Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
ukr2.doc
Скачиваний:
48
Добавлен:
06.03.2016
Размер:
2.65 Mб
Скачать

Importance of vitamin d

Calcium is essential for strong bones, but to enhance the amount of calcium that ultimately reaches your bones you also need vitamin D.

Your body makes vitamin D from two sources – sunlight and food. Most of the vitamin D the body makes starts with the sun. When you are exposed to ultraviolet (UV) light rays, a chemical in the skin is changed into an inactive form of vitamin D.

Butter, eggs, and fatty fish such as herring, mackerel, and salmon naturally contain vitamin D. Other food sources are foods fortified with vitamin D such as milk, margarine, and some breakfast cereals.

The liver and kidneys work to change vitamin D into the active form the body can use. Despite the availability of the sun and vitamin D-rich foods, several factors can interfere with obtaining enough of this essential nutrient:

Age. As you get older, your body turns UV rays into vitamin D less efficiently. If you spend limited time outdoors exposed to the sun and don’t drink 2 or more cups of milk a day, you may want to consider a supplement. Don’t take more than 400 IU (units) of vitamin D a day unless prescribed by your physician.

Illness. Kidney or liver disease reduces the ability to change vitamin D into its usable form. Medications such as phenytoin, prescribed for seizure disorders, can also lead to vitamin D deficiency.

Vitamin D is like no other nutrient in that one of the best ways to obtain it has nothing to do with food. Although excessive sun exposure isn’t healthful for your skin, a little bit of sun good for your bones.

Ex. 26. Speak on the importance of vitamin D.

Ex. 27. Read the following abstract and memorize it:

Myth: Vitamins provide energy.

Fact: Calories from fat, carbohydrate, and protein provide energy. Vitamins don’t have calories, so they can’t give energy. The myth likely stems from the action of B vitamins. They don’t actually provide energy. Yet each of the eight B vitamins plays a critical role in the chemical reactions that release energy from foods.

Ex. 28. Make up short dialogues using the data of the following table:

VITAMIN

FAT (F) OR WATER (W) SOLUBLE

SOURCE

vitamin A

F

From provitamin carotene found in yellow and green vegetables; preformed in liver, egg yolk, butter, and milk.

vitamin B1

W

Yeast, grains, and milk.

vitamin B2

W

Green vegetables, liver, wheat germ, milk, and eggs.

pantothenic acid

W

Liver, yeast, green vegetables, grains, and intestinal bacteria.

vitamin B3

W

Fish, liver, red meat, yeast, grains, beans, and nuts.

vitamin B6

W

Fish, liver, yeast, tomatoes, and intestinal bacteria.

folic acid

W

Liver, green leafy vegetables, and intestinal bacteria.

vitamin B12

W

Liver, red meat, milk, and eggs.

vitamin C

W

Citrus fruit, tomatoes, and green vegetables.

vitamin D

F

Fish liver oil, enriched milk and eggs.

vitamin E

F

Wheat germs, rice oil, grain, and liver.

vitamin K

F

Liver, spinach, vegetable oils, cabbage, and intestinal bacteria.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]