Vitamin A also called retinol is a micronutrient and fat-soluble dietary compound that is essential for healthy vision, growth, immune response and reproduction. Studies show that it is necessary for bone development, ovarian function and visual adaptation to darkness. Research shows that the liver can store up to a year's supply of vitamin A. However, it depletes when a person has an infection or sickness.
The active form of vitamin A that is found in the body is called retinol, however, the vitamin A found in plants is called beta-carotene which needs to be converted into its active form so that the body can utilize it. The process of conversion takes place in the liver and intestinal mucosa.
Researches also show that retinol is a natural antioxidant that can help fight against free radical damage or oxidative stress. Also, since retinol is a fat-soluble vitamin, it can be stored inside body fats or organs such as the liver. Discover the uses of vitamin A and know the benefits that you can get from this essential micronutrient.
Origin and History
In 1816, French physiologist François Magendie begun conducting experiments on dogs and noted that malnourished dogs tend to have corneal ulcers and increased risk of death. From the 1880s to 1900s, a number of researchers have conducted experiments to discover the essential nutrients in foods that are responsible for their health-promoting properties. Experiments were carried out on the diets of laboratory mice and rats.
In 1912, English biochemist Frederick Gowland Hopkins found unknown factors that are present in milk that aid growth in rats. Hopkins did not investigate his "milk factor" further but in 1913 Yale researchers Elmer McCollum, Marguerite Davis, Thomas Osborne and Lafayette Mendel discovered that butter contained a fat-soluble nutrient soon known as vitamin A.
Vitamin A has been known for its benefits for the eyes that helps in the prevention of eye problems such as glaucoma and cataracts.
Beta-carotene is responsible for the yellow, red and orange colouration of fruits and vegetables.
Vitamin A is the general term for a large number of related compounds called retinoids.
Beta-carotene is an antioxidant that converts to vitamin A.
The liver can store up to a year's supply of vitamin A.
Hypovitaminosis A and Hypervitaminosis A
According to the World Health Organization, vitamin A deficiency is one of the most common forms of micronutrient malnutrition. It is a public health problem in more than half of all countries, especially in South East Asia and Africa. Deficiency of the vitamin is also called hypovitaminosis A.
On the other hand, hypervitaminosis A or vitamin A toxicity in the system may do more harm than good and can lead to serious side effects and can be life-threatening. You can get it from consuming too much supplementation or consumption of vitamin A-rich foods. Here are the following signs and symptoms for hypovitaminosis and hypervitaminosis A:
- night blindness and dry eyes - dry skin and acne breakouts - vulnerability to infections - poor wound healing - growth retardation - diarrhoea - infertility
- swelling of the bones - nausea and vomiting - abdominal pain - loss of appetite - blurry vision - irritability - hair loss - jaundice
1. Eye Health. Vitamin A supplementation can promote your eye health and reduces your risk of having eye problems such as dry eyes, night blindness and age-related macular degeneration. Studies show that vitamin A deficiencies are linked to several vision disorders that involve the cornea and retina.
2. Immunity Boost. It boosts immunity for it is known as an anti-inflammatory agent and it also stimulates white blood cells which increases the activity of antibodies that gives your protection against bacteria, viruses and toxins. Deficiency of the vitamin is also associated with increased risk of infections.
3. Promotes Skin Health. It helps promote your skin health and protect you from premature ageing from the sun. Research shows that ointments and oral preparations containing retinoids, which is a synthetic form of vitamin A can prevent and treat skin disorders like acne, warts, psoriasis and rosacea.
4. Supports Bone Health. When it comes to bone health, the right balance of vitamin A is needed. It helps with normal bone development. Low levels of it can contribute to the development of osteoporosis, while high doses of it can lead to bone loss. We suggest getting your daily dose of vitamin A from food sources.
5. Healthy Growth and Development. Vitamin A promotes optimal health, normal growth and development. It is also essential for pregnant women for it helps with fetal healthy growth. Deficiency of the vitamin among pregnant and lactating women include risk of increased anaemia and slower infant growth.
6. Anti-inflammatory Properties. Researches show that vitamin A is an effective anti-inflammatory agent where supplementation of the vitamin has been found to be helpful in various inflammatory conditions which include skin disorders like acne vulgaris. Eating foods that are rich with vitamin A can reduce inflammation.
7. Tissue Repair. Vitamin A helps heal burns, cuts and wounds faster for it repairs tissue and skin. The vitamin plays an integral part in the cellular differentiation and reproduction which needs to occur for new tissues to grow and regenerate. Also, it is important in reducing the risk of infection on your wounds.
8. Antioxidant Properties. Studies show that vitamin A and carotenoids can be effective antioxidants which can be effective in fighting free radicals that can damage cells leading to a range of diseases and causes early signs of ageing like wrinkles. It can also be effective in the prevention of heart diseases.
9. Reproductive Health. Retinal which is one of the many forms of vitamin A is involved with your reproduction system. Studies show that retinoic acid help supports healthy female and male reproduction. Moreover, it can also be beneficial for normal development and growth of embryo during pregnancy.
10. Digestive Health.Promotes gut health by protecting the epithelial tissues or mucous membranes in your gastrointestinal tract against parasites and infections. Studies also show that it can reduce your risk of inflammatory diseases that affect the intestine such as ulcerative colitis and Crohn's disease.
There are two types of vitamin A that can be obtained from your daily diet. The preformed vitamin A and provitamin A. Preformed vitamin A is found in animal products like dairy foods, meat, fish and poultry. While provitamin A is found in vegetables, fruits and plant-based products.
You should include the following foods in your daily diet for you to stay fit and healthy. Health professionals suggest maintaining the needed vitamin A for you to have a strong immune system and reduce your risk of having health problems. Here are some of the following food sources of vitamin A:
Vegetables (carrots, sweet potatoes, kale, spinach, bell peppers, broccoli, squash)
We recommend consulting your healthcare provider when it comes to taking supplements and medications since they know what is right and best for your health. According to the Office of Dietary Supplements, vitamin A is also available as a dietary supplement. It often comes in the form of retinyl palmitate or retinyl acetate (preformed vitamin A), beta-carotene (provitamin A) or a combination of provitamin and preformed vitamin A.
This vitamin is available in tablets, capsules, liquids, gummies, intravenous. But it is still better to get your daily intake through various food sources. It is essential for treating vitamin A deficiency. Research also shows that vitamin A supplementation reduces the risk of having infections and increased mortality rates.
Dosage and Duration
We highly suggest talking to your nutritionist or healthcare provider for medical advice about the right dosage and duration if you are planning to take vitamin A supplements.
The recommended dietary allowance for vitamin A varies depends on age and needs. It is very important not to exceed the tolerable upper limit of 10,000 IU (3,000 mcg) for adults in order to prevent toxicity. Here is the upper limit intake of Vitamin A:
Birth to 12 months
Children 1 to 3 years
Children 4 to 8 years
Children 9 to 13 years
Teens 14 to 18 years
9, 333 IU
Adults 19 years and older
10, 000 IU
Precautions and Side Effects
Children and Pregnant Women. Keep out of reach of children. If not properly administered, it can lead to adverse side effects. During pregnancy, vitamin A is safe only when used in recommended doses. Make sure to consult first your healthcare provider before taking any kinds of medications and supplements to prevent any overdose.
Overdose. High doses of vitamin A can lead to serious side effects such as liver damage, severe nausea, vomiting, sleepiness, headache and dizziness. Studies also show that excessive use of vitamin A before and during pregnancy can be harmful to babies.
Hypersensitivity. If you are hypersensitive to vitamin A or any component of the formulation, you should not take supplements. We suggest getting your daily requirement of vitamin A from natural foods. Also, we advise consulting your healthcare provider and dietitian to recommend the right dosage of vitamin A in your daily diet.
Anticoagulants. You should avoid taking high doses of vitamin A together with anticoagulants or blood-thinning medications, particularly warfarin for it can lead to an increased risk of bleeding. We advise consulting your healthcare professional before taking vitamin A supplements.