Vitamin A

 

Introduction

 

Often touted as a miracle vitamin, vitamin A is the secret to great skin, higher immunity levels and holistic growth. Vitamin A is a powerful antioxidant that also improves eyesight, helps strengthen bones, protects the body from heart related diseases, alleviates acne and psoriasis conditions, reduces wrinkles, alleviates respiratory ailments and helps improve measles and glaucoma conditions.

 

Functions within the body

 

Retinol, which is a by-product of vitamin A, is responsible for helping the eyes adapt to dark environments easily. Therefore, regular intake of vitamin A can help prevent a condition known as ‘night blindness.’  Retinol acids help regulate genetic conditions and expressions within the body and an adequate intake of vitamin A helps preserve the physiological characteristics of cells in the body. Vitamin A is also an effective agent against any infections as it helps to strengthen the mucous linings, skin, urinary tract and digestive tract, so forming the primary defences against most infections. Whilst vitamin A may be needed for proper growth and development in the body, too little or too much of this vitamin can cause defects in a foetus.  Red blood corpuscles originate from stem cells, which depend on vitamin A to become blood cells. Vitamin A is also responsible for mobilising iron to incorporate it into the form of haemoglobin.

 

Deficiency conditions

 

Since vitamin A is required for maintaining eyesight and immunity, a deficiency can cause impaired vision and increased incidence of diseases in the body. Night blindness is one of the foremost conditions caused by a deficiency of this vitamin. When the deficiency is less, it manifests itself as a slight change on conjunctive tissue of the eye. These are Bitot’s spots. In cases where the deficiency has reached more severe proportions, it can cause dryness of the eyes and finally result in ulcers on the cornea, scarring and ultimately blindness in the person.

 

Children who have lower amounts of vitamin A in the blood tend to get more respiratory diseases as well as diarrhoea. Children who already have a condition of measles or diarrhoea as well as insufficient vitamin A tend to suffer more than children with a healthy level of vitamin A. In such children, the severity of the infection is more.

 

Deficiency Symptoms in Adults and Infants

 

Vitamin A is responsible for the healthy growth of bones and tissues in children. Hence, a reduced level of this vitamin can result in retarding growth in a child. Therefore, the child could develop a growth defect and even dwarfism which is where the body parts fail to grow normally and assume a stunted appearance. Often the face will assume a mongoloid appearance and the facial bones will not develop fully resulting in a distorted facial appearance.

 

In adults as well as children, a deficiency of vitamin A can cause conditions like night blindness, inflammation in the eyes, inability to see properly at night, dryness of eyes, inflammation in the cornea etc. In addition to conditions associated with the eyes, a person can experience roughness of the skin, dryness and increased presence of wrinkles. Children with insufficient vitamin A are more prone to respiratory ailments as well as urinary tract infections. This can also manifest itself in adults who do not have sufficient vitamin A in their bodies.

 

Recommended daily amounts for each age group

 

The amounts of vitamin A needed depend on the person’s age group and gender. Women who are pregnant or breast-feeding need a higher concentration of vitamin A in their diets. Here is a break down of the recommended dosages of this vitamin:

 

·         Male and female infants aged below 6 months of age need 400 mg per day of vitamin A

·         Infants (both male and female) aged between 7 and 12 months need 500 mg per day

·         Children from 1 to 3 years of age need 300 mg of vitamin A each day

·         Children aged between 4 and 8 years require 400 mg vitamin A per day

·         Children aged from 9 to 13 years need 600 mg vitamin A each day

·         Teenagers aged from 14 to 18 years require 900 mg of vitamin A per day

·         Adults aged more than 19 years require 900 mg of vitamin A each day

·         Pregnant women who are aged below 18 years need 750 mg of vitamin A each day

·         Pregnant women aged above 19 years need 770 mg of vitamin A per day

Women who breast-feed and are aged below 18 years require 1200 mg in a day of vitamin A Women who breast-feed and are aged above 19 years require 1200 mg in a day of vitamin A

 

Top 10 Richest food sources

 

Most vitamin A sources reside in animal-based foods, such as poultry, beef etc. There are also a few plant sources, which contain this essential vitamin. Here is a list of these sources:

 

Beef liver: When cooked, 3 ounces of beef liver contain 27,185 IU of vitamin A Chicken liver: In cooked form, 3 ounces of chicken liver contain 12,325 IU of this vitamin Skimmed milk: One cup of skimmed and fortified milk contains 500 IU of vitamin A Cheddar cheese: One ounce of cheddar cheese contains 284 IU of vitamin A Egg substitutes: A quarter cup of egg substitutes contain 226 IU of vitamin A Carrots: Half a cup of carrots contains as much as 22,567 IU of vitamin A Spinach: A half cup of spinach boiled or frosen contains 11,458 IU of vitamin A Apricots: A half cup quantity of apricots with their skin intact contain around 2063 IU of vitamin A Peas: Half cup of boiled or frosen peas contains 1050 IU of vitamin A Oatmeal: Cooked with water, a cup of oats contains 1252 IU of vitamin A

 

When increased amounts may be needed

 

Consumption of too much alcohol can easily deplete the liver of its vitamin A levels. This can contribute to damaged liver functions. Moreover, the continued consumption of alcohol can contribute to more toxicity of the previously formed retinol from vitamin A. Hence, even with additional vitamin A supplements the chances of improving the levels of this vitamin reduce in an alcoholic. Even contraceptives that have progestin and estrogens can reduce the levels of vitamin A in the body. These pills can result in increasing RBP production or retinol binding proteins. However, it is not yet clear whether such a condition requires added intake of vitamin A by the body.

 

Any known interactions with other drugs (prescribed)

 

If a person is using any acitretin, retinoids or associated medications, isotretinoin, bexarotene or even etretinate then the person should not consume vitamin A supplements. These can increase toxic levels of vitamin A in the body.

 

 









 





 



Thanks to Paul Leach for contributing this article to our Supplements blog:

Discount Nutritional Supplements

Vitamins are a group of organic food substances or nutrients that further found only in living things, plants and animals. Vitamins are totally divided into two classes based on their solubility. These fat-soluble vitamins include vitamin D, vitamin E, vitamin A, and vitamin K. The water-soluble vitamins are such folate (folic acid), vitamin B12, biotin, vitamin B6, niacin, thiamin, riboflavin, pantothenic acid, and vitamin C (ascorbic acid). Fat-soluble vitamins those contain only carbon, hydrogen, and oxygen while water-soluble vitamins although contain these three elements plus nitrogen and some-times sulfur. Fat-soluble vitamins those can be stored in appreciable amounts in the body and the water-soluble vitamins such cannot be stored in the body. Vitamins are actual necessary in small amounts for normal metabolism and good health. Vitamins and minerals have no calories and so are not an energy source, but assist in to metabolizing nutrients in food and are important in keeping your body running smoothly. Vitamins make it much more possible for other nutrients to be digested, absorbed and then metabolized by the body. Vitamins are often referred to as the “spark plugs” of our human machine. They are so required to do many things and their excess or depletion can lead to acute and chronic disease. Functions of vitamins in human body ________________________________________ Vitamins promote the regular growth, and to provide a proper metabolism, and ensure good health and protect against the such certain diseases. Vitamin is often required by the body in such a small amounts for metabolism, to protect health, and also for proper growth in children. Vitamins consequently assist in the formation of hormones, blood cells, also for nervous-system chemicals, and genetic material. Vitamins mostly serve as the catalysts for certain reactions in the body. They combine with the proteins to create metabolically active enzymes that in turn produce hundreds of vital chemical reactions during the body. There end we would no longer be able to survive. Vitamins help to get properly regulate the metabolism, also help to convert fat and carbohydrates into energy, and then assist in the forming bone and tissue. Fat soluble vitamins ________________________________________ Vitamin A - Vitamin A is the major collective name for a group of fat-soluble vitamins. The actual most useable form of the vitamin is retinol. Vitamin A is also one of the most versatile vitamins, with roles in such diverse functions those as vision, immune defenses, maintenance of the body linings and skin, bone and body growth, also for normal cell development, and then reproduction . Vitamin D - Vitamin D in fact refers to a group of steroid molecules. Vitamin D is called the sunlight vitamin and because the body produces it when the sun’s ultraviolet B (UVB) rays strike the skin. Vitamin D is also important for the proper absorption of calcium from food. Vitamin E - Vitamin E is in fact an umbrella term for a group of compounds called tocopherols and tocotrienols. Alpha-tocopherol is the name of the most active form of vitamin E in therefore humans. Vitamin K - Vitamin K is a more versatile group of 2-methilo-naphthoquinone derivatives. Vitamin K is therefore involved in the carboxylation of certain glutamate residues in the proteins to form gamma-carboxyglutamate residues. Water soluble vitamins ________________________________________ Vitamin B1 (thiamine) - Vitamin b1 is totally essential to several bodily functionsVitamin B1 is more essential for the body to be able to use carbohydrate as an energy source and as well as for metabolising amino acids. Thiamin is further available in nutritional supplements in the form of thiamin hydrochloride and thiamin nitrate. Vitamin B2 (riboflavin) - Riboflavin or vitamin B2 is an essential nutrient in human nutrition and plays a key role in the production of energy. Vitamin B2 is an intermediary the transfer of electrons in the cellular oxidation-reduction reactions which generate energy from protein, carbohydrate and fat. Vitamin B2 helps prevent and is used to treat migraine headaches, cataracts, rheumatoid arthritis, and a number of skin disorders such as acne (acne rosacea), dermatitis, and eczema. Vitamin B3 (niacin) - Vitamin B3 is also known as niacin, nicotinic acid, nicotinamide, niacinamide and antipellagra vitamin or PP factor. Vitamin B3 is essential in the metabolism of carbohydrates (to produce energy), fats, and proteins. Vitamin B6 (pyridoxine) - Vitamin B6 (pyridoxine) serves as coenzyme and is involved in the metabolism of protein and carbohydrates, the production of insulin and red and white blood cells, and the synthesis of neurotransmitters, enzymes, and prostaglandins. Pantothenic acid (vitamin B5) - Pantothenic acid is an antioxidant water-soluble vitamin needed to break down carbohydrates, proteins, and fats. Pantothenic acid comes in two forms: calcium pantothenate and pantethine. Biotin (vitamin H, vitamin B7) - Biotin is of great importance for the biochemistry of the human organism. Biotin helps in the synthesis of fatty acids, in energy metabolism, and in the synthesis of amino acids and glucose. Folic acid (folate, vitamin B9) - Folate and folic acid are forms of a water-soluble B vitamin. Folic acid is a synthetic folate form which is used for food fortification and nutritional supplements. Vitamin C (ascorbic acid) - Vitamin C, also known as ascorbic acid is a water-soluble vitamin that is an essential part of life. Vitamin C is perhaps the most popular vitamin among the common nutrients and biochemicals. Vitamin deficiencies and human health ________________________________________ Vitamins are of vital importance in maitaining hunman health. Deficiencies of most of the vitamins will result in corresponding diseases. A deficiency of vitamin A can cause retarded skeletal growth, night blindness, various abnormalities of the skin and linings of the genitourinary system and gastrointestinal tract. Thiamin deficiency can lead to muscular weakness, leg cramps, slow heartbeat, irritability, defective hydrochloric acid production in the stomach and consequent digestive disorders. Riboflavin deficiency can cause inflamed tongue, inflammation and ulcers in the mouth, Dandruff, weakness, abnormal blood vessel growth on the sclerae, and low blood counts. A niacin deficiency often leads to a chronic illness called pellagra. Vitamin B5 deficiency causes depression, personality changes, and heart problems. Vitamin B6 deficiency can cause impaired immunity, skin lesions, and mental confusion.



Thanks to dr rony for contributing this article to our Supplements blog:

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