Vitamins

Question

This piglix contains articles or sub-piglix about Vitamins

Answer 1

Alpha-GPC

Alpha-GPC

L-Alpha glycerylphosphorylcholine (alpha-GPC, choline alfoscerate) is a natural choline compound found in the brain. It is also a parasympathomimetic acetylcholine precursor which may have potential for the treatment of Alzheimer's disease and other dementias.

Alpha-GPC rapidly delivers choline to the brain across the blood–brain barrier and is a biosynthetic precursor of acetylcholine. It is a non-prescription drug in most countries and in the United States it is classified as generally recognized as safe (GRAS).

Studies have investigated the efficacy of alpha-GPC for cognitive disorders including stroke and Alzheimer's disease. An Italian multicentre clinical trial on 2,044 patients suffering from recent stroke were supplied alpha-GPC in doses of 1,000 mg/day for 28 days and 400 mg three times per day for the five ensuing months. The trial confirmed the therapeutic role of alpha-GPC on the cognitive recovery of patients based on four measurement scales, three of which reached statistical significance. Commonly used doses are 300 to 1,200 mg daily.

Industrially, alpha-GPC is produced by the chemical or enzymatic deacylation of phosphatidylcholine enriched soya phospholipids followed by chromatographic purification. Alpha-GPC may also be derived in small amounts from highly purified soy lecithin.

Many users report degradation of alpha-GPC when stored openly or for long periods of time. Alpha-GPC is hygroscopic and will pull moisture in from the surrounding air. This will cause the powder to turn into what appears to be a gel. Alpha-GPC with >99% purity will undergo this process at a visible rate (seconds to minutes) and thus requires minimized exposure to the air. This hygroscopic quality can cause gel capsules not fully packed with alpha-GPC to dissolve. Proper storage methods need to be used with alpha-GPC and include removing all air from the container, double bagging with plastic bags rated for chemicals (less likely to leak air), and storing bulk/excess inside the freezer. Vacuum sealed bags are highly recommended. For people accessing alpha-GPC daily it is advisable to separate a month's supply from excess and storing the excess as best as possible. Vacuum sealing a large supply into many 1 month dividends is a method positively reported by many users. It is important to note that hygroscopy is not degradation and leaves the substance still usable, however, the ability to accurately weigh a dose is no longer possible as the substance being weighed will be a mixture of powder and water. Liquefied or gelled alpha-GPC may also be indicative of poor storage and thus have an increased likelihood of actual degradation.

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Answer 2

Adenine

Adenine

Adenine /ˈædᵻnᵻn/ (A, Ade) is a nucleobase (a purine derivative). Its derivatives have a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). It also has functions in protein synthesis and as a chemical component of DNA and RNA. The shape of adenine is complementary to either thymine in DNA or uracil in RNA.

The image on the right shows pure adenine, as an independent molecule. When connected into DNA, a covalent bond is formed between deoxyribose sugar and the bottom left nitrogen, so removing the hydrogen. The remaining structure is called an adenine residue, as part of a larger molecule. Adenosine is adenine reacted with ribose as used in RNA and ATP; deoxyadenosine adenine attached to deoxyribose, as is used to form DNA.

Adenine forms several tautomers, compounds that can be rapidly interconverted and are often considered equivalent. However, in isolated conditions, i.e. in an inert gas matrix and in the gas phase, mainly the 9H-adenine tautomer is found.

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Answer 3

Prenatal vitamins

Prenatal vitamins are vitamin and mineral supplements intended to be taken before and during pregnancy and during postnatal lactation. Although not intended to replace a healthy diet, prenatal vitamins provide women of child bearing age with nutrients recognized by the various health organizations including the American Dietetic Association as helpful for a healthy pregnancy outcome. It may be appropriate to start taking prenatal vitamins once the female enters childbearing age. Prenatal vitamins are similar to other multivitamins, but do contain different amounts of specific nutrients to better suit the needs of an expecting mother.

Vitamins and minerals such as folic acid, calcium and iron are in higher concentrations while nutrients such as vitamin A are reduced to reflect the current understanding of the role that these compounds play in fetal development.

The increased dosage of folic acid or folates reflects the American Dietetic Associations position that women should consume “400 μg per day of synthetic folic acid from fortified foods (cereals and other grains), supplements or both, in addition to consuming folate from foods in a varied diet.” Taking the appropriate amount of folic acid before conception can reduce or prevent the incidence of neural tube defects by as much as 70%. The recommendation to start folic acid before conception is supported by a meta-analysis of 41 studies, but is beneficial after conception as well Often prenatal vitamins also have a reduced dosage of vitamins that may be detrimental to the fetus when taken in high doses (such as vitamin A).

Many prenatal manufacturers have chosen to include the omega-3 fatty acid, docosahexaenoic acid (DHA) in their product, either as an ingredient in the formula, or as a complementary softgel. Although explicitly in many formulas to support neural development, the omega-3 fatty acids are used by both mother and fetus to create the phospholipid bilayer that makes up cell membranes.

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Answer 4

Anthranilic acid

Anthranilic acid

Anthranilic acid (o-amino-benzoic acid, 2-aminobenzoic acid, 2-AA, 2AA, AA) is an aromatic acid with the formula C₆H₄(NH₂)(CO₂H). The molecule consists of a substituted benzene ring, hence is classed as aromatic, with two adjacent, or "ortho-" functional groups, a carboxylic acid and an amine. The compound is consequently amphoteric. In appearance, anthranilic acid is a white solid when pure, although commercial samples may appear yellow. It is sometimes referred to as vitamin L₁ and has a sweetish taste. The anion [C₆H₄(NH₂)(CO₂)]^−, obtained by the deprotonation of anthranilic acid, is called anthranilate.

Although not usually referred to as such, it is an amino acid. Solid anthranilic acid consists of both the amino-carboxylic acid and the zwitterionic ammonium carboxylate forms.

Many routes to anthranilic acid have been described. Industrially it is produced from phthalic anhydride, beginning with amination:

The resulting sodium salt of phthalamic acid is decarbonylated via a Hofmann rearrangement of the amide group, induced by hypochlorite:

A related method involves treating phthalimide with sodium hypobromite in aqueous sodium hydroxide, followed by neutralization. In the era when indigo dye was obtained from plants, it was degraded to give anthranilic acid.

Anthranilic acid was first obtained by base-induced degradation of indigo.

Anthranilic acid is biosynthesized from chorismic acid. It is the precursor to the amino acid tryptophan via the attachment of phosphoribosyl pyrophosphate to the amine group.

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Answer 5

Bleach and recycle

The "bleach and recycle" process is used within the retina to ensure that the chromophore, 11-cis retinal, is present within opsin molecules in sufficient quantities to allow phototransduction to occur. It uses vitamin A (retinol) derivatives.

Vitamin A must be consumed in the diet, as it is not synthesisable by the body. It may, however, be consumed indirectly, in the form of carotenoids such as beta carotene, which can be cleaved to form two retinol molecules. It is absorbed in the gut and is transported around the body via two pathways. In the first, and most predominant, it is esterified with a fatty acid to form a retinyl ester, and packaged into a chylomicron. In the second minor pathway, it is bound to Retinol Binding Protein (RBP) and Transthyretin, which prevents its filtration in the glomeruli. It is via this RBP-Transthyretin pathway that the retina receives most of its retinoids.

As in transport via the RBP-Transthyretin pathway, retinoids must always be bound to chaperone molecules, for several reasons. Retinoids are toxic, insoluble in aqueous solutions, and prone to oxidation, and as such they must be bound and protected when within the body. The body uses a variety of chaperones, particularly in the retina, to transport retinoids.

When a photon of light is absorbed, 11-cis retinal is transformed to all-trans retinal, and it moves to the exit site of rhodopsin. It will not leave the opsin protein until another fresh chromophore comes to replace it, except for in the ABCR pathway. Whilst still bound to the opsin, all-trans retinal is transformed into all-trans retinol by all-trans Retinol Dehydrogenase. It then proceeds to the cell membrane of the rod, where it is chaperoned to the Retinal Pigment Epithelium (RPE) by Interphotoreceptor Retinoid Binding Protein (IRBP). It then enters the RPE cells, and is transferred to the Cellular Retinol Binding Protein (CRBP) chaperone.

When inside the RPE cell, bound to CRBP, the all-trans retinol is esterified by Lecithin Retinol Acyltransferase (LRAT) to form a retinyl ester. The retinyl esters of the RPE are chaperoned by a protein known as RPE65. It is in this form that the RPE stores most of its retinoids, as the RPE stores 2-3 times more retinoids than the neural retina itself. When further chromophore is required, the retinyl esters are acted on by isomerohydrolase to produce 11-cis retinol, which is transferred to the Cellular Retinaldehyde Binding Protein (CRALBP). 11-cis retinol is transformed into 11-cis retinal by 11-cis Retinol Dehydrogenase, then it is shipped back to the rod photoreceptors via IRBP. There, it replaces the spent chromophore in opsin molecules, allowing the opsin to function again as a light receptor.

Under some circumstances, the spent chromophore may leave the opsin molecule prior to its replacement, when it is bound to the ABCA4 protein (also known as ABCR), when it is also transformed to all-trans retinol, and then leaves the photoreceptor outer segment via the IRBP chaperone. It then follows the conventional pathway of recycling. It is from this pathway that the presence of opsin without a chromophore can be explained.

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Answer 6

Calcifediol

Calcifediol

Calcifediol (INN), also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D (abbreviated 25(OH)D), is a prehormone that is produced in the liver by hydroxylation of vitamin D₃ (cholecalciferol) by the enzyme cholecalciferol 25-hydroxylase which was isolated by Michael F. Holick. Physicians worldwide measure this metabolite to determine a patient's vitamin D status. At a typical daily intake of vitamin D3, its full conversion to calcifediol takes approximately 7 days.

Calcifediol is then converted in the kidneys (by the enzyme 25(OH)D-1α-hydroxylase) into calcitriol (1,25-(OH)₂D₃), a secosteroid hormone that is the active form of vitamin D. It can also be converted into 24-hydroxycalcidiol in the kidneys via 24-hydroxylation.

In medicine, a 25-hydroxy vitamin D (calcifediol) blood test is used to determine how much vitamin D is in the body. The blood concentration of calcifediol is considered the best indicator of vitamin D status.

This test can be used to diagnose vitamin D deficiency, and it is indicated in patients with high risk for vitamin D deficiency and when the results of the test would be used as supporting evidence for beginning aggressive therapies. Patients with osteoporosis, chronic kidney disease, malabsorption, obesity, and some other infections may be high risk and thus have greater indication for this test. Although vitamin D deficiency is common in some populations including those living at higher latitudes or with limited sun exposure, the 25(OH)D test is not indicated for entire populations. Physicians may advise low risk patients to take over-the-counter vitamin D in place of having screening.

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Answer 7

Carotene

The term carotene (also carotin, from the Latin carota, "carrot") is used for many related unsaturated hydrocarbon substances having the formula C₄₀H_x, which are synthesized by plants but in general cannot be made by animals (with the exception of some aphids and spider mites which acquired the synthetic genes from fungi). Carotenes are photosynthetic pigments important for photosynthesis. Carotenes contain no oxygen atoms. They absorb ultraviolet, violet, and blue light and scatter orange or red light, and (in low concentrations) yellow light.

Carotenes are responsible for the orange colour of the carrot, for which this class of chemicals is named, and for the colours of many other fruits, vegetables and fungi (for example, sweet potatoes, chanterelle and orange cantaloupe melon). Carotenes are also responsible for the orange (but not all of the yellow) colours in dry foliage. They also (in lower concentrations) impart the yellow coloration to milk-fat and butter. Omnivorous animal species which are relatively poor converters of coloured dietary carotenoids to colourless retinoids have yellowed-coloured body fat, as a result of the carotenoid retention from the vegetable portion of their diet. The typical yellow-coloured fat of humans and chickens is a result of fat storage of carotenes from their diets.

Carotenes contribute to photosynthesis by transmitting the light energy they absorb to chlorophyll. They also protect plant tissues by helping to absorb the energy from singlet oxygen, an excited form of the oxygen molecule O₂ which is formed during photosynthesis.

β-Carotene is composed of two retinyl groups, and is broken down in the mucosa of the human small intestine by β-carotene 15,15'-monooxygenase to retinal, a form of vitamin A. β-Carotene can be stored in the liver and body fat and converted to retinal as needed, thus making it a form of vitamin A for humans and some other mammals. The carotenes α-carotene and γ-carotene, due to their single retinyl group (β-ionone ring), also have some vitamin A activity (though less than β-carotene), as does the xanthophyll carotenoid β-cryptoxanthin. All other carotenoids, including lycopene, have no beta-ring and thus no vitamin A activity (although they may have antioxidant activity and thus biological activity in other ways).

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Answer 8

Beta-Carotene

β-Carotene

β-Carotene is an organic, strongly colored red-orange pigment abundant in plants and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons. Among the carotenes, β-carotene is distinguished by having beta-rings at both ends of the molecule. β-Carotene is biosynthesized from geranylgeranyl pyrophosphate.

β-Carotene is the most common form of carotene in plants. When used as a food coloring, it has the E number E160a. The structure was deduced by Karrer et al. in 1930. In nature, β-carotene is a precursor (inactive form) to vitamin A via the action of beta-carotene 15,15'-monooxygenase.

Isolation of β-carotene from fruits abundant in carotenoids is commonly done using column chromatography. It can also be extracted from the beta-carotene rich algae, Dunaliella salina. The separation of β-carotene from the mixture of other carotenoids is based on the polarity of a compound. β-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is very lipophilic.

Plant carotenoids are the primary dietary source of provitamin A worldwide, with β-carotene as the most well-known provitamin A carotenoid. Others include α-carotene and β-cryptoxanthin. Carotenoid absorption is restricted to the duodenum of the small intestine and dependent on class B scavenger receptor (SR-B1) membrane protein, which are also responsible for the absorption of vitamin E (α-tocopherol). One molecule of β-carotene can be cleaved by the intestinal enzyme β,β-carotene 15,15'-monooxygenase into two molecules of vitamin A.

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Answer 9

Cerefolin

Cerefolin is a prescription medication made by Pamlab that contains 5.635 mg of folate as L-methylfolate, 1 mg of vitamin B₁₂ as methylcobalamin, 50 mg of vitamin B₂ as riboflavin, and 5 mg of vitamin B₆ as pyridoxine. It is approved by the U.S. Food and Drug Administration for the treatment or prevention of vitamin deficiencies.

"Cerefolin NAC" contains L-methylfolate (as Metafolin) 5.6 mg, methylcobalamin 2 mg, N-acetylcysteine 600 mg.

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Answer 10

Choline

Choline

Choline (/ˈkoʊliːn/) is a water-soluble vitamin. The term cholines refers to the class of quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation (X^− on the right denotes an undefined counteranion).

The cation appears in the head groups of phosphatidylcholine and sphingomyelin, two classes of phospholipid that are abundant in cell membranes. Choline is the precursor molecule for the neurotransmitter acetylcholine, which is involved in many functions including memory and muscle control.

Some animals cannot produce choline, but must consume it through their diet to remain healthy. Humans make choline in the liver. Whether dietary or supplemental choline is beneficial or harmful to humans is undefined. Possible dangers include increased risk of cardiovascular disease and cancer, while possible benefits include reducing the risk of neural tube defects and fatty liver disease.

According to the US Institute of Medicine, there is not enough evidence to establish a Recommended Daily Intake for choline. The Australian and New Zealand national nutrition bodies note that while deficiency has been seen during experiments, there have been no reports of choline deficiency in the general population. All three have published an "Adequate Intake" value, discussed below. The European Union's food safety authority says there are no Recommended Daily Intakes in the EU and "no indications of inadequate choline intakes available in the EU".

Methionine and folate are known to interact with choline while homocysteine is undergoing methylation to produce methionine. Recent studies have shown that choline deficiency may have adverse effects, even when sufficient amounts of methionine and folate are present.

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