All you need to know about vitamin A and why it is essential for our health and immune system
Today we talk all about vitamin A, which is one of the most underestimated vitamins. The body needs it for a healthy intestine, for an active immune system and for beautiful and firm skin.
In addition, our fat metabolism relies on vitamin A. However, many people unconsciously suffer from vitamin A deficiency and it is particularly beneficial in chronic diseases to pay attention to this nutrient. Find out everything you need to know regarding this vitamin here.
What is vitamin A?
Vitamin A is an umbrella term for various chemically related substances from the retinoid group: These include retinol, retinal, retinoic acid and retinyl ester.
The substances active in the body are 9-cis-retinal, which binds to the receptors RAR and RXR, as well as all-trans-retinal, which binds exclusively to RAR, and retinoic acid. The latter partly works without the classic receptors RAR and RXR.
Together with vitamin D, vitamin E and vitamin K2, vitamin A is one of the fat-soluble vitamins.
Beta-carotene, the orange dye found in carrots and modified in tomatoes (lycopene), is called provitamin A. It gets converted into active vitamin A in small amounts in the body, but is significantly less bioavailable than the substances mentioned above.
In the further course of this topic, vitamin A summarizes both ß-carotene and the substances of the retinoid group.
What is the daily requirement?
According to the FDA, the following applies to daily needs:
Men 19 years and older: 1 mg retinol equivalent, women 0.8 mg
Pregnant women from the fourth month (increased need) 1.1 mg daily, breastfeeding mothers 1.5 mg
Children under four months: 0.5 mg
Children up to and including three years: 0.6 mg;
4-6 years: 0.7 mg;
7-9 years: 0.8 mg
10-12 years: 0.9 mg
Girls 13-14 years: 1.0 mg
Girls 15-18 years: 0.9 mg
Boys 13-18 years: 1.1 mg
Foods with vitamin A
Let’s get started straight away and clarify in which foods this vitamin occurs frequently and is important in order to meet the vitamin A requirement.
The following foods show the requirement per 100 g of the food:
Food – vitamin A per 100 grams
Liver (calf) 21.9 mg
Kale 8.7 mg
Carrot 8.5 mg
Liver sausage, roughly 8.3 mg
Parsley 5.9 mg
Dried apricots 5.8 mg
Savoy cabbage 4.7 mg
Dill 4.5 mg
Palm oil 4.3 mg
Corn salad 3.9 mg
Red pepper 3.5 mg
Chicory 3.4 mg
Spinach 3.3 mg
Egg yolk, cooked, 1.1 mg
Eel, smoked 0.9 mg
In plant sources, it presents itself as provitamin A (beta-carotene or lycopene). The bioavailability, i.e. the proportion that gets absorbed into the body, is significantly lower with plant products than with animal products.
It is, therefore, difficult to estimate how much from vegetable sources one needs to meet the real requirements. Therefore, the recommendations to eat liver and/or organic eggs regularly are correct and well-meant.
Added to this is the loss of vitamins when cooking plant-based foods. Provitamin A ends up in the cooking water, gets destroyed during cooking, and is no longer available to the body.
What is very clear, however, is that healthy nutrition is important to meet the demand and the vitamin A requirement, with abundant green vegetables, carrots, tomatoes, meat from species-appropriate husbandry, fish from wild catch, and organic eggs.
Based on this knowledge, we go over what effects this vitamin has in the body
What is the effect of vitamin A in the body?
Vitamin A is an important growth factor for many cells in the body and, therefore, essential for health. Unfortunately, it is too often underestimated and disregarded; This vitamin has the following important duties in the body:
“Seeing” means that light information translates into electrical signals and, thereby, produces an image in the brain.
The translation of light into electrical information happens in the eyes. The absorption of light in the rods and suppositories only works with a protein called rhodopsin, which needs active vitamin A.
Growth factor for the intestine
The epithelial cells in the intestine are an important line of defense between the interior of the intestine with its numerous toxins and potential pathogens, and the immune system of the lamina propria and lymph nodes.
Epithelial cells have an average survival of 4-5 days due to constant bombardment. These gaps need to be filled quickly with new epithelial cells. These require vitamin A as a growth factor1.
Immune cell maturation
Some immune cells, especially those with anti-inflammatory properties, require vitamin A to develop. These include regulatory T cells and anti-inflammatory M2 macrophages.
Another substance that drives the maturation of regulatory T cells is vitamin D, another deficiency vitamin.
Production of mucus
The entire intestine and respiratory tract are covered with mucus. This mucus contains antimicrobial substances and acts as both a chemical and a physical barrier against pathogens. For the production of mucus and the antibacterial protein (mucins), you guessed it, our body needs vitamin A.
PPARα and PPARγ are important regulators in metabolism, especially in fat metabolism. The activated vitamin A receptor RAR activates these important proteins and, thus, contributes to a smooth metabolism.
There are many antibodies in the intestine, in the respiratory tract and in the placenta, which hunt pathogens. This special type of antibody also requires vitamin A for education and information.
If you suffer from some food allergies, you could take a closer look at vitamin A: Because the effects of the vitamin on the immune system are also based on developing tolerance to harmless food proteins.
What does vitamin A do in the skin?
Just like in the intestine, vitamin A is an important growth factor on the skin. It replaces and renews dead cells, forms the protective layer of mucus on the skin and reduces inflammatory processes.
For a beautiful, firm and radiant skin this vitamin is an essential co-factor together with zinc, vitamin C and vitamin E. Collagen, too, is an important nutrient for the skin.
Other relevant effects of retinal and retinoic acid on:
Fat transport in the blood
Testosterone production in the Leydig cells of the scrotum
Development of brown adipose tissue for heat production
I hope you found interesting facts in this post that includes all about vitamin A. Please, feel free to communicate your thoughts, experience and additional info with me in a comment below. I’m always very happy to read from you.
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