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The educational materials presented here
今天展示的教育材料
were developed by students and faculty
是由爱荷华州立大学营养学
of the department of food science and human nutrition
和人体营养学系的
at Iowa State University.
学生和老师提供的
Funding for this project was provided by grants
该项目的资金由
from the American Cancer Society Mid West
美国中西部地区癌症协会
and the Lance Armstrong Foundation.
及兰斯，阿姆斯斯壮基金会提供
The materials are intended for educational use
这些材料仅用于教学
and are not meant to provide medical advice.
并非用以提供医疗指导
We welcome your feedback about these materials.
欢迎大家对这些材料做出反馈
Please use the evaluation survey link on the homepage
请用主页上提供的调查评价链接
to provide your comments and suggestions.
提交你们的评价和建议
You are probably aware that the emphasis
大家也许意识到
that has been placed on reducing fats in your diet
人们总是在谈论如何减少饮食中的脂肪
but let's talk about why some fat is necessary.
但今天我会讲讲为什么某些脂肪是必需的
We will explore which fats you should limit
我们将会讨论应当控制哪些脂肪的摄入
and which fats you should focus on
而哪些脂肪应当受到重视
getting into your diet.
纳入饮食范围
Fats are an essential part of every diet,
脂肪是所有饮食的必要组成部分
fats not only yield energy but they are also necessary
脂肪不仅能够产生能量而且是必需的
for the absorption of certain vitamins,
因为可以吸收某些维生素
for the production of hormones
也能够产生一些激素
and fats also play a role in protecting vital organs.
而且脂肪还有助于保护生命器官
Whereas carbohydrates and protein
然而糖类和蛋白质
each provide 4 calories per gram,
每克会提供4卡路里热量
fats provide a bit more energy and yield 9 calories
脂肪提供的能量更多一点，而且每克脂肪
for each gram of fat.
会产生9卡路里热量
Therefore diets containing high amounts of fat
因此，含大量脂肪的食物
are also considered to be calorie dense.
也会被认为含有大量的热量
Saturated fats are typically found as solids
饱和脂肪一般在室温下是固态
at room temperature. These fats are found
这些脂肪一般来源于
in animals sources, especially in red meat
动物身上，特别是在红肉
and dairy products such as cheese and ice cream.
和奶制品中，例如奶酪和冰激凌
Saturated fats are also found in some plant sources
饱和脂肪也来源于一些植物中
such as coconut oil and palm oil.
例如椰子油和棕榈油
For this reason all oils should not be considered
为此，不应该认为所有的油类
the same relative to their health effects.
对人体健康的作用是一样的
You probably have heard about polyunsaturated fats
大家也许听说过多元不饱和脂肪
because of the emphasis of omega 3
因为含有欧美加3和欧美加6这两种
and omega 6 fatty acids. Polyunsaturated fats
不饱和脂肪酸，多元不饱和脂肪
are liquid at room temperature and therefore include
在室温下是液态，因此它包括
most vegetable oils such as soy bean, corn, canola
大多数植物油，例如豆油，玉米油，菜籽油
and safflower oil. Also nuts and seeds are a good source
和红花油，所有的坚果和种子都是
of polyunsaturated fats as well as fatty fish
多元不饱和脂肪的最佳来源，也包括多脂鱼
including salmon and herring.
例如大马哈鱼和青鱼
Polyunsaturated fats come in 2 main classes;
多元不饱和脂肪主要有两类
omega 6 and omega 3.
欧美加3和欧美加6
These terms are derived from their chemical structures
这两个名词来源于它们的化学结构
but also their biological functions.
也源于它们的生物学功能
These fats are essential
这些脂肪是必须的
because humans cannot modify the double bond structure
因为人体不能够修改双键结构
which give these fats their confirmation,
而这些双键结构能够确认脂肪
therefore they must be consumed in the diet.
因此这些脂肪必须从饮食中摄入
Over the past 50 years
过去的50年中
Americans have increased consumption of omega 6 fats
美国人已经提高了植物油中的欧美加6脂肪的摄入量
from vegetable oils which have been suggested to
据说欧美加6脂肪
contribute to some chronic disease risks.
会提高患慢性疾病的风险
At the same time consumption
与此同时，欧美加3脂肪的摄入量
of omega 3 fats have decreased.
增加了
The omega 3 fats come mainly from fish but recently
欧美加3脂肪主要来自于鱼肉，但最近
plant sources are becoming increasingly available
植物来源中也有越来越多的欧美加脂肪
such as canola oil and flaxseed.
菜籽油和亚麻仁
Omega 3 fats generally reduce the risk
欧美加3脂肪一般可以降低
of chronic diseases. Omega 3 also known as
患慢性疾病的风险，欧美加3也被称为
linolenic acid is converted in the body
亚麻酸，在体内被转化为
to EPA and DHA.
EPA和DHA
These acids are known to
这些酸
have anti inflammatory effects in the body
在体内有抗炎效果
and are also involved in brain function
也参与大脑运行和发育过程
and development. Omega 3 is found in flaxseed
欧美加3脂肪存在于亚麻仁
and canola oils, walnuts, salmon and cod.
菜籽油，核桃，大马哈鱼和鳕鱼中
Omega 6 or linoleic acids, is converted to
欧美加6或亚油酸在体内转化为
arachidonic acid in the body and plays a role
花生油酸，对免疫功能
in immune function.
也起着重要作用
Contrary to omega 3, omega 6 demonstrates
跟欧美加3相反，欧美加6体现出
a pro inflammatory effect and thus a balance
有增加炎症的效果，因此，二者间达到平衡
between the two keeps the body in order.
才能保持身体健康
As mentioned earlier, omega 6 fatty acids
就像之前提到的，欧美加6脂肪酸
are quite prevalent in the American diet
在美国饮食中十分常见
as they are found in corn oil, soy bean oil,
它们常见于玉米油，大豆油
peanut oil, eggs and dairy products
花生油，鸡蛋和奶制品中
whereas omega 3 foods are not
而含欧美加3脂肪酸的食物不太常吃
as commonly consumed and a conscious decision
因此人们特意
to add these to a diet is usually necessary.
将这些食物加入饮食通常是有必要的
One other group of unsaturated fats
另一类不饱和脂肪
which are generalized as the good fats
一般统称为有益脂肪
are the monounsaturated fats;
它们是单一不饱和脂肪
monounsaturated fats are found in plants
单一不饱和脂肪常见于植物
such as nuts and seeds and various oils
例如坚果，种子和各种油类
including flaxseed, olive and canola oil.
包括亚麻仁油，橄榄油，菜籽油
Avocados contain monounsaturated fatty acids as well.
鳄梨也含有单一不饱和脂肪酸
