Vitamin plasma

The most recent RDA has included a vitamin C recommendation of 100 mg/day for cigarette smokers. An increasing number of investigators have concluded that the current RDA for vitamin C may not be adequate for elderly individuals. Plasma vitamin C level is generally accepted as an indicator of vitamin C status. 

Transport. Transcobalamin II dehvers the absorbed vitamin 3 2 to cells and is the primary plasma vitamin B22-binding transport protein. It is found in plasma, spinal fluid, semen, and extracellular fluid. Many cells, including the bone marrow, reticulocytes, and the placenta, contain surface receptor sites for the transcobalamin II—cobalamin complex. 

Other plasma vitamin B 2 proteins, transcobalamines I and III, appear to have primarily a storage function and only a lesser role in transport. 

Vitamin D withdrawal is an obvious treatment for D toxicity (219). However, because of the 5—7 d half-life of plasma vitamin D and 20—30 d half-life of 25-hydroxy vitamin D, it may not be immediately successful. A prompt reduction in dietary calcium is also indicated to reduce hypercalcemia. Sodium phytate can aid in reducing intestinal calcium transport. Calcitonin glucagon and glucocorticoid therapy have also been reported to reduce semm calcium resulting from D intoxication (210). 

Gey, K.F., Puska, J.M., Jordan, P. and Moser, U.K. (1991). Inverse correlation between plasma vitamin E and mortality from ischaemic heart disease in cross-cultural epidemiology. Am. J. CUn. Nutr. 53, 3265-3345. 

Epidemiological studies in Europe reveal an inverse relationship between plasma vitamin E levels and the incidence of ischaemic heart disease (Gey and Puska 1989), and the risk of angina pectoris appears to increase with low plasma levels of vitamins E, A and C (Rie-mersma et al., 1991). These interesting observations require further population-based controlled intervention trials with specific supplements of antioxidant vitamins (Gey etal., 1991). 

Gey, K.F. and Puska, P. (1989). Plasma vitamins E and A inversely related to mortality from ischaemic heart disease in cross-cultural epidemiolc. Ann N. York Acad. Sci. 570, 268-282. 

Sanchez-Moreno C, Cano MP, De Ancos B, Plaza L, Olmedilla B, Granado F, Elez-Martinez P, Martin-Belloso O and Martin A. 2004a. Pulsed electric fields-processed orange juice consumption increases plasma vitamin C and decreases F2-isoprostanes in healthy humans. J Nutr Biochem 15(10) 601—... 

Calcium/Vitamin Bq Low serum calcium and low plasma vitamin 85 levels were... 

In summary, our bioavailability study provided for fhe firsf time data for fhe shorf-ferm bioavailability of ot-tocopherol solubilizate in comparison to regular fat-soluble preparations. Our results pointed to a higher short-term bioavailability of vitamin E in micelles versus fat-soluble forms of fhis vifamin in healthy adult volunteers both with regard to AUCs and with regard to maximum increases in plasma vitamin concentrations. 

Vitamin A absorption from the small intestine requires dietary fat and pancreatic lipase to break down retinyl esters and bile salts to promote the uptake of retinol and carotene. Drugs, such as mineral oil, neomycin and cholestyramine, that can modify lipid absorption from the gastrointestinal tract can impair vitamin A absorption. The use of oral contraceptives can signihcantly increase plasma vitamin A levels. 

Alterations in plasma vitamin concentrations have been observed in oral contraceptive users, and attributed to reduced absorption and changes in plasma protein-binding capacity (177). 

A 73-year-old woman taking metformin 1000 mg bd and warfarin 5 mg/day developed epistaxis, hematuria, gingival bleeding, a retroperitoneal hematoma, and bilateral perinephric blood with obstruction of both collecting systems (152). She received fresh frozen plasma, vitamin K, 10 mg, and packed erythrocytes. In the next 8 hours she developed a metabolic acidosis... 

FIGURE 11.8 Plasma Vitamin E concentration after oral administration of a Vitamin E solid dispersion. Key ( ) PEG-32 glyceryl laureate (Gelucffe44/14) solid dispersion and commercial product. (Adapted from Barker, S.A., Yap, S.P., Yuen, K.H., McCoy, C.P., Murphy, J.R., and Craig, D.Q.M. (2DGQ>ntrol. Rel., 91 477-488.)... 

There are many types of preparations that contain retinol. Absorption is greatest for aqueous preparations, intermediate for emulsions, and slowest for oil solutions. Whereas oil-soluble preparations may lead to greater hepatic storage of the vitamin, water-miscible preparations usually provide higher concentrations in plasma. Vitamin A is available as capsules. Tretinoin (all-trans-retinoic acid Retin A) is available for topical use. Isotretinoin (13-ri.s-retinoic acid Accutane) is available for oral use, as is etretinate (Tegison). 

Traber, M.G. 1997. Regulation ofhuman plasma vitamin E. Adv. Pharmacol. 38 49-63. 

Fyfe (F10) has investigated plasma vitamin A levels. He observed that the fasting levels in infants with idiopathic hypercalcemia were higher than in the normal and that after a large oral dose of vitamin A,... 

Fyfe (F10), too, in showing that the fasting plasma vitamin A levels and the levels 4 hours after a standard dose of vitamin A are significantly higher in idiopathic hypercalcemia than in the normal, has adduced this... 

Chronic malabsorption does not fully explain the different extents of fat-soluble vitamin deficiencies associated with ABL. More specifically, why are plasma vitamin E levels more severely affected than those of vitamins A or K The answer for this can be traced to apoB lipoprotein biosynthesis and catabolism (Fig. 27-2). Just as observed for lipids, hydrophobic, fat-soluble vitamins require apoB lipoproteins as vehicles for plasma transport. The reliance of each fat-soluble vitamin on apoB lipoproteins varies, and this variable dependency is directly related to the severity of symptoms observed in ABL. 

IU/day by the oral route with routine blood work to monitor plasma levels. Toxicity due to excess vitamin A is not common but is potentially fatal. Acute toxicity presents as vertigo, diplopia, seizures, and exfoliative dermatitis. Chronic toxicity manifests very differently (i.e., dry skin, alopecia, amenorrhea, symptoms of liver fibrosis, etc.). It is imperative to monitor plasma vitamin A levels regularly, especially in the setting of the large doses required to treat ABL. 

TCII is a 50,000-d p-globulin synthesized in the ileum and the liver. It is the transport protein for recendy absorbed vitamin B12. About 20% of the plasma vitamin B12 is bound to TCII the remainder of the vitamin B12 in plasma is transported by TCI and TCIII, primarily in the form of 5-methylcobalamin. Normal serum contains 0.7-1.5 nmol/L of TCII, which is capable of binding 600-1300 ng of vitamin B12 however, only about 15% of its binding capacity is used at any one time. Unlike TCI and TCIII, the... 

Several extensive human epidemiologic studies have also been published. For example, two U.S. studies, one involving 87,245 female nurses (S23) and the other 38,910 male physicians (R5), both concluded that vitamin E supplementation was directly associated with reduced risk for ischemic heart disease. In addition, Gey and associates (G6) reported on a large cross-cultural European population which differed sixfold in age-specific mortality from CAD. The data supported their conclusions that this highly significant difference in CAD was primarily due to increased plasma vitamin E levels in those with a relatively low incidence of... 

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