Vitamin D is an essential nutrient that your body needs for many vital processes, including building and maintaining strong bones.
Low vitamin D intake is considered a major public health concern across the globe. In fact, vitamin D deficiency is estimated to affect 13% of the world’s population
Vitamin D is a fat-soluble vitamin that primarily aids calcium absorption, promoting growth and mineralization of your bones. It’s also involved in various functions of your immune, digestive, circulatory, and nervous systems (1Trusted Source).
Emerging research suggests that vitamin D may help prevent a variety of illnesses, such as depression, diabetes, cancer, and heart disease. However, vitamin D’s relationship to these conditions is still poorly understood (1Trusted Source).
How much do you need?
There is significant debate within the scientific community about how much vitamin D your body needs.
While the U.S. National Academy of Medicine considers 600–800 IU of daily vitamin D to be sufficient for the majority of the population, the U.S. Endocrine Society recommends 1,500–2,000 IU per day (2Trusted Source, 3Trusted Source).
The Reference Daily Intake (RDI) is currently set at 600-800 IU of vitamin D for adults, based on the U.S. National Academy of Medicine’s recommendations (2Trusted Source).
The optimal blood level of vitamin D is not concretely established but likely falls between 20 and 50 ng/ml (4Trusted Source, 5Trusted Source, 6Trusted Source).
The U.S. National Academy of Medicine further suggests that a daily intake up to 4,000 IU of vitamin D per day is safe for most people, although much higher doses may be temporarily necessary in order to raise blood levels in some individuals (4Trusted Source).
Although toxicity is rare, it is best to avoid long-term vitamin D doses in excess of 4,000 IU without supervision from a qualified healthcare professional.
The standard value of human vitamin D concentration?
According to the research institute affiliated to the National Academy of Sciences (Institute of Medicine), the most popular average standard value is as follows: Note 1
When vitamin D2 or D3 is ingested in the body, it is converted into 25-hydroxy vitamin D form by the liver, which is used clinically to determine the blood concentration.
Extreme deficiency: less than 12ng/mL (equivalent to 30nmol/L), which may cause rickets in children or rickets in adults
Insufficiency: less than 12-20ng/mL (equivalent to 30-50nmol/L)
Sufficient (standard value): between 20-50ng/mL (equivalent to 50-125mol/L)
Too high: more than 50ng/mL (equivalent to 125mol/L)
According to a paper published in the Journal of Clinical Endocrinology & Metabolism, the blood concentration of vitamin D between 20 to 36 ng/mL has the lowest mortality and heart disease risk, while less than 10 ng/mL increases it 91%, 10 to 20 ng/mL increased by 26%, higher than 36 ng/mL increased by 13%, so too high or too low is not good for health.
6 kinds of effects and side effects of vitamin D (the first kind is the most important)
- Vitamin D overdose
- The recommended dose of vitamin D (how much is an overdose)?
- The dosage of vitamin D depends on the blood value and age, so it is different for everyone. The following is the recommended daily dosage announced by the US official
- Infants under 1 year old: 400 IU
- Over 1 year old to under 70 years old: 600 IU
- Over 70 years old: 800 IU
The recommended daily standard value is about 400IU-800IU. In most studies, this dose appears to be low for most people who are deficient. For 90% of people who are deficient, 1000-2000IU is the most suitable daily dose. 20 (It is recommended to take blood after taking it for a period of time, and then lower the dose if it reaches the standard value)
There is no standard as to how much excess is counted, and the upper limit is listed below
- 0 to 6 months: 1000 IU
- 7 to 12 months: 1500 IU
- 1 to 3 years old: 2500 IU
- 4 to 8 years old: 3000 IU
- Over 9 years old: 4000 IU
When is vitamin D most effective?
Since vitamin D is fat-soluble, studies have found that when taken with fatty foods, the maximum blood concentration of Vitamin D can be 32% higher (compared to the group taken with protein), so fat does increase the absorption rate of Vitamin D The most important factor. The type of fat (saturated or unsaturated fatty acid) does not affect the absorption rate. Note 21
SUMMARY
Vitamin D is necessary for calcium absorption and bone health. While there is no set guidance, dosage recommendations range from 600–2,000 IU per day — but some people may need heavier doses to reach and maintain healthy blood levels.