Detrimental effects of 6 months exposure to very low doses of a mixture of six pesticides associated with chronic vitamin deficiency on rats

This study aimed to evaluate the long-term low-dose effects of exposure to a mixture of 6 pesticide active substances (diquat, imazamox, imazethapyr, tepraloxydin, bentazone, acifluorfen) and to elucidate if chronic vitamin deficiency can influence their toxicity. Two hundred Wistar rats were divided in 4 groups: a vitamin-sufficiency control group, a vitamin-deficiency control group, a vitamin sufficiency test group and a vitamin-deficiency test group. The test groups were treated with the aforementioned pesticides at doses 100 times lower than the corresponding NOAEL. After 6 months, ten rats from each group were sacrificed and a complete evaluation of blood and urine biochemistry, biomarkers of oxidative stress, xenobiotic detoxification enzymes and lysosomal enzymes and organ histopathology was performed. The pesticides mixture and vitamin deficiency determined an increase in alkaline phosphatase levels and urinary calcium levels, abnormal serum lipid profile, and a decrease of total blood proteins levels, red blood cells, haematocrit and haemoglobin. The combination of the two stressors up-regulated CYP1A1, CYP1A2, CYP2B1 and GST levels. This study provides a new proof for the need to move forward from single chemical testing to a more complex approach to account for the multitude of stressors that can challenge the setting of real safety levels.

Nutritional and vitamin status in patients with neuroendocrine neoplasms

Symptoms of gastroenteropancreatic located neuroendocrine neoplasms (GEP-NENs) are often related to food intake and manifest as abdominal pain or diarrhoea which can influence patients nutritional status. Malnutrition is common in cancer patients and influences quality of life, treatment options and survival but is also present in up to 40% of patients with GEP-NENs. As part of malnutrition there are often deficiencies in fat-soluble vitamins, mainly vitamin D. Little knowledge exists on trace elements. Several factors influence the development of malnutrition such as size and localisation of the primary tumour as well as metastases, side effects from treatment but also hormone production of the tumour itself. One of the main influencing factors leading to malnutrition is diarrhoea which leads to dehydration and electrolyte disturbances. Treatment of diarrhoea should be guided by its cause. Screening for malnutrition should be part of routine care in every GEP-NEN patient. Multidisciplinary treatment including dietician support is necessary for all malnourished patients with GEP-NENs.

Oral Manifestations of Inflammatory Bowel Diseases: Two Case Reports

Inflammatory bowel diseases (IBD) are known as chronic inflammatory disorders of the digestive tract, represented mainly by Crohn's disease (CD) and ulcerative colitis (UC). Among the main oral manifestations of IBD are cobblestoning of the oral mucosa, labial swellings with vertical fissures, pyostomatitis vegetans, angular cheilitis, perioral erythema, and glossitis. In this sense, understanding these nosological entities by dentists would help reach early and differential diagnosis. Thus, two case reports are presented and discussed based on theoretical references obtained by a literature review. The first case report refers to an adult patient whose IBD diagnosis was established after stomatological assessment. The second case was a patient with CD diagnosed in childhood with characteristic oral lesions.

[Influence of combined vitamin deficiency on unconditioned reflexes and learning in growing rats]

The aim of this study was to investigate the effect of combined deficiency of all vitamins on the manifestation of unconditioned reflex and learning (in response to an electric current) in growing Wistar rats with initial body weight 53.4 ± 1.2 g (45.5-62.0 g). 20 of 46 tested male rats (latent period of transition from the illuminated chamber to the dark compartment did not exceed 60 s) were included in the experiment. Rats were randomly divided into 2 groups (control and experimental) for the duration of the latent period and body mass. Within 23 days the rats of the control group received a complete semisynthetic diet. Combined vitamin deficiency in tested rats was caused by 5-fold diet decrease of the amount of vitamin mixture without vitamin E. On the 12th day the second phase of testing was performed, during which the rat received electrocutaneous irritation on paws (current 0.4 mA, 8 seconds) after transition to the dark compartment of the chamber. Preservation of the conducted reflex was performed 24 h and 9 days after training. On the 23rd day pre-anesthetized with ether rats were taken out from the experiment by decapitation. The content of vitamin A (retinol and retinol palmitate) and E (tocopherols) in plasma and liver and in the sunflower oil was analyzed by HPLC, the level of vitamins B1 and B2 in liver and casein by fluorimetric method, blood serum malondialdehyde content--by spectrophotometric method. Reducing of vitamin mixture amount of the diet lead to significant reduction in liver vitamin A, E, B1, and B2 level and in blood plasma vitamin A and E concentration by the end of the experiment, but had no effect on blood plasma MDA concentration. On the 12th day of vitamin deficiency in rats manifestation of unconditioned reflex (photophobia) has been deteriorated, as evidenced by the significant 3,2-fold increase of latent period of transition to the dark compartment compared with animals fed a complete diet (47.8 ± 15.8 vs 14.8 ± 3.6 sec), but their ability to learn hadn't been effected. Based on the data that vitamin deficiency, especially of vitamin-antioxidants, causes oxidative stress, and that increase of corticosterone level in hippocampus during aging significantly inhibits the function of the brain, we can assume that increasing of corticosterone level may be one of the cause of the detected cognitive impairment, as isolated vitamin A deficiency in rats increases tissue corticosterone levels.

Interrelationships of undernutrition and neurotoxicity: food for thought and research attention

The neurotoxic actions of chemical agents on humans and animals are usually studied with little consideration of the subject's nutritional status. States of protein-calorie, vitamin and/or mineral undernutrition are associated with a range of neurodevelopmental, neurological and psychiatric disorders, commonly with involvement of both the central and the peripheral nervous system. Undernutrition can modify risk for certain chemical-induced neurologic diseases, and in some cases undernutrition may be a prerequisite for neurotoxicity to surface. In addition, neurologic disease associated with undernutrition or neurotoxicity may show similarities in clinical and neuropathological expression, especially in the peripheral nervous system. The combined effects of undernutrition and chemical neurotoxicity are most relevant to people with low incomes who experience chronic hunger, parasitism and infectious disease, monotonous diets of plants with neurotoxic potential (notably cassava), environmental pollution from rapid industrial development, chronic alcohol abuse, or prolonged treatment with certain therapeutic drugs. Undernutrition alone or in combination with chemical exposure is also important in high-income societies in the setting of drug and alcohol abuse, old age, food faddism, post-bariatric surgery, and drug treatment for certain medical conditions, including cancer and tuberculosis. The nutritional demands of pregnancy and lactation increase the risk of fetal and infant undernutrition and chemical interactions therewith.

Chronic severe axonal polyneuropathy associated with hyperthyroidism and multivitamin deficiency

OBJECTIVES

Hyperthyroidism is often associated with various neuromuscular disorders, most commonly proximal myopathy. Peripheral nerve involvement in hyperthyroidism is very uncommon and has rarely been reported. We describe a 29-year-old woman with untreated hyperthyroidism who presented with chronic severe axonal sensory-motor polyneuropathy. Peripheral nerve involvement developed together with other symptoms of hyperthyroidism 2 years before presentation. She also had anorexia nervosa for the past 6 months, resulting in multivitamin deficiency.

RESULTS

Electrophysiological and pathological findings as well as clinical manifestations confirmed the diagnosis of severe axonal polyneuropathy. Anorexia nervosa has been considered a manifestation of untreated hyperthyroidism. We considered hyperthyroidism to be an important causal factor in the polyneuropathy in our patient, although peripheral nerve involvement in hyperthyroidism is rare. To our knowledge, this is the first documented case of chronic severe axonal polyneuropathy ascribed to both hyperthyroidism and multivitamin deficiency.

CONCLUSION

Our findings strongly suggest that not only multivitamin deficiency, but also hyperthyroidism can cause axonal polyneuropathy, thus expanding the clinical spectrum of hyperthyroidism.

Psychological stress and vitamins

Conditions of stress and anxiety have complex interactions with insufficient vitamin intake and malnutrition. This study, based on literature research in Medline, analyzes the inter-relationship between vitamins and stress. This report concerns a number of vitamins that have been receiving much attention in earlier reviews of the literature, for their potential to protect against stress-related events, and focus is placed upon recent findings.

[Actual vitamin and main foodstuffs consumption by recovered patients suffered from hemorrhagic fever with renal syndrome]

Actual consumption of vitamins A, E, beta-carotene, ascorbic acid, thiamin, pyridoxine and main foodstuffs by recovered patients suffered from hemorrhagic fever with renal syndrome has been given. Frequency analysis of foodstuffs consumption was used to study actual nourishment of recovered patients. Surplus consumption of fat mainly due to the use of saturated fatty acids, deficiency of poly unsaturated fatty acids, surplus sugar consumption and predominance of proteins of animal origin over proteins of vegetable origin in ration has been revealed. Deficiency of water soluble vitamins equals to 41,6-78,7% of all examined patients, deficiency of fat water soluble vitamins is lower (21,4-38,3%).

How Can We Prevent Multisystem Complications of Cystic Fibrosis?

Cystic fibrosis (CF) is a multisystem disease. Some of this is accounted for by CF transmembrane regulator (CFTR) dysfunction in individual organs but in some cases this is compounded by the effects of systemic inflammation. The inflammation is in response to the chronic infection in the airways and is particularly important as a contributor to CF-related bone disease, CF-related diabetes mellitus, CF-related arthropathy, and vasculitis. Preventing these multisystem complications is difficult. Aggressive specific therapies to treat complications is critically important to maintain nutrition, stop the damaging effects of diabetes, and improve bone mineral density. Aggressive treatment of lung disease to reduce systemic inflammation is likely to be of benefit in preventing the development of CF-related bone disease and may be beneficial in at least delaying the onset of CF-related diabetes. Aggressive treatment of pulmonary infection and inflammation in conjunction with holistic management plans to treat specific organ diseases is an important strategy in improving morbidity and reducing mortality in people with CF.

Vitamin D and aging: old concepts and new insights

Aging is a complex biological process driven by a selective class of molecules and pathways that affect overall deterioration of physiological functions to increase the risk of age-related diseases. A role of vitamin D in mammalian aging is well documented. Since vitamin D has an essential role in bone formation and mineralization, its deficiency results in impaired bone mineralization, such as rickets in children, osteomalacia in adults and osteoporosis in the aged population. Vitamin D replacement therapy therefore is one of the most commonly prescribed treatments for the elderly. Recent studies using genetically altered mouse models, such as in Fgf-23(-/-) and klotho mutant mice, that exhibit altered mineral ion metabolism due to high vitamin D activities showed features of premature aging that include atherosclerosis, emphysema, osteopenia/osteoporosis, hypogonadism, soft tissue calcifications and generalized atrophy of organs; the pathologic effects of vitamin D in these mouse models are obvious, as diminution or genetic ablation of the vitamin D pathway ameliorated most of the above-mentioned phenotypes, by reversing mineral ion metabolism, and the resultant effect being prolonged survival of the mutant mice. These in vivo mouse studies, although subject to further molecular characterization, add new insights into the role of vitamin D in aging.

Neurologic complications of gastric bypass surgery for morbid obesity

BACKGROUND

The number of bariatric procedures is rapidly growing as the prevalence of obesity in the USA is increasing. Such procedures are not without complications, and those affecting the nervous system are often disabling and irreversible. We now describe our experience with these complications and review the pertinent literature.

METHODS

We describe 26 patients with major neurologic conditions that seemed causally related to bariatric surgery encountered in the neurology service of a tertiary referral university medical center over a decade.

RESULTS

The neurologic complications affected most regions of the nervous system: encephalopathy, optic neuropathy, myelopathy, polyradiculoneuropathy, and polyneuropathy. Myelopathy was the most frequent and disabling problem; symptoms began about a decade after surgery. Encephalopathy and polyradiculoneuropathy were acute and early complications. Except for vitamin B(12) and copper deficiencies in patients with myelopathy, we could not correlate specific nutritional deficiencies to the neurologic complications. All patients had multiple nutritional deficiencies, but their correction did not often yield dramatic results. The best result was achieved in one patient after surgical revision to reduce the bypassed jejunum.

CONCLUSIONS

A wide spectrum of serious neurologic conditions may follow bariatric surgery. These complications may occur acutely or decades later.

Nutritional and metabolic complications of bariatric surgery

Bariatric surgery is an effective treatment for patients with clinically severe obesity. In addition to significant weight loss, it is also associated with improvements in comorbidities. Unfortunately, bariatric surgery also has the potential to cause a variety of nutritional and metabolic complications. These complications are mostly due to the extensive surgically induced anatomical changes incurred by the patient's gastrointestinal tract, particularly with roux-en-Y gastric bypass and biliopancreatic diversion. Complications associated with vertical banded gastroplasty are mostly due to decreased intake amounts of specific nutrients. Macronutrient deficiencies can include severe protein-calorie malnutrition and fat malabsorption. The most common micronutrient deficiencies are of vitamin B12, iron, calcium, and vitamin D. Other micronutrient deficiencies that can lead to serious complications include thiamine, folate, and the fat-soluble vitamins. Counseling, monitoring, and nutrient and mineral supplementation are essential for the treatment and prevention of nutritional and metabolic complications after bariatric surgery.

Chronic low intake of protein or vitamins increases the intestinal epithelial cell apoptosis in Wistar/NIN rats

OBJECTIVE

Malnutrition decreases antioxidant defense and increases oxidative stress in the intestine. We studied the effects of long-term restriction of food, protein, and vitamins on intestinal epithelial cell (IEC) apoptosis and the underlying mechanisms.

METHODS

Weanling, Wistar/NIN male rats were fed ad libitum with a control diet, 75% protein-restricted diet, or 50% vitamin-restricted diet for 20 wk. The food-restricted group received 50% of the diet consumed by control rats. IEC apoptosis was monitored by morphometry, Annexin V binding, M30 CytoDeath assay, and DNA fragmentation. Structural and functional integrity of the villus were assessed by the ratio of villus height to crypt depth, and alkaline phosphatase and lys, ala-dipeptidyl aminopeptidase activities, respectively. Oxidative stress parameters, caspase-3 activity, and expression of Bcl-2 and Bax were determined to assess the probable mechanisms of altered apoptosis.

RESULTS

Protein and vitamin restrictions but not food restriction significantly increased IEC apoptosis and only vitamin restriction altered structural and functional integrity of villi. Increased levels of protein carbonyls, thiobarbituric acid reactive substances, and caspase-3 activity along with decreased glutathione levels and Bcl-2 expression were observed in IECs of these rats, whereas food restriction did not affect these parameters.

CONCLUSIONS

Protein restriction increased only IEC apoptosis, whereas vitamin restriction also affected the structure and function of villi. Modulation of the pathway mediated by mitochondria through increased oxidative stress appears to be the probable mechanism underlying this effect.

Nutritional inadequacy in adults with muscular dystrophy

Patients with muscular dystrophy may be prone to nutrient deficiency due to mobility limitations or oropharyngeal weakness. Patients with myotonic muscular dystrophy (DM1) may be particularly prone to nutritional deficiencies from associated dysmotility of the entire gastrointestinal tract. We prospectively evaluated nutritional intake, body composition, and muscle strength in adult patients with DM1 (n = 29) and other muscular dystrophies (n = 22) on two occasions separated by approximately 6 months. Handgrip was significantly lower and knee extension higher for DM1 compared to other dystrophies, with no between-group differences in nutritional intakes. Many patients in both groups demonstrated inadequate nutrient intake of protein, energy, vitamins (water and fat soluble), and minerals (calcium and magnesium). Significant correlations were found between measures of strength and certain individual nutrients (e.g., copper and water-soluble vitamins). These data indicate that a substantial number of adults with muscular dystrophy do not meet current dietary intake recommendations. The potential clinical implications of these findings are discussed.

Effects of vitamin restriction and supplementation on rat intestinal epithelial cell apoptosis

Diet influences intestinal growth and function and vitamins modulate intestinal cell turnover. We have assessed the effects of chronic, moderate (50% of control) vitamin restriction and supplementation on intestinal epithelial cell (IEC) apoptosis and the relevance of this to alterations in tissue oxidative stress and antioxidant status. Feeding a vitamin-restricted diet to male, weanling WNIN rats for 20 weeks significantly increased IEC apoptosis, but only in the villi region, as evident from increased annexin V staining, M30 positivity, histological observations, DNA ladder formation, and reduced expression of Bcl-2. This was associated with elevated levels of lipid peroxides and protein carbonyls in the intestinal mucosa despite the increased activities of superoxide dismutase, catalase, and glutathione peroxidase. Consistent with the increased oxidative stress and apoptosis, structural and functional integrity of the villi were compromised as evident from the lowered ratio of villus height:crypt depth and the decreased activities of the membrane marker enzymes alkaline phosphatase and Lys-Ala dipeptidyl aminopeptidase. These changes were reversed by supplementation with a vitamin mixture or vitamin E alone, whereas riboflavin or folic acid supplementation reduced the apoptotic rates, but only partially. Further, oxidative stress was the least in vitamin E- or vitamin mixture-supplemented rats and correlated well with their IEC apoptotic rates. Increased tissue oxidative stress seems to mediate the vitamin-restriction-induced apoptosis of the IECs in rats.

Nutritional aspects of alcoholic liver disease

Development of ethanol-induced fatty liver, alcoholic hepatitis, and cirrhosis has been attributed in part to nutritional deficiencies for many years. Special attention must be focused on treating alcohol-induced liver disease while providing replacement of deficient amino acids, vitamins, minerals, and other nutrients. Avoidance of alcohol intake is required to eliminate progressive liver disease in alcoholics. This is best achieved by using educational and social programs to convince patients and their caretakers of the great necessity to eliminate alcohol intake.

Maternal dietary vitamin restriction increases body fat content but not insulin resistance in WNIN rat offspring up to 6 months of age

AIMS/HYPOTHESIS

Epidemiological evidence suggests that some adult diseases like insulin resistance syndrome and diseases associated with it originate in fetal life. The role of maternal macronutrient malnutrition but not of micronutrients in the fetal origin of adult disease is well studied. We hypothesise that chronic maternal vitamin restriction predisposes the offspring to insulin resistance syndrome.

METHODS

Female weanling Wistar/NIN rats received a control diet ( n=6) or a 50% vitamin-restricted diet ( n=14) for 12 weeks and mated with control males. Four dams on the restricted diet were shifted to the control diet from parturition. Pups born to the remaining 10 dams on the restricted diet were weaned on to control diet or continued on the restricted diet. All groups had 8 male pups from weaning onwards.

RESULTS

Birthweights of pups were comparable among different groups. Weaning body weights were low in the restricted diet group, but on rehabilitation they caught up with control animals by post-natal day 100. None of the pups had impaired oral glucose tolerance and their insulin resistance status was comparable on days 40, 70, 100 and 180. Compared with offspring on the control diet, offspring on the restricted diet had a significantly higher percentage of body fat and higher plasma triglycerides, as well as lower lean body mass and fat-free mass. They also had increased oxidative stress. Rehabilitation from parturition or weaning prevented the changes in body fat percent, lean body mass, fat-free mass and oxidative stress.

CONCLUSIONS/INTERPRETATION

Since changes in adiposity and fat metabolism are considered forerunners of insulin resistance syndrome, our observations suggest that maternal dietary vitamin restriction predisposes the offspring to insulin resistance syndrome in later life.

Neuromuscular diseases and disorders of the alimentary system

This review outlines the relationship and interaction between neuromuscular diseases and disorders of the alimentary system. Neuromuscular manifestations of gastrointestinal and hepatobiliary diseases are first considered. Such diseases may cause neuromuscular disorders by leading to nutritional deficiency or by more direct mechanisms. The pathogenesis, clinical features, and treatment of these various neuromuscular manifestations are discussed. The impact of disorders of nerve, neuromuscular transmission, and muscle on the alimentary system is then reviewed. The main sequelae are impaired deglutition and gastrointestinal dysmotility. The management of these complications is considered.

[Multimodal evoked potentials in malabsorption syndrome]

The multimodal evoked potentials (visual, somatosensory and auditory brainstem) in 23 patients with malabsorption syndrome of different origin were investigated. The diagnosis of the disease was confirmed on the basis of histological examination and result of D-ksyloza test. The control group consisted of 30 healthy persons. Examination of visual evoked potentials revealed significant prolongation of latency of P 100 component in examined group in comparison with controls. Latency of N13 and N20 of somatosensory evoked potentials in patients with malabsorption syndrome were also significantly prolonged when compared to controls, otherwise transit time to cortex (TTC) was merely prolonged. Auditory brainstem potentials were also abnormal. Changes involved prolongation of latency of I, III and V responses and prolongation of interpeak latencies of I-III, III-V, I-V as well. The amplitudes of the examined evoked potentials between patients and controls did not differ significantly. On the basis of obtained results in was pointed out that different specific afferent systems are affected in patients with malabsorption syndrome what seems to be connected with vitamin's deficiency, especially B12 and E. Authors conclude that multimodal evoked potentials examinations are useful in the diagnosis and monitoring of the disease, specially in subclinical cases.

Nutritional modulation of malaria morbidity and mortality

This review critically examines the relationship between nutritional status and malaria. The data indicate that protein-energy malnutrition is associated with greater malaria morbidity and mortality in humans. In addition, controlled trials of either vitamin A or zinc supplementation show that these nutrients can substantially reduce clinical malaria attacks. Data for iron indicate that supplementation may minimally aggravate certain malariometric indices in some settings and also strongly improve hematologic status. Withholding of iron supplements from deficient population is, therefore, not currently indicated. Available evidence for other nutrients describe varied effects, with some deficiencies being exacerbative (e.g., thiamine), protective (e.g., vitamin E), or both exacerbative and protective in different settings (e.g., riboflavin, vitamin C). The roles of folate, other B vitamins, unsaturated fatty acids, amino acids, and selenium are also examined. Study of the interactions between nutrition and malaria may provide insight to protective mechanisms and result in nutrient-based interventions as low-cost and effective adjuncts to current methods of malaria prevention and treatment.

Toward a new definition of essential nutrients: is it now time for a third 'vitamin' paradigm?

The concepts of vitamin 'deficiency' diseases and the recommended dietary allowances (RDAs) have not kept pace with the growing understanding of the cellular and molecular functions of vitamins and other micronutrients. As a consequence, many researchers and clinicians rely on outdated signs and symptoms in assessing nutritional deficiencies. A new paradigm, presented here, proposes that: (1) deficiencies can be identified on biochemical and molecular levels long before they become clinically visible; (2) the definition of essential micronutrients be broadened to include some carotenoids and flavonoids, as well as various human metabolites, such as coenzyme Q10, carnitine, and alpha-lipoic acid, which are also dietary constituents; (4) individual nutritional requirements are partly fixed by genetics but also dynamically influenced by variations in the body's biochemical milieu and external stresses; and (5) the distinction between nutritional and pharmacological doses of vitamins is meaningless, since high doses of micronutrients may be required to achieve normal metabolic processes in some people.

Phenotype in retinol deficiency due to a hereditary defect in retinol binding protein synthesis

PURPOSE

To describe the phenotype caused by a retinol deficiency in a family with compound heterozygous missense mutations (Ile41Asn and Gly75Asp) in the gene for serum retinol binding protein (RBP).

METHODS

The two affected sisters, 17 (BR) and 13 (MR) years old, were examined clinically and with perimetry, color vision tests, dark adaptometry, rod- and cone-isolated electroretinograms (ERGs), multifocal ERGs, electrooculograms (EOGs), and laboratory tests.

RESULTS

There were no complaints besides night vision problems and no history of systemic disease. Visual acuity was reduced to 20/40 (BR) and 20/25 (MR). Anterior segments were normal except for a discrete iris coloboma. Both patients showed a typical "fundus xerophthalmicus," featuring a progressed atrophy of the retinal pigment epithelium. Dark adaptation thresholds were elevated. In the scotopic ERG, only reduced mixed responses were recordable. The photopic ERG was reduced in BR and normal in MR; implicit times were highly (BR) to slightly (MR) elevated. There was no (BR) to little (MR) light reaction in the EOG. All-trans retinol levels were 0.19 microM and 0.18 microM (normal range, 0.7-1.5 microM) for BR and MR, respectively, and did not increase in a dose-response test. RBP was below detection threshold, and retinyl esters were normal.

CONCLUSIONS

Both affected siblings had no detectable serum RBP, one sixth of normal retinol levels, and normal retinyl esters. The retinal pigment epithelium was severely affected, but besides acne there were no changes to other organs. This gives evidence for an alternative tissue source of vitamin A, presumably retinyl esters from chylomicron remnants. The normal retinol levels in the tear fluid explain the lack of xerophthalmia. However, considering the role of RBP in the tear fluid and, during development, in the yolk sac there is also evidence that there are organ-specific RBP forms not affected by the genetic defect.

Vitamin A deficiency exacerbates methotrexate-induced jejunal injury in rats

Two studies were conducted to investigate whether vitamin A-deficient rats were more susceptible to intestinal injury caused by methotrexate (MTX), since vitamin A deficiency alone causes only mild changes to jejunal structure and function. Weanling male rats were fed a vitamin A-deficient diet (-VA) for 40-42 d and compared to rats either pair-fed (PF) or with free access (+VA) to the same diet. Drinking water of PF and +VA rats was supplemented with 37.5 microg (Study 1) or 75 microg (Study 2) vitamin A (Rovimix A 500W)/d. Rats in each group received MTX (-VAMTX, PFMTX, +VAMTX) or vehicle. MTX administration reduced intestinal mucosal wet weight, protein and DNA concentrations, and sucrase and maltase activities in -VA and PF rats (P < 0.02). In Study 1, -VAMTX rats developed a severe jejunal enteropathy and had a higher incidence of diarrhea (P < 0.005), greater weight loss (P < 0.005), more disruption of villus architecture (P < 0.0001) and lower disaccharidase activity (P < 0.007) than PFMTX rats. Similar results were observed in Study 2. Liver retinol concentration (but no other variable) was greater in rats receiving 75 microg vitamin A/d (P < 0.001) than in those receiving 37.5 microg/d. The interaction of vitamin A deficiency and small intestinal injury may explain the efficacy of vitamin A supplementation in preventing childhood diarrheal disease mortality in developing countries, and highlights the need for ensuring adequate vitamin A status in people worldwide with diseases and/or treatments which may injure the gastrointestinal tract.

High-risk subjects for vitamin deficiency

Chronic deficiency of various vitamins can influence the occurrence of some chronic degenerative diseases such as cancer, cardiovascular pathology, cataract, arthritis, disorders of the nervous system and photosensitivity. Similarly, vitamin intake can influence various disorders in infants and elderly people, in burns and in subjects following unbalanced diets or undergoing strenuous physical exercise. Among vitamins, beta-carotene, vitamin E and vitamin C have received most attention, particularly in the prevention of oxidative damage from free radicals. It is supposed that each vitamin plays a different role in the pathogenesis of various diseases, depending on the type of damage relevant to a specific disease. Results from different studies are still far from conclusive and the effects on longevity are not well defined. In industrialized countries, vitamin deficiencies seem to be related only to specific and clearly identifiable groups in the population: therefore, at the moment, it seems more advisable to target vitamin supplementation at risk groups.

The effect of a subnormal dose of vitamin B6 on plasma lipid in the rat

The study undertook to ascertain the effect of a subnormal dietary intake of vitamin B6 on plasma levels of total cholesterol, high density lipoproteins, low density lipoproteins and triglycerides. Plasma samples were assessed after 8 weeks in 3 groups of young male Wistar rats receiving a daily pyridoxine hydrochloride intake of 60 (normal control group, A) and 20 micrograms (experimental group C). Group B was the pair-fed control. Vitamin B6 status of all groups was confirmed by measuring plasma pyridoxal-5'-phosphate and pyridoxal. All groups were still in the growth phase at the end of 8 weeks, and since the mean mass for all groups remained within the norm for male Wistar rats, it would appear that caloric intake was not compromised. The fasting triglyceride levels in the normal control group were significantly higher than those of the experimental and pair-fed control groups, although all values remained within the normal range for rats. A subnormal intake of pyridoxine hydrochloride made no significant difference in the high density lipoprotein levels although it contributed to a significant increase in low density lipoprotein and total cholesterol levels. The plasma pyridoxal-5'-phosphate and pyridoxal values were in accordance with the pyridoxine hydrochloride intake of the different groups.

[Nutrition and mental function in the elderly]

A deterioration in cognitive functions is characteristic of the ageing process and is one of the principle causes for disability in old age. It is possible that some of the neuropsychiatric alterations associated with old age may be due to certain subclinical vitamin deficiencies and, as such, may be corrected in some cases with adequate nutrition. This article presents a broad review of the various research efforts published on the subject.

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)

Vitamins, iron, and physical work

Combined marginal deficiencies of iron, vitamin C, and B-group vitamins are widespread in developing countries. An understanding of the functional implications poses a continuing challenge, both for the development of new techniques of investigation and for the design of effective intervention programmes. Practical intervention in developing countries also needs to take account of the interactions of micronutrient status and disease susceptibility. It is becoming clear that combined deficiencies of certain vitamins, or of iron and vitamins, although less severe than those causing the lesions of classic clinical deficiency, can seriously reduce work performance. Riboflavin, particularly, has a special relation with iron economy.

[The effect of preventive vitamin supplementation on vitamin status and work productivity of conveyer belt workers in light industry]

The authors have studied the ways of correcting the vitamin status and influence of vitaminization on working capacity in workwomen in light industry. Prophylactic polyvitaminization (1 dragee of "Undevitum"/day, during 2 months) proved to produce positive effect on the vitamin status parameters (vitamin content in the blood and urine, clinical microsymptoms of vitamin deficiency), and on the dynamics of the physiological parameters of working capacity of workwomen at modern conveyer shoe making industry. It is recommended that persons suffering from chronic diseases influencing vitamin metabolism, first of all those over 45 years, should receive increased doses of prophylactic polyvitamins, thiamine and ascorbic acid, in particular.

Running performance in Gambian children: effects of water-soluble vitamins or iron

Sixty-nine boys and girls between 10 and 14 years, with evidence of subclinical vitamin deficiencies and poor iron status were enrolled into the study at the beginning of the rainy season. Children were allocated to three treatment groups to receive five times weekly either a placebo, 200 mg ferrous sulphate or 5 mg riboflavin and 150 mg ascorbic acid. Before receiving the supplement, and 9 weeks later, children performed an exercise regimen on a treadmill during which expired air was collected and heart rate measured. There was a general deterioration in the running performance of the children during the study period which was not affected by either the iron or the vitamin supplement.