Retinol, supplemental vitamin A and bone status

Studies of hypervitaminosis A in animals and anecdotal reports of accidental vitamin A poisoning in humans suggest impairment of bone remodeling and increased numbers of fractures. Because of the widespread use of high-dose vitamin A supplements which may produce subclinical hypervitaminosis associated with decreased bone mass and increased risk of fracture, we studied the relationship between current vitamin A supplement use, serum retinol levels, radial bone mass and fracture history in a geographically-defined population of 246 postmenopausal women, 55-80 years of age. More than 36% of this population used a vitamin A supplement with 8% of these consuming an amount in excess of 2000 retinol equivalents (RE)/day. Serum retinol was measured using high-pressure liquid chromatography and radial bone mass was measured using single photon absorptiometry. After controlling for age, current estrogen replacement, and current thiazide antihypertensive use, we observed no statistically significant relationship between vitamin A supplement use or serum retinol with radial bone mass or fractures.     

Comparison of the effects of supplemental red palm oil and sunflower oil on maternal vitamin A status

BACKGROUND: Conflicting results have been reported on the ability of dietary carotenoids to improve vitamin A status in lactating women. Red palm oil is one of the richest dietary sources of beta-carotene. OBJECTIVE: We aimed to determine the efficacy of red palm oil in increasing retinol and provitamin A status in pregnant and lactating women. DESIGN: Ninety rural, pregnant Tanzanian women from 3 randomly selected villages were recruited during their third trimester to participate in 3 dietary intervention groups: a control group, who were encouraged to maintain the traditional practice of eating staples with dark-green leafy vegetables, and 2 study groups, who were given either sunflower or red palm oil for use in household food preparations. The intervention lasted 6 mo. Plasma samples were collected at the third trimester and 1 and 3 mo postpartum, and breast-milk samples were collected 1 and 3 mo postpartum. RESULTS: Supplementation with red palm oil, which is rich in provitamin A, increased alpha- and beta-carotene concentrations significantly (P < 0.001) in both plasma and breast milk. Plasma retinol concentrations were similar in all dietary groups. Breast-milk retinol concentrations tended to decrease from 1 to 3 mo postpartum in the control group, but were maintained in both oil groups. The difference in change in breast-milk retinol concentration between the red palm oil group and the control group was significant (P = 0.041). CONCLUSIONS: Consumption of red palm oil increases concentrations of alpha- and beta-carotene in both breast milk and serum and maintains breast-milk retinol concentrations. Sunflower oil consumption seems to conserve breast-milk retinol similarly to consumption of red palm oil. Breast-milk retinol might be maintained through increased dietary intake of these vegetable oils and use of mild cooking preparation methods (such as the addition of oil at the end of cooking and avoidance of frying).     

Effect of vitamin E supplementation on vitamin K status in adults with normal coagulation status

BACKGROUND: Cases of enhanced anticoagulant effect in response to high-dose vitamin E supplementation have been reported among patients taking oral anticoagulants. Although a vitamin E-vitamin K interaction was proposed to underlie this effect, it has not been systematically investigated in adults with normal baseline coagulation status. OBJECTIVE: The objective was to study the effect of 12 wk of supplementation with 1000 IU RRR-alpha-tocopherol/d on biochemical measures of vitamin K status in men and women not taking oral anticoagulants. DESIGN: Vitamin K status, which was assessed with the use of plasma phylloquinone concentrations, the degree of under-gamma-carboxylation of prothrombin (proteins induced by vitamin K absence-factor II, PIVKA-II), and the percentage of undercarboxylated osteocalcin (ucOC), was determined in 38 men and women with rheumatoid arthritis (study A) and in 32 healthy men (study B) participating in 2 independent, 12-wk randomized clinical trials of vitamin E supplementation (1000 IU/d). RESULTS: Mean (+/- SD) PIVKA-II increased from 1.7 +/- 1.7 to 11.9 +/- 16.1 ng/mL (P < 0.001) in study A and from 1.8 +/- 0.6 to 5.3 +/- 3.9 ng/mL (P < 0.001) in study B in response to 12 wk of vitamin E supplementation. An increase in PIVKA-II is indicative of poor vitamin K status. In contrast, the other measures of vitamin K status (ie, plasma phylloquinone concentration and percentage of ucOC) did not change significantly in response to the supplementation. CONCLUSIONS: High-dose vitamin E supplementation increased PIVKA-II in adults not receiving oral anticoagulant therapy. The clinical significance of these changes warrants further investigation, but high doses of vitamin E may antagonize vitamin K. Whether such an interaction is potentially beneficial or harmful remains to be determined.     

Effect of vitamin E supplementation on the vitamin content of lipoprotein in young men and women

The effect of supplementary Vitamin E on the vitamin content of lipoproteins in young men and women. Inappropriate vitamin and trace element supplementation may facilitate the development of atherosclerosis. It is known that Vitamin E protects lipids from oxidative stress, while clinical signs of atherosclerosis appear later in women compared to men. AIMS: (1) The increase of vitamin E in plasma and plasma lipoproteins after 4 weeks of supplementation vitamin E was investigated, (2) furthermore it was tested whether a proportion shift occurs in alpha-tocopherol content of lipoproteins, (3) and checked for gender-related differences in plasma and plasma lipoprotein vitamin E levels before, during and after treatment, (4) plasma CRP levels as a marker of lipid peroxidation were also followed. METHODS: 5-5 young healthy men and women took part in the study, receiving 700 IU/day Vitamin E for one month. Each subject was studied before and at the end of treatment, and also one month after treatment. HDL and LDL-VLDL containing lipoproteins were separated. Vitamin E and hsCRP levels were measured (by HPLC and an immunoturbidimetric method, respectively). RESULTS: Vitamin E treatment induced in both genders an approximately threefold increase in vitamin E concentration in HDL-cholesterol (8.1 +/- 1.7 micromol/l vs. 22.5 +/- 7.5 micromol/l, p < 0.001), and a twofold increase in LDL-VLDL-cholesterol (22.0 +/- 3.7 micromol/l vs. 49.0 +/- 9.0 micromol/l, p < 0.001). Plasma and HDL vitamin E levels were higher in women than in men at the onset of treatment (6.8 +/- 0.96 micromol/l vs. 9.5 +/- 1.10 micromol/l), but during the treatment these gender-related differences disappeared. When plasma vitamin E concentration were considered 100% and the changes of the vitamin E concentrations of lipoproteins were calculated, it was found that supplementation with vitamin E in men increased the vitamin E concentration of LDL-VLDL cholesterol to a higher extent compared to women (LDL-VLDL % in men: 59.8 +/- 7.43%, in women: 49.3 +/- 7.41%, p < 0.05). All the observed changes regressed one month after cessation of supplementation. The level of hsCRP decreased during vitamin E treatment (1.07 +/- 0.9 mg/l vs. 0.2 +/- 0.14 mg/l, p < 0.001), and remained suppressed after the cessation of treatment (0.37 +/- 0.4, p < 0.01). CONCLUSIONS: These results support the hypothesis that women at young age are better protected against lipid-peroxidation as compared to men because of higher HDL vitamin E concentrations. Vitamin E supplementation in men eliminates this concentration difference between genders, and also increases LDL-VLDL vitamin E. In both genders high concentration of vitamin E in lipoproteins was associated with low hsCRP concentration.     

Selenium and vitamin E status: impact on viral pathogenicity

Selenium (Se), an essential trace element, and vitamin E, a lipid soluble antioxidant, are important mediators for protection against oxidative stress. Recent work has demonstrated that deficiencies in either Se or vitamin E result in increased viral pathogenicity and altered immune responses. Furthermore, deficiencies in either Se or vitamin E results in specific viral mutations, changing relatively benign viruses into virulent ones. Thus, host nutritional status should be considered a driving force for the emergence of new viral strains or newly pathogenic strains of known viruses.     

Determinants of vitamin D status in adult Crohn's disease patients, with particular emphasis on supplemental vitamin D use

OBJECTIVE: To investigate determinants (pathophysiologic and physiologic, behavioural and lifestyle) of vitamin D status in Irish Crohn's disease (CD) patients. DESIGN: A cross-sectional observational study. SETTING: Cork City, Ireland (52 degrees N). SUBJECTS: Crohn's Disease patients (n=58; mean age 38.1 years) were recruited from Cork University Hospital. RESULTS: Fifty and nineteen percent of Irish CD patients were vitamin D deficient (defined by serum 25 hydroxyvitamin (OH) D levels <50 nmol/l) during winter and summer, respectively. Multiple regression analysis showed that summer-time serum 25 (OH) D levels were positively associated with use of vitamin D supplements (P=0.033) and negatively associated with smoking (P=0.006) and being male (P=0.063). During winter-time, use of vitamin D supplements (P=0.041) and sun habits (P=0.066) were positively associated, whereas small intestinal involvement (P=0.005) and body mass index (BMI) (P=0.083) were negatively associated with serum 25 (OH) D levels. There was no significant association between other non-pathophysiologic (age, dietary calcium or vitamin D) or pathophysiologic factors (steroid use, resection), and serum 25 (OH) D levels, at either season. Approximately 41 and 60% of the total variation in summer- and winter-time serum 25 (OH) D, respectively, was explained by this model. CONCLUSION: A high proportion of Irish CD patents had some level of vitamin D deficiency (<50 nmol/l) during late-wintertime. Use of regular low-dose supplemental vitamin D, particularly by patients with small intestinal involvement, cessation of smoking and adequate, but responsible, exposure to summer sunlight as well as maintaining BMI in the normal range could help maintain adequate vitamin D levels during wintertime.     

Effect of vitamin E on cholesterol plasma lipoprotein distribution and metabolism in rabbit

In the rabbit, after nine weeks on a basal synthetic diet supplemented with stripped corn oil and varying amount of vitamin E, plasma cholesterol level was depressed as the supplementation of vitamin E was increased. This hypocholesterolemic effect was accompanied by an increase in hepatic cholesterol-7 alpha-hydroxylase activity and cytochrome P-450 level and by a redistribution of plasma lipoprotein-cholesterol resulting in the elevation of high density to low density lipoprotein-cholesterol ratio.     

Konjac mannan improves the vitamin B-6 status of rats fed a vitamin B-6-deficient diet

To investigate how dietary fiber in the diet affects vitamin B-6 nutriture of rats which have been deprived of vitamin B-6, rats were made vitamin B-6-deficient by feeding a vitamin B-6-deficient 70% casein diet. They were fed 2% cellulose powder-based vitamin B-6-deficient diets supplemented with 3% of additional dietary fiber sources (agar, konjac mannan, pectin and cellulose powder) for subsequent 18 days. Vitamin B-6 status was evaluated according to several biological criteria (weight gain, urinary excretion of xanthurenic acid after tryptophan loading, plasma pyridoxal 5'-phosphate, apparent pyridoxal 5'-phosphate-saturation of liver kynureninase, urinary excretion of 4-pyridoxic acid and fecal output of vitamin B-6). Vitamin B-6 status evaluated by these criteria was considerably improved in the konjac mannan-fed group, when compared with the respective data of the vitamin B-6 supplemented group. The relative mean effect of the konjac mannan diet was about 40% of the vitamin B-6 supplemented diet. In conclusion, konjac mannan was effective for improving the vitamin B-6 nutritional state in vitamin B-6-deprived rats.     

The vitamin E status among glucose-6 phosphate dehydrogenase deficient patients and effectiveness of oral vitamin E

The effect of oral vitamin E therapy (800 IU/day) on correcting haematologic variables and on raising the plasma vitamin E level among glucose-6 phosphate dehydrogenase deficient subjects with history of hemolysis was studied. After 16 week period there was a positive response to vitamin E administration presented by sustained improvement in blood hemoglobin and plasma vitamin E concentrations. In the meanwhile, the vitamin E supplementation led to reduced reticulocytosis and control % hemolysis.     

Altered lipoprotein metabolism in spontaneous vitamin E deficiency of owl monkeys

Certain owl monkeys (AOT) develop spontaneous hemolytic anemia that responds to vitamin E. The anemia is associated with red blood cell lipid peroxidation and altered red blood cell membrane lipid composition. To investigate these changes, plasma lipid and lipoprotein profiles were characterized in anemic, anemia-susceptible, and anemia-resistant AOT. The plasma vitamin E and vitamin A concentrations were assessed as an index of fat absorption and the effect of corn oil supplementation and vitamin E-selenium injection were measured. Anemia-susceptible AOT had depressed plasma levels of vitamin E and A and an altered lipoprotein metabolism characterized by elevated ratios of low/high density lipoprotein cholesterol and free to esterified cholesterol in these lipoproteins. Vitamin E-selenium injection in anemia-susceptible AOT increased the plasma vitamin E, and vitamin E and corn oil supplements reduced the high density lipoprotein free to esterified cholesterol ratio. The data suggest that the AOT suffer from fat malabsorption and that the consequences (including tocopherol deficiency) result in altered cholesterol metabolism.     

Effect of in-vivo supplementation with low-dose vitamin E on susceptibility of low-density lipoprotein and high-density lipoprotein to oxidative modification.

We have examined the effects of in-vivo supplementation with low-dose vitamin E on the susceptibility of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) to oxidative modification, and compared the oxidizability of HDL with that of LDL.

Normal humans (n = 8) ingested vitamin E (150 mg/day for 1 week, followed by 300 mg/day for 3 weeks) in divided doses with meals. The subjects did not use any medications or vitamins before being enrolled in this study. Fasting blood samples were drawn before and at the end of supplementation. LDL and HDL were separated by sequential ultracentrifugation and susceptability to copper-mediated oxidation was measured.

After vitamin E supplementation, vitamin E content of LDL increased 1.9-fold and that of HDL increased 1.8-fold. Lag time before initiation of LDL oxidation lengthened significantly (+20%, p < 0.01), and the propagation rate of LDL decreased significantly (?10%, p < 0.05). The lag time of HDL oxidation did not change significantly, but the propagation rate of HDL oxidation decreased significantly (?24%, p < 0.001). The lag time of HDL oxidation was shorter than that of LDL. HDL contained the same or higher concentrations of vitamin E relative to lipid mass as LDL, but contained lower concentration of CoQ10 relative to lipid mass and fewer molecules of vitamin E and beta-carotene per particle than LDL.

We conclude that in-vivo supplementation of low-dose vitamin E protects LDL against oxidative modification and decreases the propagation rate of HDL oxidation significantly. We suggest that supplementation with low-dose vitamin E would be beneficial for ameliorating atherosclerosis.     

600名婴幼儿维生素D制剂应用现状及影响因素

目的 了解0~3岁婴幼儿维生素D的应用现状,分析其影响因素,为指导维生素D的合理应用提供依据。方法 随机抽取2016年1-12月在郑州大学第三附属医院儿童保健门诊进行健康体检和计划免疫的600名0~3岁婴幼儿作为调查对象,采用自制问卷对婴幼儿的主要带养人进行调查。结果 郑州市婴幼儿维生素D制剂的使用率为63.5%,平均添加时间为3月龄,平均停服时间为15月龄。多因素Logistic回归分析显示,婴幼儿年龄(OR＝0.816,95%CI:0.586~0.912)、母亲文化水平(OR＝0.573,95%CI:0.319~0.881)和喂养方式(OR＝0.346,95%CI:0.272~0.874)是影响维生素D制剂应用的因素。结论 维生素D制剂在婴幼儿中应用不规范,建议开展有效的健康教育活动,指导儿童家长合理补充维生素D制剂。     

Effect of intraperitoneally injected tocopherol on vitamin E status of dairy cow

The effect of intraperitoneal (IP) administration of vitamin E on the concentration of tocopherol in the blood and milk of cows was studied. Two trials were carried out using a total of twenty-four Holstein cows. In the first trial, two doses of dl-alpha-tocopherol (1 g and 5 g) were given to six cows in each treatment. Administration of 1 g caused a small increase in blood and milk concentrations; dosing with 5 g IP caused appreciable increases in both plasma and milk concentrations. Plasma and milk concentrations peaked 1 d after dosing with a maximum value of 10.7 micrograms/ml plasma and 1.39 micrograms/ml milk. Then there was a continuous decline during the 14 d experimental period. In the 2nd trial, twelve cows were dosed IP with the acetate form of vitamin E. Six cows were given 5 g and six others 10 g of dl-alpha-tocopherol acetate. Maximum plasma vitamin E concentrations occurred at d 2 (7.4 micrograms/ml) and d 1 (10.9 micrograms/ml) for the cows dosed with 5 and 10 g of the ester form, respectively. Milk vitamin E concentrations were significantly higher (P less than .05) during the first 4 d for cows dosed with 10 compared to those given 5 g. During the 14 d experimental period, maximum milk vitamin E concentration for the 10 g group was 141 micrograms vitamin E/g fat 2 d after dosing and for the 5 g group 62 micrograms vitamin E/mg fat also at 2 d after dosing. The technique of dosing cows with vitamin E by IP proved to be an effective way for increasing vitamin E status. These treatments had no effect on cholesterol content of milk fat. However, it was noted that cholesterol level was lower in PM milking as compared to AM milking.     

Effect of dietary supplementation of vitamin E on serum lipids and lipoproteins in rabbits fed a cholesterolemic diet.

The effect of dietary supplementation of vitamin E on serum cholsterol, triglycerides, lipoproteins and lipoprotein composition was studied in rabbits fed a one per cent cholesterol diet for a period of twelve weeks. Vitamin E supplemented animals were found to maintain significantly lower concentrations of serum cholesterol, triglycerides and very low density lipoproteins (d less than 1.006). The difference in the serum lipid content was mainly in the very low density lipoproteins of d less than 1.006. The possibility of an increased clearance of chylomicron remnants and decreased inhibition of extrahepatic lipoprotein lipase in hypercholesterolemic rabbits as a result of vitamin E supplementation is discussed in the light of the results obtained.