Why vitamin A is important...

Vitamin A (e.g. as retinol & retinal) plays an important role in maintaining the health
of your eyes, as well as your skin, teeth, bones and mucous membranes, including your respiratory tract.
This important vitamin also improves your resistance to infections and
supports growth. It is also involved in the repair of body tissues, including
muscle growth.

Now, new studies have shown that vitamin A has a direct impact on energy production
in the body.

In the said study, scientists examined cultures of both human and
mouse cells with specific genetic alterations in the chemical pathway involved in the
energy development of mitochondria (the powerhouses of cells). The
researchers allowed the cells to grow - once with and once without vitamin A.

The result: retinol, the main component of vitamin A, is essential (vital) for
the metabolic capacity of the mitochondria. This vitamin also acts as a nutrient sensor
for energy production in the cells. However, if too much or too little vitamin A
is present, the mitochondria do not function properly; they cause devastating damage to
the organs.

So you should not overdo it!
Megadoses of vitamin A can be very harmful. High doses lead to
fractures in the hip in older men and women. There is also a risk that
pregnant women will suffer miscarriages. If you regularly take 25,000 International Units
(IU) of vitamin A per day for several months, it develops a toxic effect. Since
vitamin A mainly accumulates in the liver, this eventually leads to
liver disease.

One of the reasons for this is that vitamin A is fat-soluble; - therefore the body cannot simply
flush it out - unlike water-soluble vitamins. Water-soluble vitamins are simply flushed out when
overdosed.

The body can produce vitamin A on its own from carotenoids, especially beta-carotene.
Beta-carotene is found in orange, red and green vegetables, as well as in fruit.
Beta-carotene is the precursor of vitamin A. It is basically "inactive vitamin A". The good thing about it
is that if the body's own vitamin A levels are too low, the body then converts it into active
vitamin A.

The recommended daily allowance (RDA) suggests that men should be in the region of 3,000 IU
of vitamin A per day. For women, the standard is 2,330 IU of vitamin A. The safe
upper limit for men and women is 10,000 IU of vitamin A. To increase absorption
you should take vitamin A together with a teaspoon of oil.

Good sources of vitamin A are

• general liver foods (e.g. liver sausage, beef liver)
• egg yolk
• carrots
• sweet potato