婴幼儿以及成人正确补充维生素D（来自FDA和AAP的权威资料）

发现很多家长经常对维生素D的用量有些疑问，花了些时间找到些权威的资料，发帖如下，希望能够给大家一些帮助，特别是针对宝宝，一定要注意。

来自FDA（美国食品和药物管理局）对VD膳食补充剂企业的致信（FDA Letter to Industry Concerning Liquid Vitamin D Dietary Supplements），现对关键部分引用如下:

Most liquid vitamin D products marketed today use a dropper to measure and deliver the vitamin D. FDA has concerns regarding any liquid vitamin D products that could deliver a significantly excessive amount of vitamin D. The concern is that the droppers can hold a considerably greater amount of liquid vitamin D than an infant should receive. This could lead to a parent inadvertently or mistakenly giving an unsafe amount of vitamin D to an infant.

大多数的婴幼儿VD膳食补充剂采用滴管形式来计量，FDA担心这种方式可能会喂给婴儿显著过量（并且是不安全剂量）的维生素D。


以下资料来源自美国儿科学会（AAP）

关键信息粘帖如下：

”In November 2008, the American Academy of Pediatrics(AAP) doubled the recommended daily intake of vitamin D for infants
and children, from 200 IU/day (2003 recommendation) to 400 IU/day We aimed to assess the prevalence of infants meeting the AAP recommended intake of vitamin D during their ?rst year of life.“

2008年十一月，美国儿科学会（AAP）将婴幼儿童维生素D的每日推荐摄入提高了一倍，从200 IU /天（2003推荐）提高到400 IU /天，目的是尽量保证婴幼儿在出生后的第一年摄入到足量的维生素D。

“The American Academy of Pediatrics (AAP) advises that children younger than 6 months be kept out of the sun altogether and that those aged 6 months or older wear protective clothing and sunscreen to minimize sun exposure. Some re searchers  recommend short episodes of sun exposure as a way of obtaining vitamin D; however, the safety of this method for infants with regard to future skin cancer is not known. In addition, one’s ability to produce vitamin D is affected by latitude, season, sunscreen use, skin pigmentation, and air pollution, whichmake sun exposure an unreliable source of vitamin D. Thus, infants need to obtain vitamin D either primarily or entirely from their diet.”

美国儿科学会（AAP）建议，6个月以下幼儿应当避免晒太阳、6个月以上幼儿应当 采取防晒措施来尽量减少阳光暴晒。尽管有一些研究建议以晒太阳的方式来获取维生素D，但是，这种方法对诱发婴幼儿皮肤癌的风险评估数据尚不清楚，此外，人 体自身合成维生素D的能力受纬度、季节、是否使用防晒霜、皮肤色素沉着、日照强度和空气浊度的影响，所以依靠日晒的方式获取足量的VD并不可靠。

“According to the 2008 AAP recommen-dation, all breastfed, mixed-fed, andformula-fed infants who consume 1L/day of formula should receive an oral vitamin D supplement. ”

根据美国儿科学会（AAP）的推荐，所有母乳喂养、半母乳喂养、奶粉喂养（低于1L/天）的婴儿，应该接受口服补充维生素D。

“We found that most infants, not just those who are breastfed, may re-quire an oral vitamin D supplementdaily, beginning within their ?rst few days of life, to meet the 2008 AAP rec-ommendation that infants consume at least 400 IU/day of vitamin D.”

我们发现大多数婴儿（不单是母乳喂养）在出生后的几天内就需要口服补充维生素D，来达到2008AAP推荐的每日最小摄入量（400IU VD）。

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Preterm Infants May Need 800 IU of Vitamin D3 Per Day

5/5/2013 AAP（美国儿科学会）

Largest study to date of preemies shows 800 IU more effective than 400 IU in decreasing vitamin D insufficiency
WASHINGTON, DC – Preterm infants may need to be given 800 international units (IU) of vitamin D a day to ensure they develop strong bones, according to a study to be presented Sunday, May 5, at the Pediatric Academic Societies (PAS) annual meeting in Washington, DC.

Preemies are known to be at risk for vitamin D insufficiency. If levels of vitamin D are too low, infants and children can get rickets, which leads to softening and weakening of the bones.

Recommendations from medical organizations on how much vitamin D should be given to preemies range from 400 IU to 1000 IU per day. This lack of consensus prompted researchers from All India Institute of Medical Sciences, New Delhi, to conduct the largest study to date on vitamin D supplementation in preterm infants.

Subjects included 96 infants born between 28 and 34 weeks’ gestation who were receiving milk feeding. Blood samples were taken from the infants to determine their serum vitamin D levels. The infants then were randomly assigned to receive either 800 IU or 400 IU of oral vitamin D3. Neither the parents nor the primary investigator was aware of which dose the infants were receiving.

Researchers compared whether the prevalence of vitamin D insufficiency (VDI) at 40 weeks and at 3 months corrected age differed between the groups. They also looked at whether infants with higher vitamin D levels also had stronger bones at 3 months corrected age and whether supplementation led to vitamin D levels that were too high.

Results showed that VDI was common in both groups before they received supplements (79 percent of the 800 IU group and 83 percent of the 400 IU group).

After supplementation, the prevalence of VDI at 40 weeks was 43 percent lower in the 800 IU group than the 400 IU group (38 percent vs. 67 percent). In addition, VDI was significantly lower in the 800 IU group when the infants were 3 months old (12 percent vs. 35 percent).

Four infants needed to be supplemented with 800 IU daily to reduce one case of vitamin D insufficiency, said lead author Chandra Kumar Natarajan, DM.

“The study results show conclusively that in preterm infants with high rates of vitamin D insufficiency at baseline, supplementation with 800 IU of vitamin D3 per day compared to 400 IU per day reduces vitamin D insufficiency at term equivalent age and at 3 months,” Dr. Natarajan said. “There also is a trend toward a decrease in the prevalence of vitamin D insufficiency even in the 400 IU group at 3 months. Therefore, 400 IU per day may be sufficient after 3 months.”

Despite significant improvement in serum vitamin D levels in the 800 IU group, higher levels did not result in better bone mineralization at 3 months of age as measured by dual energy X-ray absorptiometry (DEXA). In addition, weight, length and head circumference did not differ significantly between the groups.

Dr. Natarajan also noted that one infant in the 800 IU group had vitamin D levels that were higher than recommended levels at 3 months of age despite the levels at term age being normal. Excess vitamin D for at least one month can cause decreased muscle tone, decreased appetite, irritability and constipation, among other problems. The infant did not experience any major effects.

“The incidence of vitamin D excess in the 800 IU group may indicate the need for monitoring vitamin D levels in infants on vitamin D supplementation, but we need larger studies to answer this,” he said. “Similarly, larger studies with longer duration of follow-up may be needed to find out any meaningful difference in clinical outcomes such as bone mineralization.”
To reduce the likelihood of dosing errors, FDA recommends that 400 units be clearly and accurately marked on the dropper accompanying your product. In addition, for products intended for infants, FDA recommends that the dropper hold no more than 400 units.

为减少过量的可能性，FDA建议滴管上应当显著标识400IU的刻度线，并且一次性最多只能吸取400IU的液体VD。

Vitamin D is a generic term that is used to refer to the secosterols, ergocalciferol or Vitamin D2, and cholecalciferol or Vitamin D3 and their metabolites and analogues. Vitamin D is normally produced in the skin from a pro-vitamin using ultraviolet B (UV-B), and with adequate sun exposure, Vitamin D is not required in daily dietary intake. Vitamin D is the principal regulator of calcium, and is therefore important for skeletal development, bone mineralization and bone homeostasis, among other functions.

维生素D是一个通用术语，它是麦角钙化醇（维生素D2），胆钙化甾醇（维生素D3）及其代谢产物和类似衍生物的统称。 人体的皮肤在阳光底下自身就可以合成维生素D，所以当有足够日晒时，人体并不需要补充维生素D。维生素D是钙的主要“监管者”，因此，它对人体的骨骼发育、骨骼矿化、维持骨骼稳定以及其他一些功能中都非常重要。

The Institute of Medicine’s (IOM) recommended Upper Limit (UL) for chronic Vitamin D intake for infants (children less than 1 year of age) is 25 mcg/day (1,000 IU/d), and for children age 1 year and older the recommended UL is 50 mcg/day (2,000 IU/d), based upon the specific vitamin D molecule being D3 from naturally occurring substances, such as fatty fish and fish liver oils. The UL for pregnancy and lactation is the same as for non-pregnant adults at 50 mcg/day (2000 IU/d). The UL value for adults ages 18 and older was based on a safety factor of 1.2 applied to a no adverse effect level (NOAEL) of 60 mcg/d. The lowest adverse effect level (LOAEL) in the IOM analysis was 95 mcg/d. The adverse effect used in the risk assessment was hypercalcemia, serum calcium elevated above the normal range, specified as above 2.75 mmol/liter (11 mg/dL)1.

美国医学研究所建议1岁以下婴幼儿长期摄入维生素D（维生素D3来自于诸如鱼油和鱼肝油等的天然物质）的上限设定为25mcg/天（1000IU/d），1岁以上儿童上限设定为50mcg/天（2000IU/d），孕妇和哺乳的妈咪摄入上限与非怀孕的成年人一样都设定为50mcg/天（2000IU/d），18岁以上成人上限设定值采用NOAEL（无明显损害作用水平，60mcg/d）的1.2倍（安全系数），就是72mcg/天（2880IU/d）.美国医学研究所监测分析到的LOAEL（可观察到的最低有害剂量）为95mcg/天（3800IU/d）。『在美国医学研究所的风险评估中，以发生高钙血症（血钙升高超过正常范围，血钙浓度超过2.75mmol/L）作为摄入过量的判定依据』

In 2008 the American Academy of Pediatrics (AAP) recommended that all breast-fed and partially breast-fed infants (beginning in the first 2 months after birth) consume 400 IU/day of Vitamin D . Initial symptoms of Vitamin D toxicity are usually associated with resultant high serum calcium and include weakness, fatigue, lassitude, headache, nausea, vomiting, and diarrhea; mental status changes and coma may also develop. Renal function may be affected early. Cardiac arrhythmias may also ensue. Prolonged hypercalcemia can lead to soft tissue deposition of calcium; favored areas include the kidney, resulting in other associated problems such as hypertension. Additionally, other soft tissues that are affected include blood vessels, heart, lungs, and skin. Osteomalacia may also occur. Blood chemistry changes include elevated calcium and urea, with inconsistent elevation of phosphorus. If the problem is caught early, treatment may completely reverse the symptoms. Residual sequelae may include permanent renal impairment, and osteoporosis。

2008年，美国儿科学会（AAP）建议，所有母乳喂养、出生后前2个月即开始部分母乳喂养的婴儿应（补充）摄入维生素D 400 IU /天。 维生素D中毒的最初症状通常高血钙症相关联，包括虚弱，疲劳，精神不振，头痛，恶心，呕吐，腹泻，精神状态低迷以、昏迷、 早期肾功能会受到影响、 也有可能发生心律失常。 长期高钙血症可导致软组织钙沉积、可影响肾脏、导致其他相关的问题如高血压。 此外，受影响的其它软组织包括血管，心脏，肺和皮肤、也有可能导致软骨病。 血液化学变化包括钙和尿素升高，磷浓度异常等， 如果问题发现得早，可能可以痊愈。 残留的后遗症可能包括永久性肾功能不全和骨质疏松症。