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PubMed1985

Vitamin A during lactation: relationship of maternal diet to milk vitamin A content and to the vitamin A status of lactating rats and their pups.

We have investigated the effects of maternal vitamin A intake during pregnancy and lactation or during lactation alone on the concentration of vitamin A in rat's milk and on vitamin A levels in plasma and liver of dams and their pups. Groups of Sprague-Dawley rats were fed diets having either a high vitamin A content [15 retinol equivalents (R.E.)/g diet] or a low vitamin A content (0.6 R.E./g) for 42 d, including 7-8 d prior to pregnancy, pregnancy, and for 14 d of lactation. The concentration of vitamin A in milk on d 14 of lactation was significantly greater on the high vitamin A diets [114 +/- 16 micrograms/dl (mean +/- SEM; n = 8) versus 52 +/- 7.3 micrograms/dl (n = 11), P less than 0.005]. However, milk vitamin A concentration on d 1 of lactation did not vary with maternal vitamin A intake during pregnancy. In a second study in which supplementation with vitamin A (30 R.E./g diet) was begun on d 1 postpartum, the milk vitamin A content increased progressively with duration of lactation. Maternal plasma vitamin A concentrations did not differ between rats fed the higher or lower vitamin A diets. However, liver vitamin A concentrations both of dams and of their 14-d-old pups were significantly higher when dams were fed the higher vitamin A diets during pregnancy and/or lactation. The results of these studies indicate that the transfer of vitamin A from mother to offspring by milk and the vitamin A status of dams and their suckling neonates is influenced by maternal vitamin A intake during lactation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Population Groups↗
PubMed1999

Interdependence of serum concentrations of vitamin K1, vitamin E, lipids, apolipoprotein A1, and apolipoprotein B: importance in assessing vitamin status.

Vitamin E (alpha-tocopherol) and vitamin K1 (phylloquinone) are fat-soluble vitamins and are important nutrients in health and disease. In this study serum concentrations of vitamin E and vitamin K1, lipids and apolipoproteins A1 and B were measured in neonates, normal and hyperlipidaemic individuals in an attempt to establish their interrelationships. A high degree of correlation was observed between the concentrations of the vitamins and those of lipids and apolipoproteins (r ranged from 0.42 to 0.92; p<0.001). Stepwise linear regression methods determined that serum concentrations of both vitamin E and vitamin K1 could best be predicted by using equations excluding lipids but containing only apolipoprotein A1 and B concentrations. Correlation coefficients between predicted and measured values were 0.89 for serum vitamin E, and 0.83 for serum vitamin K1 concentrations. To test the validity of the derived formulae, measured and estimated vitamin K1 and vitamin E concentrations in serum were determined in another group of neonates, normal adults and hypercholesterolemic adults and the comparisons were shown to be very good. These results indicate that the serum levels of both vitamins depend critically on the concentration of the lipoprotein carriers, apolipoproteins A1 and B. Hence, in order to identify variations in serum vitamin K1 and vitamin E concentrations, which are independent of variations in carrier concentration, it will be necessary to express these serum vitamins as ratios of vitamins to apolipoprotein A1 and B carriers.

Adult↗
PubMed2006

Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials.

BACKGROUND: Vitamin B(12) deficiency is common, increasing with age. Most people are treated in primary care with intramuscular vitamin B(12). Several studies have reported equal efficacy of oral administration of vitamin B(12). OBJECTIVES: We set out to identify randomized controlled trial (RCT) evidence for the effectiveness of oral versus intramuscular vitamin B(12) to treat vitamin B(12) deficiency. METHODS: We conducted a systematic review searching databases for relevant RCTs. Outcomes included levels of serum vitamin B(12), total serum homocysteine and methylmalonic acid, haemoglobin and signs and symptoms of vitamin B(12) deficiency. RESULTS: Two RCTs comparing oral with intramuscular administration of vitamin B(12) met our inclusion criteria. The trials recruited a total of 108 participants and followed up 93 of these from 90 days to 4 months. In one of the studies, mean serum vitamin B(12) levels were significantly higher in the oral (643 +/- 328 pg/ml; n = 18) compared with the intramuscular group (306 +/- 118 pg/ml; n = 15) at 2 months (P < 0.001) and 4 months (1005 +/- 595 versus 325 +/- 165 pg/ml; P < 0.0005) and both groups had neurological responses. In the other study, serum vitamin B(12) levels increased significantly in those receiving oral vitamin B(12) and intramuscular vitamin B(12) (P < 0.001). CONCLUSIONS: The evidence derived from these limited studies suggests that 2000 microg doses of oral vitamin B(12) daily and 1000 microg doses initially daily and thereafter weekly and then monthly may be as effective as intramuscular administration in obtaining short-term haematological and neurological responses in vitamin B(12)-deficient patients.

Administration, Oral↗
PubMed2005

Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency.

BACKGROUND: Vitamin B12 deficiency is common and rises with age. Most people with vitamin B12 deficiency are treated in primary care with intramuscular vitamin B12 which is a considerable source of work for health care professionals. Several case control and case series studies have reported equal efficacy of oral administration of vitamin B12 but it is rarely prescribed in this form, other than in Sweden and Canada. Doctors may not be prescribing oral formulations because they are unaware of this option or have concerns regarding effectiveness. OBJECTIVES: To assess the effectiveness of oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. SEARCH STRATEGY: Searches were undertaken of The Cochrane Library, MEDLINE, EMBASE and Lilacs in early 2005. The bibliographies of all relevant papers identified using this strategy were searched. In addition we contacted authors of relevant identified studies and Vitamin B12 research and pharmaceutical companies to enquire about other published or unpublished studies and ongoing trials. SELECTION CRITERIA: Randomised controlled trials (RCTs) examining the use of oral or intramuscular vitamin B12 to treat vitamin B12 deficiency. DATA COLLECTION AND ANALYSIS: All abstracts or titles identified by the electronic searches were independently scrutinised by two reviewers. When a difference between reviewers arose, we obtained and reviewed a hard copy of the papers and made decisions by consensus. We obtained a copy of all pre-selected papers and two researchers independently extracted the data from these studies using piloted data extraction forms. The whole group checked whether inclusion and exclusion criteria were met, and disagreement was decided by consensus. The methodological quality of the included studies was independently assessed by two researchers and disagreements were brought back to the whole group and resolved by consensus. MAIN RESULTS: Two RCT's comparing oral with intramuscular administration of vitamin B12 met our inclusion criteria. The trials recruited a total of 108 participants and followed up 93 of these from 90 days to four months. High oral doses of B12 (1000 mcg and 2000 mcg) were as effective as intramuscular administration in achieving haematological and neurological responses. AUTHORS' CONCLUSIONS: The evidence derived from these limited studies suggests that 2000 mcg doses of oral vitamin B12 daily and 1000 mcg doses initially daily and thereafter weekly and then monthly may be as effective as intramuscular administration in obtaining short term haematological and neurological responses in vitamin B12 deficient patients.

Administration, Oral↗
PubMed1977

Vitamin A stimulation of parathyroid hormone: interactions with calcium, hydrocortisone, and vitamin E in bovine parathyroid tissues and effects of vitamin A in man.

The effect of vitamin A, a membrane surface-active agent, on parathyroid hormone secretion was studied in vitro, using bovine parathyroid tissue, and in vivo in man. Parathyroid tissues were incubated with vitamin A (retinol), retinoic acid, and calcium, and with hydrocortisone and vitamin E, agents that antagonize the membrane effects of vitamin A. The stimulation of parathyroid hormone release by vitamin A, 10(-6) to 10(-9) mol/1 in vitro, was dose and time dependent. Retinoic acid did not stimulate secretion. High calcium concentration, hydrocortisone, 10(-5) mol/1 and 10(-6) mol/1, and vitamin E, 10(-5) mol/1, antagonized vitamin A-induced parathyroid hormone secretion. Vitamin A increased the lysosomal cathepsin D activity of parathyroid tissues. In human studies, eleven healthy men received two intramuscular injections of vitamin A palmitate, 25 000 units each, within 24 h. In every subject, serum parathyroid hormone increased after vitamin A administration. Our studies indicate that: (1) vitamin A stimulates parathyroid hormone secretion in vitro, possibly through modification of the cell or secretion granule membrane, or through stimulation of lysosomal proteolytic activity, and (2) vitamin A increases serum parathyroid hormone in vivo, and this effect may be important in clinical states of vitamin A excess.

Adult↗
PubMed2002

Protective role of supplemental vitamin E and selenium on lipid peroxidation, vitamin E, vitamin A, and some mineral concentrations of Japanese quails reared under heat stress.

This study was conducted to determine the effects of vitamin E and selenium (Se) on lipid peroxidation (MDA), serum and liver concentration of antioxidant vitamins, and some minerals of Japanese quails reared under heat stress (34 degrees C). One hundred twenty 10-d-old Japanese qualis (60 males, 60 females) were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The experiment was designed in a 2x2 factorial arrangement using two levels of vitamin E (125 and 250 mg/kg of diet) and two levels of selenium (0.1 and 0.2 mg/kg of diet). Greater dietary vitamin E and selenium inclusions resulted in a greater (p = 0.001) serum vitamin E and vitamin A, but lower (p = 0.001) MDA concentrations. Liver vitamin E and vitamin A concentrations increased (p = 0.001) and MDA concentrations decreased (p = 0.001) when both dietary vitamin E and selenium increased. No interactions between vitamin E and selenium were detected (p > or = 0.11) for any parameters. Increasing both dietary vitamin E and selenium caused an increase in serum concentrations of Fe and Zn (p = 0.001), but a decrease in serum concentration of Cu (p = 0.001). Results of the present study showed that dietary vitamin E and selenium have synergistic effects and that supplementing a combination of dietary vitamin E (250 mg/kg of diet) and selenium (0.2 mg/kg of diet) offers a good management practice to reduce heat stress-related depression in performance of Japanese quails.

Animals↗
PubMed1985

[Vitamin A requirement of growing swine. 2. Effect of the vitamin A supply on the vitamin A concentrations in the liver and plasma of piglets and fattening swine].

In 9 experiments the vitamin A content of the livers of 64 newborn (still births and deaths up to 48 h p.p.) and 69 weaned piglets, 122 growers and 110 fattening pigs was investigated after slaughtering or autopsy. Liver samples were taken from 78 growers by means of biopsy after latarotomy. A fluorometric analysis of the plasma vitamin A level was made. At the time of birth the vitamin A content of the piglet livers was less than 100 IU/g and did not show any differences between the experiments. At the time of weaning, however, the livers of piglets from large-scale production showed a three times higher content (175 IU/g liver) in comparison to those from traditional production. Highly significant linear relations were established between the vitamin A content of the feed and the liver. According to these, a liver content of vitamin A of approximately equal to 30 IU/g is ensured by approximately equal to 2,000 IU in weaning piglets and by approximately equal to 800 IU vitamin A/kg feed in fattening pigs. The vitamin A activity of the beta-carotene in weaners was ascertained as less than 100 IU/mg. The plasma vitamin A level indicated the vitamin A status only in the range of deficient supply. A different plasma content could not be detected between 1,000 and 4,000 IU vitamin A/kg feed. According to this, a semilogarithmic relation was calculated according to the model of a saturation curve between the vitamin A content of the plasma and the liver. The threshold value for the decrease of the plasma level under 45 IU vitamin A/dl is 35 IU/g liver. Due to the low definiteness measure (B = 0.52) the relation cannot be applied to the individual animal. A contamination of 1,000 mg nitrite/kg feed had a low, and in the course of the experiment decreasing, influence on the vitamin A content of plasma and liver.

Aging↗
PubMed1989

Changes in the concentrations of vitamin D and its metabolites in the plasma of healthy subjects orally given physiological doses of vitamin D2 by multivitamin or vitamin D preparations.

Changes in the concentrations of vitamin D and its metabolites in plasma of healthy subjects orally given physiological doses of vitamin D2 by multivitamin or vitamin D liquid preparations were determined and the bioavailability of vitamin D was studied. Separative assay on the D2 and D3 compounds of vitamin D, 25-hydroxyvitamin D (25-OH-D), 24R,25-dihydroxyvitamin D [24,25(OH)2D], and 1 alpha,25-dihydroxyvitamin D [1,25(OH)2D] was performed in plasma of eight healthy male volunteers. When the concentrations of vitamin D and its metabolites in plasma of volunteers were assayed after daily oral administration of 400 IU of vitamin D2 in a form of multivitamin tablet for 1 week, the variations of vitamin D3 and its metabolites in plasma levels were very small. In contrast, the concentrations of 25-OH-D2 and 1,25(OH)2D2 slightly increased after the administration, while neither vitamin D2 nor 24,25(OH)2D2 was detected. A single dose of 4,000 IU of vitamin D2 was orally given to the volunteers in a form of a vitamin D liquid preparation and the hourly variations were observed during 24 h. These concentrations of vitamin D2, 25-OH-D2, and 1,25(OH)2D2 were slightly higher than those of the repeated doses. The result suggests that even the high dose of 4,000 IU has little effect on the plasma levels of vitamin D2 and its metabolites by a single dose, indicating a low risk for hypervitaminosis D.

Administration, Oral↗
PubMed1975

Human plasma R-type vitamin B12-binding proteins. II. The role of transcobalamin I, transcobalamin III, and the normal granulocyte vitamin B12-binding protein in the plasma transport of vitamin B12.

The normal human granulocyte vitamin B12-binding protein, transcobalamin I, and transcobalamin III, have been labeled with 125I-labeled N-succinimidyl 3-(4-hydroxyphenyl)propionate and utilized for plasma clearance studies performed with rabbits. Both moieties of 125I-labeled granulocyte vitamin B12-binding protein-[57Co]vitamin B12 were cleared rapidly from the plasma (is less than 90% by 5 min) by the liver. After 30 min, the bulk of the 125I reappeared in the plasma in small molecular weight (less than 1000) form and was rapidly excreted in the urine. After 60 min the bulk of the [57Co]vitamin B12 reappeared in the plasma bound to rabbit transcobalamin II and was subsequently taken up by a variety of tissues. Approximately 15% of the 125I-labeled granulocyte vitamin B12-binding protein-[57Co-a1vitamin B12 was excreted intact into the bile during the period from 10 to 80 min after injection. The hepatic uptake of the protein-vitamin B12 complex was blocked by the prior injection of desialyzed fetuin but not by native fetuin. Similar results were obtained with 125I-labeled transcobalamin III-[57Co]vitamin B12. Approximately 90% of both moieties of 125I-labeled transcobalamin I-[57Co]vitamin B12 had prolonged plasma survivals similar to that of 125I-labeled bovine serum albumin. After treatment with neuraminadase, both moieties of the 125I-labeled transcobalamin I-[57Co]vitamin B12 complex were cleared rapidly from the plasma by the liver in a manner that was indistinguishable from that observed in the case of untreated granulocyte vitamin B12-binding protein and transcobalamin III. These observations indicate that desialyzed transcobalamin I and the native forms of the granulocyte vitamin B12-binding protein and transcobalamin III are cleared from plasma by the mechanism elucidated by Ashwell and Morell (Ashwell, G., and Morell A. G. (1974) Adv. Enzymol. 41, 99-128) that is capable of clearing a wide variety of asialoglycoproteins. These observations have implications concerning the function of the human R-type vitamin B12-binding proteins, the nature of the enterohepatic circulation of vitamin B12, the biological significance of the mechanism described by Ashwell and Morell, and the etiology of the increased plasma concentration of human R-type protein that occurs frequently in chronic myelogenous leukemia and occasionally in hepatocellular carcinoma and other solid tumors.

Animals↗
PubMed1979

Assay for vitamin D2 and vitamin D3 in plasma of dairy cows: changes after massive dosing of vitamin D3.

A sensitive, precise assay for vitamin D in plasma is described. Three to five milliliters of plasma were extracted with methanol:methylene chloride (2:1). The lipid extract was chromatographed on Sephadex LH-20 and then on lipidex-5000 columns. After high pressure liquid chromatography with a reverse phase chromatographic system, vitamin D2 and vitamin D3 were quantitated by ultraviolet absorbance. We used this assay system for monitoring daily changes of vitamin D3 in plasma of two Jersey cows after four intramuscular doses (15 x 10(6) IU) of vitamin D3 administered at weekly intervals. Basal vitamin D in plasma was 3.2 +/- .99 ng/ml with a range of 1.7 to 4.9 ng/ml. Vitamin D3 in plasma remained relatively low (10 to 45 ng/ml) the week after the first vitamin D3 injection. Vitamin D3 was high (130 to 234 ng/ml) after the second, third, and fourth injections. Vitamin D3 decreased steadily to 88 ng/ml by 38 days after the fourth vitamin D3 injection. Phosphorus in plasma increased sharply to a plateau at 9.5 mg/100 ml during the week after the second vitamin D3 injection and returned to normal (4.5 mg/100 ml) at the end of the experiment. Calcium, however, gradually increased to 14.0 mg/100 ml 20 days after the fourth vitamin D3 injection. Both animals remained hypercalcemic (calcium 11.5 mg/100 ml) during the experiment.

Animals↗
PubMed1990

[Vitamin K 1 concentration and vitamin K-dependent clotting factors in newborn infants after intramuscular and oral administration of vitamin K 1].

Serum concentration of vitamin K1 and activity of vitamin-K-dependent factors II, VII, IX and X were determined before and after vitamin K1 administration in infants. The babies received vitamin K1 intramuscularly or orally. 12 hours after vitamin K1 treatment the mean concentration was increased in the groups receiving vitamin K1 intramusculary or orally, respectively. Serum level of vitamin K1 fell exponentially, the mean half life was about 30 hours in both groups. Activity of vitamin K-dependent clotting factors did not change significantly after intramuscular or oral vitamin K1 administration during the first four-five days of life. It was no direct correlation between the concentration of vitamin K1 and the activity of vitamin-K-dependent clotting factors. This study suggest that oral administration of vitamin K1 is as effective as the intramuscular route.

Administration, Oral↗
PubMed1979

Vitamin B6 nutriture during pregnancy and lactation. I. Vitamin B6 intake, levels of the vitamin in biological fluids, and condition of the infant at birth.

Vitamin B6 nutriture was assessed during pregnancy and lactation to determine possible relationships among vitamin B6 intake, levels of the vitamin in biological fluids and the condition of the infant at birth. Vitamin B6 levels were measured in maternal serum and in urine at 5 and 7 months gestation and at delivery, in cord serum and in milk at 3 and 14 days postpartum. Intake of vitamin B6, less than the Recommended Dietary Allowances (1974) for pregnancy and lactation, 2.5 mg/day, resulted in lower levels of the vitamin in maternal serum at delivery and in cord serum than higher intakes. Mothers whose infants had unsatisfactory Apgar scores at 1 min, (less than 7) had significantly low intakes of vitamin B6 and lower levels of the vitamin in both serum and milk than mothers whose infants had satisfactory scores, (greater than or equal to 7). At 5 months gestation, levels of vitamin B6 in maternal serum were significantly correlated with levels of the vitamin in cord serum and in milk at 14 days postpartum. This stage of gestation precedes the period of rapid growth of the central nervous system of the fetus, and is, therefore, a critical time for the assessment of maternal vitamin B6 nutriture.

Adolescent↗
PubMed1984

Simultaneous measurement of 1.25-dihydroxy-vitamin D, 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D from a single two milliliters serum specimen. Preliminary clinical application.

A simple method for extraction, purification and separation of the principal vitamin D metabolites from a single serum sample is described. The method involved extraction of serum with acetonitrile followed by a first purification employing C-18 Sep-pak cartridges eluted with methanol/water and acetonitrile. Final separation before assay was carried out by high pressure liquid chromatography. 1.25-dihydroxy-vitamin D was measured with radioimmunoassay using an antiserum (S11) with high selectivity for 1 alpha-OH function of the hormone at a final dilution of 1:100,000. 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D were measured employing a competitive binding assay with normal rat serum at a final dilution of 1:10,000 as source of binding protein. The mean (+/- SD) serum 1.25-dihydroxy-vitamin D, 24.25-dihydroxy-vitamin D and 25-hydroxy-vitamin D concentrations for a group of healthy subjects were 50.4 +/- 17.3 pg/ml, 2.3 +/- 2.6 ng/ml and 20.8 +/- 12.3 ng/ml, respectively. 1.25-dihydroxy-vitamin D concentrations were low or undetectable in patients on dialysis or with mild renal failure. High 1.25-dihydroxy-vitamin D levels were found in 2 out of 17 patients with primary hyperparathyroidism. In 4 normal subjects treated for two weeks with large doses of 25-hydroxy-vitamin D, serum 25-hydroxy-vitamin D rose from 12.5 ng/ml to 119 ng/ml and from 0.89 ng/ml to 15 ng/ml, respectively; no changes in the 1.25-dihydroxy-vitamin D assay were found.

24,25-Dihydroxyvitamin D 3↗
PubMed1985

Effects of different levels of vitamin C intake on the vitamin C concentration in human milk and the vitamin C intakes of breast-fed infants.

The influence of maternal intake of vitamin C on the vitamin C concentration in human milk and on the vitamin C intakes of breast-fed infants has not been demonstrated conclusively. This study examined these influences of diet and supplementation in 25 lactating women administered 90 mg of ascorbic acid for 1 day followed by 250, 500 or 1000 mg/day for 2 days or unsupplemented for 1 day followed by either 0 or 90 mg ascorbic acid supplement for 2 days. Vitamin C content in milk and urine was determined by the 2,4-dinitrophenylhydrazine method. Vitamin C intakes of infants were calculated from milk volume, as determined by the test-weighing method and from vitamin C levels in milk samples obtained at each feeding. Total maternal intakes of vitamin C, which exceeded 1000 mg/day or 10-fold the RDA for lactation (100 mg/day), did not significantly influence the vitamin C content in milk or the vitamin C intakes of infants. However, maternal vitamin C intake was positively correlated (r = 0.7) with maternal urinary excretion. These differences in milk and urine response to vitamin C intake suggest a regulatory mechanism for vitamin C levels in milk.

Adult↗
PubMed2004

Breakfast cereal fortified with folic acid, vitamin B-6, and vitamin B-12 increases vitamin concentrations and reduces homocysteine concentrations: a randomized trial.

BACKGROUND: High homocysteine and low B vitamin concentrations have been linked to the risk of vascular disease, stroke, and dementia and are relatively common in older adults. OBJECTIVE: We assessed the effect of breakfast cereal fortified with folic acid, vitamin B-6, and vitamin B-12 on vitamin and homocysteine status. DESIGN: A randomized, double-blind trial was conducted in 189 volunteers aged 50-85 y. The subjects had no history of hypertension, anemia, asthma, cancer, or cardiovascular or digestive disease and did not regularly consume multiple or B vitamin supplements or highly fortified breakfast cereal. Subjects were randomly assigned to consume 1 cup (0.24 L) breakfast cereal fortified with 440 microg folic acid, 1.8 mg vitamin B-6, and 4.8 microg vitamin B-12 or placebo cereal for 12 wk. Blood was drawn at 0, 2, 12, and 14 wk. Methionine-loading tests were conducted at baseline and week 14. RESULTS: Final baseline-adjusted plasma homocysteine concentrations were significantly lower and B vitamin concentrations were significantly higher in the treatment group than in the placebo group (P < 0.001). The percentage of subjects with plasma folate concentrations < 11 nmol/L decreased from 2% to 0%, with vitamin B-12 concentrations < 185 pmol/L from 9% to 3%, with vitamin B-6 concentrations < 20 nmol/L from 6% to 2%, and with homocysteine concentrations > 10.4 micromol/L (women) or > 11.4 micromol/L (men) from 6.4% to 1.6%. The percentage of control subjects with values beyond these cutoff points remained nearly constant or increased. CONCLUSIONS: In this relatively healthy group of volunteers, consumption of 1 cup fortified breakfast cereal daily significantly increased B vitamin and decreased homocysteine concentrations, including post-methionine-load homocysteine concentrations.

Aged↗
PubMed1979

Analysis of fat-soluble vitamins. XXIII. High performance liquid chromatographic assay for vitamin D in vitamin D3 and multivitamin preparations.

Vitamin D is determined in preparations containing other fat-soluble vitamins by high performance liquid chromatography (HPLC). The unsaponifiable residue is extracted and separated from interferences by reverse phase chromatography; the fraction corresponding to vitamin D3 is collected and quantitated using normal phase chromatography (amylalcohol-n-hexane as mobile phase) by measuring the vitamin D3 and pre-vitamin D3 peaks at 254 nm. Previtamin D3 content is calculated as vitamin D3 with a conversion factor (determined on the equipment used). Application of the method to vitamin AD3 mixtures in oils gives 98-102% recovery. The reproducibility, using an external standard, is 2-3%, calculated as the coefficient of variation; with an internal standard, the coefficient of variation is 1-1.5%. The method measures potential vitamin D3 content in preparations containing greater than or equal to 200 IU/g in the presence of all known vitamin D3 isomers, vitamin A, and vitamin E.

Cholecalciferol↗
PubMedDate not supplied

Long-term effects of vitamin B(12), folate, and vitamin B(6) supplements in elderly people with normal serum vitamin B(12) concentrations.

BACKGROUND: In the elderly, deficiencies of folate, cobalamin (vitamin B(12)) and pyridoxal phosphate (vitamin B(6)) are common. The metabolites homocysteine, methylmalonic acid, 2-methylcitric acid and cystathionine have been reported to be sensitive markers of these vitamin deficiencies. OBJECTIVE: The long-term (269 days) effect of an intramuscular vitamin supplement containing 1 mg vitamin B(12), 1.1 mg folate, and 5 mg vitamin B(6) on serum concentrations of homocysteine (tHcy), methylmalonic acid (MMA), 2-methylcitric acid (2-MCA), and cystathionine (Cysta) was studied in 49 elderly subjects with normal levels of vitamin B(12). METHODS: Vitamin supplement was administered 8 times over a 21-day period, metabolite concentrations were measured until day 269 (e.g. 248 days after the end of vitamin supplementation). RESULTS: From day 0 to 21, the serum levels of the 3 vitamins increased significantly, after cessation of supplementation the levels returned to baseline within the follow-up period. The MMA, 2-MCA and tHcy levels decreased during the treatment period significantly and did not reach baseline values within the 248-day period. Cysta levels did not differ significantly from baseline, either during or after treatment. CONCLUSION: MMA and 2-MCA levels rather reflect the availability of vitamins, especially cobalamin, than the actual serum levels. Since deficiencies of folate, cobalamin and pyridoxal phosphate in the elderly may cause hyerhomocysteinemia and hence may have unfavorable effects on mental performance, determination of MMA and 2-MCA levels in elderly patients with mental disturbances may be a cost-effective measure to improve or maintain mental performance.

Aged↗