Vitamin A is the generic term for a group of fat-soluble compounds highly important for human health.
They’re essential for many processes in your body, including maintaining healthy vision, ensuring the normal function of your immune system and organs, and aiding the proper growth and development of babies in the womb.
It’s recommended that men get 900 mcg, women 700 mcg, and children and adolescents 300–600 mcg of vitamin A per day.
Vitamin A compounds in animal and plant foods come in two different forms: preformed vitamin A and provitamin A.
Preformed vitamin A is the active form of the vitamin, which your body can use just as it is. It’s found in animal products including meat, chicken, fish, and dairy and includes the compounds retinol, retinal and retinoic acid.
Provitamin A carotenoids — alpha-carotene, beta-carotene, and beta-cryptoxanthin — are the inactive form of the vitamin found in plants.
These compounds are converted to the active form in your body. For example, your small intestine converts beta-carotene to retinol (an active form of vitamin A).
Here are six important health benefits of vitamin A.
1. Vitamin A protects your eyes from night blindness and age-related decline
Vitamin A is essential for preserving your eyesight.
The vitamin is needed to convert the light that hits your eye into an electrical signal that can be sent to your brain.
One of the first symptoms of vitamin A deficiency can be night blindness, known as nyctalopia.
Night blindness occurs in people with vitamin A deficiency, as the vitamin is a major component of the pigment rhodopsin.
Rhodopsin is found in the retina of your eye and is extremely sensitive to light.
People with this condition can still normally see during the day but have reduced vision in darkness as their eyes struggle to pick up light at lower levels.
In addition to preventing night blindness, eating adequate amounts of beta-carotene may help slow the decline in eyesight that some people experience as they age.
Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world. Though its exact cause is unknown, it’s thought to be the result of cellular damage to the retina attributable to oxidative stress.
The Age-Related Eye Disease Study found that giving people over 50 with some eyesight degeneration an antioxidant supplement (including beta-carotene) reduced their risk of developing advanced macular degeneration by 25%.
However, a recent Cochrane review found that beta-carotene supplements alone won’t prevent or delay the decline in eyesight caused by AMD.
Summary: Eating adequate amounts of vitamin A prevents the development of night blindness and may help slow the age-related decline of your eyesight.
2. Vitamin A may lower your risk of certain cancers
Cancer occurs when abnormal cells begin to grow or divide uncontrolled.
As vitamin A plays a vital role in the growth and development of your cells, its influence on cancer risk and its role in cancer prevention is of interest to scientists.
In observational studies, eating higher amounts of vitamin A in the form of beta-carotene has been linked to a decreased risk of certain types of cancer, including Hodgkin’s lymphoma and cervical, lung, and bladder cancer.
Yet, though high intakes of vitamin A from plant foods have been associated with a reduced risk of cancer, animal foods that contain active forms of vitamin A aren’t linked in the same way.
Similarly, vitamin A supplements haven’t shown the same beneficial effects.
In some studies, smokers taking beta-carotene supplements experienced an increased risk of lung cancer.
The relationship between vitamin A levels in your body and cancer risk is still not fully understood.
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Still, current evidence suggests that getting adequate vitamin A, especially from plants, is vital for healthy cell division and may reduce your risk of some types of cancer.
Summary: Adequate vitamin A intake from whole plant foods may reduce your risk of certain cancers, including Hodgkin’s lymphoma and cervical, lung, and bladder cancer. However, the relationship between vitamin A and cancer is not fully understood.
3. It supports a healthy immune system
Vitamin A plays a vital role in maintaining your body’s natural defenses.
This includes the mucous barriers in your eyes, lungs, gut, and genitals which help trap bacteria and other infectious agents.
It’s also involved in the production and function of white blood cells, which help capture and clear bacteria and other pathogens from your bloodstream.
A deficiency in vitamin A can increase your susceptibility to infections and delay your recovery when you get sick.
In fact, in countries where infections like measles and malaria are common, correcting vitamin A deficiency in children has decreased the risk of dying from these diseases.
Summary: Having enough vitamin A in your diet helps keep your immune system healthy and functioning at its best.
4. Vitamin A reduces your risk of acne
Acne is a chronic, inflammatory skin disorder.
People with this condition develop painful spots and blackheads, most commonly on the face, back, and chest.
These spots occur when the sebaceous glands get clogged with dead skin and oils. These glands are found in the hair follicles on your skin and produce sebum, an oily, waxy substance that keeps your skin lubricated and waterproof.
Though the spots are physically harmless, acne may seriously affect people’s mental health and lead to low self-esteem, anxiety, and depression.
The exact role that vitamin A plays in the development and treatment of acne remains unclear.
It has been suggested that vitamin A deficiency may increase your risk of developing acne, as it causes an overproduction of the protein keratin in your hair follicles.
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This would increase your risk of acne by making it more difficult for dead skin cells to be removed from hair follicles, leading to blockages.
Some vitamin-A-based medications for acne are now available with a prescription.
Isotretinoin is one example of an oral retinoid that is effective in treating severe acne. However, this medication can have serious side effects and must only be taken under medical supervision.
Summary: The exact role of vitamin A in the prevention and treatment of acne is unclear. Yet, vitamin-A-based medications are often used to treat severe acne.
5. Vitamin A supports bone health
Protein, calcium, and vitamin D are the key nutrients needed for maintaining healthy bones as you age.
However, eating enough vitamin A is also necessary for proper bone growth and development, and a deficiency in this vitamin has been linked to poor bone health.
People with lower blood levels of vitamin A are at a higher risk of bone fractures than people with healthy levels.
Additionally, a recent meta-analysis of observational studies found that people with the highest amounts of total vitamin A in their diet had a 6% decreased risk of fractures.
Yet, low levels of vitamin A may not be the only problem in bone health. Some studies have found that people with high intakes of vitamin A have a higher risk of fractures.
Even so, these findings are based on observational studies, which cannot determine cause and effect.
This means that the link between vitamin A and bone health is not fully understood, and more controlled trials are needed to confirm what has been seen in observational studies.
Remember that vitamin A status alone does not determine your risk of fractures, and the impact of the availability of other key nutrients, like vitamin D, also plays a role.
Summary: Eating the recommended amount of vitamin A may help protect your bones and reduce your risk of fractures, though the connection between this vitamin and bone health is not fully understood.
6. Vitamin A promotes healthy growth and reproduction
Vitamin A is essential for maintaining a healthy reproductive system in both men and women and ensuring the average growth and development of embryos during pregnancy.
Rat studies examining the importance of vitamin A in male reproduction have shown that a deficiency blocks the development of sperm cells, causing infertility.
Likewise, animal studies have suggested that vitamin A deficiency in females can impact reproduction by reducing egg quality and affecting egg implantation in the womb.
In pregnant women, vitamin A is also involved in the growth and development of many major organs and structures of the unborn child, including the skeleton, nervous system, heart, kidneys, eyes, lungs, and pancreas.
Yet, though much less common than vitamin A deficiency, too much vitamin A during pregnancy can also harm the growing baby and may lead to birth defects.
Therefore, many health authorities recommended that women avoid foods containing concentrated amounts of vitamin A, such as pâté and liver, and supplements containing vitamin A during pregnancy.
Summary: Adequate amounts of vitamin A in the diet are essential for reproductive health and the healthy development of babies during pregnancy.
Taking too much vitamin A can be risky
Vitamin A is a fat-soluble vitamin that is stored in your body. This means that excess consumption can lead to toxic levels.
Hypervitaminosis A is caused by consuming too much preformed vitamin A through your diet or supplements containing the vitamin.
Symptoms can include nausea, dizziness, headaches, pain, and even death.
Though it can be caused by excessive intake from the diet, this is rare compared to overconsumption of supplements and medications.
Additionally, eating a lot of provitamin A in its plant form doesn’t carry the same risks, as its conversion to the active form in your body is regulated.
Summary: Eating high amounts of the active form of vitamin A from animal foods, medications or supplements can be toxic. Excessive consumption of provitamin A from plant foods is unlikely.
Vitamin A is vital for many important processes in your body.
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It’s used to maintain healthy vision, ensure the normal functioning of your organs and immune system, and establish the average growth and development of babies in the womb.
Both too little and too much vitamin A could negatively affect your health.
The best way to ensure you get the balance right is to consume vitamin-A-rich foods as part of your everyday diet and avoid supplementing with excessive amounts.