Nutrition guide

Vitamin A: Essential Nutritional Guide

Some older people do not receive the recommended daily allowance of vitamin A.

What is vitamin A?

Vitamin A is a collective term for a group of powerful antioxidants, called retinoids, found in foods of animal and plant origin.

Who is deficient?

According to the National Food and Nutrition Survey, 12% of men and 8% of women aged 19 to 65 do not get enough vitamins in their diet. Among those over 65, 10% of men and 7% of women do not comply with the recommended daily allowances in their diet.

Deficiency is sometimes diagnosed in people with absorption problems, chronic liver disease, or alcohol dependence associated with a poor diet.

One of the first signs of vitamin A deficiency is loss of sensitivity to green light, followed by difficulty adjusting to dim light (night blindness), hence the adage that ” carrots help to see in the dark ”. A more severe deficiency can lead to:

  • Scaly skin with raised pimply hair follicles (keratosis pilaris)
  • Scalp peeling
  • Brittle and dull hair
  • Loss of appetite
  • Reduced male fertility
  • Impaired hearing, taste and smell
  • Dry, burning, itchy eyes (xerophthalmia)
  • Hardening of the cornea
  • Corneal ulceration
  • Visual loss, including blindness
  • Low resistance to infections

Why do we need it?

Vitamin A is necessary for the maintenance of normal growth and development, sexual health and fertility, healthy skin, teeth, bones and mucous membranes, healing of wounds, wounds and burns, and color vision . In the eye, vitamin A is converted to a pigment, rhodopsin, also known as visual violet. It is also important for immunity as it plays a key role in maintaining the body’s natural defenses, including the mucous barriers in the lungs, eyes, and gut that trap bacteria and other pathogens.

How it works?

It binds to receptors in the nucleus of cells to regulate how genes are turned on. It is vital to produce many proteins, including enzymes, hormones and growth factors.

Assortment of foods rich in vitamin A
An assortment of foods rich in vitamin A.

Where can we get it from?

Foods of animal origin contain preformed vitamin A in a form that your cells can use:

  • animal and fish liver
  • Meat
  • fatty fish oil and cod liver
  • dairy products
  • eggs
  • milk and dairy products
  • butter (margarine is also fortified by law to contain as much vitamin A as in butter).

Plant-based foods such as dark green leaves, fruits and vegetables contain carotenoid pigments some of which can be converted into vitamin A. However, they are easily destroyed by exposure to light and heat, so once you cook food by boiling or frying it, its vitamin A content decreases

How can I include it in my diet?

Starting the day with an egg is a good way to make sure you’re getting a good amount of vitamin A in your diet, and you can serve it with smoked salmon for another good source. A simple stir-fry made with beef and green vegetables like broccoli, greens, and orange peppers will also provide you with a large amount of vitamin A. Even a simple breakfast smoothie made with milk, yogurt and Orange fruits like mango or canned peaches can offer another useful source of vitamin A.

Supplements

Vitamin A is included in multivitamin and mineral supplements, usually as mixed carotenoids.

The EU Dietary Reference Value for vitamin A (retinol) is 800 mcg per day. The next highest level of safety for long term intake from both diet and supplements is suggested 1500mcg (5000 IU).

Do not exceed the recommended dose as an excess can cause side effects such as headache, irritability, blurred vision, nausea, weakness, fatigue, abdominal pain and loss of appetite.

What to avoid

Taking high-dose beta-carotene supplements has been associated with an increased risk of lung cancer in smokers and in those with previous occupational exposure to asbestos. Although this is controversial, it is safe for smokers to avoid taking beta carotene supplements and get these compounds naturally by eating lots of red-yellow-orange-green fruits and vegetables.

Not relevant most likely, but something to know, pregnant women are advised to avoid foods rich in vitamin A like liver and to avoid supplements containing retinol vitamin A (except under medical supervision). Excess vitamin intake has been linked to some birth defects. The safest way to get the recommended daily allowance during pregnancy is through the natural carotenoids found in fruits and vegetables, which are converted to retinol when needed.

To learn more about supplements or if you have any questions about taking supplements, you can visit lifetime or talk to a qualified nutritionist.

If you enjoyed this guide to vitamins, you can find more stories on our health channel by Sarah Brewer and Rob Hobson.

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Written by Sarah Brasseur
11:12
Nutrition


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