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Soluble Vitamins

Description of Method. The water-soluble vitamins Bi (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and Be (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodlum dIhydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecyl-sulfate. Detection Is by UV absorption at 200 nm. An Internal standard of o-ethoxybenzamide Is used to standardize the method. [Pg.607]

Reported cases of vitamin toxicity owing to overdose are usually associated with increased over-the-counter availabiHty of supplemental vitamins and indiscriminate supplementation. The misconception that if a Httle is good a lot is better has compounded toxicological problems with the vitamins. Eat-soluble vitamins tend to accumulate in the body with relatively inactive mechanism for excretion and cause greater toxicological difficulties than do water-soluble vitamins. [Pg.479]

Of the water-soluble vitamins, intakes of nicotinic acid [59-67-6] on the order of 10 to 30 times the recommended daily allowance (RE)A) have been shown to cause flushing, headache, nausea, and moderate lowering of semm cholesterol with concurrent increases in semm glucose. Toxic levels of foHc acid [59-30-3] are ca 20 mg/d in infants, and probably approach 400 mg/d in adults. The body seems able to tolerate very large intakes of ascorbic acid [50-81-7] (vitamin C) without iH effect, but levels in excess of 9 g/d have been reported to cause increases in urinary oxaHc acid excretion. Urinary and blood uric acid also rise as a result of high intakes of ascorbic acid, and these factors may increase the tendency for formation of kidney or bladder stones. AH other water-soluble vitamins possess an even wider margin of safety and present no practical problem (82). [Pg.479]

Bde salts, cholesterol, phosphoHpids, and other minor components are secreted by the Hver. Bile salts serve three significant physiological functions. The hydrophilic carboxylate group, which is attached via an alkyl chain to the hydrophobic steroid skeleton, allows the bile salts to form water-soluble micelles with cholesterol and phosphoHpids in the bile. These micelles assist in the solvation of cholesterol. By solvating cholesterol, bile salts contribute to the homeostatic regulation of the amount of cholesterol in the whole body. Bile salts are also necessary for the intestinal absorption of dietary fats and fat-soluble vitamins (24—26). [Pg.415]

A commercially interesting low calorie fat has been produced from sucrose. Proctor Gamble has patented a mixture of penta- to octafatty acid ester derivatives of sucrose under the brand name Olestra. It was approved by the FDA in January 1996 for use as up to 100% replacement for the oil used in preparing savory snacks and biscuits. Olestra, a viscous, bland-tasting Hquid insoluble in water, has an appearance and color similar to refined edible vegetable oils. It is basically inert from a toxicity point of view as it is not metabolized or absorbed. It absorbs cholesterol (low density Hpoprotein) and removes certain fat-soluble vitamins (A, D, E, and K). Hence, Olestra has to be supplemented with these vitamins. No standard LD q tests have been performed on Olestra however, several chronic and subchronic studies were performed at levels of 15% in the diet, and no evidence of toxicity was found. No threshold limit value (TLV), expressed as a maximum exposure per m of air, has been estabhshed, but it is estimated to be similar to that of an inert hpid material at 5 mg/m. ... [Pg.33]

A major pharmaceutical use of poly(oxyethylene) sorbitan fatty acid esters is in the solubilization of the oil-soluble vitamins A and D. In this way, multivitamin preparations can be made which combine both water- and oil-soluble vitamins in a palatable form. [Pg.54]

Vitamins are classified by their solubiUty characteristics iato fat-soluble and water-soluble groups. The fat-soluble vitamins A, E, and K result from the isoprenoid biosynthetic pathway. Vitamin A is derived by enzymic cleavage of the symmetrical C q beta-carotene, also known as pro-vitamin A. Vitamins E and K result from condensations of phytyldiphosphate (C2q) with aromatic components derived from shikimic acid. Vitamin D results from photochemical ring opening of 7-dehydrocholesterol, itself derived from squalene (C q). [Pg.5]

Along with increasing evidence of health benefits from consumption of vitamins at levels much higher than RE) A recommendations comes concern over potential toxicity. This topic has been reviewed (19). Like all chemical substances, a toxic level does exist for each vitarnin. Traditionally it has been assumed that all water-soluble vitamins are safe at any level of intake and all fat-soluble vitamins are toxic, especially at intakes more than 10 times the recommended allowances. These assumptions are now known to be incorrect. Very high doses of some water-soluble vitamins, especially niacin and vitamin B, are associated with adverse effects. In contrast, evidence indicates that some fat-soluble micronutrients, especially vitamin E, are safe at doses many times higher than recommended levels of intake. Chronic intakes above the RDA for vitamins A and D especially are to be avoided, however. [Pg.8]

Brewers and bakers dried yeasts are used as dietary supplements. They contribute some protein and trace minerals, and some B vitamins, but no vitamin C, vitamin B 2 or fat-soluble vitamins. The glucose tolerance factor (GTE) of yeast, chromium nicotinate, mediates the effect of insulin. It seems to be important for older persons who caimot synthesize GTE from inorganic dietary chromium. The ceU wall fraction of bakers yeast reduces cholesterol levels in rats fed a hypercholesteremic diet. [Pg.393]

Ascorbic acid commonly known as vitamin C, is one of the most important water soluble vitamins. Ascorbic acid is involved in many biological processes and it is an essential compound in the human diet [1]. The determination of ascorbic acid has gained increase significance in pharmaceutic, clinical, and food applications. So far, different methods have been developed for determination of ascorbic acid [2, 3]. [Pg.154]

In studies in Denmark in the 1920s, Henrik Dam noticed that chicks fed a diet extracted with nonpolar solvents developed hemorrhages. Moreover, blood taken from such animals clotted slowly. Further studies by Dam led him to conclude in 1935 that the antihemorrhage factor was a new fat-soluble vitamin, which he called vitamin K (from koagulering, the Danish word for coagulation ). [Pg.607]

Gel permeation ehromatography (GPC)/normal-phase HPLC was used by Brown-Thomas et al. (35) to determine fat-soluble vitamins in standard referenee material (SRM) samples of a fortified eoeonut oil (SRM 1563) and a eod liver oil (SRM 1588). The on-line GPC/normal-phase proeedure eliminated the long and laborious extraetion proeedure of isolating vitamins from the oil matrix. In faet, the GPC step permits the elimination of the lipid materials prior to the HPLC analysis. The HPLC eolumns used for the vitamin determinations were a 10 p.m polystyrene/divinylbenzene gel eolumn and a semipreparative aminoeyano eolumn, with hexane, methylene ehloride and methyl tert-butyl ether being employed as solvent. [Pg.232]

Figure 10.9 Cliromatogi ams of foitified coconut oil obtained by using (a) normal-phase HPLC and (b) GPC/noimal-phase HPLC. Peak identification is as follows 1 (a,b), DL-a-toco-pheryl acetate, 2 (b), 2,6-di-tert-butyl-4-methylphenol 2 (a) and 3 (b), retinyl acetate 3 (a) and 4 (b), tocol 4 (a) and 5 (b), ergocalciferol. Reprinted from Analytical Chemistry, 60, J. M. Brown-Thomas et al., Determination of fat-soluble vitamins in oil matrices by multidimensional liigh-peiformance liquid cliromatography , pp. 1929-1933, copyright 1988, with permission from the American Chemical Society. Figure 10.9 Cliromatogi ams of foitified coconut oil obtained by using (a) normal-phase HPLC and (b) GPC/noimal-phase HPLC. Peak identification is as follows 1 (a,b), DL-a-toco-pheryl acetate, 2 (b), 2,6-di-tert-butyl-4-methylphenol 2 (a) and 3 (b), retinyl acetate 3 (a) and 4 (b), tocol 4 (a) and 5 (b), ergocalciferol. Reprinted from Analytical Chemistry, 60, J. M. Brown-Thomas et al., Determination of fat-soluble vitamins in oil matrices by multidimensional liigh-peiformance liquid cliromatography , pp. 1929-1933, copyright 1988, with permission from the American Chemical Society.
Selected applications of coupled SEE-SEC consider the analysis of tocopherols in plants and oil by-products (65) or the analysis of lipid-soluble vitamins (66) by using a dynamic on-line SEE-SEC coupling, integrated in the SE chromatograph, based on the use of micropacked columns. [Pg.241]

K. Johansen and P. O. Edlund, Determination of water-soluble vitamins in blood and plasma by coupled-column liquid clrromatography , 7. Chromatogr. 506 471-479 (1990). [Pg.295]

High-pressure pumps operating at up to 6000 psi are required to force solvent through a tightly packed HPLC column, and electronic detectors are used to monitor the appearance of material eluting from the column. Alternatively, the column can be interfaced to a mass spectrometer to determine the mass spectrum of every substance as it elutes. Figure 12.18 shows the results of HPLC analysis of a mixture of 10 fat-soluble vitamins on 5 jam silica spheres with acetonitrile as solvent. [Pg.432]

Figure 12.18 Results of an HPLC analysis of a mixture often fat-soluble vitamins. Figure 12.18 Results of an HPLC analysis of a mixture often fat-soluble vitamins.
In vitro and ex vivo studies have shown that FATPs transport LCFAs and very long-chain fatty acids (VLCFAs) but no medium-chain fatty acids, fatty acid esters, or lipid-soluble vitamins [4]. LCFA transport is inhibited by prior protease treatment. Synthetic substrates for FATPs include 14C-labeled fatty acids and the fluorescently labeled fatty acid analogue C1 -BODEP Y-Cl 2. Using the latter substrate, differences in fatty acid uptake kinetics between FATP expressing 3T3 LI adipocytes and 3T3 LI fibroblasts, which are devoid of FATPs, can be readily appreciated (Fig. 2). [Pg.496]

Although vitamin K is a fat soluble vitamin, only little stores are found in the body which have to be refilled permanently via dietary input. The role of vitamin K derived from bacteria in the colon is controversely discussed, as the concentration of biliary acids for the resorption the fatsoluble vitamin K is very low in the colon. In addition, only diseases of the small intestine lead to a deficit in vitamin K concentration which cannot be restored by K2 production of colonic bacteria. However, watersoluble vitamin Ks can be resorbed by the colonic mucosa. Maybe because of the little stores for vitamin K, the process of vitamin K-dependent carboxylation of proteins is part of a cycle with several steps during which vitamin K normally is regenerated (see Fig. 1) and thus can be used several times. [Pg.1298]

Bile acid sequestrants may interfere with die digestion of fats and prevent die absorption of die fat-soluble vitamins (vitamins A, D, E, and K) and folic acid. When die bile acid sequestrants are used for long-term therapy, vitamins A and D may be given in a water-soluble form or administered parenterally. If bleedingtendencies occur as die result of vitamin K deficiency, parenteral vitamin K is administered for immediate treatment, and oral vitamin K is given for prevention of a deficiency in the futum... [Pg.413]

Because Olestra is not digested, it behaves much like mineral oil. The laxative properties, which are widely discussed, appear on the label. Like other indigestible lipids, Olestra can dissolve fat-soluble vitamins and carotenoids, which makes them unavailable for absorption. [Pg.96]

The molecules in Olestra have been modified since it was first marketed, to avoid some of the more unpopular side effects, but some remain. Adding carotenoids and fat-soluble vitamins to the product has also been done, but this does not eliminate all of the problems with nutrient absorption. [Pg.96]

Salatrim is a mixture of many triglycerides that have the characteristics mentioned above. Because it is partially absorbed, Salatrim does not have the problems associated with Olestra. It does not have any laxative effects nor does it prevent the absorption of fat-soluble vitamins and carotenoids. [Pg.97]

Gliszczyhska-Swigl, A. (2006). Antioxidant activity of water soluble vitamins in the TEAC (trolox equivalent antioxidant capacity) and the FRAP (ferric reducing antioxidant power) assays. Food Chemistry, Vol.96, No.l, (May 2006), pp. 131-136, ISSN 0308-8146. [Pg.21]

Precursor and derived lipids These include fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, and ketone bodies (Chapter 22), hydrocarbons, hpid-soluble vitamins, and hormones. [Pg.111]

Hypolipoproteinemias Abetaiipoproteinemia No chylomicrons, VLDL, or LDL are formed because of defect in the loading of apo B with lipid. Rare blood acylglycerols low intestine and liver accumulate acylglycerols. Intestinal malabsorption. Early death avoidable by administration of large doses of fat-soluble vitamins, particularly vitamin E. [Pg.228]

The major lipids in the diet are triacylglycerols and, to a lesser extent, phospholipids. These are hydrophobic molecules and must be hydrolyzed and emulsified to very small droplets (micelles) before they can be absorbed. The fat-soluble vitamins— A, D, E, and K— and a variety of other lipids (including cholesterol) are absorbed dissolved in the lipid micelles. Absorption of the fat-soluble vitamins is impaired on a very low fat diet. [Pg.475]


See other pages where Soluble Vitamins is mentioned: [Pg.422]    [Pg.213]    [Pg.153]    [Pg.377]    [Pg.5]    [Pg.5]    [Pg.28]    [Pg.41]    [Pg.56]    [Pg.311]    [Pg.282]    [Pg.586]    [Pg.603]    [Pg.247]    [Pg.161]    [Pg.256]    [Pg.257]    [Pg.1160]    [Pg.1295]    [Pg.1298]    [Pg.476]    [Pg.253]    [Pg.111]    [Pg.118]   


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