What Is Vitamin A?
Vitamin A acts as a strong antioxidant within the body and it’s also involved in reducing inflammation through fighting radical damage.
Vitamin A is found in two primary forms: “Active vitamin A (also called retinol, which ends up in retinyl esters) and beta-carotene”.
Retinol comes from animal-derived foods and is a sort of “pre-formed” vitamin A that will be used directly by the body. The other type, which is obtained from colorful fruits and vegetables, is within the sort of provitamin carotenoids. Beta-carotene and other sorts of carotenoids found in plant-based products are first converted to retinol, the active sort of vitamin A, to be utilized by the body. Another sort of vitamin A is palmitate, which usually comes in capsule form.
What is Beta Carotene?
The physical body converts beta carotene into vitamin A (retinol).
Beta carotene may be a precursor of vitamin A. We need vitamin A for “healthy skin, mucus membranes, our system, and also for good eye health and vision”.
Beta carotene in itself isn’t an important nutrient, but vitamin A is an important one.
Vitamin A is also the source of the food we eat through beta carotene or in supplement form. The advantage of dietary beta carotene is that the body only converts the maximum amount it needs. Excess vitamin A is toxic. There are various uses and benefits of beta carotene, which benefits human health. Below, are some examples:
- Beta carotene is an antioxidant.
An antioxidant is a substance that inhibits the oxidation of other molecules, it protects the body from free radicals. Several studies have shown that antioxidants through diet, help people’s immune systems, protect against free radicals, and lower the danger of developing cancer and heart condition.
- Some studies have suggested that those that consume a minimum of four daily servings of beta carotene-rich fruits and/or vegetables have a lower risk of developing cancer or heart condition.
- Beta carotene keeps the lungs healthy as people age.
- The BMJ published a report in March 2006 which showed that high blood beta carotene levels compensate for some of the damage to the lungs caused by oxygen free radicals.
They measured the FEV1 of 535 participants and measured their beta carotene blood levels. FEV1 measures how much air you can breathe out in one go. They found that those with high beta carotene levels had a much slower decline in FEV1 measures.
Deficiency
Though vitamin A deficiency is rare in developed countries like the US, it’s common in developing countries, as these populations may have limited access to food sources of vitamin A and provitamin A carotenoids.
- Vitamin A deficiency can lead to severe health complications.
- Vitamin A deficiency also increases the severity and risk of dying from infections like measles and diarrhea.
- Additionally, vitamin A deficiency raises the risk of anemia and death in pregnant women and negatively impacts the fetus by slowing growth and development.
- Certain groups such as premature infants, people with cystic fibrosis, and pregnant or breastfeeding women in developing countries are more at risk of vitamin A deficiency.
Food Sources
Your body’s ability to effectively convert carotenoids, like beta-carotene, into active vitamin A depends on many factors including genetics, diet, overall health, and medications. For this reason, those who follow plant-based diets especially vegans should be vigilant about getting enough carotenoid-rich foods.
- Foods highest in preformed vitamin A are:
Egg yolks, Beef liver, Liverwurst, Butter, Cod liver oil, Chicken liver, Salmon, Cheddar cheese, Liver sausage, King mackerel, Trout, etc.
- Foods high in pro-vitamin A
Sweet potatoes, Pumpkin, Carrots, Kale, Spinach, Dandelion greens, Cabbage, Swiss chard, Red peppers, Collard greens, Parsley, Butternut squash.
Toxicity and Dosage Recommendations.
- Just as vitamin A deficiency can negatively impact health, getting an excessive amount also can be dangerous.
The recommended daily allowance (RDA) for vitamin A is 900 mcg and 700 mcg per day for men and women, respectively — which may be easily reached by following a whole-food diet. - However, it’s important to not exceed the tolerable upper limit (UL) of 10,000 IU (3,000 mcg) for adults to stop toxicity.
Though it’s possible to consume excessive preformed vitamin A through animal-based sources like liver, toxicity is most ordinarily linked to excessive supplement intake and treatment with certain medications, like Isotretinoin.
Since vitamin A is fat-soluble, it’s stored in your body and may reach unhealthy levels over time.
Taking too much vitamin A can lead to serious side effects and can even be fatal if ingested at extremely high doses. Acute vitamin A toxicity occurs over a brief period when one, excessively high dose of vitamin A is consumed, while chronic toxicity occurs when doses quite 10 times the RDA are ingested over a longer period.
The most common side effects of chronic vitamin A toxicity include:
• Vision disturbances
• Joint and bone pain
• Poor appetite
• Nausea and vomiting
• Sunlight sensitivity
• Hair loss
• Headache
• Dry skin
• Liver damage
• Jaundice
• Delayed growth
• Decreased appetite
• Confusion • Itchy skin
Though less common than chronic vitamin A toxicity, acute vitamin A toxicity is related to more severe symptoms, including liver damage, increased cranial pressure, and even death. Vitamin A toxicity can negatively impact maternal and fetal health and can cause birth defects.
To avoid toxicity, steer beyond high-dose vitamin A supplements.
- The UL for vitamin A applies to animal-based food sources of vitamin A, which also act as vitamin A supplements.
- A high intake of dietary carotenoids is not associated with toxicity.
Though studies link beta-carotene supplements with an increased risk of lung cancer and heart disease in smokers. Since an excessive amount of vitamin A is often harmful, consult your doctor before taking vitamin A supplements.
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