Bioavailability of vitamin D2 from UV-B-irradiated button mushrooms in healthy adults deficient in serum 25-hydroxyvitamin D: a randomized controlled trial.

BACKGROUND/OBJECTIVES: Mushrooms contain very little or any vitamin D(2) but are abundant in ergosterol, which can be converted into vitamin D(2) by ultraviolet (UV) irradiation. Our objective was to investigate the bioavailability of vitamin D(2) from vitamin D(2)-enhanced mushrooms by UV-B in humans, and comparing it with a vitamin D(2) supplement. SUBJECTS/METHODS: Fresh mushrooms were irradiated with an UV-B dose of 1.5 J/cm(2), increasing vitamin D(2) content from <1 to 491 µg/100 g and made to an experimental soup. In this 5-week, single-blinded, randomized, placebo-controlled trial, 26 young subjects with serum 25-hydroxyvitamin D (25OHD) ≤ 50 nmol/l were randomly assigned into three groups ((a) mushroom, (b) supplement and (c) placebo). They received during winter (a) 28,000 IU (700 µg) vitamin D(2) via the experimental soup, or (b) 28,000 IU vitamin D(2) via a supplement or (c) placebo, respectively. RESULTS: After 2 weeks, serum 25OHD was significantly higher in the mushroom than in the placebo group (P=0.001). The serum 25OHD concentrations in the mushroom and supplement groups rose significantly and similarly over the study period by 3.9 nmol/l (95% confidence interval (95% CI): 2.9, 4.8) and by 4.7 nmol/l per week (95% CI: 3.8, 5.7), respectively. CONCLUSIONS: We are the first to demonstrate in humans that the bioavailability of vitamin D(2) from vitamin D(2)-enhanced button mushrooms via UV-B irradiation was effective in improving vitamin D status and not different to a vitamin D(2) supplement. This trial was registered at http://germanctr.de as DRKS00000195.

Water, electrolytes, vitamins and trace elements - Guidelines on Parenteral Nutrition, Chapter 7.

A close cooperation between medical teams is necessary when calculating the fluid intake of parenterally fed patients. Fluids supplied parenterally, orally and enterally, other infusions, and additional fluid losses (e.g. diarrhea) must be considered. Targeted diagnostic monitoring (volume status) is required in patients with disturbed water or electrolyte balance. Fluid requirements of adults with normal hydration status is approximately 30-40 ml/kg body weight/d, but fluid needs usually increase during fever. Serum electrolyte concentrations should be determined prior to PN, and patients with normal fluid and electrolyte balance should receive intakes follwing standard recommendations with PN. Additional requirements should usually be administered via separate infusion pumps. Concentrated potassium (1 mval/ml) or 20% NaCl solutions should be infused via a central venous catheter. Electrolyte intake should be adjusted according to the results of regular laboratory analyses. Individual determination of electrolyte intake is required when electrolyte balance is initially altered (e.g. due to chronic diarrhea, recurring vomiting, renal insufficiency etc.). Vitamins and trace elements should be generally substituted in PN, unless there are contraindications. The supplementation of vitamins and trace elements is obligatory after a PN of >1 week. A standard dosage of vitamins and trace elements based on current dietary reference intakes for oral feeding is generally recommended unless certain clinical situations require other intakes.

[Antioxidants--helpful or harmful?]. / Antioxidanzien--hilfreich oder schädlich?

Fortified food claiming to exert a special function are increasingly offered on the market. Antioxidants (vitamin C, E and beta-carotene) are the major compounds in fortified foods. Due to the fact that the fortified vitamins do not exceed the recommended daily allowances within a food there is no risk for the consumer. Even in speculative cases of accumulation of antioxidants from different fortfied food sources there is no real risk. However, fortified food should not be taken to compensate an unbalanced and unhealthy diet. This risk is far more real because fortified food contains only a few antioxidants whereas a balanced diet contains hundreds. Whether the consumer may have a benefit from fortified food has not yet been evaluated with respect to antioxidant vitamins.

High-dose intravenous vitamin C is not associated with an increase of pro-oxidative biomarkers.

OBJECTIVE: High-dose vitamin C therapy might mediate beneficial clinical effects by counteracting reactive oxygen species. However, concerns are raised whether this approach might provoke diametrical (ie pro-oxidative) effects. The objective was to determine ascorbyl free radical (AFR) concentrations and potential variables of pro-oxidative damage. DESIGN: Crossover study; six healthy males received daily infusions of 750 or 7500 mg vitamin C for six consecutive days. Fasting concentrations of vitamin C and AFR were determined daily. On day 1, concentrations of vitamin C and AFR were measured at 0.25, 0.5, 1, 2, 4 and 8 h post infusion. Plasma concentrations of thiobarbituric acid-reactive substances (TBARS), tocopherol and urine concentrations of 8-oxoguanosine were determined on days 1 and 6. RESULTS: Kinetic studies on day 1 showed that concentrations of vitamin C and AFR displayed parallel dose- and time-dependent kinetics and elimination was highly efficient. Vitamin C and AFR fasting concentrations on days 2-6 were slightly above the baseline, suggesting new, stable steady states. TBARS decreased in both groups, whereas tocopherol and 8-oxoguanosine concentrations remained unchanged. CONCLUSION: Kinetics of AFR largely depend on plasma vitamin C concentrations and AFR is eliminated efficiently. Our data do not support induction of pro-oxidative effects in healthy volunteers given intravenous high-dose vitamin C. SPONSORSHIP: Pascoe Pharmazeutische Präparate GmbH, Giessen, Germany.

Importance of vitamin-A for lung function and development.

Vitamin-A is essential for growth and development of cells and tissues. In its active form, retinoic acid, it controls the regular differentiation as a ligand for retinoic acid receptors (RAR, RXR) and is involved in the integration (gap junction formation) of cell formations [Nature 37 (1994) 528; International Review of Cytology. San Diego Academic Press, 1-31]. Vitamin-A plays a substantial role, especially in the respiratory epithelium and the lung. During moderate vitamin-A-deficiency, the incidence for diseases of the respiratory tract is considerably increased and repeated respiratory infections can be influenced therapeutically by a moderate vitamin-A-supplementation [Aust. Paediatr. J. 22 (1986) 95; Lancet 338 (1991) 67]. In addition to the importance of the vitamin for the lung function, vitamin-A is also responsible for the development of many tissues and cells as well as for the embryonic lung development. Recent studies proved that the control occurs by different expressions of retinoid receptors as well as by time-dependent changes of the vitamin-A-metabolism respectively via cellular vitamin-A-binding proteins (CRBP: cytoplasmatic retinol binding protein; CRABP: cytoplasmatic retinoic acid binding protein).

Uptake of vitamin A in buccal mucosal cells after topical application of retinyl palmitate: a randomised, placebo-controlled and double-blind trial.

Retinoids have been reported to produce regressions in metaplastic changes of the mucosal epithelium. In order to define the role of these micronutrients in the prevention of squamous metaplasia of the oral cavity, it is necessary to measure their uptake in target tissues such as the buccal mucosal epithelium. We demonstrated in a trial that retinyl palmitate applied topically via a toothpaste is taken up by buccal mucosal cells in young healthy volunteers. In the randomised, parallel-designed, placebo-controlled and double-blind trial, forty volunteers divided in two groups cleaned their teeth either with a placebo toothpaste or a retinyl palmitate-containing toothpaste (1 mg/g) for 56 d. Buccal mucosal cells samples were taken from the healthy volunteers during the retinyl palmitate application and the following wash-out phase to determine the concentration of retinyl palmitate and retinol by HPLC. Supplementary blood samples were taken from the volunteers on days 0 and 56 to investigate changes in plasma retinyl palmitate and retinol concentrations. Results from only thirty participants (sixteen placebo and fourteen treated subjects) were used in the statistical evaluation as the remaining sample results were spoiled by a technical defect during the HPLC analysis. A significant (P<0.05) uptake of retinyl palmitate in buccal mucosal cells after 7 d and a significant (P<0.05) increase of plasma retinol after 17 d was demonstrated in our present study. The uptake of retinyl palmitate and the following hydrolysis to retinol led to an enrichment of vitamin A in buccal mucosal cells.

Carotenoids are decreased in biopsies from colorectal adenomas.

UNLABELLED: A lower intake of carotenoids is associated with an increased risk of colorectal cancer. In order to take advantage of the chemopreventive properties of carotenoids, it is necessary to determine carotenoid concentration at the target tissue. As early stages in the adenoma-carcinoma sequence of colorectal cancer might be susceptible to chemoprevention, we sought to determine carotenoid concentrations in biopsies from colorectal adenomas. METHODS: Biopsies from colorectal adenomas and non-involved mucosa were taken from seven patients. For controls, biopsies were obtained from the ascending and descending colon of patients without polyps (n = 5). Concentration of carotenoids (alpha-, beta-carotene, lutein, lycopene, zeaxanthin, beta-cryptoxanthin) were determined by optimizing gradient HPLC-analysis. Results are expressed as pmol/microg DNA. RESULTS: Except for alpha-carotene, all carotenoids could reliably be detected in all specimens. In control patients carotenoid concentrations were highest in the ascending colon, being followed by the descending colon and non-involved mucosa from polyp-carriers. In colorectal adenomas all carotenoids were significantly reduced as compared to-non-involved mucosa (beta-carotene: 0.37 vs 0.19, P<0.03; lycopene: 0.34 vs 0.21, P<0.06, beta-cryptoxanthin: 0.14 vs 0.09, P<0.03, zeaxanthin: 0.18 vs 0.09, P<0.02; lutein: 0.18 vs 0.13,P <0.02). CONCLUSION: All carotenoids investigated are reduced in colorectal adenomas, suggesting that mucosal carotenoids could serve as biomarkers for predisposition to colorectal cancer. Moreover, anti-tumor activity exerted by carotenoids is limited due to mucosal depletion. We speculate that supplementation of a larger array of carotenoids might be beneficial for patients with colorectal adenoma.

2-Methoxyestradiol enhances reactive oxygen species formation and increases the efficacy of oxygen radical generating tumor treatment.

In an investigation of the antitumor effects of 2-methoxyestradiol (2-ME) in combination with other reactive oxygen generating treatments, 2-ME (0.5 microM) was found to completely inhibit cell proliferation of rat DS-sarcoma cells in vitro, with 71% of cells dying after exposure to 5 microM 2-ME. Concentration-dependent increases in ROS-formation, lipid peroxidation and mitochondrial changes were also observed, and an elevation in caspase-3 activity resulted in DNA fragmentation and apoptosis. Combination of 2-ME with hypoxanthine and xanthine oxidase enhanced in vitro cytotoxicity. In vivo, 2-ME caused a slight inhibition of tumor growth, with no tumors cured. Combination of 2-ME treatment with localized 44 degrees C hyperthermia, respiratory hyperoxia and xanthine oxidase caused a tumor growth delay with 51% of tumors cured. These results suggest that amplifying the levels of reactive oxygen species within tumor tissue with substances such as 2-ME may prove to be a promising strategy for adjuvant treatment of solid tumors.

Effects of RRR-alpha-tocopherol on leukocyte expression of HSP72 in response to exhaustive treadmill exercise.

Previous research revealed an increased expression of HSP72 in leukocytes after vigorous endurance exercise. We questioned whether more intensive but shorter exercise also induces leukocyte HSP72 synthesis. To delineate the role of reactive oxygen species (ROS) in exercise-related HSP72 induction, we additionally examined the effect of RRR-alpha-tocopherol (alpha-toc) on HSP72 expression using a double-blind placebo (P) controlled cross-over design. After supplementation with alpha-toc (500 I.U. daily) or P for 8 days, 9 male subjects performed a combined exhaustive treadmill protocol (total duration 29.4 +/- 2.0 min). HSP72 was assessed on mRNA (RT-PCR) and protein levels (flow cytometry). HSP72 mRNA rose 3 h after exercise only in the P group, but individual differences (alpha-toc - P) did not reveal significant treatment effects. A moderate but significant rise of HSP72 protein occurred in granulocytes up to 48 h after exercise. Three hours post-exercise, granulocyte HSP72 protein was lower when subjects received alpha-toc, but this effect vanished 24 and 48 h post-exercise. Exhaustive treadmill exercise augments HSP72 mRNA in leukocytes and induced a moderate but prolonged response of granulocyte HSP72 protein. These exercise effects are lower when compared to earlier findings obtained after vigorous endurance exercise. ROS seem to be involved, but do not play the major role in the induction of granulocyte HSP72 synthesis after exhaustive exercise.

UV light, beta-carotene and human skin--beneficial and potentially harmful effects.

Solar radiation is one of the most important environmental stress agents for human skin, causing sunburn, premature skin aging, and skin cancer. Beta-carotene is discussed to protect against photooxidative stress and thus prevent skin damage. Though beta-carotene has been successfully used against photosensitivity in patients with erythropoietic protoporphyria, its beneficial potential in normal skin is still uncertain. A number of experimental studies indicate protective effects of beta-carotene against acute and chronic manifestations of skin photodamage. However, most clinical studies have failed to convincingly demonstrate its beneficial effects so far. Nevertheless, intake of oral beta-carotene supplements before sun exposure has been recommended on a population-wide basis. Recent studies on skin cells in culture have revealed that beta-carotene acts not only as an antioxidant but also has unexpected prooxidant properties. At present, there is an ongoing debate on the protective or potentially harmful role of beta-carotene in human skin.

Protective effects of vitamins C and E on the number of micronuclei in lymphocytes in smokers and their role in ascorbate free radical formation in plasma.

Cigarette smoke is widely believed to increase free radical concentrations causing subsequent oxidative processes that lead to DNA damage and hence, to several diseases including lung cancer and atherosclerosis. Vitamin C is a reducing agent that can terminate free-radical-driven oxidation by being converted to a resonance-stabilized free radical. To investigate whether short-term supplementation with the antioxidants vitamin C and E decreases free-radical-driven oxidation and thus decreases DNA damage in smokers, we determined the frequency of micronuclei in lymphocytes in 24 subjects and monitored the electron paramagnetic resonance signal of ascorbate free radical formation in plasma. Further parameters comprised sister-chromatid exchanges and thiobarbituric acid-reactive substances. Twelve smokers and twelve non-smokers took 1000 mg ascorbic acid daily for 7 days and then 1000 mg ascorbic acid and 335.5 mg RRR-alpha-tocopherol daily for the next 7 days. Baseline concentrations of both vitamins C and E were lower and baseline numbers of micronuclei were higher (p < 0.0001) in smokers than in non-smokers. After 7 days of vitamins C and E, DNA damage as monitored by the number of micronulei was decreased in both, smokers and non-smokers, but it was more decreased in smokers as indicated by fewer micronuclei in peripheral lymphocytes (p < 0.05). Concomitantly, the plasma concentrations of vitamin C (p < 0.001) as well as the ascorbate free radical (p < 0.05) were increased. The corresponding values in non-smokers, however, did not change. Our findings show that increased ascorbate free radical formation in plasma after short-term supplementation with vitamins C and E can decrease the number of micronuclei in blood lymphocytes and thus DNA damage in smokers.

Carotenoid:methyl-beta-cyclodextrin formulations: an improved method for supplementation of cultured cells.

BC. Two days after supplementation with 5 microM BC in MbetaCD, cellular BC levels reached a maximum of 140+/-11 pmol/microg DNA, leveling off to 100+/-15 pmol/microg DNA until day 8. Incubation with BC dissolved in THF/DMSO resulted in a lower BC uptake of 105+/-14 pmol/microg DNA and 64+/-20 pmol/microg DNA respectively. No cytotoxic effects of these formulations were detected. The results show that the MbetaCD formulation is an improved method for investigations of carotenoids and other lipophilic compounds in in vitro test systems compared to methods using organic solvents.

Physical exercise-induced expression of inducible nitric oxide synthase and heme oxygenase-1 in human leukocytes: effects of RRR-alpha-tocopherol supplementation.

This study evaluated the effects of RRR-alpha-tocopherol (500 IU/day, 8 days) on in vivo cytokine response and cytoplasmic expression of inducible nitric oxide synthase (iNOS) and the antioxidant stress protein heme oxygenase-1 (HO-1) in human leukocytes after exhaustive exercise. Thirteen men were investigated in a double-blind, placebo-controlled, cross-over study with a wash-out period of 28 days. The exercise procedure consisted of an incremental treadmill test followed by a continuous run until exhaustion at 110% of the individual anaerobic threshold (total duration 28.5 +/- 0.8 min). HO-1 and iNOS protein were assessed in mono- (M), lympho-, and granulocytes (G) using flow cytometry. Plasma interleukin-6 (IL-6) and IL-8 were measured by ELISA. IL-6 rose significantly whereas IL-8 did not exhibit significant changes after exercise. Changes of IL-6 were not affected by RRR-alpha-tocopherol. Exercise induced an increase of iNOS protein primarily in M and G. A small, but significant, increase of HO-1 protein was measured in M and G. RRR-alpha-Tocopherol did not show any significant effects on cytoplasmic expression of iNOS and HO-1 at rest and after exercise. In conclusion, exhaustive exercise induces expression of iNOS and HO-1 in human leukocytes by a mechanism that is not sensitive to RRR-alpha-tocopherol supplementation.

Enhancement of the UVA induction of haem oxygenase-1 expression by beta-carotene in human skin fibroblasts.

beta-Carotene has often been discussed as a means to reduce the risk of skin photodamage. We studied the antioxidative potential of beta-carotene in human skin fibroblasts exposed to ultraviolet A light. Surprisingly, we found a pro-oxidative effect of beta-carotene. Using the induction of haem oxygenase-1 as a marker for oxidative stress, we found a strong enhancement of gene expression by beta-carotene in ultraviolet A-irradiated cells. This effect was clearly suppressed by concomitant addition of vitamin E but only moderately by vitamin C. The results show that beta-carotene has pro-oxidative properties in human skin fibroblasts exposed to ultraviolet-A light.

Enhancement of oxidative cell injury and antitumor effects of localized 44 degrees C hyperthermia upon combination with respiratory hyperoxia and xanthine oxidase.

The effects of respiratory hyperoxia (RH) and xanthine oxidase (XO) during localized hyperthermia (HT) were investigated by determining markers of oxidative damage to lipids and proteins and tumor growth. Anesthetized rats with s.c. DS-sarcomas underwent one of the following treatments: (a) localized saline-bath HT (60 min, 44 degrees C); (b) HT + RH (100% O2); and (c) HT + RH + XO (15 units/kg i.v.). Sham-treated animals served as controls. Tumors were investigated for: (a) thiobarbituric acid-reactive substance formation and protein-bound 4-hydroxynonenal, as indicators of lipid peroxidation; (b) reactive oxygen-mediated protein modifications; (c) apoptosis; and (d) tumor volume growth. Upon treatment, increases in thiobarbituric acid-reactive substances, protein-bound 4-hydroxynonenal, protein-associated carbonyl functions, and number of cells undergoing apoptosis were found in tumor tissue, together with an inhibition of tumor growth. When treatment groups were compared, effects in the group HT + RH + XO were generally most pronounced. These findings indicate that the antitumor effect of HT is at least partially mediated through the selective induction of lipid peroxidation and oxidative injury in tumor cells, leading to apoptosis. This effect was enhanced by adding RH or RH + XO, presumably due to enhanced tissue damage following an increased formation of reactive oxygen species, with higher levels of lipid peroxidation and protein oxidation.

Short-term parenteral application of alpha-tocopherol leads to increased concentration in plasma and tissues of the rat.

Numerous studies suggest that supplemental vitamin E prior to or during vast surgeries might diminish or even prevent ischemia/reperfusion-induced injuries. In the present placebo-controlled study male Sprague-Dawley rats were supplemented parenterally or orally with alpha-tocopherol for three consecutive days. The applied amount of alpha-tocopherol was 2.3 micromol per day for oral and 1.2 micromol per day for parenteral supplementation. The enrichment of vitamin E concentrations in plasma and tissue samples (aortic endothelium, liver, and lung) was determined by HPLC. The vitamin E level was elevated following intravenous supplementation in plasma (21.4 +/- 1.9 micromol/L vs. 10.2 +/- 1.7 micromol/L in parenteral control group), in aortic endothelium (1.1 +/- 0.2 pmol/mm2 vs. 0.5 +/- 0.1 pmol/mm2) and in liver and lung (41.3 +/- 7.5 pmol/mg vs. 22.9 +/- 6.5 pmol/mg and 75.6 +/- 13.6 pmol/mg vs. 51.7 +/- 5.9 pmol/mg, respectively). Oral supplementation for three days also led to an increased level in liver (38.2 +/- 7.7 pmol/mg vs. 22.9 +/- 6.6 pmol/mg in oral control group) and in lung (67.8 +/- 5.7 pmol/mg vs. 51.7 +/- 9.3 pmol/mg) but not in aortic endothelium or plasma (0.8 +/- 0.3 pmol/mm2 vs. 0.6 +/- 0.3 pmol/mm2 and 12.0 +/- 2.2 micromol/L vs. 10.7 +/- 2.6 micromol/L).

Antioxidant vitamins in prevention.

The authors are aware that there is still a need for much research to elucidate the possible preventive effects of antioxidant vitamins with regard to degenerative and neoplastic diseases. There must also be vigorous examination of the evidence that antioxidant vitamins can play a crucial part in a large number of other disorders (Alzheimer's disease, Parkinson's disease, diabetes, chronic and acute inflammations, airway disorders, reperfusion syndrome). The aim of prevention-oriented medical research must be to develop suitable measures able to make a considerable contribution to the overall prevention policy. Although there is still uncertainty about the mode of action and the optimal dosage of antioxidant nutrients and dietary constituents, particularly because of the safety when the dosage is correct, more information must be provided about early prevention of an inappropriate, low antioxidant intake; intake in the diet should definitely be preferred to supplementation because of the other beneficial effects of the recommended foodstuffs.

Interaction of vitamins E and K: effect of high dietary vitamin E on phylloquinone activity in chicks.

To determine the influence of vitamin E on phylloquinone activity, one day-old chicks were raised on a masch diet supplemented with different amounts of vitamin E for 31 days. In chicks fed a diet high in vitamin E (4000 mg allrac-alpha-tocopheryl acetate/kg) but adequate in vitamin K (0.14 mg phylloquinone/kg) a threefold increase in prothrombin time and an increase in mortality rate (five out of twelve animals died from increased bleeding tendency) was observed. The inhibiting effect of high dietary vitamin E on procoagulant factors could be prevented by increasing dietary phylloquinone supplementation. Weight development, and feed utilization were insignificantly different in chicks fed different amounts and ratios of vitamins E and K1. Plasma and liver alpha-tocopherol levels correlated with dietary amounts of vitamin E. Increased phylloquinone levels in the diet did not significantly influence alpha-tocopherol concentrations in plasma and liver, but coagulopathy caused by high vitamin E intake could be reversed.