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Vitamin A Palmitate
• Source
o Natural: Vitamin A Palmitate is found naturally in fish and fish liver oil.
o Synthetic
o Today, Vitamin A is derived from Vitamin A acetate, a synthetic organic chemical. The Vitamin A molecule is very unstable by itself. To create a more stable configuration, it is reacted with methyl palmitate. This is called Vitamin A Palmitate, which is considered a synthetic product. It is the only form of Vitamin A used to fortify dairy products.
• History of Vitamin A Palmitate
o Vitamin A Palmitate was not discovered until the 20th century. In 1830 the yellow coloration of carrots was isolated and named carotene. It took another 89 years for scientists to discover the link between carotene and Vitamin A Palmitate. Vitamin A Palmitate is a fat-soluble vitamin which supports the formation of the cells of the skin and is utilized in the process of vision. It is involved in the viability of the reproductive system, in particular fetal growth. Vitamin A Palmitate also supports the differentiation of epithelial cells. The entire body is covered with epithelial linings – skin and mucosas – that consist of mucas-secreting cells and keratinizing cells, which form hard and scaly surfaces. Both of these originate from basal cells. In the absence of Vitamin A Palmitate, only the keratinizing cells are formed. The protective mucus secreting cells are impaired, leading to damage of the cornea and a high susceptibility to infection.
o Good sources of Vitamin A Palmitate are eggs, milk, cheese, butter, liver and fish as well as vegetables that are dark green, like spinach, or orange like carrots. Foods of a plant origin do not contain Vitamin A Palmitate but are rich in sources of provitamin A, a class of compounds called carotenoids, which are involved in photosynthesis. B-Carotene is the most important of these compounds.
• History of Vitamin A Palmitate Deficiency
o In 1909, a growth factor was discovered when it was found that fat-soluble substances were needed for growth of mice and rats. This growth factor was extracted from butter and egg yolk in 1913. It was called Vitamin A Palmitate. In 1946-47, it was synthesized. There are natural sources of Vitamin A Palmitate such as fish and cattle liver, milk, eggs, green beans and carrots. It can also be found in butter and margarine (however, these are usually supplemented).
o Today, almost all Vitamin A Palmitate is synthetically produced. Chemically speaking, Vitamin A Palmitate is a long chain alcohol known as retinol. It forms as pale yellow crystals. Vitamin A Palmitate is a pure high-potency form of Retinol A.
o The main signs of a deficiency in Vitamin A Palmitate occur in the eye. Examples including night blindness, drying and/or degradation of the cornea. Excess weight loss, fever, and poor absorption may also cause minor grades of Vitamin A Palmitate deficiency. The only established signs of a deficiency in humans are lesions of the eye. A deficiency may also cause a higher susceptibility to infections due to the impairment of antibody formation. This may lead to a greater frequency of various types of cancer. The intake of high levels of Vitamin A Palmitate is toxic and can lead to neurological symptoms and damage to the eye. During pregnancy, high levels of Vitamin A Palmitate can cause brain damage in the infants.
• Description of Vitamin A Palmitate Production
1. Vitamin A acetate is prepared synthetically by treatment of pseudoionone with sulfuric acid, and by condensation of the resulting β-ionone with methyl chloroacetate to the “glycidic ester” intermediate, which is decarboxylated to β-C14-aldehyde.
2. Grignard reaction of β-C14-aldehyde with 3-methyl-2-penten-4-yn-1-ol gives the C20-alkynediol, which is catalytically hydrogenated to C20-alkenediol.
3. Reaction of C20-alkenediol with acetic anhydride and subsequent dehydration with hydrobromic acid gives then vitamin A acetate. The resulting crude product is purified by crystallization from methanol, dried, and then filled into containers.
4. Vitamin A acetate reacts with methyl palmitate in the presence of sodium methoxide (or alternatively sodium hydroxide) in a suitable solvent to give Vitamin A Palmitate, which is isolated by extraction. The product is isolated by vacuum-concentration of the organic phase and then filled into containers.
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