视频文本
Turning attention now to calcium,
让我们把目光转向钙
calcium is an essential mineral
钙是一种重要的矿物质
which must be consumed in the diet.
在膳食中，我们必须摄入钙
The daily recommended intakes for calcium
在9到18岁之间
are highest during the peak ages of bone growth
骨骼处于成长发育期
between 9 and 18 years of age.
此时的每日推荐摄入量最高
The recommended intakes remain fairly high
在18岁之后，钙的日常推荐摄入量
throughout the rest of life;
也都一直保持在高位
1000 mg for 19 to 50 years of age and then
19岁到50岁为1000毫克
1200 mg for 51 years or older.
51岁以后为1200毫克
Calcium rich foods include dairy products
富含钙的食物包括奶制品
such as milk, yogurt and cheese and dark
例如牛奶，酸奶，奶酪，还有深绿色蔬菜
green vegetables. The calcium found in
奶制品中的钙
dairy foods is very well absorbed
很容易被吸收
whereas calcium in vegetables is poorly absorbed.
而蔬菜中的钙很难被吸收
Obtaining adequate dietary calcium may be
对于那些没有定期地食用乳制品的人
a challenge for persons who do not
获取充足的膳食钙
regularly consume dairy foods and
是个难事
there's substantial evidence that calcium intake
充足的证据表明
is inadequate for many people.
很多人的钙摄入量都是不足的
For this reason many foods today
因此，现在的许多食品都在
have been fortified with calcium.
都在钙含量上进行强化
Cereals, breads, orange juice and
谷类食品，面包，橙汁等
other foods can be found with added calcium.
都有额外增加的钙含量
Milk and dairy are the richest sources of calcium.
牛奶和奶制品是钙最为丰富的来源
A glass of milk provides 300 mg and
一瓶牛奶提供300毫克钙含量
a container of yogurt, 230 mg of calcium.
一瓶酸奶提供230毫克
Spinach and fortified cereals also
菠菜和强化谷物食品
contribute to calcium intakes.
都对钙的摄取量都做出了贡献
Because vitamin D and calcium are
由于维生素D和钙
important nutrients and they can be
这两种重要的营养素
challenging to obtain from foods,
都很难从食物中摄取
there are many different forms of
所以市场上出现了
dietary supplements on the market. If you choose
多种多样的膳食补充剂
to use a supplement it is important to understand
当你想选择一种膳食补充剂
the different types. Both vitamin D and calcium
了解它们的不同类型是非常重要的
are available in different forms and
维生素D和钙有多种不同的形式可供选择
a wide range of amounts. Many supplements
其中的含量也不尽相同
contain both calcium and vitamin D because
很多膳食补充剂包含钙和维生素D
vitamin D assists in the absorption of calcium.
因为维生素D能够帮助钙的吸收
The two main forms of calcium in supplements
膳食补充剂中的钙以两种主要形式存在
are carbonate and citrate. Calcium carbonate
分别是碳酸盐和柠檬酸盐
is more commonly available and inexpensive.
碳酸钙更加普遍而且价格低廉
Both forms are absorbed well by the body
两种形式的钙都能够被人体很好地吸收
but individuals with low level of stomach acid
但是胃酸水平低的人
may absorb citrate better. Carbonate is also absorbed
对柠檬酸钙的吸收效果更好
better when taken with food
碳酸钙与食物一起会更易吸收
but citrate is unaffected by the presence of food.
但是碳酸钙不会受食物的影响
The percentage of calcium absorbed depends on
钙的吸收率取决于钙的服用数量
the amount of calcium consumed. As the amount
随着钙服用数量的增加
increases the percent absorption decreases.
吸收率会降低
It is recommended that rather than
与其一次性服用1000毫克的补充钙
taking one 1,000 mg supplement take two 500 mg
不如，分两次服用500毫克的补充钙
supplements several hours apart. Some individuals
每隔几小时服用一次
who take calcium supplements may experience gas,
有的人在服用补充钙后会排气，胃胀或便秘
bloating or constipation but these symptoms
如果在一天之中分多次服用补充钙
can often be reduced by spreading out the calcium
与三餐一起食用
dose throughout the day, taking the supplement
或者更换不同牌子的补充钙来使用
with meals or changing the brand of supplement used.
上述那些症状就会减轻

视频及简介

视频简介：

本课程的目标是，向公众提供最新的有关营养方面的信息和话题，内容涵盖饮食因素对于癌症的影响作用，健康的饮食习惯，学校能提供的营养有哪些，咖啡因与癌症的联系，水果蔬菜与癌症预防等。通过本课程的学习，人们可以学习到健康的生活饮食习惯，在每天的饮食中防癌症于未然