’t get the test, stick with 2000 IU per day.