Wednesday, September 19, 2007
染髮劑是日常生活中常使用的一種化學藥劑，特別是銀髮族與新一代的所謂 “酷哥辣妹”，為求恢復青春或是為了追求眩目外觀，接觸的機會相對地提高 。然而染髮劑畢竟是化學藥劑，使用多了難免會令人擔心它對人體可能造成的 危害；特別是染髮是否會致癌，更可能是相當多人心中揮之不去的陰影。為使 讀者能瞭解染髮劑之安全性，以下謹針對染髮劑是否致癌的常見疑問加以解答。
答：大部份染髮劑中主要的成份，為煤焦油的衍生物對苯二胺類化合物， 另外有的還含有過氧化氫、酚類化合物等氧化劑。其中對苯二胺類化合物在動 物試驗，經口餵食後確實有證據顯示可能會導致泌尿道、肝臟、皮膚、乳腺、 前胃、甲狀腺或淋巴系統的癌症。至於經由皮膚的試驗，亦有少部份證據顯示 它會經由皮膚吸收而致癌；但是也有部份動物實驗指出，皮膚給予對苯二胺類 化合物，並不會致癌。至於過氧化氫與酚類化合物，雖然其致癌的疑慮遠較對 苯二胺類化合物為低，但過氧化氫仍有實驗動物致胃癌的報告。
雖然曾有部份的研究指出，經常接觸染髮劑的人（包括美髮師及一般民眾）， 可能會較一般人有更高的罹患乳癌、子宮頸癌、外陰部癌症、淋巴瘤、白血病、 多發性骨髓瘤、肺癌、膀胱癌、及黑色素瘤的機會；但是增加的比率一般而言並 不高，且不同研究間的結論並不盡相同。在1979年發表於著名的刺胳針雜誌上， 一項針對120,000名30~55歲已婚護士的研究指出，染髮者較未染髮者約有高10% 的機會，會罹患子宮頸、陰道及會陰癌症。但因此研究並非長期追蹤研究，且在 調整抽煙及時間因素後，致癌的機率明顯降低，因此其結果受到相當程度的質疑 。至於另一項針對385名罹患血液癌症與1,432名對照者間的研究則指出，長期使 用較深色（黑色、紅色與棕色）的染髮劑，可能會明顯增加罹患非何杰金氏淋巴 瘤的機會，另外也可能會增加罹患多發性骨髓瘤與何杰金氏淋巴瘤的機會。但是 因此研究的規模仍不夠大，因此亦有人質疑其結論是否真的可信。
此外也有多篇研究顯示，常使用染髮劑者並不見得會較一般人容易罹患癌症。 以美國癌症學會，在1994年所發表的一篇針對573,369名年齡在30歲以上的婦女 ，所作一項長達6年的追蹤研究顯示；雖然長期(20年以上)使用深色染髮劑的婦女 ，可能會稍增加罹患淋巴瘤與多發性骨髓瘤的機會(3%)，但是一般而言，染髮並 不會增加罹患其他癌症的機會。而哈佛大學在同年發表的一篇針對99,000名護士 長達14年的研究亦顯示，染髮與罹患淋巴瘤、白血病、多發性骨髓瘤間，並無相 關性。因此有關染髮與癌症間究有無相關，各方說法仍莫衷一是。不過至少可以 確定的是，雖然目前還不能完全排除染髮可能罹癌的可能，但至少其可能性應不 至於太高也因此還不需要『聞染髮劑而色變』。
- 染髮時多使用含海娜(henna)或其他植物性染料的染髮劑，儘量少使用可能致癌 的含煤焦油衍生物的染髮劑。或者也可以使用漸染式的染髮劑，但因此種染髮劑常 含有醋酸鉛，會不會因染髮而導致鉛中毒，則是另一個常被提出的疑慮（但至少目 前尚無人因此而導致鉛中毒）。
答：染髮劑的標示常不清楚，確實是一個問題。由於染髮劑的包裝上如果清 楚標示，則其成份自然可由標示得知；至於標示不清或根本沒有標示，如何得知其 中有無前述的致癌成份呢？一般而言，各種染髮劑中，或多或少都會含有一些可能 致癌的物質，因此染髮就可能會有風險。不過一般而言，愈深色（例如黑色、紅色 或棕色）的染髮劑，含有前述致癌物的量通常愈高。此外，較不會褪色的染髮劑， 含有的致癌物量也多半較高，因此儘可能的話應少用上述染髮劑。
答：除了可能致癌的危險外，染髮劑最常造成的健康危害其實是對皮膚的刺激 ，甚至於產生嚴重的皮膚過敏。因此在使用一個新品牌的染髮劑前，最好先滴一小 滴於耳後皮膚上，不要洗掉觀察2天後，如無紅腫等過敏反應才可以安心使用。而 除了皮膚刺激外，染髮劑如使用不當或不慎食入，也可能產生腸胃刺激（甚至於出 血潰爛）、肝腎功能變差、變性血紅素血症（四肢皮膚及嘴唇發紫發紺），乃至於 其他更嚴重的中毒症狀，因此使用時不可不謹慎。
總之目前雖然還無法確定染髮與得癌症間究竟有無相關性，但是因為染髮劑中 常含有可能的致癌物，因此要想避免因染髮而罹患癌症的風險，最好的辦法還不要 染髮或少染髮！
Article above is from: http://www.vghtpe.gov.tw/~tcfund/information/DYE.HTM
想染髮可選用HENNA 草本染髮粉，不怕致癌危害身體 反可以護髮呢!
Thursday, September 6, 2007
Hair Dye Products
Hair dye products may be divided into three categories, i.e., permanent, semi-permanent and temporary hair colors. Permanent hair colors are the most popular hair dye products. They may be further divided into oxidation hair dyes and progressive hair dyes. Oxidation hair dye products consist of (1) a solution of dye intermediates, e.g., p-phenylenediamine, which form hair dyes on chemical reaction, and preformed dyes, e.g., 2-nitro-p-phenylenediamine, which already are dyes and are added to achieve the intended shades, in an aqueous, ammoniacal vehicle containing soap, detergents and conditioning agents; and, (2) a solution of hydrogen peroxide, usually 6%, in water or a cream lotion.
The ammoniacal dye solution and the hydrogen peroxide solution, often called the developer, are mixed shortly before application to the hair. The applied mixture causes the hair to swell and the dye intermediates (and preformed dyes) penetrate the hair shaft to some extent before they have fully reacted with each other and the hydrogen peroxide and formed the hair dye.
Progressive hair dye products contain lead acetate as the active ingredient. Lead acetate is approved as a color additive for coloring hair on the scalp at concentrations not exceeding 0.6% w/v, calculated as metallic lead (21 CFR 73.2396). Bismuth citrate, the other approved color additive (21 CFR 73.2110), is used to a much lesser extent. Progressive hair dyes change the color of hair gradually from light straw color to almost black by reacting with the sulfur of hair keratin as well as oxidizing on the hair surface.
Semi-permanent and temporary hair coloring products are solutions (on rare occasions dry powders) of various coal-tar, i.e. synthetic organic, dyes which deposit and adhere to the hair shaft to a greater or lesser extent. Temporary hair colors must be reapplied after each shampooing. The vehicle may consist of water, organic solvents, gums, surfactants and conditioning agents. The coal-tar dyes are either listed and certified colors additives or dyes for which approval has not been sought. The dyes may not be non-permitted metallic salts or vegetable substances.
A hair dye product containing a non-approved coal-tar color (but not a non-approved metallic or vegetable dye) which is known to cause adverse reactions under conditions of use cannot be considered adulterated if the label bears the caution statement provided in section 601(a) of the FD&C Act and offers adequate directions for preliminary patch testing by consumers for skin sensitivity. The caution statement reads as follows:
Caution - This product contains ingredients which may cause skin irritation on certain individuals and a preliminary test according to accompanying directions should first be made. This product must not be used for dyeing the eyelashes or eyebrows; to do may cause blindness.
If the label of a coal-tar color-containing hair dye product does not bear the caution statement of section 601(a) and the patch testing directions, it may be subject to regulatory action if it is determined to be harmful under customary conditions of use.
Several coal-tar hair dye ingredients have been found to cause cancer in laboratory animals. In the case of 4-methoxy-m-phenylenediamine (4-MMPD, 2,4-diaminoanisole) which had also been demonstrated in human and animal studies to penetrate the skin, the agency considered the risk associated with its use in hair dyes a "material fact" which should be made known to consumers. The regulation requiring a label warning on hair dye products containing 4-MMPD published in October 1979 was to become effective April 16, 1980. The regulation required that hair dyes containing 4-MMPD bear the following warning:
Warning - Contains an ingredient that can penetrate your skin and has been determined to cause cancer in laboratory animals.
Some hair dyes manufacturers held that the potential risk was too small to be considered "material" and challenged the validity of the regulation in court. The agency decided to reconsider its earlier position, entered into a consent agreement with hair dye manufacturers, and stayed the effectiveness of the regulation until completion of an assessment of the carcinogenic risk of 4-MMPD in accordance with scientifically accepted procedures.
In addition to 4-MMPD, the following other hair dye ingredients have been reported to cause cancer in at least one animal species in lifetime feeding studies: 4-chloro-m-phenylenediamine, 2,4-toluenediamine, 2-nitro-p-phenylenediamine and 4-amino-2-nitrophenol. They were also found to penetrate human and animal skin.
Article above is found from this link:
"FDA believes that at the present time there is no reason for consumers to be concerned about the use of cosmetics containing parabens."
March 20, 2006
FDA has received a number of inquiries on the safety of parabens as used in cosmetics. The following information is intended to answer questions on this subject.
What are parabens?
Parabens are the most widely used preservatives in cosmetic products. Chemically, parabens are esters of p-hydroxybenzoic acid. The most common parabens used in cosmetic products are methylparaben, propylparaben, and butylparaben. Typically, more than one paraben is used in a product, and they are often used in combination with other types of preservatives to provide preservation against a broad range of microorganisms. The use of mixtures of parabens allows the use of lower levels while increasing preservative activity.
Why are preservatives used in cosmetics?
Preservatives may be used in cosmetics to protect them against microbial growth, both to protect consumers and to maintain product integrity.
What kinds of products contain parabens?
They are used in a wide variety of cosmetics, as well as foods and drugs. Cosmetics that may contain parabens include makeup, moisturizers, hair care products, and shaving products, among others. Most major brands of deodorants and antiperspirants do not currently contain parabens.
Cosmetics sold on a retail basis to consumers are required by law to declare ingredients on the label. This is important information for consumers who want to determine whether a product contains an ingredient they wish to avoid. Parabens are usually easy to identify by name, such as methylparaben, propylparaben, butylparaben, or benzylparaben.
Does FDA regulate the use of preservatives in cosmetics?
The Federal Food, Drug, and Cosmetic Act (FD&C Act) does not authorize FDA to approve cosmetic ingredients, with the exception of color additives that are not coal-tar hair dyes. In general, cosmetic manufacturers may use any ingredient they choose, except for a few ingredients that are prohibited by regulation. However, it is against the law to market a cosmetic in interstate commerce if it is adulterated. Under the FD&C Act, a cosmetic is adulterated if, among other reasons, it bears or contains any poisonous or deleterious substance which may render it injurious under the labeled conditions of use, or under customary or usual conditions of use. For more on this subject, see FDA Authority Over Cosmetics and Key Legal Concepts: "Interstate Commerce," "Adulterated," and "Misbranded."
Are there health risks associated with the use of parabens in cosmetics?
The Cosmetic Ingredient Review (CIR) reviewed the safety of methylparaben, propylparaben, and butylparaben in 1984 and concluded they were safe for use in cosmetic products at levels up to 25%. Typically parabens are used at levels ranging from 0.01 to 0.3%.
On November 14, 2003, the CIR began the process to reopen the safety assessments of methylparaben, ethylparaben, propylparaben, and butylparaben in order to offer interested parties an opportunity to submit new data for consideration. In September 2005, the CIR decided to re-open the safety assessment for parabens to request exposure estimates and a risk assessment for cosmetic uses. In December 2005, after considering the margins of safety for exposure to women and infants, the Panel determined that there was no need to change its original conclusion that parabens are safe as used in cosmetics. (The CIR is an industry-sponsored organization that reviews cosmetic ingredient safety and publishes its results in open, peer-reviewed literature. FDA participates in the CIR in a non-voting capacity.)
A study published in 2004 (Darbre, in the Journal of Applied Toxicology) detected parabens in breast tumors. The study also discussed this information in the context of the weak estrogen-like properties of parabens and the influence of estrogen on breast cancer. However, the study left several questions unanswered. For example, the study did not show that parabens cause cancer, or that they are harmful in any way, and the study did not look at possible paraben levels in normal tissue.
FDA is aware that estrogenic activity in the body is associated with certain forms of breast cancer. Although parabens can act similarly to estrogen, they have been shown to have much less estrogenic activity than the body’s naturally occurring estrogen. For example, a 1998 study (Routledge et al., in Toxicology and Applied Pharmacology) found that the most potent paraben tested in the study, butylparaben, showed from 10,000- to 100,000-fold less activity than naturally occurring estradiol (a form of estrogen). Further, parabens are used at very low levels in cosmetics. In a review of the estrogenic activity of parabens, (Golden et al., in Critical Reviews in Toxicology, 2005) the author concluded that based on maximum daily exposure estimates, it was implausible that parabens could increase the risk associates with exposure to estrogenic chemicals.
FDA believes that at the present time there is no reason for consumers to be concerned about the use of cosmetics containing parabens. However, the agency will continue to evaluate new data in this area. If FDA determines that a health hazard exists, the agency will advise the industry and the public, and will consider its legal options under the authority of the FD&C Act in protecting the health and welfare of consumers.+++++++++++++++++++++++++++
Article above is found from this link: