Want to find out more about vitamin A? Then you can sit back, relax and read everything you need to know about this valuable vitamin in this article. Beta-carotenes, also known as provitamin A, play an important role in the supply of vitamin A and will therefore also play a role again and again in this article.
We start with a clear fact sheet on intake, function, daily requirement, risk of overdose or deficiency, through to foods containing vitamin A and food supplements. Finally, there is special information for vegans and vegetarians regarding the supply of vitamin A.
Here is in advance a short Overview for you:
- Daily requirement
- Food supplement
- Frequently asked questions
Notice: This article is not a substitute for medical advice, but merely provides general information about vitamin A. Please consult your doctor if you feel unwell or want to prevent health problems with medical care.
VITAMIN A PROFILE AT A GLANCE
Assignment: fat-soluble vitamins
Synonyms: Retinol, retinal, retinoic acids, retinoids, retinol esters
Important for: Eye health, cell division, growth process, reproduction
Daily requirement: 650-900 µg retinol activity equivalent (RAE)/day from the age of 191,2,3
Overdose: Upper limit 3,000 µg RAE/day4
Deficiency symptoms: including impaired vision, night blindness, impaired reproductive function, impaired sense of taste and smell
Food: Liver, eggs, dairy products (vitamin A), red, orange and yellow fruit and vegetables (beta-carotene)
Food supplement: mostly not necessary, if necessary as powder, tablets or capsules
HOW CAN YOU get the best possible supply of vitamin A?
Vitamin A comprises a group of essential, fat-soluble vitamins, also known as retinols. These are from Beta-carotenewhich is also known as provitamin A. Beta-carotene is a secondary plant substance and antioxidant that the body uses as needed to Vitamin A synthesis can be used. In principle, the requirement can therefore be met directly via the vitamin itself or indirectly via beta-carotene.
The Bioavailability of vitamin A is up to 75 percent, that of beta-carotene is subject to strong fluctuations and is 2-30 percent depending on how it is present in the cellular compound of the plant. The following in particular have a positive influence on the bioavailability of beta-carotene mechanical processesthat open up the cellular dressing. This includes chopping, pureeing and sufficient chewing. Gentle cooking and a Combination with high quality fats can be used to increase the bioavailability of beta-carotene.
How much vitamin A does the body need?
Now let's examine the daily requirement of vitamin A together. As you might have guessed, this is where things get complicated. After all, there are various sources of vitamin A: either the direct recording or the Uptake and synthesis of beta-carotene. Another challenge is that some nutrition societies use Retinol Activity Equivalents (RAE) and other Retinol Equivalents (RE) to determine daily requirements.
The calculation of RAE is done like this:
1 μg retinol = 12 μg β-carotene = 24 μg other provitamin A carotenoids.
And the RE calculation as follows:
1 μg RE = 1 μg retinol = 6 μg β-carotene = 12 μg other provitamin A carotenoids.5
This effectively means that the requirement remains the same, regardless of whether it is measured in RE or RAE. However, the intake required to cover this demand doubles.
The recommended daily requirement
The recommended guideline for daily vitamin A intake for adults is between 650 and 900 µg RAE or RE per day, depending on gender and age.1,2,3 The European Food Safety Authority (EFSA) has issued a rather low recommendation of 650 µg for women and 750 µg for men. The Institute of Medicine's figure is quite a bit higher, recommending a daily intake of 700 µg for women and 900 µg for men from the age of 14.
The recommendations of the German Nutrition Society (DGE) differentiate according to age and gender and are shown in the following table:
|1 to under 4 years
|4 to under 7 years
|7 to under 10 years
|10 to under 13 years
|13 to under 15 years
|15 to under 19 years
|19 to under 65 years
|65 years and older
All three nutrition societies mentioned above recommend a higher vitamin A intake for pregnant and breastfeeding women.1,2,3
What does the body need vitamin A for?
The human body needs vitamin A for the Eye Health, the Cell division and in childhood and adolescence, it becomes a challenge for the Growth process needed. After sexual maturity, the vitamin is involved in the production of testosterone and oestrogen and the development of sperm and egg cells, so that it can generally be said that vitamin A is essential for the development of the human body. Reproduction is important. The vitamin also influences the effectiveness of the Immune system and the Embryonic development.
A function that Beta-carotene The specific function of beta-carotene is to protect the skin from damage, such as that which can occur when exposed to strong sunlight. Beta-carotene also has an antioxidant effect and can reduce the absorption of Iron multiply.6
The Vitamin A importance for the human body can be summarized as follows:
- Eye Health
- Cell division
- Growth process in childhood and adolescence
- Reproduction and production of sex hormones
- Strengthening the immune system
- Embryonic development
Can hypervitaminosis occur?
Hypervitaminosis is a Toxic oversupply. This can occur with vitamin A if very high doses are taken over a longer period of time. The EFSA has defined a Tolerable Upper Intake Level (UL) of 3,000 µg RE per day for men and women.4 It should be noted that this limit is based on various studies and attempts to combine several factors. This value is therefore not set in stone.
In principle, hypervitaminosis A is a rather rare phenomenon. It occurs when the body's storage capacity is exceeded. With a purely plant-based diet such an oversupply is not possible, as the human body controls the synthesis of beta-carotene into vitamin A according to need. This means that the vitamin is only synthesized when it is actually needed. However, according to the EFSA, an oversupply of beta-carotene can lead to an increased risk of lung cancer in smokers. However, this risk only exists for smokers and only if their intake far exceeds the daily requirement.
The EFSA therefore recommends that heavy smokers should not consume more than 20 mg of beta-carotene per day.4 The Institute of Medicine did not issue a UL in their "Vitamin A -Fact Sheet for Health Professionals."2
Acute symptoms The main symptoms of hypervitaminosis A are nausea, vomiting, itching, headaches and visual disturbances. In the case of prolonged hypervitaminosis, the following can also occur Chronic disorders such as scaly skin, hair loss, fatigue and even swelling of the spleen and liver, as well as cirrhosis of the liver.
WHEN DOES IT COME TO UNDER SUPPLY?
An undersupply of vitamin A occurs when the body's own stores are depleted and lower amounts of the vitamin or beta-carotene are supplied than the body needs. The human body can store vitamin A for 1-2 years.
In industrialized countries, acute deficiency is a rarity. If a deficiency does occur, it is often Alcoholism the cause.4 However, the absence of a deficiency does not mean that the average population consumes enough vitamin A or beta-carotene to ensure a good or even optimal supply. The average consumption of liver, fruit and vegetables in Germany is too low for this.6
This was also confirmed by the large-scale survey in the National Nutrition Survey (NVS II), which came to the conclusion that up to 70 percent of the vitamin A supply in Germany must be ensured via beta-carotene.7 This is not a problem per se, as the synthesis via beta-carotene works well, but sufficient quantities of fruit and vegetables must be consumed.
Symptoms deficiency are impaired vision, night blindness, blindness, changes to the skin and mucous membranes, stunted growth, impaired sense of taste and smell, impaired reproductive function, digestive problems and increased susceptibility to infections.
What are the best sources of vitamin A?
When it comes to the supply of vitamin A, it makes sense to differentiate between foods containing vitamin A and foods containing beta-carotene. Vitamin A is only found in animal products such as liver, eggs and dairy products, while beta-carotene is only obtained from plant-based foods such as red, orange or yellow fruit and vegetables, as well as green leafy vegetables.
In order to be able to compare the different foods in the best possible way, the RAE is used again here. I generally recommend a diet with no or few animal productsbut in order to provide as much information as possible, the table also includes some animal foods:
- Beef liver (7,782 µg per 100 grams)
- Paprika (2,463 μg per 100 grams)
- Carrots, cooked (852 µg per 100 gram)
- Sweet potato (709 µg per 100 gram)
- Butter (620 µg per 100 grams)
- Butternut squash (558 µg per 100 gram)
- Honeydew melon (389 µg per 100 gram)
What MUST VEGANS AND VEGETARIANS TAKE INTO ACCOUNT with their VITAMIN A supply?
Vitamin A is recommended by the DGE not as potentially Critical nutrient for vegans and vegetarians.8 This is because it can be assumed that sufficient coverage of the daily requirement of vitamin A in a plant-based diet is achieved purely through the absorption and synthesis of beta-carotene.
Vegans consume above-average amounts of green leafy vegetables, as well as red, orange and yellow fruit and vegetables, so their intake of beta-carotene is higher than the rest of the population. The body can meet its vitamin A requirements by synthesizing beta-carotene as needed.
Are dietary supplements with vitamin A useful?
For the majority of the western population, a Supplementation of vitamin A not necessaryif you follow a balanced diet. In certain individual cases, however, a dietary supplement can be useful. It is therefore advisable to have your vitamin levels tested by your GP first.
Combination supplements are ideal for anyone who wants to be on the safe side with a plant-based diet. There are supplements that cover various nutrients that can be critical in a vegan diet and are therefore specialized in vegan nutrition.
Such a Multi-preparationwhich combines both vitamin A and a number of other nutrients that are particularly relevant for plant-based nutrition, you get here*.
Tip: In the article Nutritional supplements for a vegan diet you can get a general overview of useful supplements for a plant-based diet.
FAQ: Frequently asked questions about vitamin A
Which foods contain a lot of vitamin A?
Beef liver, for example, contains a lot of vitamin A. However, you can also meet your vitamin A requirements with fruit and vegetables containing beta-carotene, such as peppers, sweet potatoes, carrots and butternut squash.
Is vitamin A heat-resistant?
Yes, vitamin A is heat-stable. To increase bioavailability, you should combine foods containing vitamin A with high-quality fats.
What functions does vitamin A have in the body?
Vitamin A has many important functions in the body. Some of these include eye health, strengthening the immune system, sperm and egg development, as well as cell division, embryonic development and growth during childhood and adolescence.
Is vitamin A water-soluble or fat-soluble?
Vitamin A, also known as retinol, is a fat-soluble vitamin. Other fat-soluble vitamins are vitamins D, E and K.
How does a vitamin A deficiency manifest itself?
Conspicuous symptoms include reduced vision, night blindness and even blindness. Other deficiency symptoms include susceptibility to infections, digestive disorders and impaired sense of smell and taste.
Vitamin A or beta-carotene?
The question of whether you should rely on vitamin A or beta-carotene is mainly a question of individual nutrition. You can cover your needs with both nutrients. The advantage of a a wholesome plant-based diet is that an oversupply is ruled out due to the needs-based synthesis.
If you opt for a plant-based diet, you should always combine beta-carotene-containing foods such as peppers or carrots with some high-quality fat, such as olive oil or nuts, to optimize bioavailability.
Do you have any questions, suggestions or criticism about this article on vitamin A? Then please write me a comment.
All the best,
PS.: You want to know, why you should live vegan? In the article linked here, I describe the most important arguments. You will be amazed at how many reasons you would agree with me.
1 German Nutrition Society: Vitamin A, https://www.dge.de/wissenschaft/referenzwerte/vitamin-a-b-carotin/?L=0. [21.07.2021].
2 National Institutes of Health. Office of Dietary Supplements: Vitamin A. Fact Sheet for Health Professionals, https://ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#h2. [21.07.2021].
3 European Food Safety Authority: Scientific Opinion on Dietary reference values for Vitamin A, https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2015.4028 . [21.07.2021].
4 European Food Safety Authority: Tolerable Upper Intake Levels for Vitamins and Minerals, https://www.efsa.europa.eu/sites/default/files/efsa_rep/blobserver_assets/ndatolerableuil.pdf. [21.07.2021].
5 German Nutrition Society: New D-A-CH reference values for vitamin A intake, https://www.dge.de/presse/pm/neue-d-a-ch-referenzwerte-fuer-die-vitamin-a-zufuhr. [21.07.2021].
6 Zentrum der Gesundheit: The effects of beta-carotene, https://www.zentrum-der-gesundheit.de/ernaehrung/vitamine/weitere-vitamine/beta-carotin-wirkung-ia. [21.07.2021].
7 Max Rubner Institute. J. Möhring, H. F. Erbersdobler (2008). Nationale Verzehrs Studie II - Ergebnisbericht Teil 2. In: Lebensmittel-Warenkunde Für Einsteiger, (Springer), pp. 121-146. Online: https://www.mri.bund.de/de/institute/ernaehrungsverhalten/forschungsprojekte/nvsii/erg-verzehr-naehrstoffe. [14.07.2021].
8 Deutsche Gesellschaft für Ernährung e. V.: Supplement to the position of the German Nutrition Society regarding population groups with special nutritional needs, https://www.dge.de/wissenschaft/weitere-publikationen/dge-position/vegane-ernaehrung/?L=0. [21.07.2021].