核心提示：关于牛奶中IGF-1对人体的影响，美国食品药品局（FDA）早已经做出了结论。2007年5月，在FDA最新公布、经美国国家审计署审计的报告中写道：“IGF-1与癌症无关，牛奶中IGF-1浓度的变化不会增加人体罹患癌症的几率”。
事实上，OMP中所包含的是一系列多肽和蛋白类物质，总体来说，这些物质通过促进人体骨中微细血管的生长而促进骨密度的增加，共同对人体骨密度的增强发挥了重要的作用。主要成分为乳铁蛋白、乳过氧化物酶等。从检测结果看，特仑苏OMP牛奶中IGF-1的含量，与普通牛奶相比并无异常。（参见附件：美国明尼苏达州Hitech Analytical and Diagnostic Solutions实验室检测结果）而且从日本、美国、韩国等地的经验来看，也没有发现MBP等类似物质致癌的报告。
美国明尼苏达州Hitech Analytical and Diagnostic Solutions实验室检测结果
Forty-four (44) milk samples from China were analyzed for the presence of IGF-1 level. The results are given in Table 1.
分析44个来自中国的牛奶样品中的IGF-1含量，检验结果见表1。
The Analysis was done using ELISA. This assay was developed in house and uses a proprietary protocol. The presence of IGF-1 level was calculated from standard curve. The standard curve was prepared by fitting best curve plotting OD values against IGF-1 concentration/ml. The concentration of standards ranged from 200pg/ml to 3000pg/ml.
分析使用ELISA方法。建立方法和检测流程后，从标准曲线中计算出IGF-1的含量。标准曲线的浓度范围为200 pg/mL～3000 pg/mL
Ten- (10) additional milk samples from different vendors (CVS, Seven Eleven, Grand Mart, Shoppers, Giant, and Safeway) in the Washington Metropolitan area were also analyzed in the same assay along with Chinese samples. These results are summarized in Table 2.
另外10个牛奶样品来源于华盛顿地铁周边的销售商（CVS、Seven Eleven、Grand Mart、Shoppers、Giant 和 Safeway），也用同样的方法分析，结果汇总于表2。
The work was performed under GLP conditions following FDA guidelines. The standard curve and performance characteristics of the assay are also provided in the report. The protocol of the ELISA used in this analysis is attached at the end
整个流程遵循FDA指导的GLP（良好实验规范）。报告中还提供了标准曲线和性能特点，分析中应用的ELISA方法的流程附在结尾处。
Table 1: Results of IGF-1 Levels in Milk Samples.
表1：牛奶样品中IGF-1的含量（样品来源于中国）
Table 2: IGF-1 Levels in Local Milk Samples.
表2：牛奶样品中IGF-1的含量（样品来源于本地）
标准曲线
Linearity Range: 200 pg/mL to 3000 pg/mL 线性范围：200 pg/mL～3000 pg/mL
Precision: %CV ranges between 3.6 and 7.8 精密度：3.6% CV～7.8% CV
Recovery: Recovery of IGF-1 in assay buffer is 112.3% 回收率约为112.3%
Attachment: 附件
SOP#: EL001 Prepared by: A. Abdullah
Revision#: 0 Approved by: R. Kango
Revision Date: N/A Effective Date: January 2, 2009
This protocol is used for IGF-1 determination in milk samples.
Materials Used
1. Elisa Plate coated with a mouse monoclonal antibody specific to IGF-1
2. Rabbit polyclonal antibody to human IGF-1
3. Goat Anti Rabbit IgG conjugated to horseradish peroxidase.
4. Human IGF-1 Standard: Recombinant Human IGF-1
5. Assay Buffer: Tris buffer saline containing detergents
6. Wash Buffer: Tris buffer saline containing detergents
7. Stop Solution: A 1N solution of HCL in water.
8. TMB Substrate
9. Neutralizing Solution Tris base 200mM with pH 10
Assay Procedure
1. Take out number of strip to be used. Place back the remainder of the ELISA plate with desiccant in bag and store at 2-8C.
2. Bring the reagents and the strips at room temperature.
3. Prepare the quantity of Assay Buffer to be used by diluting 10X
4. Prepare the quantity of Wash Buffer to be used by diluting 20X
5. Prepare Standards using Protocol # SP002
6. Prepare Samples using protocol # SP001
7. Pipette 100ul of Assay buffer to blank well (NO STANDARDS)
8. Pipette 100ul of Standard # 1 thru #5 to the appropriate wells.
9. Pipette 100ul of Samples to appropriate wells.
10. Seal the plate. Incubate for 2 HOURS on a plate rocker (500rpm) at RT.
11. Empty wells. Wash by adding 350ul of Wash Buffer to each well. Repeat 5X
At the end tap the plate on paper towel to remove any remaining buffer.
12. Pipette 100ul of polyclonal antibody to each well (EXECPT the BLANK)
13. Seal plate. Incubate for 2 ? HOURS on a plate rocker (500rpm) at RT.
14. Repeat step 11.
15. Pipette 100ul of conjugate to each well (EXCEPT BLANK)
16. Seal plate. Incubate for 1 HOUR on a plate rocker at RT.
17. Repeat step 11.
18. Pipette 100ul substrate to each well (INCLUDING BLANK)
19. Seal the plate. Incubate for 30 MIN on plate rocker at RT.
20. Pipette 100ul of stop solution to each well (INCLUDING BLANK)
21. Read Optical Density at 450nm.
22. Convert the OD value to IGF-1 content using standard curve. Adjust the values for the dilution of the samples.
References:
1. Measurement of Bovine Somatotropin (bST) and Insulin-Like Growth Factor-1 in Bovine Milk Using an Electrocheminescent Assay: Michael F. McGrath et al
J. Agric Food Chem. 2008, 56, 7044 - 7048.
2. An Immunoenzymatic Method to Measure IGF-1 in Milk: A. Guidi et al.
Veterinary Research communication, 31(Suppl. 1) (2007) 373 - 376.
作为一种成长因子，IGF-1普遍存在于人体血液、牛奶和人的母乳之中，对人体生长发育起着重要的作用。科学研究证明，IGF-1在鲜牛奶中的含量也会随季节和牛的生理周期的变化出现大幅度波动。关于牛奶中IGF-1对人体的影响，美国食品药品局（FDA）早已经做出了结论。2007年5月，在FDA最新公布、经美国国家审计署审计的报告中写道：“IGF-1与癌症无关，牛奶中IGF-1浓度的变化不会增加人体罹患癌症的几率”。（参见附件：FDA关于IGF-1的结论）在我国人均饮奶量为21.7公斤、而世界平均水平已达100公斤，应该说，饮奶平均水平较高的国家，居民的IGF-1摄入量也相对较高，但是，统计资料表明，这些国家并没有成为癌症的“重灾区”。
附件
FDA结论：IGF-1不是天生有害物质
核心提示：公开发表一篇论文，即关于前列腺癌与IGF-1的关联。研究表明， 血浆中的IGF-1含量与前列腺癌的增长风险肯定有联系。虽然这种作用机理与引发癌症有关，但没有完全定义，但很显然IGF-1不是致癌因素。
FDA关于IGF-1的结论
Report on the Food and Drug Administration's Review of the Safety of Recombinant Bovine Somatotropin
05-03-2007
IGF-I
The Canadian report indicates that milk from rbGH-treated cows contains significantly elevated levels of insulin-like growth factor I (IGF-I) in milk, and presents human health safety concerns. IGF-I is a protein normally found in all humans, and is not intrinsically harmful. IGF-I is necessary for normal growth, development, and health maintenance. Circulating plasma血浆 levels of the hormone increase from birth to late puberty and subsequently decline in adults to approximately 100 ng (10-9 grams)/ml (range = 42 - 308 ng/ml for men and women >23 yrs). IGF-1 is structurally similar to insulin and, like insulin, is not biological effective following oral administration.
IGF－1是所有人体内自然生成的一种蛋白质，不是天生有害物质。对于人类的发育、生长和健康的维护是有必要的。人类从出生到青春后期，血浆里的荷尔蒙含量是呈增加状的。成年后下降到大概100纳克（范围：42－308纳克/毫升 男人和女人大于23岁）。IGF-1从结构上与胰岛素类似，是一种类胰岛素， 口服之后不会产生生物有效性。
The safety of IGF-I in milk was thoroughly considered by FDA in its review of the Posilac application. Some early studies suggested that treatment of dairy cows with rbGH produced a slight, but statistically significant, increase in the average milk IGF-I concentration. FDA determined that this modest increase in milk IGF-I concentration was not a human food safety concern because it was less than the natural variation in milk IGF-I levels observed during lactation 哺乳期and was less than the fluctuation observed in milk from treated and control cows prior to rbGH administration.
FDA认为牛奶中适度增加IGF-1浓度，不会造成食品安全方面的隐患。因为通过人类哺乳期的观察，增加IGF-1含量的牛奶中IGF-1的变化少于天然牛奶中的IGF-1的变化。波动也小于应用rBGH之前。
Since making that analysis, however, FDA has received and reviewed several more comprehensive studies designed to ascertain the effect of rbGH treatment on milk IGF-I levels. These studies have demonstrated that the levels of IGF-I found in milk from treated cows are within the range of those normally found in milk from untreated cows. In 1993, the JECFA Committee concluded, "the most definitive and comprehensive studies demonstrate that IGF-I concentrations [in milk] are not altered after rbGH treatment". The 1998 JECFA Committee report summarized a study showing no significant difference in commercially available milk labeled as coming from non-rbGH treated cows and milk from cows presumed to be treated with rbGH but not labeled as to treatment.
A recent study(6) has been published on the association between prostate cancer and IGF-I. This study showed a positive correlation between the level of IGF-I in plasma and the increased risk of prostate cancer. Although the mechanism responsible for induction of cancer has not been characterized fully, it is clear that IGF-I is not the causative agent.很显然IGF-1不是致癌因素。
(1998) Plasma Insulin-like Growth Factor-I and Prostrate Cancer Risk: A Prospective Study. Science, 公开发表一篇论文，即关于前列腺癌与IGF-1的关联。研究表明， 血浆中的IGF-1含量与前列腺癌的增长风险肯定有联系。虽然这种作用机理与引发癌症有关，但没有完全定义，但很显然IGF-1不是致癌因素。
FDA has examined the literature and finds no definitive evidence of any direct link between IGF-I and breast cancer. 与乳腺癌没有直接联系。Some authors have hypothesized a link, whereas others have expressed that while IGF-I is one of several growth factors and hormones that can contribute to an increase in cell numbers of many cell types invitro, no one factor is responsible for changing normal cells into cancerous cells. Furthermore, FDA has been advised that there is no substantive evidence that IGF-I causes normal breast cells to become cancerous.(7)没有足够的证据证明，IGF-1会导致正常的乳腺细胞癌变。
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