Vitamin A is a fat-soluble vitamin – it is common term for retinoids (retinoic acid, retinal and retinol) which are biologically active compounds that occur naturally in several plant and animal tissues.
Vitamin A can be stored in the body (mainly in the liver), so if you stop consuming adequate foods, you would not experience any deficiency symptoms until retinoids stores were depleted (during several months). Excessive stores of vitamin A can be toxic. This is why it is very important to consume only normal healthy doses of this vitamin.
Fruits and vegetables are good source for carotenoids (so called “provitamin A”) which usually converted by the human body into usable retinoids. Most health benefits are coming from carotenoids – they are water-soluble and do not accumulate in the body, so toxicity is almost impossible.
Scientists identified more than 500 carotenoids but only few (about 10%) can be transformed into vitamin A in the body.
Vitamin A and health
Vitamin-A is beneficial for normal vision, healthy skin, bone growth (teeth, skeletal), hormone synthesis and regulation, reproduction (including breastfeeding), immune system, white blood cells, soft tissue and mucus membranes. It is also known as retinol because it produces the pigments in the retina of the eye. Vitamin-A promotes good vision, especially in low light. Eyes need vitamin A to help them convert light into brain signals that allow you to perceive images.
Vitamin-A often works as antioxidants, fighting cell damages. It protects body from infections by helping create healthy white blood cells and by promoting healthy skin. Vitamin A helps cells divide and develop into specialized cells, like blood cells, lung cells, brain cells and other distinct tissues.
Vitamin A and vision
Vitamin A plays a vital role in healthy vision. Short-term lack of vitamin A can lead to reversible night blindness; but long-term deficit of this vitamin could cause non-reversible corneal damage (so called “xeropthalmia”). Xeropthalmis is the condition which means drying of parts of the eye that will eventually result in blindness.
In general, vitamin A is involved in varied eye functions. It should be highlighted that retinol not only creates the pigments in the retina of the eye, but also is important for good vision (especially night vision) and overall eye health. The vitamin deficiency can trigger increased risk for eye problems.
Vitamin A and skin
Vitamin A supports skins grow and repair – it insures faster cells grow, bringing fresher and more youthful skin to the surface rapidly. However, increased amounts of carotenoids (beta-carotene) can turn the skin yellow or orange. Skin’s color would return to normal once you reduce intake of beta-carotene.
Lack of vitamin A can lead to hyperkeratosis or dry, scaly skin.
Vitamin A and cancer
Carotenoids (beta-carotene) act as antioxidants, protecting cells from free radical damages. Free radicals are responsible for certain chronic diseases, aging and several types of cancer. It is well known that many antioxidants prevent cancer but there is no scientific evidence that beta-carotene can prevent cancer. At the same time, it is also well known that all natural beta-carotene that can be consumed through fresh vegetables and fruits has been found helpful in preventing cancer in several studies. Conclusion is that carotenoids such as beta-carotene could reduce the risk for cancer.
Vitamin A deficiency
Vitamin-A deficiency is common in developing countries but not in developed countries. One of the earliest signs of a deficiency is night blindness which can become permanent if the deficiency is left without any treatment. Vitamin-A deficiency can cause complicated infectious diseases (measles and pneumonia).
Vitamin-A deficiency is common among alcoholics.
Excessive vitamin A
Excessive vitamin-A can be toxic. The earliest signs of excessive vitamin include nausea, vomiting, headache, dizziness, blurred vision, hair loss, confusion, liver damage and bone loss (osteoporosis).
High intakes of beta carotene from foods have not been shown to be toxic in humans, but may cause an unwanted side effect such as yellow or orange skin.
Vitamin A food sources
The best way to get the daily requirement of essential vitamins is to eat a wide variety of fruits, vegetables, fortified dairy foods, legumes (dried beans), lentils and whole grains.
Some daily ordinary foods are rich in vitamin-A – eggs, meat, fortified milk, cheese, cream, beef liver, kidney, cod and halibut fish oil.
Most recommended vitamin sources are oranges and yellow vegetables and fruits – broccoli, spinach, carrots, kale, butternut squash, cantaloupe, mangoes, pink grapefruit, apricots, pumpkins, sweet potatoes and most dark green, leafy vegetables. Intense color of fruits and vegetable means the higher concentration of beta-carotene.
Skin is the largest organ of body. Skin is considered as body sensor, shield and communicator and reflection of external beauty. Skin has several important functions including protection, regulation and…
Vitamin E refers to a group of fat-soluble compounds with distinctive antioxidant activities – they include both tocopherols and tocotrienols. Vitamin E is the powerful antioxidant that protects cells from…
Disclaimer: It is strongly recommended to consult your doctor for professional advice. Above mentioned information and recommendations are just general and should be adapted to each person according to personal health indicators and status.