Give the function of the following:
a) Vitamin A -----------
b) Vitamin D -----------
Answers
Answer:Vitamin D
People obtain vitamin D:
1.naturally through exposure to sunlight or in the diet
2.through fortified foods
3.as supplements
4.The body obtains the compounds it needs to make vitamin D from food. It also produces vitamin D when ultraviolet (UV) light meets the skin.
Types
1.Vitamin D is not a single substance but a group of compounds collectively known as calciferol.
2.The body absorbs calciferol into the bloodstream and then converts it to calcitriol.
Two types occur naturally:
1.vitamin D-3, found in animal fats
2.vitamin D-2, found in plants, such as mushrooms
Function
Vitamin D has two main roles in the body:
1.It maintains bone health.
2.It supports the immune system.
Dietary sources
A person can obtain some vitamin D from the sun, but most people will also need to use other sources, too. The main alternative is food.
Dietary sources include:
oily fish and fish oils , fortified dairy products, plant-based milks, and cereals , beef liver , eggs
Recommended intake
Experts measure vitamin D in international units (IU).
Current guidelines recommend that people of all ages intake of 600 IU of vitamin D daily. This is hard to measure, however, as it is not easy for a person to know how much vitamin D they obtain from sunlight.
Deficiency
A vitamin D deficiency can affect:
1.older adults and children who do not spend much time out of doors
2.people with darker skin
3.some people with chronic health conditions
4.those who live far from the Equator, where winter days are short
5.those with obesity
The main effects of vitamin D deficiency include:
1.osteoporosis, or loss of bone mass
2.osteomalacia, when bones become soft
3.rickets, when a child’s bones do not develop as they should
4.increased risk of infection and autoimmunity
Overdose
It is rare for a person to have too much vitamin D, but using supplements could trigger this.
Having too much vitamin D could lead to high levels of calcium in the blood.
This can lead to:
1.nausea
2.headaches
3.low appetite and weight loss
4.a buildup of calcium in tissues and blood vessels
5.heart or kidney damage
6.high blood pressure
Vitamin D supplements are available for purchase in pharmacies and online. A person should speak to their doctor before using these supplements, however.
Vitamin E
Vitamin E is an antioxidant that can help the body destroy free radicals. Free radicals are unstable atoms that can cause oxidative stress. Oxidative stress can lead to cell damage, and this can result in cancer and other diseases. Vitamin E may help protect the body from a range of health issues.
Types
There are eight forms of vitamin E, but only alpha-tocopherol meets humans’ needs, according to the ODS.
Function
Some reasons why the body needs vitamin E are:
1.as an antioxidant
2.to boost the immune system
3.to dilate blood vessels and help prevent clotting
4.Dietary sources
Good sources of vitamin E include:
wheat, germ oil , sunflower seeds and oil , almonds, hazelnuts, and peanuts , spinach and broccoli , kiwi fruit and mango
Recommended intake
Current guidelines recommend people consume the following amounts of vitamin E. Experts measure vitamin E intake in milligrams (mg) AT, but packaging currently uses international units (IU).
Age (years) 1–3 4–8 9–13 14 and over
Female 6 mg (9IU) 7 mg (10.4 IU) 11 mg (16.4 IU) 15 mg (22.4 IU)
Male 6 mg (9IU) 7 mg (10.4 IU) 11 mg (16.4 IU) 15 mg (22.4 IU)
The ODS note that, during breastfeeding, a female should consume 19 mg (28.4 IU) each day.
Deficiency
Vitamin E deficiency is rare, but it can affect people with Crohn’s disease or cystic fibrosis. These conditions affect the liver’s ability to absorb vitamin E.
A deficiency can result in:
nerve and muscle damage that affects movement and coordination
vision problems a weakened immune system
As vitamin E is an antioxidant, a long-term deficiency could increase the overall risk of various diseases.
Overdose
Obtaining vitamin E through natural sources is unlikely to lead to an overdose, although supplement use can increase this risk.
People who use blood-thinning medication, such as warfarin (Coumadin) should ask their doctor before taking vitamin E supplements, as these may interfere with blood clotting.
Vitamin E supplements are available for purchase in pharmacies and online.
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