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Vitamin A Supplements

Drug class: vitamin
ATC code: A11CA01 (WHO) D10AD02 (WHO), R01AX02 (WHO), S01XA02 (WHO)
Legal status: US: OTC
License data: US DailyMed: Retinol
Routes of administration: by mouth, IM

Vitamin A

Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal, retinoic acid, and several provitamin A carotenoids.

Types and differences of vitamin A

Vitamin A was discovered by Dr. EV McCollum, an American scientist. Vitamin A is a compound vitamin. Isoprenoids are composed of carbon, hydrogen and oxygen and are one of the fat soluble vitamins, which are absorbed along with the body’s absorption of fat. when absorbed into the body will not be able to be excreted through the urine But if the body receives too much of this group of vitamins, it will be stored in the body.

Therefore, this vitamin does not need to be obtained from the diet every day. The vitamin A Can be divided into 2 groups: 1. A group that is already in the form of a vitamin (Proformed Vitamin A ), also known as Retinol, which is a pure vitamin A that can act (active form) immediately and 2. The group in the form A form of provitamin in the form of plant pigments or pigments (carotenes), such asβ-carotene , α-carotene and cryptoxanthin The process of converting provitamins into pure vitamin A (retinol) takes place in the small intestine (intestinal mucosa).

Where to find and where to find vitamin A

source of vitamin A In nature, there are many forms such as the source of vitamin A. In the form of pure vitamins (retinol), including in cod liver oil, marine fish, liver, meat, egg yolks, milk, butter, etc., the source ofvitamin Ais in the form of pro-vitamin. Or pigments of plants (carotenes) such as orange, green and yellow vegetables, ripe papaya, pumpkin , gourds , ripe, mangoes, spinach, broccoli, carrots, etc.

The right amount of vitamin A

The need for vitamin A per day for Thai people aged 6 years and over (according to the list attached to the notification of the Ministry of Public Health (No. 182) B.E. 2541 (1998) states that approximately 800 micrograms RE (μg RE)

The benefits and harms of vitamin A

Vitamin A has many benefits for the human body such as:

• Helps to see by 11-cis-ratinol + opsin will convert to rhodopsin, which if lack of vitamin A will make it invisible at night. or in a dimly lit place also known as night blindness
• It nourishes the skin and mucous membranes of the body, such as the epithelium, digestive system, respiratory system, and skin follicles. And most importantly, the conjunctiva of the eye. If found that if a lack of vitamin A will cause the lacrimal glands to dry blepharitis (Bitot’s spot) and becomes keratamalasia and eventually blind In the excretory and reproductive system, vitamin A also affects the formation of mucus components such as mucoproteins and mucopolysaccharides. make the skin tissues strong It is resistant to disease and bacteria.
• help in growth especially the formation of bones and teeth in young children

It also helps to reduce inflammation of acne, remove dark spots and help relieve thyroid disease. control the growth of the body especially bone growth The penalty for vitamin A is most likely to occur in the event that the amount of vitamin A is too much and has been accumulated for a long time. This will cause the body to have abnormal symptoms such as restlessness, bone pain, hair loss, fatigue, nausea, vomiting, headache, irregular menstruation, blurred vision, diarrhea, peeling skin, rashes, and enlarged liver.

Research Studies Related to Vitamin A

There are research studies on the metabolic system (Metabolism) of vitamin A.stated that the body will absorb vitamin A And carotene is good in the small intestine. By relying on fat as a solvent and bile as an aid in absorption. and then sent to the liver where it is stored The liver is an important organ that manages the levels of vitamin A in the body. 90% of the vitamin A the body receives is stored in the liver. And the liver is responsible for the distribution of vitamin A. to different parts of the body It has also been reported that the human body can store up to 600,000 IU of vitamin A.

The remainder is stored in the kidneys, lungs, node, and adipose tissue when the body needs to use vitamin A. It is then broken down into the retinal form and is transported by retinal binding protein and into the tissues where it needs it. In addition, pure retinol in the diet is fully absorbed by the body, and one third of the carotenes are absorbed. stay in food The rest will be excreted in the feces.

Toxicological studies have shown that the dose of vitamin A (retinol) for acute toxicity in adults is between 2-5 million IU after ingestion within 8 hours. Severe headache, dizziness, vomiting and diarrhea occur. This is followed by swelling, redness, cracking and peeling. This is caused by the division of mucoid cells.

Cells divide rapidly (mitosis) causing a large and rapid turnover of skin cells. Skin appears red, swollen, cracked, and peeling, but these symptoms disappear when vitamin A intake is stopped. In children, symptoms include loss of appetite, restlessness, vomiting, peeling skin, bulging fontanelles due to increased intracranial pressure.

For chronic vitamin A poisoning, symptoms will vary from person to person. This was neither dose-related nor correlated with plasma vitamin A levels. In general, toxic individuals had plasma retinol levels greater than 100 μg/100 ml (normal values ​​20-60 μg/100 ml). The symptoms of poisoning include skin changes such as dry skin, cracked skin, chapped lips, bleeding, red gums, nosebleeds, baldness, anorexia, nausea, weight loss, muscle pain after exercise, and possibly liver, enlarged spleen and paleness, pain.

Anterior head, blurred vision, or blurred vision, neurological symptoms can be severe. and may experience acute encephalitis, etc.

Recommendations and practices

Pregnant women should not use dietary supplements. or vitamin A extract because of the powerful effect which can cause fetal disability

Storing Vitamin A Extract in the form of a dietary supplement It should be stored in a cool, dark place because they are sensitive to light and heat, which can decompose vitamin A. blood lipid pills or drugs to lower blood cholesterol levels May result in the body absorbing less vitamin A, so it should not be taken at the same time.

Reference Vitamin A

Wirot Sumyai.Vitamin and nutrition therapy The Magic of Anti-Aging, Bangkok, Amarin Printing and Publishing Public Company Limited, 2002.
Soramon Sutin. Vitamins and free radicals. Huachiew Chalermprakiet Science and Technology Journal Year 2. Issue 1. January – June 2016.pages 80-92
Somsong Lekakul, Biochemistry of vitamins. 2nd edition. Bangkok. Supavanich printing 2000.
Sakulrat Usanawarong. Vitamin A poisoning. Journal of Academic Service Center Khon Kaen University Year 15. No. 4, October-December 2007. Pages 17-25.
Naina Boonthaweeyurat Nutritional Biochemistry. 2nd Edition. Bangkok Charoen Dee Mankhong printing 2000.
Narong Sikiram. Documents for studying vitamins. Department of Human Relations. Faculty of Humanities Chiang Mai University
Gerber, A., Raab, A. and Sobel, A. 1954. Vitamin A poisoning in adults: Description of case. Am. J. Med. 16, 729
Bell, WE 1978. Increased intracranial pressure-diagnosis and management. Curr. Probl. Pediatr. 8, 1.
Muenter, MD, Perry, HO and Ludwig, J. 1971. Chronic vitamin A intoxication in adults : Hepatic, neurologic and dermatologic complications. J.Am. Med. 50, 129
Goodman, DS 1979. Introduction, background, and general overview. Fed. Proc., Fed. Am. Soc. Exp. Biol. 38, 1958.
Hayes, KC and Hegsted, DM 1973. Toxicity of the vitamins. In Toxicants Occuring Naturally in Food. Natl. Acad. of Sci., Washington, D.C.
Furman, KI 1973. Acute hypervitaminosis A in an adult. Am. J. Clin. Nutr. 26, 575.
Moore, T. 1957. Vitamin A. Elsevier , New York.