鮮奶茶 asked in 科學化學 · 2 decades ago

新聞說的反式脂肪對人體的危害到底是...?

首先...我不想要網路上轉貼來轉貼去的什麼隱形殺手什麼什麼的。

我想問的不是反式脂肪的危害。

我想知道的是,新聞上說的一大堆,什麼增加心血管疾病的機率之類有的沒的,

到底是"可能"會,

還是已經有paper很確定的指出,反式脂肪是"會"增加疾病罹患的機率?

另外,反式脂肪在一般食品中的含量是多少?

對健康的人體而言,吃到多少的量是有害的?

所有讀過的資料都沒有明確指出是"會"對人體有危害,

直到看到這次新聞之前,

所以回答過反式脂肪的問題時也格外小心,

不對"對人體健康"的部分發表意見,

對新聞說得那麼斬釘截鐵,說反式脂肪對人體的危害如何如何,

我覺得很疑惑,因此請有相關知識的大大們為小妹解惑,麻煩了。

Update:

想請問Yy大大那篇文章是全文嗎?

因為網路上找不到那篇文章,目前人不在學校,也無法去圖書館查。

最後一個補充的網頁與您提供的文章是類似內容嗎?

 

另外,應該是我沒有說清楚,

因為在查我的疑問的時候,

知識+一直看到一樣的資料重覆出現,

我怕我問的問題會讓人誤會意思才會這麼說,

您的資料非常棒。

2 Answers

Rating
  • Yy
    Lv 7
    2 decades ago
    Favorite Answer

    閣下的問題充滿智慧 真是一針見血

    本來只要看到 germsai 風城 超導狂人 小弟便不獻醜了

    但這問題確實好 令人手癢難安 請Germsai 兄見諒

    若閣下仍是讀大學 建議閣下要讀研究所

    若閣下在讀研究所 建議閣下要讀博士班

    若閣下在讀博士班 建議閣下一定要做 post-doc

    好了閒話休題

    Germsai 兄說得好 說得對 現今我們飲食太複雜了 很難說要吃多少才有多少

    最近食品中 trans-faty acid 含量報告也不好找

    歐洲cookies 或 餅乾

    脂肪總量 total fat: 9.4~ 31 g/100g

    trans-faty acid : 0.1-28%

    歐洲牛角麭

    trans-faty acid : 15%

    歐洲甜甜圈:

    trans-faty acid : 32%

    JOURNAL OF FOOD COMPOSITION AND ANALYSIS 11, 161–169 (1998)

    英國牛肉

    trans-faty acid (18:1 trans) : 41-88 mg/100 g肉 ; 脂肪總量 的 2.3%

    英國羊肉

    trans-faty acid (18:1 trans) : 118-142 mg/100 g肉 ; 脂肪總量的 4.6-4.9%

    Meat Science 49(3) 329-341 (1998)

    New Zealand 人造奶油 (margarine)

    16.4g/100g脂肪酸總量

    人造奶油 (margarine)與奶油混合

    9.6 g/100g脂肪酸總量

    奶油

    6.4 g/100g脂肪酸總量

    馬鈴薯片

    0.5 g/100g脂肪酸總量

    JOURNAL OF FOOD COMPOSITION AND ANALYSIS 9, 365–374 (1996)

    以下是 2003 年發表在 lancet 的論文 題目便是 反式脂肪酸議題的複雜性

    只摘錄第一段 文中部份在後面

    "反式脂肪酸會增加低密度脂蛋白-膽固醇的量同時減少高密度脂蛋白-膽固醇的量。一個十年的追蹤研究顯示反式脂肪酸高攝取量與心血管疾病相關。

    在1985年研究開始時,反式脂肪酸的攝取量為一天熱量的 4.3%,十年後14個歐洲國家的反式脂肪酸的攝取量為一天熱量的0.5-2.1%而美國的反式脂肪酸的攝取量則是2.6%。所以這研究早期研究對像的攝取量高過後期的。

    一般認為每增加 一天熱量的2% 之反式脂肪酸的攝取量會導至心血管可能性25%增加率 (中度) 。"

    Ref: Complexity of issue of dietary trans fatty acids

    THE LANCET ‧ Vol 357 ‧ March 10, 2001 732

    後面更精彩

    As awareness of the unfavourable effects on lipoproteins of trans fatty acids has increased, margarines containing no or low concentrations of such acids have become commonly available in Europe, but industrial shortenings and fats for deep-frying remain high in trans fatty acids. For reasons of stability and texture deep-fried and processed fatty foods contain saturated or trans fatty acids or both, so it seems prudent to limit intakes of these foods. Consumption of margarines containing no trans fatty acids reduces the proportion of total dietary trans fatty acids from partly hydrogenated vegetable oils and increases the relative amount of trans fatty acids of ruminant-animal origin. In the study by Oomen and colleagues, ruminant trans fatty acids accounted for 16% of total trans fatty acid intake at baseline. In 1995, these fatty acids made up about 30% of total trans fatty acid intake in the Netherlands, and 52–75% in France and the Mediterranean countries. Oomen and colleagues state that the health effects of trans fatty acids from ruminant sources and from manufactured sources are similar, but this conclusion is far from convincing. In fats from ruminant animals, trans fatty acids are accompanied by more than tenfold amounts of saturated fatty acids. The ratio between trans and saturated fatty acids is fairly constant, with only slight seasonal variation. Therefore it is impossible to distinguish between the health effects of the two types of fatty acids in observational studies. Furthermore, in two studies from the USA, ruminant trans fatty acid intake did not show significant associations with risk of CHD.

    Partial hydrogenation of vegetable or fish oils results in a spectrum of C18:1 trans isomers, among which the delta-9 (elaidic acid) and delta-10 isomers are most prominent. By contrast, rumen bacteria produce mainly the delta-11 isomer (vaccenic acid), which generally makes up about 50% of all ruminant trans fatty acids. In dietary trials on the effects on lipoproteins of trans fatty acids, chemically produced mixtures of trans fatty acids have been used, and there are no studies addressing specifically the effects of transvaccenic acid from ruminant fat.

    A common, but wrong, assumption is that all trans isomers have similar metabolic effects. Trans-vaccenic acid is desaturated to 9-cis,11-trans conjugated linoleic acid (CLA) by the delta-9 desaturase both in the cow and in man, but this pathway is not available for the delta-9 and delta-10 isomers. There is much interest in CLA because of its anticarcinogenic effects in laboratory studies, and methods are being developed to increase the amounts of CLA in milk fat. By modifying the feeding of cows, saturated fatty acids in milk fat can be decreased and replaced with CLA, but the amounts of the precursor trans-vaccenic acid increase concomitantly. Therefore the issue of dietary trans fatty acids will not be settled before the metabolic effects of trans-vaccenic acid can be examined separately from those of other trans isomers, to understand whether modification of milk fat by substituting trans-vaccenic acid and CLA for saturated fatty acids is beneficial or not for CHD risk.

    其他綜論

    Elvira Larque´a, , Salvador Zamoraa, Angel Gilb “Dietary trans fatty acids in early life: a review.” Early Human Development 65 Suppl. (2001) S31–S41

    Alice H. Lichtenstein, “Trans fatty acids and blood lipid levels, Lp(a), parameters of cholesterol metabolism, and hemostatic factors.”

    Nutrition biochemistry, 9:244-248 (1998)

    T. L. Roberts, D. A. Wood, R. A. Riemersma, P. J. Gallagher, F. C. Lampe, “Trans isomers of oleic and linoleic acids in adipose tissue and sudden cardiac death.” Lancet, 345, 278-282 (1995)

    A Aro et. al. “Adipose tissue isomeric trans fatty acids and risk of myocardial infartion in nine countries: the EURAMIC study.” Lancet, 345, 273-278 (1995)

    補充:

    雖然題目規定不要 po 網頁 但下值得一看

    http://www.soybean.org.tw/news-10.htm

    http://www.soybean.org.tw/news-9.htm

    http://www.soybean.org.tw/soy-news-7.htm

    http://www.soybean.org.tw/soy-news-2.htm

    2005-08-31 17:59:16 補充

    想請問Yy大大那篇文章是全文嗎?

    因為網路上找不到那篇文章,目前人不在學校,也無法去圖書館查。

    Lancet 那篇只節錄翻譯第一段

    第一段後的原文都在 不敢貼全文 copyright 問題

    這文獻應在 醫圖找

    電子期刊則可用 Sciencedirect 或 SDOS (Elsevier 出版社)

    最後一個補充的網頁與您提供的文章是類似內容嗎?

    都是中文的 在台灣黃豆協會的

    一個是關於食品含量

    另外則是說反式脂肪酸在歐美都想要立例限其量

    因此 Lancet 作者才說那十年研究中 人們服用反式脂肪酸愈來愈少了

    加油啊

  • 念申
    Lv 7
    2 decades ago

    生物體製造和代謝脂肪所用的的機制(或稱機轉mechanism)都是以順式脂肪酸為對象.所有參與到的酵素也都只針對順式的脂肪酸..所以反式脂肪酸在生物體裡面是廢物..可是生物體對脂肪的吸收機轉並不會分辨順式或反式的..因此反式脂肪酸會被吸收但是卻沒辦法代謝.仍然順著血液到處流竄.一但停在血管內面管璧就很容易造成血栓.導致心血管疾病的機會增高.依照這個理論基礎可以確定反式脂肪酸一定會造成危害..要做這種臨床試驗必須先分離出反式脂肪酸然後餵食老鼠..作安全性試驗.可是反式脂肪酸並不是很容易與順式脂肪酸分離(seperation)之後純化.所以目前反式脂肪酸的危害應該仍是推論.沒有人知道吃多少會有問題..反式脂肪酸只在加工過程中會產生.一般未加工的食品是沒有反式脂肪酸的..

    2005-08-29 08:57:18 補充:

    哈哈!!太好了.謝謝Yy提供的資料.很久沒看文獻了.我現在連找資料都懶懶的囉.....知識都舊了...哪有辦法跟你一樣唸post...

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