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分清脂肪类型再吃:饱和脂肪vs不饱和脂肪vs反式脂肪

Unsaturated vs Saturated vs Trans Fats, Animation

饱和脂肪vs不饱和脂肪vs反式脂肪
Saturated, Unsaturated and Trans Fats
与一般人的认知相反
contrary to popular belief not all
并非所有的脂肪都会引起心脏病 或是有害的
fats are heart disease and are bad
事实上
in fact most fats
需要适当数量的脂肪来维持身体功能的正常运转
in adequate amounts are required for normal bodily functions
特别是大脑功能 也有有益脂肪
especially brain functions there arealso good fats that actually decrease
实际上降低了患心血管疾病的风险
the risks for cardiovascular diseases.
一个脂肪分子是由一分子的甘油
A fat molecule is composed of a glycerol
和三分子的脂肪酸结合而成
head and three fatty acid tails each
每个分子都是一条长的碳氢链
of which is a long hydrocarbon chain a
一种与氢原子结合的碳骨架
carbon skeleton bound to hydrogen atoms
当所有的碳与氢完全结合时
when all the carbons are fully bound to
脂肪酸被认为是饱和的
hydrogens the fatty acid is said
碳原子之间的
to be saturated all the bonds between carbon
所有键都是单一的
atoms are single and the hydrocarbon
碳氢链呈一条直线状
chain has a straight shape a fat
那些完全由
molecule made entirely
饱和脂肪酸构成的分子就是饱和脂肪
of saturated fatty acids is a saturated fat due to
由于它们的尾巴直
their straight tails saturated fats are
饱和脂肪在室温下是致密的固体
compact and solid at room temperature on
另一方面 当碳氢化合物
the other hand when the hydrocarbon
链上含有较少的氢
chain has fewer hydrogens it is said to
就说明是不饱和的
be unsaturated instead
一些碳原子不是与最大数量的氢结合
of binding to a maximum number of hydrogens some carbon
而是通过双键相互结合
atoms bind to each other
双键的存在可能会
via a double bond the presence of double bonds may
使碳氢链弯曲 造成分子间的间隙
bend the hydrocarbon chain creating gapsbetween molecules making them less
使分子变得不那么紧凑
compact as a result unsaturated fats
因此 不饱和脂肪通常在室温下是液态的
are usually liquid at room temperature a fat
只有一个双键的脂肪分子
molecule that contains only one double
是单不饱和脂肪
bond is a monounsaturated fat while one
而具有多个双键的脂肪分子是多不饱和脂肪
that has multiple double bonds ispolyunsaturated dietary fats provide
膳食脂肪为细胞膜的合成
fatty acids for the synthesis
提供脂肪酸 细胞膜是所有动物细胞的
of the cell membrane a vital component of all
重要组成部分 膜可以在不饱和脂肪酸的间隙中流动
animal cells the gaps in unsaturatedfatty acids provide membrane fluidity
促进膜的运转和细胞信号的传递
facilitating membrane transport andcellular signaling while both types of
虽然细胞膜的最佳组成
fats are needed for an optimal composition
需要两种脂肪
of the cell membrane too
但过多的饱和脂肪
much saturated fat which is commonly the case
在典型的美国饮食中通常如此
in a typical American diet would
会使细胞膜变硬 且阻碍细胞的反应性
make the membrane rigid and hindercellular responsiveness membrane
在神经系统中 膜流动性是最重要的
fluidity is most important in thenervous system where neuronal response
神经元的反应需要极快的细胞通讯
requires extremely fast cellularcommunication a certain ratio of
髓磷脂的形成也需要一定比例的不饱和脂肪酸
unsaturatedto saturated fatty-acids is also required for
髓磷脂
the formation of myelin the insulating
是包裹在神经元轴周围
material that wraps around axons of
并加速电信号传导的
neurons and speeds up the conduction
绝缘材料
of electrical signals the body is capable
身体可以合成所需的脂肪酸
of synthesizing all the fatty acids it needs
除了多不饱和脂肪酸
with the exception of
Omega-3和Omega-6
polyunsaturated fatty acids omega-3 and omega-6
必须从饮食中获得
which must be obtained from the
这些被称为必需脂肪酸
diet these are known as essential fatty acids
一般来说
in general unsaturated fats are
不饱和脂肪酸比饱和脂肪酸更健康
healthier than saturated fatsunsaturated fats decrease the risks for
不饱和脂肪酸通过减少坏胆固醇LDL
heart disease by reducing the amount
提高好胆固醇HDL的含量 来降低患心脏病的风险
of bad cholesterol LDL and increasing the
而饱和脂肪则会增加好的和坏的胆固醇
good cholesterol HDL while saturatedfats increase both good and bad
但并不是所有的不饱和脂肪都一样
cholesterol but not all unsaturated fats are equal
事实上 一种不饱和脂肪
in fact a type of unsaturated
被称为反式脂肪 是最不健康的
fat known as trans fat is the unhealthiest
双键可以
of all a double-bond can
产生两种可能的构型
give rise to two possible configurations
顺式和反式
cis and trans cis is when the two
顺式是两个氢原子在键的同侧
hydrogen atoms are on the same side of the bond
反式则相反
while trans is when they are on
两个氢原子在键的对立面
the opposite sides.
顺式双键使脂肪酸分子弯曲
A cis double bondbends the fatty acid molecule while the
而更对称的反式构型则不弯曲
somewhat more symmetric transconfiguration does not a trans fat is
因此 反式脂肪在结构上与饱和脂肪相似
therefore similar in structure to asaturated fat more importantly trans
更重要的是 反式脂肪很少出现在自然界
fats rarely occur
所以我们的身体没有必要的酶
in nature so the body does not have the necessary enzymes to
来分解它们
break them down diets rich
富含反式脂肪的饮食会增加坏胆固醇LDL
in trans fats increase the bad cholesterol LDL and
降低好胆固醇HDL水平
reduce the good cholesterol HDL having
对血管的影响极其不利
the most detrimental effect on blood
反式脂肪主要存在于
vessels trans fats are found mainly
部分氢化油产品中
in partially hydrogenated oil products such
例如人造黄油
as margarine because unsaturated fats are
由于不饱和脂肪缺乏稳定性 变质速度更快
less stable and spoil faster food
食品制造商通过一种称为部分加氢的方法添加氢使其更加饱和
manufacturers add hydrogens to makethem more saturated through a process
该工艺不仅延长了植物油的保质期
known as partial hydrogenation thisprocess not only prolongs shelf-life of
而且会使植物油变成固态
vegetable oils but also turns them
或半固态产品
into solid or semi-solid products which are
这是商业面包师青睐的
preferred by commercial bakers
低成本 多质地的产品
for their low cost and wide range of different
不幸的是 部分加氢
textures unfortunatelypartial hydrogenation also converts some
也将一些顺式双键转化为反式结构生成反式脂肪
of the cis double bonds into transconfiguration producing trans fats
2018年6月 美国食品及药物管理局已正式禁止生产
the FDA has officially banned production
部分氢化油脂
of partially hydrogenated oils in June
但早期生产的产品可能仍将
2018 but products made earlier may still be
使用到2020年1月份
in use until January 2020

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视频概述

脂肪,一种我们耳熟能详却又不甚了解的物质。

听录译者

收集自网络

翻译译者

Evelyn

审核员

审核员_AK

视频来源

https://www.youtube.com/watch?v=brs2nMubr84

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