Vitamin A and its pro-vitamins serve our body in many ways. Through them we can see and be fruitful. At the same time, they support the healing of many parts of the body, such as bones, teeth and skin.
In addition, it is involved in the formation of white and red blood cells. Vitamin A describes all substances that are based on a uniform retinol structure. Some substances can be used directly and others have to be converted beforehand.
This article expands on the topic of vitamin A and its deficiency and answers all relevant questions. Foods that are rich in vitamin A are shown, as well as possible drug interactions. A vitamin A overdose is also pointed out and the possible effects described.
the essentials in brief
- Vitamin A is an essential part of our diet because the vitamin is involved in many of the body's maintenance processes. This includes night vision, strengthening the immune system and maintaining fertility.
- However, a vitamin A deficiency is just as dangerous as a vitamin A overdose. An overdose is particularly dangerous during pregnancy and breastfeeding, since the child can suffer from growth and development disorders.
- In the following article we will answer all your questions about vitamin A deficiency. We will then give you tips and tricks on how to avoid a vitamin A deficiency without suffering from an overdose.
Definition: What is a vitamin A deficiency?
Vitamin A is a fat-soluble nutrient involved in many biological processes such as vision, immune function, cell division and embryonic development. Vitamin A describes a group of compounds whose effect is called vitamin A.
The preformed vitamin A, from retinol and retinyl ester, is only found in animal foods, especially the liver. The precursors of the vitamin, the so-called pro-vitamins, are found in plant foods. These pro-vitamins, such as beta-carotene and beta-apo-carotene, are then converted into vitamin A.
The reference value of the vitamin requirement varies according to gender, age and risk group. If this value is undercut for a longer period of time, one speaks of a deficiency (1). A vitamin deficiency is known in the specialist genre as hypovitaminosis. On the other hand, there is hypervitaminosis, an overdose of the vitamin (2).
Background: What you should know about a vitamin A deficiency
Vitamins are essential for the body because they are involved in building many organs and body components. In this magazine we will go into more detail about the topic of vitamin A deficiency and answer all the important questions about the topic. For example, we address questions that answer the benefits of the vitamin, the recommended amount and signs of illness.
Why do we need vitamin A anyway?
Vitamins are very useful for our body. Vitamin A consists of various compounds such as retinol or retinoic acid. Vitamin A is essential for:
- Our eyes: With the help of vitamin As, the eyes form the so-called visual pigment, which enables us to see light and dark. So without the vitamin we would be night blind.
- Our skin: Vitamin A keeps our skin more elastic and regenerates faster.
- Building and healing of various body elements: such as the bones, cartilage and teeth.
- Immune system: The vitamin A precursor, beta-carotene, captures free radicals (aggressive oxygen compounds that damage cells) (3).
- Formation of blood cells: Vitamin A is involved in the formation of red blood cells and facilitates the incorporation of iron. In addition, the vitamin and the pro-vitamin increase the number of white blood cells, which strengthen the immune system.
- Protein and fat metabolism: The vitamin is involved in fat metabolism in the liver and in protein synthesis (protein synthesis). If you suffer from stress or a serious illness and need more protein, you also need more vitamin A. The same applies to a high-protein diet.
- Fertility: Vitamin A is involved in the formation of the sex hormones estrogen and testosterone. A lack of vitamin A can cause infertility or miscarriage.
- Nervous system: Vitamin A keeps nerve cells in the brain, spinal cord and peripheral nerve tracts healthy.
- Mucosa: Vitamin A is involved in maintaining the health of the digestive, urinary, genital and respiratory tracts (4).
What is the daily requirement of vitamin A?
The daily requirement of vitamin A is measured in milligrams. This is equivalent to 1mg of retinol or 6mg of beta-carotene. The following table shows the daily requirement in different groups (5).
| Old | Vitamin A requirement in mg per day men | Vitamin A requirement in mg per day women |
|---|---|---|
| 0 - 3 years | 0.5 - 0.6 | 0.5 - 0.6 |
| 4 - 9 years | 0.7 - 0.8 | 0.7 - 0.8 |
| 10 - 14 years | 0.9 - 1.1 | 0.9 - 1.0 |
| 15 - 18 years | 1.1 | 0.9 |
| 19 - 65 years and older | 1.0 | 0.8 |
If you would like more information about vitamin A deficiency, you can contact the DGE - the "German Society for Nutrition eV" .
The table shows that adolescents and between the ages of 10 and 15 have an increased need for vitamin A, which is due to the growth phase. The need for vitamin A also increases during pregnancy and breastfeeding. This is where the need lies, from a pregnancy in the 4th month at 1.1 mg and for breastfeeding women even at 1.5 mg.
Hypervitaminosis during pregnancy can be harmful to the unborn child.
However, you should make sure that you do not get hypervitaminosis, i.e. an overdose. Especially in the first trimester of pregnancy can harm the unborn baby. It is therefore advisable to avoid liver and liver-containing foods that are particularly rich in vitamin A (6). If, despite this, there are problems in covering the high vitamin A requirement, one can fall back on vitamin supplements.
What do I have to consider with medication and vitamin A requirements?
In principle, the vitamin A requirement increases with infections, especially with a high fever . Because vitamin A scavenges free radicals. If there are more of them in the body, the need for vitamin A also increases. Drugs are listed below for which the vitamin A requirement could change (4).
- Active ingredients such as tretinoin: This substance helps treat acne and may increase the risk of vitamin overdose.
- Active ingredients such as colestipol or cholestyramine: These substances are used to treat lipid metabolism disorders. They inhibit vitamin A absorption, which increases the need for it.
- Active ingredients such as neomycin: This substance is used to treat inflammation of the eyes, ears and skin. This also inhibits the absorption of vitamin As, which increases the need.
- Dicoumarol, phenprocoumon, warfarin: The effect of the drug increases when vitamin A is taken in at the same time.
How do you recognize a vitamin A deficiency?
A vitamin A deficiency is easy to diagnose. If the skin changes and becomes a bit drier and scaly, a vitamin A deficiency can be considered. Another sign are small white spots in the eye (the so-called Bitot spots). Softening of the cornea or a poor sense of taste and smell are also signs of a vitamin A deficiency.
Vitamin A is essential for our body and our bodily functions. Among other things, the vitamin is involved in the formation of visual pigments, which enables us to see at night. (Image Source: Amanda Dalbjorn / Unsplash)
If you notice symptoms of this kind, it is advisable to consult a doctor and have a blood test done. There, a test can be used to determine the vitamin A content in the blood. If you are suffering from a deficiency, it is advisable to have a follow-up test to monitor the changes in vitamin A levels in the blood (7).
What effects does a vitamin A deficiency have on the body?
A vitamin A deficiency should not be underestimated. A deficiency can have a strong impact on vision or fertility. If the visual pigment is no longer formed, this can lead to impaired vision, night blindness or even complete blindness.
Furthermore, one becomes more susceptible to respiratory infections since the immune system is weakened by a vitamin A deficiency (8). The reason for the high risk of infection is the lack of the vitamin A precursor, which captures free radicals. These radicals damage the body's cells. In addition, the skin and mucous membrane can harden and corneal ulcers can occur (4).
The precursor of vitamin A, the so-called beta-carotene, is present in green vegetables in particular, such as spinach, broccoli, kale and beans. (Image Source: Ella Olsson / Unsplash)
If a deficiency occurs in children and adolescents, this can lead to growth restrictions and developmental disorders. In pregnant women, a deficiency can affect the development of the child (8).
Who is particularly susceptible to vitamin A deficiency?
There are various risk groups that can suffer from a vitamin A deficiency particularly quickly. These include:
- Alcoholics: People who consume alcohol very frequently over a long period of time are very prone to liver disease. Since vitamin A is stored in the liver, absorption disorders of the vitamin can occur, which can lead to deficiency symptoms.
- People with digestive disorders: The vitamin is one of the fat-soluble vitamins. People who suffer from digestive disorders often also suffer from fat digestion, which can also lead to absorption disorders of the vitamin and a deficiency could arise.
- Pregnant and lactating women: Deficiency symptoms can occur during pregnancy and lactation if the diet continues as "normal". The reason for this phenomenon is the increased demand over time.
- Seniors and premature babies: Seniors and premature babies are also more often affected by deficiency symptoms due to an increased need. The same applies here: change your diet.
- Vegetarians / vegans: Vitamin A is particularly common in animal products such as meat and eggs. As a result, people who do not eat animal foods can suffer from deficiency symptoms more quickly. However, many types of fruit and vegetables contain the vitamin precursor of the vitamin beta-carotene (9). It should be borne in mind that the body needs six times the intake of beta-carotene than vitamin A to meet the daily requirement (6).
How common is vitamin A deficiency?
The basis for an adequate supply of vitamins and minerals is a healthy and balanced diet. This requires fertile soil, clean water and fish stocks in the sea. However, as these resources become less and less available and the precious goods have been redistributed, more and more people suffer from hunger and malnutrition.
Almost 20 percent of the total population cannot meet their vitamin and mineral requirements through food.
According to the Food and Agriculture Organization (FAO), an average of almost 673 million people suffer from malnutrition (as of 2017 - 2019) - which accounts for almost 10 percent of the world's population. In addition, the quality of the food must be guaranteed.
Almost 20 percent of the world's population is unable to afford high-quality nutrition. This creates the so-called "hidden hunger". The food is sufficient to fill you up - but not to cover the nutrient and vitamin requirements.
The majority of starving people live in countries of the Global South. Africa is the most affected with 19.1 percent (starving people compared to the number of inhabitants). In contrast, Asia and Central and Latin America have improved, with the number of hungry people falling to 8.3 percent and 7.4 percent, respectively (10). As with almost all other vitamin and mineral deficiencies, these countries are also particularly badly affected by vitamin A deficiency.
When should I see a doctor if I suspect a vitamin A deficiency?
If you suspect symptoms of a vitamin deficiency, it is always advisable to consult a doctor. He can closely monitor your process to accommodate your needs. A vitamin A deficiency is determined by a blood count.
The doctor examines your blood for the vitamin content and can give you a precise insight and guide possible treatment measures. Furthermore, your vitamin content will be monitored in subsequent tests and a possible overdose will be prevented.
What are the effects of overdosing on vitamin A?
An overdose of vitamin A, so-called hypervitaminosis, can be just as dangerous as a lack of vitamin A. In the case of acute poisoning, due to the excessive intake of vitamin A, headaches, nausea, vomiting, dizziness, itchy skin or even visual disturbances can occur .
If the vitamin is taken permanently in too high a dose, chronic damage can occur. These include diseases such as jaundice. An enlarged liver, skin tears and hair loss are also possible consequences. Sometimes there is joint and muscle pain, bleeding and even damage to the skeletal system.
Beta-carotene can promote the development of lung cancer, especially in smokers. It should be noted that beta-carotene is often referred to as "E 160" and is used as a coloring agent in various foods. The precursor of vitamin As is also frequently found in soft drinks. The BfR recommends that smokers in particular refrain from taking food supplements with beta-carotene (11).
Vitamin A deficiency: The best tips & tricks against a deficiency
In the following we will show you tips and tricks against a vitamin A deficiency. We will go into various foods that are rich in vitamin A. Furthermore, we go into nutritional supplements and describe all the opportunities and risks of the supplements.
Foods high in vitamin A
Vitamin A is primarily found in liver and liver-containing foods. However, it is also present in lower amounts in animal products such as eggs and meat. The precursor of vitamin A, beta-carotene and beta-apo-carotene, is also known as a pro-vitamin and is found in many plant-based foods. These pro-vitamins are converted to vitamin A in the lungs, liver and colon after ingestion.
The following table shows exactly which substance is contained in which food.
| Groceries | Vitamin (12) | Dose of vitamin per 100g (13) |
|---|---|---|
| Liver and foods containing liver | Vitamin A | High |
| eggs, meat, cheese | Vitamin A | Medium (cheese rather low) |
| Green vegetables like spinach, kale, beans, lamb's lettuce, broccoli | Pro-Vitamins | Middle |
| Intensely colored vegetables such as carrots, pumpkin, peppers and tomatoes | Pro-Vitamins | Middle |
| Fruits like apricot, mango, honeydew melon | Pro-Vitamins | Medium (dried: high) |
Vitamin A supplements
A vitamin A deficiency can have serious consequences. If you have a high vitamin A requirement, it can make sense to take food supplements or vitamin tablets . There are also multivitamins that can help you meet your needs for different vitamins at the same time. However, caution is also required with the preparations: overdosing is not to be joked about.
The Federal Institute for Risk Assessment (BfR) therefore recommends no more than 0.2 mg, i.e. 200 µg, of vitamin A per day for food supplements.
The reason for this is that many foods already contain vitamin A and the body can absorb plenty of vitamin A. However, if you still want to take supplements, you should follow the recommendation of the Federal Institute for Risk Assessment.
Pregnant and breastfeeding women should discuss the intake of dietary supplements with their doctor beforehand. The same goes for smokers who want to take beta-carotene through supplements. Since there is a high probability that there is a link between high vitamin A intake and low bone density, the EFSA recommends reducing vitamin A intake in menopausal women .
The restriction is only the reduction of vitamin A and not the reduction of beta-carotene (from plant foods). These substances are currently approved as dietary supplements for vitamin A:
- retinol
- retinyl acetate
- retinyl palmitate
- β-carotene (beta carotene)
This approval applies to Germany and all other EU countries (11).
Diverse diet
In many cases, a balanced and healthy diet can avoid a vitamin A deficiency. As shown in "Foods High in Vitamin A" above, the vitamin or pro-vitamin is available in many foods. However, you should protect your food from heat, light and oxygen, since almost 20 percent of the vitamin A content in food is lost through these factors.
Furthermore, one should note that a maximum of 75 percent of vitamin A is actually absorbed by the body. The amount of fat consumed plays a major role in this. For this reason, it is recommended to enrich the food with a little oil or fat, as the fat-soluble vitamin can be better absorbed.
The vitamin can be stored up to 95%, which enables a year-long supply.
However, the vitamin's limited absorption and loss through storage isn't too bad. The body can store 95 percent of the vitamin and its precursor in the liver, so that adults can obtain vitamin A from stores for up to a year. In addition, the lungs, eyes and digestive tract create additional storage for the pro-vitamins.
The 2008 National Consumption Study II shows that only 15 percent of men and 10 percent of women are deficient. The intake only referred to food and not to food supplements (11).
Conclusion
Vitamin A helps our body maintain all important functions. With the right diet, possible side effects and effects of a deficiency can be avoided. The vitamin A content can often be covered by a balanced and varied diet. In addition, the body is able to form reserves of the vitamin in the body, which can prevent a deficiency.
If you want to take supplements, you may want to have your blood levels of vitamin A checked by a doctor to avoid overdose and its effects. Furthermore, one should adhere to the recommendation of the Federal Institute for Risk Assessment.
References
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- Statist Research Department (2021): Food Security and Hunger Statistics In: Agriculture Retrieved: 2021-05-26 Source
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