Vitamin A – benefits, sources and deficiency

Vitamin A is an essential nutrient that plays a crucial role in our health and well-being. It is a fat-soluble vitamin found in two main forms: retinoids, which are found in animal products, and carotenoids, which are found in plant foods. Vitamin A is essential for a variety of bodily functions, including maintaining vision, supporting the immune system and promoting skin health.

The importance of vitamin A for health cannot be overemphasised. It contributes to the normal function of the immune system, helps with cell division and differentiation and is important for the development and maintenance of skin and mucous membranes. A deficiency of vitamin A can have serious health consequences, including vision problems, a weakened immune system and skin disorders. In this article, we will look at the different aspects of vitamin A, its health benefits, natural sources and optimal daily intake.

What is vitamin A?

Definition and different forms of vitamin A

Vitamin A is a fat-soluble vitamin that occurs in various forms and fulfils a variety of biological functions in the body. It is an essential nutrient that the body cannot produce itself and must therefore obtain from the diet. Vitamin A is known for its role in maintaining vision, supporting the immune system, skin health and cell division.

Retinoids and carotenoids

Vitamin A exists in two main forms: Retinoids and carotenoids.

Retinoids: This form of vitamin A is mainly found in animal foods and includes various compounds such as retinol, retinal and retinoic acid. Retinol is the most abundant form and is metabolised in the body into retinal and retinoic acid, which are important for vision and cell function. Retinoids are directly bioavailable and can be utilised by the body immediately. Sources of retinoids are liver, fish oil, dairy products and eggs.

Carotenoids: These are plant-based precursors of vitamin A that the body can convert into retinol. There are over 600 different carotenoids, but only about 50 of them can be converted into vitamin A. The best-known carotenoids are beta-carotene, alpha-carotene and beta-cryptoxanthin. Carotenoids also have antioxidant properties that help to combat free radicals. Plant sources of carotenoids include carrots, sweet potatoes, spinach, kale and other green, orange and yellow vegetables.

Both forms of vitamin A are essential for health, and a balanced diet should include both retinoids and carotenoids to meet the body’s needs.

Health benefits of vitamin A

Support of the immune system

Vitamin A plays a central role in maintaining a healthy immune system. It contributes to the normal function of immune cells such as T-cells and B-cells, which are essential for defence against infection and disease. Adequate levels of vitamin A help the body to fight infections more effectively and strengthen the immune system overall. A lack of vitamin A can weaken the immune system and increase susceptibility to infections.

Preservation of vision

Vitamin A is crucial for eye health and maintaining vision. It is a component of rhodopsin, a protein in the eyes that converts light into electrical signals that the brain can interpret. A lack of vitamin A can lead to night blindness and other vision problems. Adequate intake of vitamin A helps prevent age-related eye diseases such as macular degeneration and cataracts and supports overall eye health.

Promotion of skin health

Vitamin A is essential for the maintenance and repair of the skin. It promotes the production and maturation of skin cells and helps to keep the skin supple and resilient. Retinoids, a form of vitamin A, are often used in topical skin care products to treat acne, wrinkles and other skin problems. Vitamin A also supports the healing of wounds and can help treat skin conditions such as psoriasis and eczema.

Role in cell division and differentiation

Vitamin A is crucial for cell division and differentiation, processes that are fundamental to the growth and development of the body. It helps cells to develop into specialised forms and perform their specific functions. This is particularly important for the development of embryos and the regeneration of tissues throughout the body. A lack of vitamin A can lead to growth disorders and impaired development.

The health benefits of vitamin A are numerous and include supporting the immune system, maintaining vision, promoting skin health and playing a role in cell division and differentiation. Adequate intake of this important vitamin is crucial for overall well-being and disease prevention.

Sources of vitamin A

Animal sources

Vitamin A in the form of retinoids is mainly found in animal foods. This form of the vitamin is directly bioavailable and can be utilised by the body immediately. Here are some of the best animal sources of vitamin A:

• Liver: Liver is one of the richest sources of vitamin A. Both beef and chicken liver contain high amounts of retinol.
• Fish oil: Cod liver oil in particular, the oil from the liver of fish such as cod, is rich in vitamin A and omega-3 fatty acids.
• Dairy products: Milk, cheese, butter and other dairy products also contain vitamin A, especially in whole milk products.
• Eggs: Egg yolk is a good source of vitamin A.

Plant sources

Plant sources of vitamin A contain carotenoids, which the body can convert into retinol. This form of the vitamin has additional antioxidant properties. Here are some of the best plant sources of carotenoids:

• Carrots: one of the best-known sources of beta-carotene, which is converted by the body into vitamin A.
• Sweet potatoes: Contain high amounts of beta-carotene and are an excellent source of vitamin A.
• Spinach: Rich in beta-carotene as well as other important nutrients such as iron and calcium.
• Kale: Another leafy green vegetable that is rich in carotenoids.
• Mango and papaya: These tropical fruits also contain beta-carotene.
• Red capsicum: Provides vitamin A as well as a good dose of vitamin C.

Food supplements

For those who find it difficult to get enough vitamin A from their diet, supplements can be a practical solution. There are various forms of vitamin A supplements:

• Retinol: direct form of vitamin A used in many supplements.
• Beta-carotene: A plant-derived precursor of vitamin A, also available as a supplement.
• Multivitamin supplements: Many multivitamin supplements contain vitamin A in combination with other important vitamins and minerals.

When taking supplements, it is important not to exceed the recommended daily dose, as an overdose of vitamin A can be toxic. A balanced diet that includes both animal and plant sources of vitamin A is the best way to meet daily requirements.

Recommended daily intake and requirements

The recommended daily intake of vitamin A varies depending on age, gender and lifestyle. Here is a table with the daily recommendations:

These values will help you plan your daily vitamin A intake and ensure you get enough of this important nutrient to support your health. By consuming these varied sources, you can ensure that you are getting enough vitamin A to support your health and well-being.

Vitamin A deficiency

Symptoms and effects of vitamin A deficiency

A lack of vitamin A can have serious health consequences, as this vitamin is essential for many important bodily functions. The most common symptoms and effects of vitamin A deficiency include

• Night blindness: one of the earliest signs of vitamin A deficiency is night blindness, where the ability to see in dim light is significantly impaired. This is because vitamin A is an essential component of rhodopsin, a protein in the retina that is required for low-light vision.
• Dry eyes and xerophthalmia: A progressive vitamin A deficiency can lead to drying of the eyes, known as xerophthalmia. This can lead to corneal ulcers and blindness if left untreated.
• Increased susceptibility to infection: Vitamin A is crucial for the normal functioning of the immune system. A deficiency can weaken the immune defences and increase the risk of infections, especially respiratory infections and diarrhoea in children.
• Dry skin and skin problems: Vitamin A is important for maintaining healthy skin. A deficiency can lead to dry, flaky skin and an increased susceptibility to skin infections and conditions such as eczema.
• Growth disorders: In children, severe vitamin A deficiency can lead to stunted growth and impaired development.
• Problems with cell division and differentiation: Vitamin A plays a key role in cell division and differentiation. A deficiency can impair the normal development and function of cells in various tissues.

Causes of a vitamin A deficiency

Vitamin A deficiency can be caused by various factors:

• Inadequate intake: a diet low in vitamin A and carotenoids can lead to a deficiency. This is particularly common in regions where food variety is limited and animal products and colourful vegetables are rarely consumed.
• Malabsorption: Diseases that impair fat absorption, such as coeliac disease, Crohn’s disease and pancreatitis, can impair the absorption of vitamin A, as it is a fat-soluble vitamin.
• Increased requirement: Certain phases of life, such as pregnancy and breastfeeding, increase the need for vitamin A. If this requirement is not met, a deficiency can develop.
• Liver diseases: As vitamin A is stored in the liver, liver diseases can impair the storage capacity and availability of vitamin A.

Prevention and treatment

Prevention of vitamin A deficiency includes a balanced diet rich in vitamin A-containing foods. This can be achieved by consuming animal sources such as liver, fish oil, dairy products and eggs, as well as plant sources such as carrots, sweet potatoes and green leafy vegetables.

In cases of diagnosed vitamin A deficiency, treatment may include taking vitamin A supplements under medical supervision. The dosage and duration of supplementation depend on the severity of the deficiency and individual needs.

By eating a healthy diet and using supplements if necessary, you can ensure that your vitamin A levels are in the optimum range and support your health.

Conclusion

Vitamin A is an essential nutrient that plays a key role in many important bodily functions. It supports the immune system, maintains vision, promotes skin health and is crucial for cell division and differentiation. Both animal and plant sources can contribute to meeting daily requirements, while supplements offer a practical option, especially in cases of increased need or malabsorption.

Vitamin A deficiency can have serious health consequences, including night blindness, dry eyes, increased susceptibility to infections, skin problems and stunted growth. A balanced diet rich in vitamin A and carotenoids is crucial for preventing a deficiency, and you can effectively support and maintain your health in the long term by consciously consuming foods rich in vitamin A and, if necessary, dietary supplements.