The scientific name of vitamin A is Retinol. Vitamins are organic substances that are essential for normal cell function, growth, and development. There are 13 essential vitamins that the body cannot produce on its own, so they must be obtained from food or dietary supplements.
Vitamins are divided into two categories: fat-soluble and water-soluble. Fat-soluble vitamins (A, D, E, and K) are stored in the body's fatty tissues and can be accumulated over time. Water-soluble vitamins (C and the B vitamins) are not stored in the body and must be consumed on a regular basis.
Vitamins play a variety of roles in the body, including:
- Maintaining healthy vision (vitamin A)
- Supporting the immune system (vitamins A, C, D, and E)
- Producing red blood cells (vitamin B12)
- Converting food into energy (vitamins B1, B2, B3, B5, B6, and B12)
- Building and repairing tissues (vitamin C)
- Clotting blood (vitamin K)
Definition of Vitamin A:
Vitamin A is a fat-soluble vitamin that is essential for many bodily functions, including vision, immunity, and growth. It is a group of compounds that includes retinol, retinal, retinoic acid, and several provitamin carotenoids, most notably beta-carotene.
- Retinol: This is the active form of vitamin A that is found in animal products. It is converted to the retinal in the body, which is then converted to retinoic acid.
- Retinal: This is an intermediate form of vitamin A that is found in the retina of the eye. It is essential for vision, especially in low light.
- Retinoic acid: This is the most active form of vitamin A. It is involved in many cellular functions, including cell growth and differentiation, immune function, and bone development.
- Provitamin A carotenoids: These are plant pigments that can be converted to vitamin A in the body. The most common provitamin A carotenoid is beta-carotene.
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Vitamins, Food Source And Functions:
Here is a table of the 13 essential vitamins, their functions, and food sources:
Vitamin |
Function |
Food Sources |
Vitamin A |
Maintains healthy vision, supports the immune system |
Sweet potatoes, carrots, spinach, cantaloupe, mangoes |
Vitamin B1 (thiamine) |
Converts food into energy |
Pork, legumes, whole grains, nuts, seeds |
Vitamin B2 (riboflavin) |
Converts food into energy, helps the body use oxygen |
Dairy products, leafy green vegetables, eggs, fish |
Vitamin B3 (niacin) |
Converts food into energy, helps the body use oxygen |
Meat, poultry, fish, peanuts, whole grains |
Vitamin B5 (pantothenic acid) |
Converts food into energy, helps the body use oxygen |
Meat, poultry, fish, whole grains, beans, bananas |
Vitamin B6 (pyridoxine) |
Converts food into energy, helps the body use oxygen |
Fish, poultry, whole grains, bananas, potatoes |
Vitamin B7 (biotin) |
Helps the body use energy, supports skin and hair health |
Eggs, liver, nuts, seeds, legumes |
Vitamin B9 (folate) |
Important for cell growth and development, supports pregnancy health |
Dark leafy green vegetables, citrus fruits, legumes, whole grains |
Vitamin B12 (cobalamin) |
Produces red blood cells, helps the body use oxygen |
Meat, poultry, fish, dairy products, fortified cereals |
Vitamin C |
Supports the immune system, builds and repairs tissues |
Citrus fruits, berries, tomatoes, broccoli, potatoes |
Vitamin D |
Maintains healthy bones and teeth, supports the immune system |
Fatty fish, egg yolks, fortified milk |
Vitamin E |
Protects cells from damage, supports the immune system |
Vegetable oils, nuts, seeds, leafy green vegetables |
Vitamin K |
Clots blood, supports bone health |
Leafy green vegetables, broccoli, Brussels sprouts, liver |
Classification Of Vitamins:
Here is a brief classification of vitamins:
- Fat-soluble vitamins: These vitamins are stored in the body's fatty tissues and can be accumulated over time. They include vitamins A, D, E, and K.
- Vitamin A: is important for vision, growth, and reproduction.
- Vitamin D: is important for bone health and the immune system.
- Vitamin E: is an antioxidant that protects cells from damage.
- Vitamin K: is important for blood clotting.
2. Water-soluble vitamins: These vitamins are not stored in the body and must be consumed on a regular basis. They include vitamin C and the B vitamins.
- Vitamin C: is an antioxidant that supports the immune system.
- B vitamins: are involved in a variety of functions, including energy production, metabolism, and nerve function.
The best way to get the vitamins you need is to eat a balanced diet that includes a variety of fruits, vegetables, and whole grains. If you are concerned that you may not be getting enough vitamins, talk to your doctor. They may recommend that you take a dietary supplement.
Here is a table summarizing the classification of vitamins:
Vitamin |
Classification |
Vitamin A |
Fat-soluble |
Vitamin D |
Fat-soluble |
Vitamin E |
Fat-soluble |
Vitamin K |
Fat-soluble |
Vitamin C |
Water-soluble |
Vitamin B1 (thiamine) |
Water-soluble |
Vitamin B2 (riboflavin) |
Water-soluble |
Vitamin B3 (niacin) |
Water-soluble |
Vitamin B5 (pantothenic acid) |
Water-soluble |
Vitamin B6 (pyridoxine) |
Water-soluble |
Vitamin B7 (biotin) |
Water-soluble |
Vitamin B9 (folate) |
Water-soluble |
Vitamin B12 (cobalamin) |
Water-soluble |
Benefits And Functions Of Vitamin A:
The advantages of including Vitamin A in your diet are as follows:
- Vision: Vitamin A is essential for good vision, especially in low light. It helps to form the pigments in the retina of the eye, which are necessary for seeing in dim light.
- Immunity: Vitamin A is important for a healthy immune system. It helps to protect the body against infection by fighting off bacteria and viruses.
- Growth and development: Vitamin A is important for growth and development in children. It helps to form healthy skin, bones, and teeth.
- Reproduction: Vitamin A is important for reproduction. It helps to maintain a healthy pregnancy and to ensure the health of the baby.
- Skin health: Vitamin A is important for healthy skin. It helps to keep the skin hydrated and protected from damage.
- Eye health: Vitamin A is important for eye health. It helps to prevent night blindness and other eye problems.
Causes of Vitamin A Deficiency:
Vitamin A deficiency is a condition that occurs when the body does not get enough vitamin A. Vitamin A is a fat-soluble vitamin that is essential for many bodily functions, including vision, immunity, and growth.
There are many causes of vitamin A deficiency, including:
- A diet that is low in vitamin A-rich foods. This is the most common cause of vitamin A deficiency, especially in developing countries where people may not have access to a variety of fruits, vegetables, and animal products.
- Malabsorption disorders. These disorders can interfere with the body's ability to absorb vitamin A from food. Examples of malabsorption disorders include celiac disease, cystic fibrosis, and chronic pancreatitis.
- Liver disease. The liver is responsible for storing vitamin A, so liver disease can lead to a deficiency.
- Pregnancy and lactation. Women who are pregnant or breastfeeding have increased requirements for vitamin A, so they are at an increased risk of deficiency.
- Infections. Some infections, such as measles and diarrhea, can increase the risk of vitamin A deficiency.
Vitamin A Deficiency: Symptoms
Symptoms of vitamin A deficiency can vary depending on the severity of the deficiency. Mild deficiency may not cause any symptoms, while severe deficiency can lead to serious health problems, including:
- Night blindness. This is the inability to see in low light.
- Dry eyes.
- Skin problems.
- Increased risk of infections.
- Growth retardation.
- Retinopathy. This is a condition that can damage the retina of the eye and lead to blindness.
If you are concerned that you or your child may have a vitamin A deficiency, talk to your doctor. They can do a blood test to check your vitamin A levels. If you are found to be deficient, your doctor may recommend that you take a vitamin A supplement.
Here are some tips to help prevent vitamin A deficiency:
- Eat a balanced diet that includes a variety of fruits, vegetables, and animal products.
- If you are pregnant or breastfeeding, talk to your doctor about your vitamin A needs.
- If you have a malabsorption disorder, talk to your doctor about how to get enough vitamin A.
- If you live in a developing country, talk to your doctor about taking a vitamin A supplement.
Diseases Caused By Definition Of Vitamin A:
Vitamin A deficiency is a condition that occurs when the body does not get enough vitamin A. Vitamin A is a fat-soluble vitamin that is essential for many bodily functions, including vision, immunity, and growth.
There are many causes of vitamin A deficiency, including:
- Malabsorption disorders. These disorders can interfere with the body's ability to absorb vitamin A from food. Examples of malabsorption disorders include celiac disease, cystic fibrosis, and chronic pancreatitis.
- Liver disease. The liver is responsible for storing vitamin A, so liver disease can lead to a deficiency.
- Pregnancy and lactation. Women who are pregnant or breastfeeding have increased requirements for vitamin A, so they are at an increased risk of deficiency.
- Infections. Some infections, such as measles and diarrhea, can increase the risk of vitamin A deficiency.
Best Vitamin A Foods:
The following foods are very rich in Vitamin A:
- Sweet potato. One medium sweet potato (200 grams) contains 1,400 micrograms (mcg) of vitamin A, or 155% of the Daily Value (DV). Sweet potatoes are also a good source of fiber, potassium, and vitamin C.
- Carrots. One medium carrot (61 grams) contains 266 mcg of vitamin A, or 29% of the DV. Carrots are also a good source of fiber, potassium, and vitamin K.
- Beef liver. One ounce (28 grams) of beef liver contains 4,300 mcg of vitamin A, or 475% of the DV. Beef liver is also a good source of protein, iron, and zinc.
- Salmon. One 3-ounce (85-gram) serving of salmon contains 250 mcg of vitamin A, or 27% of the DV. Salmon is also a good source of protein, omega-3 fatty acids, and selenium.
- Mango. One medium mango (165 grams) contains 190 mcg of vitamin A, or 20% of the DV. Mangoes are also a good source of fiber, potassium, and vitamin C.
- Pumpkin. One cup (245 grams) of cooked pumpkin puree contains 223 mcg of vitamin A, or 24% of the DV. Pumpkin is also a good source of fiber, potassium, and vitamin C.
- Eggs. One large egg (50 grams) contains 60 mcg of vitamin A, or 7% of the DV. Eggs are also a good source of protein, choline, and selenium.
- Milk. One cup (240 milliliters) of whole milk contains 130 mcg of vitamin A, or 14% of the DV. Milk is also a good source of protein, calcium, and vitamin D.
Advantages Of Other Vitamins:
Some of the benefits of vitamins are as follows:
- Vitamin D: helps the body absorb calcium and phosphorus, which are essential for strong bones and teeth. It also plays a role in the immune system and may help reduce the risk of some chronic diseases.
- Vitamin E: is an antioxidant that protects cells from damage. It may also help reduce the risk of heart disease and cancer.
- Vitamin K: is important for blood clotting. It also plays a role in bone health and may help reduce the risk of fractures.
- Vitamin C: is an antioxidant that supports the immune system. It also helps the body heal wounds and form collagen, which is a protein that gives skin its strength and elasticity.
- Vitamin B1 (thiamine): helps the body convert food into energy. It is also important for nerve function and muscle movement.
- Vitamin B2 (riboflavin): helps the body convert food into energy and is also important for cell growth and development.
- Vitamin B3 (niacin): helps the body convert food into energy and is also important for skin health.
- Vitamin B5 (pantothenic acid): helps the body convert food into energy and is also important for the production of hormones.
- Vitamin B6 (pyridoxine): helps the body convert food into energy and is also important for nerve function and the production of red blood cells.
- Vitamin B7 (biotin): helps the body convert food into energy and is also important for skin health and hair growth.
- Vitamin B9 (folate): is important for cell growth and development, especially during pregnancy. It is also important for preventing birth defects.
- Vitamin B12 (cobalamin): helps the body convert food into energy and is also important for nerve function and the production of red blood cells.