Ⅴd3，333国际单位啥意思_备孕

您好：国际单位（International Unit）是用生物活性来表示某些抗生素、激素、维生素及抗毒素量的学单位。

1、1个IU的维生素E 换算后对应 1mg DL-α-生育酚

2、1粒养生堂的天然维生素E含量 97.5mg DL-α-生育酚

也就是说200国际单位比2粒维生素E的含量略多一点儿。

每袋儿童含的碳酸钙是0.75克(相当于钙0.3克)，维生素D3100国际单位(2.5微克)。

看在辛苦打字的份上，！

一个国际单位相当于0.025微克的维生素D3，一微克的维生素D3有40国际单位.所以7.5微克的维生素d相当于300单位的维生素d。 1ug等于40单位的维生素d，7.5ug应该相当于300单位。我们每天维生素d的生理需要量，至少应该在400到600单位。

Vitamin A Technical Details:

Vitamin A is a fat-soluble vitamin. It is important for vision, bone growth and cell division.

Vitamin A consists of Retinol from animal sources, and Provitamin A Carotenoids from plant sources.

Retinol is referred to as pre-formed vitamin A. This means that it can be used directly by the body.

Provitamin A Carotenoids are Vitamin A precursors . This means that they are converted to Vitamin A by the body. However, conversion of the carotenoids is less efficient than that of retinol.

The Provitamin A Carotenoids are beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopein, lutein and zeaxanthin (lutein and zeaxanthin are combined in the current database). The carotenoids are responsible for the red and yellow pigments of plants.

A unit called Retinol Activity Equivalents (RAE) is used to compare the Vitamin A activity of the different forms of Vitamin A. 1 µg (microgram) of retinol is equivalent to 1 µg RAE. However it takes 12 µg beta-carotene to equal 1 µg RAE, and 24 µg of the other carotenoids to equal 1 µg RAE. The following table summarizes the conversion of vitamin A values to RAE:

Historical Measures of Vitamin A

Previously, a unit called International Units (IU) was used to describe Vitamin A activity. However, at the time International Units for Vitamin A were defined (1989), it was thought that beta-carotene was half as concentrated as retinol (beta-carotene is now considered to be only 1/12 as concentrated as retinol).

Because of this, Vitamin A measurements expressed as IU tend to over-state the contribution of the provitamin A carotenoids. The following table summarizes the conversion of Vitamin A values to IU:

When it was determined that IU tended to overstate the contribution of the provitamin A carotenoids, a new unit called Retinol Equivalents (RE) was defined to describe the new values. At the time beta-carotene was thought to be 1/6 as concentrated as retinol. The following table describes the conversion of vitamin A values to RE:

In 2001, the National Academy of Sciences Institute of Medicine (NAS IOM) determined that Vitamin A activity from carotenoids is only half of what was previously believed. To account for this difference, and to avoid confusion, the new unit Retinol Activity Equivalents (RAE) was defined. Retinol Equivalents (RE) are no longer used.

The following table summarizes the relationship between the different measures:

IU Details

At the time of this writing (2004), the RDI (Reference Daily Intake) of Vitamin A is 5000 IU. However, IU is an inaccurate measure of vitamin A activity because it overstates the contributions of the provitamin A carotenoids (by a factor of 6). The FDA (US Food and Drug Administration) is considering changing the RDI to express it in terms of RAE.

Because the conversion of IU to RAE is different for retinol and the carotenoids, you cannot convert IU to RAE (or RAE to IU) for Total Vitamin A unless you know the proportion of retinol to carotenoids in the sample.

For example, knowing that you have 40 IU of Total Vitamin A is not enough information to determine how much retinol and carotenoids you have. 40 IU of Total Vitamin A can come from 12 µg RAE of retinol, or from 2 µg RAE of carotenoids, or from 6 µg RAE retinol plus 1 µg RAE carotenoids, or from many other combinations of retinol and carotenoids. The following table summarizes:

nutraCoster Details

Entering Retinol or Carotenoids Values

When you enter RAE for retinol or any of the carotenoids, nutraCoster automatically calculates the IU and %RDI values for the nutrient.

Finally, nutraCoster willrecalculate the IU and %RDI values of Total Vitamin A based on the new values for retinol and carotenoids.

Example: Suppose you have 80 µg RAE Total Vitamin A, which is composed of 60 µg RAE retinol and 20 µg RAE total carotenoids. The following table lists the values for the example:

Now change the Total Vitamin A RAE to 120 µg RAE. nutraCoster performs the following steps:

Total Vitamin A RAE was the sum of the retinol and carotenoids values, so nutraCoster increases retinol and carotenoids proportionally to 90µg RAE and 30 µg RAE.

The new value of 90 µg RAE for retinol converts to 300 IU and 6 %RDI.

The new value of 30 µg RAE for carotenoids converts to 600 IU and 12 %RDI.

Using the new IU and %RDI values, Total Vitamin A is now 900 IU and 18 %RDI.

The following table shows the results after the change:

nutraCoster performs a similar series of steps when you enter IU or %RDI values for Total Vitamin A.

CarotenoidDetails

When you enter or change a value for Total Carotenoids, nutraCoster checks to see if the Total Carotenoids value was equal to the sum of the individual Provitamin A Carotenoids before the change. If it was, nutraCoster recalculates the individual carotenoid values so the sum of the values equals the new Total Carotenoids value, while keeping the proportions the same.

When you enter or change a value for any of the individual carotenoids, nutraCoster checks to see if the Total Carotenoids value was equal to the sum of the individual Provitamin A Carotenoids before the change. If so, nutraCoster adjusts the Total Carotenoids value to equal the sum of the individual carotenoid values after the change.

为了统一计量膳食中的维生素A，而提出的一个概念。其含义是包括视黄醇和β-胡萝卜素在内的具有维生素A活性物质所相当的视黄醇量。

由于人体维生素A 来源于动物性食物的维生素A和植物性食物中的胡萝卜素（维生素A原），而维生素A的常用计量单位为国际单位（IU），胡萝卜素的常用计量单位为μg（微克）或者mg（毫克），为了统一计量膳食中的维生素A， FAO /WHO（1967）提出了视黄醇当量（Retinol Equivalent, RE)概念。其含义是包括视黄醇和 β-胡萝卜素在内的具有维生素A活性物质所相当的视黄醇量。

视黄醇当量、维生素A 、 β-胡萝卜素的换算关系如下：

1μg β-胡萝卜素=0.167μg视黄醇当量（理论上1分子β-胡萝卜素能形成2分子维生素A，但因为胡萝卜素的吸收率为1/3，而吸收后转化为维生素A的转化率又只有1/2，所以，1μg的胡萝卜素只能折算为0.556IU维生素A，即0.167μg视黄醇当量。1IU维生素A=0.3μg视黄醇当量）

一个国际单位=0.000000025克。

国际单位制（international system of

units）是国际计量大会（CGPM）采纳和推荐的一种一贯单位制。

在国际单位制中，将单位分成三类：基本单位、导出单位和辅助单位。7个严格定义的基本单位是：长度（米）、质量（千克）、时间（秒）、电流（安培）、热力学温度（开尔文）、物质的量（摩尔）和发光强度（坎德拉）。

基本单位在量纲上彼此独立，导出单位很多，都是由基本单位组合起来而构成的。辅助单位只有两个，纯系几何单位。当然，辅助单位也可以再构成导出单位。

扩展资料：

国际单位制按一贯计量单位制的原则构成，采用十进制构成其倍数和分数单位；只能通过SI词头构成倍数和分数的单位。

其基本单位及其定义只能由国际计量大会决定，SI导出单位的专门名称及其符号只能由国际计量大会选定。根据上述规则，诸如体积单位升、质量单位吨、光亮度单位尼特（nt，1尼特=1坎/平方米）等都不是国际单位制的单位。

两类SI单位：在国际单位制中，7个基本单位以及按一贯性原则从基本单位导出的单位，总称为SI单位。

参考资料来源：百度百科-国际单位