Vitamin supplementation in healthy patients: What does the evidence support?

This review, with handy tables, summarizes which vitamins offer proven benefits-and which don't.

Autism, seasonality and the environmental perturbation of epigenome related vitamin levels

An argument is put forward for environmental modulators of photolabile or photosynthetic vitamins mediating autism risk via a complex downstream interaction of genetic/epigenetic phenomena that provide an explanation for seasonality in this and other developmentally originated disorders.

Mice fed on a diet enriched with genetically engineered multivitamin corn show no sub-acute toxic effects and no sub-chronic toxicity

Multivitamin corn is a novel genetically engineered variety that simultaneously produces high levels of β-carotene, ascorbate and folate, and therefore has the potential to address simultaneously multiple micronutrient deficiencies caused by the lack of vitamins A, B9 and C in developing country populations. As part of the development process for genetically engineered crops and following European Food Safety Authority (EFSA) recommendations, multivitamin corn must be tested in whole food/feed sub-chronic animal feeding studies to ensure there are no adverse effects, and potential allergens must be identified. We carried out a 28-day toxicity assessment in mice, which showed no short-term sub-acute evidence of diet-related adverse health effects and no difference in clinical markers (food consumption, body weight, organ/tissue weight, haematological and biochemical blood parameters and histopathology) compared to mice fed on a control diet. A subsequent 90-day sub-chronic feeding study again showed no indications of toxicity compared to mice fed on control diets. Our data confirm that diets enriched with multivitamin corn have no adverse effects on mice, do not induce any clinical signs of toxicity and do not contain known allergens.

Increased 3-nitrotyrosine levels in mitochondrial membranes and impaired respiratory chain activity in brain regions of adult female rats submitted to daily vitamin A supplementation for 2 months

Vitamin A supplementation among women is a common habit worldwide in an attempt to slow aging progression due to the antioxidant potential attributed to retinoids. Nonetheless, vitamin A elicits a myriad of side effects that result from either therapeutic or inadvertent intake at varying doses for different periods. The mechanism behind such effects remains to be elucidated. In this regard, we performed the present work aiming to investigate the effects of vitamin A supplementation at 100, 200, or 500IU/kgday(-1) for 2 months on female rat brain, analyzing tissue lipid peroxidation levels, antioxidant enzyme activities (both Cu/Zn-superoxide dismutase - SOD - and Mn-SOD); glutathione S-transferase (GST) and monoamine oxidase (MAO) enzyme activity; mitochondrial respiratory chain activity and redox parameters in mitochondrial membranes, as well as quantifying α- and β-synucleins, β-amyloid peptide(1-40), immunoglobulin heavy-chain binding protein/78kDa glucose-regulated protein (BiP/GRP78), receptor for advanced glycation end products (RAGE), D2 receptor, and tumor necrosis factor-α (TNF-α) contents in rat frontal cortex, hippocampus, striatum, and cerebellum. We observed increased lipid peroxidation marker levels, altered Cu/Zn-SOD and Mn-SOD enzyme activities, mitochondrial nitrosative stress, and impaired respiratory chain activity in such brain regions. On the other hand, we did not find any change in MAO and GST enzyme activities, and on α- and β-synucleins, β-amyloid peptide(1-40), GRP78/BiP, RAGE, D2 receptor, and TNF-α contents. Importantly, we did not observed any evidence regarding an antioxidant effect of such vitamin at low doses in this experimental model. The use of vitamin A as an antioxidant therapy among women needs to be reexamined.

Intermedin inhibits vascular calcification by increasing the level of matrix gamma-carboxyglutamic acid protein

AIMS

Vascular calcification (VC) is highly associated with increased morbidity and mortality in patients with advanced chronic kidney disease. Paracrine/autocrine factors such as vasoactive peptides are involved in VC development. Here, we investigated the expression of the novel peptide intermedin (IMD) in the vasculature, tested its ability to prevent VC in vivo and in vitro, and examined the mechanism involved.

METHODS AND RESULTS

Rat VC was induced by administration of vitamin D3 plus nicotine (VDN). IMD (100 ng kg(-1) h(-1)) was systemically administered by a mini-osmotic pump. VDN-treated rat aortas showed lower IMD content and increased expression of its receptors, along with increased vascular calcium deposition and alkaline phosphatase (ALP) activity. Low IMD levels were accompanied by increased calcium deposition in human atherosclerotic plaques. In vivo administration of IMD greatly reduced vascular calcium deposition and ALP activity in VDN-treated rats when compared with vehicle treatment, which was further confirmed in cultured vascular smooth muscle cells. Concurrently, the loss of smooth-muscle lineage markers and matrix gamma-carboxyglutamic acid (Gla) protein (cMGP) in aortas was ameliorated by administering IMD to rats with VC, and the increased phosphor-Smad(1/5/8) and core binding factor alpha-1 levels in calcified vasculature were also reduced. However, the inhibitory effects of IMD on VC were eliminated upon pre-treatment with warfarin or small interfering RNA to reduce cMGP.

CONCLUSION

Reduced endogenous IMD levels are associated with increased mineralization in vivo, and administration of IMD inhibits VC development by increasing cMGP levels. IMD may be an endogenous vasoprotective factor for VC.

Simultaneous induction of non-neoplastic and neoplastic lesions with highly proliferative hepatocytes following dietary exposure of rats to tocotrienol for 2 years

It was recently shown that 1-year chronic exposure of rats to tocotrienol (TT) induced highly proliferative liver lesions, nodular hepatocellular hyperplasia (NHH), and independently increased the number of glutathione S-transferase placental form (GST-P)-positive hepatocytes. Focusing attention on the pathological intrinsic property of NHH, a 104-week carcinogenicity study was performed in male and female Wistar Hannover rats given TT at concentrations of 0, 0.4 or 2% in the diet. The high-dose level was adjusted to 1% in both sexes from week 51 because the survival rate of the high-dose males dropped to 42% by week 50. At necropsy, multiple cyst-like nodules were observed, as in the chronic study, but were further enlarged in size, which consequently formed a protuberant surface with a partly pedunculated shape in the liver at the high dose in both sexes. Unlike the chronic study, NHH was not always accompanied by spongiosis, and instead angiectasis was prominent in some nodules. However, several findings in the affected hepatocytes such as minimal atypia, no GST-P immunoreactivity and heterogeneous proliferation, implied that NHH did not harbor neoplastic characteristics from increased exposure despite sustained high cell proliferation. On the other hand, in the high-dose females, the incidence of hepatocellular adenomas was significantly higher than in the control. There was no TT treatment-related tumor induction in any other organs besides the liver. Thus, the overall data clearly suggested that NHH is successively enlarged by further long-term exposure to TT, but does not become neoplastic. In contrast, TT induces low levels of hepatocellular adenomas in female rats.

Beta-carotene degradation products - formation, toxicity and prevention of toxicity

Carotenoids are widely used as important micronutrients in food. Furthermore, carotenoid supplementation has been used in the treatment of diseases associated with oxidative stress such as various types of cancer, inflammatory diseases or cystic fibrosis. However, in some clinical studies harmful effects have been observed, e.g. a higher incidence of lung cancer in individuals exposed to extraordinary oxidative stress. The causal mechanisms of harmful effects are still unclear. Carotenoid breakdown products (CBPs) including highly reactive aldehydes and epoxides are formed during oxidative attacks in the course of antioxidative action. We investigated the formation of CBPs by stimulated neutrophils (and at further conditions), tested the hypothesis that CBPs may exert mitochondriotoxicity and tried to prevent toxicity in the presence of members of the antioxidative network. Stimulated neutrophils are able to degrade beta-carotene and to generate a number of CBPs. Concerning mitochondriotoxicity, we found that CBPs strongly inhibit state 3 respiration of rat liver mitochondria at concentrations between 0.5 and 20 microM. This was true for retinal, beta-ionone, and for mixtures of cleavage/breakdown products. The inhibition of mitochondrial respiration was accompanied by a reduction in protein sulfhydryl content, decreasing GSH levels and redox state, and elevated accumulation of malondialdehyde. Changes in mitochondrial membrane potential favor functional deterioration in the adenine nucleotide translocator as a sensitive target. The presence of additional antioxidants such as alpha-tocopherol, ascorbic acid, N-acetyl-cysteine or others could mitigate mitochondriotoxicity. The findings reflect a basic mechanism of increasing the risk of cancer induced by carotenoid degradation products.

On the association between low resting heart rate and chronic aggression: retinoid toxicity hypothesis

Low resting heart rate is a strong and consistent predictor of conduct disorder and chronic aggression. Explanations such as fearlessness and low arousal-induced stimulus-seeking have been offered, assuming a causal association between the phenomena, but the origin of low heart rate and its significance for understanding aggression and violence remain obscure. Retinoids (vitamin A and its congeners) play important roles in embryogenesis and neural development. Several lines of evidence also suggest a causal role of retinoids in aggression as well as cognitive and mood disorders. The hypothesis is proposed that retinoid overexpression in utero induces, via a noradrenergic-to-cholinergic switch, alterations in cardiac functioning and hemodynamics resulting in low resting heart rate, brain structural and functional changes, minor physical anomalies, and persistent aggression. Retinoid toxicity occurring early in pregnancy could represent a final common pathway by which various prenatal challenges result in conduct disorder and chronic aggression (e.g., maternal cigarette smoking, alcohol consumption, drug use, exposure to environmental chemicals, stress, trauma or infection). Implications of the model for understanding related aspects of chronic aggression are discussed, as well as strategies for prevention and treatment.

Oxidative stress in the hippocampus, anxiety-like behavior and decreased locomotory and exploratory activity of adult rats: Effects of sub acute vitamin A supplementation at therapeutic doses

Vitamin A participates in the maintenance of normal hippocampal function during embryonic and postnatal stages of the vertebrate life. Some works demonstrated that vitamin A metabolites impair learning and induce a depression-like behavior in mice, among other effects. Since vitamin A has prooxidant effects on other experimental models, we decided to investigate whether vitamin A can induce oxidative stress in the adult rat hippocampus. We analyzed the sub acute effects of therapeutic (1000 and 2500 I.U./kg) or excessive (4500 and 9000 I.U./kg) vitamin A doses on the hippocampal redox state, as well as on levels of anxiety, and locomotory and exploratory activity. Vitamin A supplementation induced lipid peroxidation, protein carbonylation, and oxidation of the protein thiol content in the rat hippocampus in all periods analyzed. Increased superoxide dismutase (SOD) activity and decreased catalase (CAT) activity were also observed, which gives rise to an imbalance in the principal cellular enzymatic antioxidant system. Then, our results show, for the first time, that vitamin A induced oxidative stress in the adult rat hippocampus, is anxiogenic, and decreases locomotion in and exploration of an open field.

Acute and chronic vitamin A supplementation at therapeutic doses induces oxidative stress in submitochondrial particles isolated from cerebral cortex and cerebellum of adult rats

Vitamin A is an essential micronutrient to the normal brain function. However, there is an increasing concern regarding the use of vitamin A at high doses even therapeutically. Here, we show that acute and chronic vitamin A supplementation induces oxidative stress to submitochondrial particles (SMP) isolated from rat cerebral cortex and cerebellum. Both chronic and acute vitamin A supplementation at therapeutic (1000 IU/kg or 2500 IU/kg) or excessive (4500 IU/kg or 9000 IU/kg) doses induced lipid peroxidation, protein carbonylation, and oxidation of protein thiol groups in cerebral cortex and cerebellum SMP. Furthermore, vitamin A supplementation induced an increase in the superoxide (O(2)(-)) anion production, indicating an uncoupling in the electron transfer chain (ETC). Locomotory and exploratory activity, which are associated to cerebral cortex and cerebellum, also were affected by both acute and chronic vitamin A supplementation. Vitamin A induced a decrease in both locomotory and exploratory behavior. Together, these results show that vitamin A could be toxic at the sub cellular level, inducing mitochondrial dysfunction and altering cerebral cortex and/or cerebellum-dependent behavior.

Vitamin A requirements of alipochromatic ('recessive-white') and coloured canaries (Serinus canaria) during the breeding season

Six pairs of alipochromatic ('recessive-white') canaries (Serinus canaria) and six pairs of coloured canaries were kept through a complete breeding cycle while being fed a diet providing 12,000 iu vitamin A/kg. The eggs of three pairs (one recessive-white and two coloured) were all unfertilised and there were only 23 hatchlings (14 recessive-white and nine coloured), of which 14 (10 recessive-white and four coloured) were alive after the first moult. However, there was no clinical, biochemical or pathological evidence that the recessive-white canaries were suffering from vitamin A deficiency or that the coloured canaries were suffering from vitamin A toxicity, suggesting that the diet met the vitamin A requirements of both groups.

Lack of urinary bladder carcinogenicity of sodium L-ascorbate in human c-Ha-ras proto-oncogene transgenic rats

Sodium L-ascorbate (Na-AsA) is widely known to be a tumor promoter of rat bladder carcinogenesis but tests negative in standard 2-year bioassays. In the present study, bladder-cancer-susceptible transgenic rats designated Hras128 were used to further examine the tumorigenicity of Na-AsA. A total of 40 7-week-old male transgenic (Tg) and 42 littermate nontransgenic (Non-tg) rats were divided into 4 groups and given powdered MF diet with or without 5% Na-AsA for 57 weeks. Tg rats showed significantly short survival compared with Non-tg, independent of Na-AsA treatment. Tg rats treated with Na-AsA showed a slightly higher incidence of carcinoma (29.6%) as compared to those without Na-AsA treatment (15.4%), but this was without statistical significance. Moreover, the total bladder tumor incidences, including papillomas, did not differ statistically (with Na-AsA, 37.0%; without Na-AsA, 30.8%). No bladder tumor was detected in Non-tg rats. Various kinds of other lesions in various organs were noted in Tg rats treated with or without Na-AsA treatment, but no intergroup differences were evident. In conclusion, Na-AsA did not show tumorigenicity in highly bladder-cancer-susceptible transgenic Hras128 rats. These results suggest that Na-AsA is a pure promoter but not a complete carcinogen in rats.

Antitumor activity of cytotropic heterogeneous molecular lipids (CHML) on human breast cancer xenograft in nude mice

Cytotropic heterogeneous molecular lipid (CHML), which is a new anticancer agent with US patent number 5,260,067, has recently been shown to suppress tumor cell growth in multiple tumor lines and induce apoptosis in vitro (1). These results indicate that CHML may be an effective antitumor agent. In the present study, using both local injection and intravenous injection, we have investigated the suppressive effect of CHML on human breast caner cells MCF-7 xenograft in nude mice. In the local injection, CHML was introduced into nude mice implanted with human breast cancer xenograft at doses of 25 mg/tumor area (cm2), 35 mg/tumor area (cm2), or 50 mg/tumor area (cm2), once every two days, total 3 times. The inhibition of tumor growth was 81.3%, 93.8% and 100%, respectively. In the intravenous injection, the nude mice bearing MCF-7 xenografts were treated with CHML at 10 mg/kg/day, or 15 mg/kg/day, or 20 mg/kg/day, once a day, total 7 days, the growth inhibition of tumor area was 58.1%, 77.4%, and 83.9%, respectively. At the same time, the toxicity of CHML was determined through examining the number of the white blood cell (WBC) and the activity of the serum glutamic-pyruvic transaminase (SGPT). However, no evident alterations of WBC and SGPT were detected in all animals treated with CHML, suggesting that CHML has little toxicity on nude mice. Taken together, these results indicate that CHML is an effective agent that suppresses breast tumor growth and suggest the possibility of using CHML in the clinical trial in the near future.

Changes in bone metabolism and epiphysial growth plate in bovine Hyena disease induced by administration of vitamin AD3E premix or Vitamin A

The changes in bone metabolism and morphology of chondrocytes in bovine Hyena disease caused by administration of vitamin AD3E premix (V-AD3E) or vitamin A (V-A) were examined. At the each age, 5 calves were used. Among them, Hyena disease was recognized in 3 calves; a calf administered a high dose of V-AD3E premix (V-A 3,000,000, V-D3 300,000, and V-E 1,200 I.U./day), a calf administered a half dose of the V-AD3E premix, and a calf administered only V-A 3,000,000 I.U./day. The remaining calves without Hyena disease were a calf administered only V-D3 300,000 I.U./day and a control calf. Each agent was administered orally for 10 days from 1 week after birth. In the 3 calves with Hyena disease, the bone metabolism in bone histomorphometry of ilium was in the state of low turnover at the age of 50 days. The bone volume was small at the age of 12 months. The epiphysial growth plates of the distal femurs and the proximal tibias partially disappeared and the chondrocyte lacunas in them were flattened. The matrix fibers of epiphysial growth plates were thinner in diameter and higher in density than those of the control calf. In the calf administered only V-D3, the values of bone volume decreased with aging. In conclusion, Hyena disease may be caused by excessive administration of V-A, because hypervitaminosis A suppressed the activity of differentiation and proliferation in chondrocytes and osteoblasts, and excessive administration of V-D3 may promote these actions.

Vitamin neurotoxicity

Vitamins contain reactive functional groups necessary to their established roles as coenzymes and reducing agents. Their reactive potential may produce injury if vitamin concentration, distribution, or metabolism is altered. However, identification of vitamin toxicity has been difficult. The only well-established human vitamin neurotoxic effects are those due to hypervitaminosis A (pseudotumor cerebri) and pyridoxine (sensory neuropathy). In each case, the neurological effects of vitamin deficiency and vitamin excess are similar. Closely related to the neurological symptoms of hypervitaminosis A are symptoms including headache, pseudotumor cerebri, and embryotoxic effects reported in patients given vitamin A analogs or retinoids. Most tissues contain retinoic acid (RA) and vitamin D receptors, members of a steroid receptor superfamily known to regulate development and gene expression. Vitamin D3 effects on central nervous system (CNS) gene expression are predictable, in addition to the indirect effects owing to its influence on calcium and phosphorus homeostasis. Folates and thiamine cause seizures and excitation when administered in high dosage directly into the brain or cerebrospinal fluid (CSF) of experimental animals but have rarely been reported to cause human neurotoxicity, although fatal reactions to i.v. thiamine are well known. Ascorbic acid influences CNS function after peripheral administration and influences brain cell differentiation and 2-deoxyglucose accumulation by cultured glial cells. Biotin influences gene expression in animals that are not vitamin-deficient and alters astrocyte glucose utilization. The multiple enzymes and binding proteins involved in regeneration of retinal vitamin A illustrate the complexity of vitamin processing in the body. Vitamin A toxicity is also a good general model of vitamin neurotoxicity, because it shows the importance of the ratio of vitamin and vitamin-binding proteins in producing vitamin toxicity and of CNS permeability barriers. Because vitamin A and analogs enter the CNS better than most vitamins, and because retinoids have many effects on enzyme activity and gene expression, Vitamin A neurotoxicity is more likely than that of most, perhaps all other vitamins. Megadose vitamin therapy may cause injury that is confused with disease symptoms. High vitamin intake is more hazardous to peripheral organs than to the nervous system, because CNS vitamin entry is restricted. Vitamin administration into the brain or CSF, recommended in certain disease states, is hazardous and best avoided. The lack of controlled trials prevents us from defining the lowest human neurotoxic dose of any vitamin. Large differences in individual susceptibility to vitamin neurotoxicity probably exist, and ordinary vitamin doses may harm occasional patients with genetic disorders.(ABSTRACT TRUNCATED AT 400 WORDS)

Overnutrition: an epidemic problem in pet animal practice?

This review demonstrates that manufactured pet foods contain more than adequate levels of all the essential nutrients needed by normal dogs and cats. Under normal circumstances, therefore, it is completely unnecessary to supplement the rations of these animals with protein, energy, fatty acids, vitamins, or minerals. We have tried to show that, in addition to being unnecessary, supplementation of the rations of normal animals may be quite dangerous, leading to serious--indeed, sometimes fatal--clinical consequences. Pet food manufacturers have responded to newer information regarding increased requirements for specific nutrients such as taurine and potassium. Thus, supplements of these nutrients, as well, are unnecessary in the absence of specific clinical indications. As practitioners, we should be wary of beneficial effects claimed for nutritional supplements. Anecdotal comments, in particular, should be discounted completely. Objective data, including statistical evaluation demonstrating efficacy, should be demanded before accepting claims for such products. Finally, the use of nutritional supplements should be restricted to those cases in which specific clinical problems dictate their use.

Ingestions considered nontoxic

The authors have compiled a list of common household products and drugs that are frequently ingested by children and may be considered nontoxic unless taken deliberately or in large amounts. An understanding of the nontoxic ingestion should prevent overtreatment and decrease emergency room visits.

Vitamin therapy in the absence of obvious deficiency. What is the evidence?

Vitamins are a group of organic compounds occurring naturally in food and are necessary for good health. Lack of a vitamin may lead to a specific deficiency syndrome, which may be primary (due to inadequate diet) or secondary (due to malabsorption or to increased metabolic need), and it is rational to use high-dose vitamin supplementation in situations where these clinical conditions exist. However, pharmacological doses of vitamins are claimed to be of value in a wide variety of conditions which have no, or only a superficial, resemblance to the classic vitamin deficiency syndromes. The enormous literature on which these claims are based consists mainly of uncontrolled clinical trials or anecdotal reports. Only a few studies have made use of the techniques of randomisation and double-blinding. Evidence from such studies reveals a beneficial therapeutic effect of vitamin E in intermittent claudication and fibrocystic breast disease and of vitamin C in pressure sores, but the use of vitamin A in acne vulgaris, vitamin E in angina pectoris, hyperlipidaemia and enhancement of athletic capacity, of vitamin C in advanced cancer, and niacin in schizophrenia has been rejected. Evidence is conflicting or inconclusive as to the use of vitamin C in the common cold, asthma and enhancement of athletic capacity, of pantothenic acid in osteoarthritis, and folic acid (folacin) in neural tube defects. Most of the vitamins have been reported to cause adverse effects when ingested in excessive doses. It is therefore worthwhile to consider the risk-benefit ratio before embarking upon the use of high-dose vitamin supplementation for disorders were proof of efficacy is lacking.

Physico-chemical properties and local toxic effects of injectables

In Japan, many cases of muscle contracture as a sequela of injections have been reported. We studied the physico-chemical properties and muscle-damaging potential of many injectables which are commonly used in hospitals. Contrary to our expectations, the pH of the injectables was found to range widely from 1.4 to 12.8, and the osmotic ratio from 0.2 to 36. It was also found that their hemolytic potential was closely related to the severity of the muscle lesions in animal experiments and that there were many injectables with strong muscle-damaging potentials. Therefore, doctors should be informed of the physico-chemical properties and tissue-damaging potential of each injectable; pharmaceutical companies should exert all possible efforts to improve injectables; and doctors should keep the administration of intramuscular injections to a minimum and use them only in cases of actual need.