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PubMed2000

[Effects of biologically active food additives with different contents of vitamins on the vitamin status in humans].

The comparative study of influence of two biologically active food additives with the different contents of vitamins is carried out: a drink "Zolotoi Shar", the dose of vitamins in which makes 50-90% from recommended daily consumption, and "Vitabalance 2000", the contents of vitamins in which at 2-17 of time exceeds need of organism. The use of both additives within 3 weeks resulted in increase of levels of vitamins C, A, E, B2, B6 and carotenoids in blood serum. However if in case of consumption of a drink an authentic level was reached only for vitamin C and beta-carotene, in a case "Vitabalance 2000" for all investigated vitamins except vitamin A. Thus, if the consumption of a drink has lowered frequency of deficiency of 3-4 vitamins, but has not allowed to liquidate it completely, in case of "Vitabalance 2000" consumption the simultaneous deficiency 3-4 vitamins. The received data allow to believe the biologically active food additives containing vitamins in amounts exceeding recommended consumption, are convenient for fast liquidation of hypovitaminoses, and the preparations containing vitamins in doses making 30-50% from need of organism, are acceptable for daily filling of insufficient consumption of vitamins with a usual diet for a long time.

Adenine↗
PubMed1991

Modification of hepatic vitamin E stores in vivo. I. Alterations in plasma and liver vitamin E content by methyl ethyl ketone peroxide.

Since experiments with freshly isolated rat hepatocytes have shown that cellular vitamin E is consumed in response to insult by compounds that induce an oxidative stress only after cellular glutathione (GSH) concentrations have been substantially depleted, experiments were performed to determine whether this sequence of events occurred in response to oxidative insult in vivo. The role that plasma vitamin E plays in the response to chemically induced oxidative injury in vivo was also assessed. Treatments with 40 mg/kg of methyl ethyl ketone peroxide (MEKP) quickly induced lipid peroxidation in vivo and from one to 4 h after treatment caused a depression in the plasma content of vitamin E and the liver content of GSH, as well as signs of toxicity (elevations in serum activities of alanine and aspartate aminotransferases). At these time points however, the liver content of vitamin E was either indistinguishable from or slightly elevated from controls. By 12 to 24 h after treatment the liver content of vitamin E was reduced by 20-25% whereas values for all other indicators had returned toward control levels. Pretreatment of rats with L-buthionine-S,R-sulfoximine, an inhibitor of GSH by 4 or 24 h after treatment, did not alter the time course or extent of hepatic vitamin E depletion that was observed after treatment with MEKP. Other compounds that induce oxidative stress and lipid peroxidation to the liver, carbon tetrachloride and menadione, did not provoke an alteration in hepatic vitamin E levels as compared to controls 1 day after treatment. These findings indicate that depletion of hepatic vitamin E may not occur as an immediate consequence of oxidative insult to the liver and that the depletion of hepatic vitamin E levels may not be related to the extent of prior GSH depletion. Moreover, these findings suggest that alterations in the plasma concentration of vitamin E may not reflect concurrent alterations in hepatic vitamin E levels. A mechanism whereby liver vitamin E stores are mobilized for the maintenance of plasma vitamin E levels is proposed.

Alanine Transaminase↗
PubMed1989

Effects of a vitamin-A-free diet on tissue vitamin A concentration and dark adaptation of aging rats.

Changes in serum, hepatic, and ocular vitamin A levels were followed in 9-month-old Long Evans rats fed either a vitamin-A-free or vitamin-A-sufficient diet for up to 18 months. After 18 months, hepatic total vitamin A fell exponentially from 2542 +/- 433 to 48 +/- 12 micrograms/g wet weight, but these stores maintained normal serum retinol and ocular total vitamin A concentrations in vitamin-A-deprived rats. However, retinal dark-adaptation time, a functional indicator of photoreceptor integrity, was prolonged in elderly vitamin-A-deprived rats as compared to vitamin-A-sufficient controls (p less than 0.05). Aging appeared to be the most important factor that depressed the rate of dark adaptation, with vitamin A status having a secondary effect. The proportion of total ocular retinaldehyde decreased (p less than 0.05) and the concentration of retinyl ester increased (p less than 0.05) in the eyes of 27-month-old vitamin-A-deprived rats compared to age-matched vitamin-A-sufficient animals. Possible mechanisms of visual dysfunction include abnormal retinal rhodopsin recycling caused by a dependence on newly absorbed dietary vitamin A (e.g., chylomicron). Alternatively, in the vitamin-A-deprived rat, decreased hepatic oxidation of pentobarbital (used for electroretinographic anesthesia) could prolong retinal anesthetic exposure and either directly depress neural transmission or indirectly alter transmission by affecting rhodopsin recycling.

Aging↗
PubMed1999

Maternal vitamin A nutriture and the vitamin A content of human milk.

Because of the many functions of vitamin A in human physiology, deficiency or excess of the vitamin in lactating women or their infants can adversely affect their health. Infants are born with low body stores of vitamin A, and rely on vitamin A in milk to meet their needs. The vitamin A content of milk is related to maternal vitamin A status and maternal dietary vitamin A intake during lactation. Low-income lactating women in non-industrialized countries have lower milk vitamin A concentrations than lactating women in industrialized countries. Supplementation of lactating women in non-industrialized countries with vitamin A or beta-carotene has resulted in increased milk vitamin A concentrations. However, the optimal timing and dose for sustaining adequate levels of vitamin A in milk throughout the lactation period has not been determined. Further research is needed to understand factors affecting the transfer of vitamin A to milk, and to evaluate various strategies for improving the vitamin A status of mothers and infants.

Breast Feeding↗
PubMed2000

Vitamin A in blood plasma and urine of dogs is affected by the dietary level of vitamin A.

Dogs differ from other species with respect to the occurrence of a high percentage of retinyl esters in blood plasma and the excretion of substantial amounts of vitamin A in the urine. Our investigation focussed on the effects of different concentrations of vitamin A in the diet, ranging from concentrations below NRC requirements of 25 IU/kg body weight (BW) to 2400 IU/kg BW, on the levels of retinol and retinyl esters (palmitate/oleate and stearate) in canine blood plasma and urine. The plasma levels of retinyl esters paralleled the levels of vitamin A in the feed (r = 0.91; p < 0.001). The highest plasma level (12.1 +/- 0.4 mg/l) was observed at the highest level in the diet. This observation may be explained by the fact that in dogs retinyl esters are associated with lipoproteins. Even under prolonged feeding on vitamin A levels below NRC requirements, retinyl esters were still present in the plasma (2.8 +/- 0.1 mg/l). Levels of retinol were not affected (1.2 +/- 0.03 vs. 1.0 +/- 0.03 mg/l, respectively). In the urine, the concentration of retinol and retinyl palmitate/oleate increased with the first increase of vitamin A in the diet to 1.2 +/- 0.4 mg/l of total vitamin A. Urinary levels were elevated and fluctuated with up to four peaks while dietary vitamin A levels were above NRC requirements. But the amount of retinol and retinyl esters excreted did not show any dependence on the amount of vitamin A in the diet. When the amount of vitamin A in the diet was at or below requirements, only traces of retinol and retinyl esters were detected in urine. Thus, contrary to current knowledge for most other mammals, retinyl ester levels in plasma and retinol and retinyl esters in the urine of dogs proved to be clearly but differently affected by the amount of vitamin A supplied with the diet. Contrary to retinol, plasma levels of retinyl esters closely reflect the actual supply of vitamin A with the feed. The occurrence of retinol and retinyl esters in urine may, however, be due to dietary supply of vitamin A in excess of standard requirements, thereby providing a useful indicator of a dietary supply of vitamin A above requirement. The mechanism involved in the possible regulation of urinary excretion of retinol and retinyl esters remains to be elucidated.

Animal Feed↗
PubMed2000

Effect of vitamin K2 on osteoblast apoptosis: vitamin K2 inhibits apoptotic cell death of human osteoblasts induced by Fas, proteasome inhibitor, etoposide, and staurosporine.

Vitamin K2 is used for the treatment of osteoporosis, but the precise mode of action is still not clear. We investigated the effects of vitamin K2 on apoptosis of human osteoblasts. Human osteoblastic cell line MG63 cells and human primary osteoblast-like cells obtained from bone fragments in corrective surgery were used as human osteoblasts. Cells were cultured with or without various concentrations of vitamin K2 and tumor necrosis factor-alpha (TNF-alpha). We then determined the proliferative response, expression of Fas and Bcl-2-related proteins, and Fas-mediated apoptosis of these cells induced by anti-Fas immunoglobulin M (IgM). In addition, the effect of vitamin K2 in osteoblast apoptosis induced by Z-Leu-Leu-Leu-aldehyde (LLL-CHO), etoposide, or staurosporine was also examined. Human osteoblasts did not show spontaneous apoptosis in culture, even in the presence of vitamin K2 or TNF-alpha. Furthermore, proliferation of the cells was not influenced by vitamin K2 or TNF-alpha. Fas was functionally expressed on human osteoblasts, and the treatment with TNF-alpha significantly enhanced both Fas expression and Fas-mediated apoptosis of osteoblasts. The addition of vitamin K2 to the culture resulted in a dose-dependent inhibition of functional Fas expression on osteoblasts, in the presence or absence of TNF-alpha. Treatment of human osteoblasts with vitamin K2 clearly suppressed Bax expression of the cells, although the expression of Bcl-2 was not influenced by vitamin K2. Fas ligand (FasL) cDNA transformants were cytotoxic against osteoblasts, and the cytotoxicity was increased when osteoblasts were treated with TNF-alpha. The addition of vitamin K2 to osteoblasts significantly decreased the cytotoxic effects of FasL cDNA transformants. Furthermore, apoptosis of human osteoblasts induced by LLL-CHO, etoposide, or staurosporine was also clearly suppressed in vitamin K2-treated osteoblasts. Our results suggest that vitamin K2 inhibits apoptotic cell death of osteoblasts and maintains the number of osteoblasts. These actions may explain the therapeutic efficacy of vitamin K2 in osteoporosis.

Apoptosis↗
PubMed2001

Supplementation with vitamin E but not with vitamin C lowers lipid peroxidation in vivo in mildly hypercholesterolemic men.

Although the use of vitamin E supplements has been associated with a reduction in coronary events, assumed to be due to lowered lipid peroxidation, there are no previous long-term clinical trials into the effects of vitamin C or E supplementation on lipid peroxidation in vivo. Here, we have studied the long-term effects of vitamins C and E on plasma F2-isoprostanes, a widely used marker of lipid peroxidation in vivo. As a study cohort, a subset of the "Antioxidant Supplementation in Atherosclerosis Prevention" (ASAP) study was used. ASAP is a double-masked placebo-controlled randomized clinical trial to study the long-term effect of vitamin C (500 mg of slow release ascorbate daily), vitamin E (200 mg of D-alpha-tocopheryl acetate daily), both vitamins (CellaVie), or placebo on lipid peroxidation, atherosclerotic progression, blood pressure and myocardial infarction (n = 520 at baseline). Lipid peroxidation measurements were carried out in 100 consecutive men at entry and repeated at 12 months. The plasma F2-isoprostane concentration was lowered by 17.3% (95% CI 3.9-30.8%) in the vitamin E group (p = 0.006 for the change, as compared with the placebo group). On the contrary, vitamin C had no significant effect on plasma F2-isoprostanes as compared with the placebo group. There was also no interaction in the effect between these vitamins. In conclusion, long-term oral supplementation of clinically healthy, but hypercholesterolemic men, who have normal vitamin C and E levels with a reasonable dose of vitamin E lowers lipid peroxidation in vivo, but a relatively high dose of vitamin C does not. This observation may provide a mechanism for the observed ability of vitamin E supplements to prevent atherosclerosis.

Aged↗
PubMedDate not supplied

[The vitamin A requirement and the vitamin A status of growing cattle. 2. Studies of fattening cattle].

Three long time individual feeding experiments (greater than 258 days) with 48 beef cattle each (dairy breed and beef breed, 50% each) were carried out in order to measure the influence of various vitamin A supply (0, 2,500, 5,000 and 10,000 IU vitamin A per 100 kg body weight and day) on fattening and slaughtering performance, vitamin A concentration of liver and serum as well as carotene concentration of serum. The bulls consumed corn silage (experiments 1 and 2; 9.4 and 18.3 mg carotene per kg dry matter) or NaOH-treated and pelleted straw (experiment 3; no carotene). The roughages were supplemented with 2 (exp. 1 and 2) and 3 kg (exp. 3) concentrate per day. The vitamin A supply of corn silage diet did not significantly influence the dry matter intake (exp. 1: means: 6.95; 6.91 to 7.05; exp. 2: means: 6.54; 6.53 to 6.54 kg dry matter per animal and day) and the daily weight gain of bulls (exp. 1: means: 1076; 1028 to 1157; exp. 2: means: 1058; 1041 to 1057 g per animal). The bulls consumed 8.87 kg dry matter per day, the daily weight gain amounted to 1030 g per animal and day in experiment 3. The bulls of unsupplemented group reduced feed intake and weight gain after 150 days, an additional vitamin A supply was necessary. At the end of experiments 1 and 2 the liver vitamin A concentration of unsupplemented groups amounted to 38.8 and 65.9 mumol/kg, it increased after vitamin A supply (up to 153.4 mumol/kg). Feeding of pelleted straw effected a liver vitamin A concentration lower than 10 mumol/kg except the group supplemented with 10,000 IU vitamin A per 100 kg body weight and day (35.7 mumol per kg fresh matter of liver). The vitamin A concentration of blood is unsuitable for evaluation of vitamin A status of cattle. The carotene content of feeds and level of vitamin A supply determined the carotene concentration of blood. Recommendations for a suitable vitamin A supply of ration of growing cattle were given depending on body weight and type of diet.

Animal Feed↗
PubMed1997

Vitamin A status during the third trimester of pregnancy in Spanish women: influence on concentrations of vitamin A in breast milk.

We examined the relation between the vitamin A status of Spanish women during pregnancy and concentrations of vitamin A in breast milk. The subjects were 57 healthy, lactating women aged 18-35 y. Vitamin A intake was determined during the third trimester of pregnancy by using a 5-d dietary record that included a Sunday and by recording the quantities provided by supplements. HPLC was used to determine vitamin A concentrations in subjects' serum during the third trimester, in transitional breast milk (on days 13-14 of lactation), and in mature breast milk (on day 40). During the third trimester, 33.3% of subjects had vitamin A intakes from diet and supplements < 800 microg/d, the recommended value. These subjects had serum and breast milk vitamin A concentrations that were significantly lower than those of subjects who consumed greater quantities of the vitamin. Furthermore, subjects with serum vitamin A concentrations < 1.05 micromol/L during the third trimester (22.8%) had lower mean (+/- SD) concentrations of the vitamin in mature breast milk than did subjects with higher serum concentrations (1.8 +/- 1.2 micromol/L compared with 2.6 +/- 0.8 micromol/L; P < 0.05). These results show that vitamin A intake and serum vitamin A concentrations during pregnancy influence the composition of breast milk. Given that 12.3% of subjects had < 1.40 micromol vitamin A/L in mature breast milk, it seems advisable to follow and, if necessary, improve vitamin A status during pregnancy and lactation.

Adolescent↗
PubMed1999

Use of the deuterated-retinol-dilution technique to assess total-body vitamin A stores of adult volunteers consuming different amounts of vitamin A.

BACKGROUND: The deuterated-retinol-dilution (DRD) technique provides a quantitative estimate of total body stores of vitamin A. However, it is not known whether the technique can detect changes in vitamin A pool size in response to different intakes of vitamin A. OBJECTIVE: Our objective was to determine the responsiveness of the DRD technique to 3 different daily supplemental vitamin A intakes during a period of 2.5-4 mo. DESIGN: Two oral doses of [(2)H(4)]retinyl acetate [52.4 micromol retinol equivalent (RE)] were administered on study days 1 and 91 to 26 men (18-32 y of age) who were consuming controlled, low-vitamin A diets, and receiving daily either 0, 5.2, or 10.5 micromol RE of unlabeled supplemental retinyl palmitate during a 75- or 129-d period. Plasma isotopic ratios of [(2)H(4)]retinol to retinol on day 115 were used to estimate final vitamin A body stores per Furr et al (Am J Clin Nutr 1989;49:713-6). RESULTS: Final ( +/- SD) estimated vitamin A pool sizes were 0.048 +/- 0.031, 0.252 +/- 0.045, and 0.489 +/- 0.066 mmol in the treatment groups receiving 0, 5.2, and 10.5 micromol RE/d, respectively (P < 0.001). Estimated mean changes in vitamin A pool sizes were similar to those expected for the vitamin A-supplemented groups [estimated:expected (95% CI of change in pool size): 1.08 (0.8, 1.2) and 1.17 (1.0, 1.3)]. CONCLUSIONS: The DRD technique can detect changes in total body stores of vitamin A in response to different daily vitamin A supplements. However, abrupt changes in dietary vitamin A intake can affect estimates of total-body vitamin A stores.

Adolescent↗
PubMed2001

Increased rat mammary tissue vitamin A associated with increased vitamin A intake during lactation is maintained after lactation.

Although increases in dietary vitamin A increase milk vitamin A, little is known about effects of vitamin A intake on mammary tissue vitamin A levels during and after the reproductive cycle. First, we measured vitamin A concentrations in milk, mammary tissue and liver of lactating rats fed 0, 4, or 50 micromol of vitamin A/kg diet during pregnancy and through d 12 of lactation. Liver vitamin A concentration was significantly affected by diet in lactating females and pups 12 d after parturition. Milk vitamin A concentrations were significantly higher (7.1 +/- 2.2 micromol/L, n = 8) in dams fed 50 micromol/kg than in those fed 0 or 4 micromol/kg (1.9 +/- 0.3, n = 5 and 2.9 +/- 0.7 micromol/L, n = 7; P < 0.001), as were mammary tissue vitamin A concentrations (5.1 +/- 1.1 versus 2.2 +/- 0.4 and 2.4 +/- 0.6 nmol/g; P < 0.001). Next, we maintained female rats on 50 or 10 micromol vitamin A/kg diet during pregnancy and lactation and then on 4 micromol/kg diet after pups were weaned on d 21. On d 21, mammary tissue vitamin A concentrations were 3.14 +/- 0.75 versus 1.52 +/- 0.21 nmol/g in dams fed 50 versus 10 micromol/kg (n = 4/group; P < 0.001). Mammary tissue vitamin A concentrations were not significantly affected by time from 7 to 49 d after lactation and averaged 8.5 +/- 0.4 and 4.9 +/- 0.8 nmol/g on d 49 in dams fed 50 versus 10 micromol/kg (n = 4; P < 0.001). We conclude that diet-induced differences in rat mammary tissue vitamin A developed during pregnancy and lactation are maintained for > or =7 wk after lactation.

Animals↗
PubMed1998

Vitamin E status in preterm infants: assessment by plasma and erythrocyte vitamin E-lipid ratios and hemolysis tests.

BACKGROUND: Vitamin E is an essential component of the antioxidant defenses, but supplementation can have side effects in the preterm infant. Careful monitoring of vitamin E status is thus essential, however no consensus has been reached on the best clinical method. METHODS: In 47 healthy preterm infants, several methods for assessment of vitamin E status were evaluated: plasma and erythrocyte vitamin E levels were measured, vitamin E lipid ratios were calculated, and two variations of the hydrogen peroxide hemolysis test were conducted. RESULTS: At birth, the plasma and erythrocyte vitamin E levels were low. After birth, the plasma levels rose gradually, whereas the erythrocyte levels remained low. In contrast, the vitamin E-total-lipid ratio was in the low normal range from birth onwards. Vitamin E-lipid ratios using two lipid components (cholesterol with triglycerides, or cholesterol with phospholipids) or one lipid component (cholesterol) correlated with the vitamin E-total-lipid ratio with a good sensitivity and specificity. The susceptibility of erythrocytes to hydrogen peroxide-induced damage (measured as potassium release or malondialdehyde production) was high at birth and declined after birth. However, this susceptibility did not correlate with plasma or erythrocyte vitamin E levels or vitamin E-total-lipid ratio, and the hydrogen peroxide hemolysis test is not a reliable indicator of vitamin E status in preterm infants. CONCLUSIONS: Our study indicated that a gold standard for clinical assessment of vitamin E status in preterm infants is yet to be found.

Erythrocytes↗
PubMed1997

Control of nuclear transcription of vitamin D-dependent genes by vitamin D.

Vitamin D acts on the genome via its active metabolite, calcitriol, which is bound to its nuclear receptor (vitamin D receptor) and a DNA response element. The characterization of the DNA target of the vitamin D receptor in vitamin D-activated or -repressed genes and structure-function analysis of the vitamin D receptor have led to several advances. These include a better understanding of the mechanisms of transactivation via the vitamin D receptor by the description of direct and indirect interactions of the vitamin D receptor with the basal transcriptional machinery. Physiological evidence for heterodimerization of the vitamin D receptor with the retinoid X receptor, and with other liganded or unliganded nuclear receptors, has indicated how the genetic response to vitamin D can be modulated. This modulation can also be brought about by cooperation between vitamin D receptor and transcription factors, by the action of a dominant negative isoform of vitamin D receptor, and by cross-talk between the signalling pathways for vitamin D and growth factors. These new concepts, plus the development of analogues of calcitriol, all indicate considerable progress towards vitamin D therapy for several disorders, including renal diseases.

Animals↗
PubMed2006

Influence of supplemental magnesium, tryptophan, vitamin C, vitamin E, and herbs on stress responses and pork quality.

This study investigated the effects of supplemental Mg, Trp, vitamin C, vitamin E, and herbs on stress responses, skin lesions, and meat quality of slaughter pigs (106.0 +/- 8.6 kg of BW). These 5 supplements were tested in 4 similar experiments. In Exp. 1, 2 treatments were tested: 1) control treatment without supplementation, and 2) supplementation of an herbal product (2.5 g/L of drinking water for 2 d). Eighty-eight pigs per treatment were involved, of which 40 were selected for meat quality measurements (over 4 replicates). The experimental design of Exp. 2 and 3 was the same as Exp. 1, except that in Exp. 2 Mg (3 g/L of drinking water for 2 d) was supplemented and in Exp. 3 Trp (6 g/kg of feed, as-fed basis) was supplemented. In Exp. 4, 3 treatments were tested: 1) control treatment without supplementation, 2) supplementation of vitamin C (300 mg/kg of feed for 21 d, as-fed basis), and 3) supplementation of vitamin E (150 mg/kg of feed for 21 d, as-fed basis). In Exp. 4, 66 pigs per treatment were used, of which 42 were evaluated for meat quality (over 6 replicates). Pigs supplemented with vitamin E ate less than control (P = 0.03) or vitamin C-supplemented pigs (P = 0.03). Pigs were transported to a commercial slaughterhouse and were slaughtered after a lairage period. Blood sampling at slaughter revealed no differences between the control and supplemented pigs in plasma cortisol, glucose, lactate, or creatine kinase concentrations. Pigs provided with Mg (P = 0.002) or Trp (P = 0.04) had lower plasma NEFA concentrations than control pigs, and pigs supplemented with vitamin C had greater concentrations than the control (P = 0.03) or vitamin E-supplemented pigs (P = 0.01). Supplementation of the herbal product increased the frequency of pigs with shoulder (P = 0.05) and loin lesions (P = 0.03), whereas Mg lowered the incidence of loin lesions (P = 0.01). Measurements of pH and temperature in the LM and biceps femoris 45 min postmortem revealed no differences among treatments, and no influence of treatments on LM pH, electrical conductivity, and water holding capacity was observed 48 h postmortem. Compared with the control loins, loins of pigs supplemented with vitamin C (Japanese color scale, L*, and a* value; P < 0.05) or vitamin E (Japanese color scale and a* value; P < 0.03) were redder and less pale, and the loin of vitamin E-supplemented pigs was more yellow (b* value; P = 0.04). Generally, Mg could lower loin damage, whereas vitamin C and vitamin E supplementation resulted in a color improvement of the loin.

Animal Feed↗
PubMed2005

Bioavailability of vitamin D from fortified process cheese and effects on vitamin D status in the elderly.

We conducted 2 studies to determine the effect of vitamin D-fortified cheese on vitamin D status and the bioavailability of vitamin D in cheese. The first study was designed to determine the effect of 2 mo of daily consumption of vitamin D3-fortified (600 IU/d) process cheese on serum 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), and osteocalcin (OC) concentrations among 100 older (> or =60 yr) men and women. Participants were randomized to receive vitamin D-fortified cheese, nonfortified cheese, or no cheese. Serum levels of 25-OHD, PTH, and OC were measured at the beginning and end of the study. There were no differences in 25-OHD, PTH, or OC after 2 mo of fortified cheese intake. The vitamin D-fortified cheese group had a greater decrease in 25-OHD than other groups, due to higher baseline 25-OHD. A second study was conducted to determine whether the bioavailability of vitamin D2 in cheese (delivering 5880 IU of vitamin D2/56.7-g serving) and water (delivering 32,750 IU/250 mL) is similar and whether absorption differs between younger and older adults. The second study was a crossover trial involving 2 groups of 4 participants each (younger and older group) that received single acute feedings of either vitamin D2-fortified cheese or water. Serial blood measurements were taken over 24 h following the acute feeding. Peak serum vitamin D and area under the curve were similar between younger (23 to 50 yr) and older (72 to 84 yr) adults, and vitamin D2 was absorbed more efficiently from cheese than from water. These studies demonstrated that vitamin D in fortified process cheese is bioavailable, and that young and older adults have similar absorption. Among older individuals, consuming 600 IU of vitamin D3 daily from cheese for 2 mo was insufficient to increase serum 25-OHD during limited sunlight exposure.

Absorption↗
PubMedDate not supplied

Direct evidence for bioconversion of vitamin E acetate into vitamin E: an ex vivo study in viable human skin.

For better stability, vitamin E is commonly used as the non-active esterified pro-drug. Such esters are postulated to be hydrolyzed to the free active form by skin-related esterases. So far, successful conversion of esterified vitamin E to free vitamin E (tocopherol) has been mainly delineated from observed biological effects. Quantitative evidence in human skin is poor. In vitro and in vivo studies on human and animal skin have proved ambiguous. Formulation-based effects may have added to this controversy. In the present study, comparable amounts of vitamin E acetate (i) in oil (Mygliol-812N), (ii) surfactant-solubilized in water, (iii) encapsulated in liposomes, or (iv) encapsulated in Nanotopes were applied to human skin mounted in modified Franz-perfusion chambers that permit emulation of both open or occlusive conditions. The distribution of vitamin E(total) (vitamin E acetate + vitamin E) was assessed on the skin surface, in the horny layers, and in the underlying skin by high-pressure liquid chromatography (HPLC), with a recovery higher than 90%. Vitamin E acetate in Mygliol deposited exclusively on the surface and in the stratum corneum. In contrast, solubilized or encapsulated vitamin E acetate deposited also in the underlying skin. Nanotopes performed best, followed by liposomes and solubilized vitamin E acetate. Non-occlusive application favored deposition in the skin relative to occlusive application. Conversion of vitamin E acetate to vitamin E was not observed on the skin surface or in the horny layers, while in the underlying skin up to 50% of the vitamin E(total) was deacetylated.

Biotransformation↗
PubMed1975

Human plasma R-type vitamin B12-binding proteins. I. Isolation and characterization of transcobalamin I. TRANSCOBALAMIN III. and the normal granulocyte vitamin B12-binding protein.

Transcobalamin I and transcobalamin III have been purified approximately 6,000,000- and 3,000,000-fold, respectively, from normal human plasma using a purification scheme consisting of immunoadsorption, dialysis against 7.5 M guanidine HCl to remove endogenous vitamin B12, and affinity chromatography on vitamin B12-Sepharose. The two proteins were separated from each other subsequently by chromatography on DEAE-cellulose. The vitamin B12-binding protein present in granulocytes obtained from normal subjects has been purified approximately 5000-fold using affinity chromatography on vitamin B12-Sepharose as the sole purification technique. The final preparations of all three proteins were homogeneous based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Transcobalamin I and transcobalamin III belong to the R-typed class of vitamin B12-binding proteins and are indistinguishable from each other, and from the human granulocyte, milk, and saliva R-type vitamin B12-binding proteins, when studied by immunodiffusion with rabbit anti-human milk vitamin B12-binding protein sera. The carbohydrate compositions, expressed as moles of carbohydrate per mole of vitamin B12, of transcobalamin I, transcobalamin III, and the normal granulocyte vitamin B12-binding protein, respectively, are: sialic acid, 18, 11, 11; fucose, 9, 20, 24; galactose, 41, 51, 46; mannose, 24, 22, 20; galactosamine, 2, 2, 2; and glucosamine, 46, 54, 46. The high sialic acid content of transcobalamin I appears to account for the fact that this protein elutes after transcobalamin III and the normal granulocyte vitamin B12-binding protein during chromatography on DEAE-cellulose. This observation provides support for the hypothesis that differences among the R-type vitamin B12-binding proteins are due to differences in carbohydrate content. The similarities in carbohydrate composition and other properties of transcobalamin III and the granulocyte vitamin B12-binding protein provide support for the hypothesis that human plasma transcobalamin III is derived from granulocytes. The differences observed between transcobalamin I and the normal granulocyte vitamin B12-binding protein suggest that transcobalamin I may not be derived from granulocytes.

Blood Proteins↗
PubMed1987

[Effect of vitamins B1, B2, B6, folic acid and vitamin C on the motor activity of chicken's intestines in chronic experiments and in vitro].

The studies were carried out on 33 chickens of the broiler breed in chronic experiments and in vitro. In the chronic experiments the motility of the jejunum under the influence of vitamins of group B and vitamine C was recorded in 8 chickens. The vitamins were used at concentrations from 10 mg/l to 2.5 x 10(3) mg/l. In the experiments in vitro, the motility of the isolated segment of the jejunum was recorded by the method of Magnus. In this part of experiments the chickens were divided into 3 groups, of which group I (15 chickens) were fed with DKA finischer mixture, group II (5 hens) received, besides the mixture, per os 200 mg of vitamin C for 2 weeks, group III (5 hens) received the mixture and for 2 weeks intraperitoneally 200 mg of vitamin C. The effect of vitamins of group B in vitro was determined in chickens of group I, whereas that of vitamin C in chickens of group I, II and III. At the same time the level of vitamin C in the wall of the jejunum was determined by the method of Roe-Kuenther. It was shown that vitamin B2 and folic acid caused stimulation of intestine motility in the chickens, while vitamin B1, B6 and C decreased the motoric activity. Increased level of vitamin C in the intestinal wall resulted in increased intestine sensitivity. Chicken intestines sensitivity to vitamins was 10 times stronger to vitamins than that of the intestines of rabbits.

Animals↗