International Journal for Vitamin and Nutrition Research. Supplement

In the Tour de France competing cyclists must pedal about 4000 km over a period of three weeks with only one day allowed for rest. The course includes 30 mountains, the highest of which reaches an altitude of approximately 2700 m. The energy expenditure values of these cyclists range from a mean of 25.4 MJ/day to peak values of 32.7 MJ/day. These are the highest values that have ever been reported for a period longer than seven days. On the basis of the food records of 5 cyclists, it turned out that 62 En.% is derived from CHO, 15 En...

The clinical use of nicotinic acid, nicotinamide, and pyridylcarbinol as drugs against hypercholesterolemia is critically reviewed. Though several questions remain open as to the mode of action of these compounds, it is concluded that they indeed belong to the most useful drugs for the treatment of hypercholesterolemia and for the prevention of coronary disease.

Reports suggesting that gram doses of ascorbic acid are beneficial for the prevention and treatment of several disorders have led to widespread ingestion of vitamin C supplements. Possible adverse health effects of this practice have, therefore, received considerable scrutiny. Of major concern has been the influence of ingesting gram amounts of ascorbic acid on renal calcium oxalate stones, systemic conditioning, uricosuria, vitamin B12 destruction, mutagenicity, and iron overload. Despite contradictory reports, the consensus from an extensive literature is that these adverse health effects are not induced in healthy persons by ingesting large doses of ascorbic acid...

Without vitamin D supplementation, the majority of infants seems to be at risk of vitamin D-deficiency rickets. On the other hand, routine vitamin D supplementation of breast-fed infants is not recommended by all authors. In this paper we give an overview of vitamin D metabolism and vitamin D regulation in newborns, which may differ in a certain way from the regulation in adults. Based on this, minimal and optimal requirements for vitamin D in newborns and infants is determined. Furthermore, the paper aims at defining dosages and conditions that are at risk of vitamin D intoxication...

There are two sources of vitamin D available to man: The more important source is the cholecalciferol (vitamin D3), which is produced photochemically in the skin from the provitamin, 7-dehydrocholesterol; vitamin D ingested with food is of secondary importance, but assumes a critical role when an individual is deprived of solar exposure. Vitamin D therefore is not strictly a vitamin. A deficiency of vitamin D ultimately results in osteomalacia in adults and rickets in children, and provision of sunlight or small oral doses of the vitamin can cure this bone condition...

The use of elevated dosages of vitamin E in humans has led to the discovery of vitamin E deficiency syndromes in neurological areas. This evidence comes from careful clinical studies in which elevated vitamin E dosages were applied. In long-term studies it has now been established that retinal and neurological abnormalities are due to vitamin E deficiency and can be ameliorated by therapy with a large amount of the vitamin enterally or parenterally, which can possibly completely prevent the development of clinical manifestations if adequate treatment is given from an early age...

Subjects with a variety of enteropathies, hemolytic anemias, acute respiratory distress syndrome, hepatitis, Gaucher's disease as well as those on TPN and hemodialysis, often have low ("deficient") blood levels of vitamin E. A deficiency of vitamin E can be manifested by accelerated red blood cell destruction and neuromuscular deficit. Supplementation of these patients may be advisable. Neurological dysfunction has been observed in adults with prolonged vitamin E deficiency resulting from lipid malabsorption...

There are few documented reports in humans that link teratogenic consequences to high intakes of supplemental R or RE, taken either acutely or chronically. This is in contrast to the well-documented teratogenicity in humans of RA and some of its synthetic derivatives. Both R and RE are documented teratogens in animals. Therefore, until more is known about the mechanisms of placental transfer and control as well as about the dose-related teratogenicity of vitamin A at different stages of gestation, there are few justifications for routine ingestion by fertile women of supplemental vitamin A in excess of 8-10,000 IU...

Vitamin A deficiency is a serious problem throughout the developing world. An estimated 25-50 million children may well suffer the physiologic consequences of vitamin A deficiency; 5 million develop xerophthalmia, of whom 250,000 to 500,000 go blind every year; and untold numbers are at increased risk of diarrhea, respiratory disease, and death. Even mild vitamin A deficiency has been associated with a 14- to 10-fold increase in mortality, and controlled field trials have demonstrated vitamin A supplementation can reduce childhood death rates by 30%-70%...

Scientific theories allow definition of the requirements of vitamins for humans, and reasonable judgements lead to recommendations for the daily dietary allowance. However, the scarceness of the available experimental data allows only for rough estimates of the requirements, and the lack of consensus between the various national and international bodies in making reasonable and normative judgments has led to a plurality of recommendations.

In comparison with drugs, the postabsorptive curves of nutrients must be interpreted differently concerning their pharmacokinetic behavior: (1) Most nutrients do not behave as "nonreactives" in a strict sense. (2) For nutrients, the calculation of the retained quantity is important and not the calculation of the attainable concentration as in the case with drugs. These principles are shown for a lipid and a water soluble substance by calculated and observed cumulation curves: (1) The carotenoid canthaxanthin shows limited absorption...

Epidemiological and experimental research indicated some time ago that vitamins might act as protective agents in carcinogenesis. However, only more recently prospective studies proved a significant inverse correlation between certain vitamins and cancer at different site. The Basel Study (comprising 3756 healthy adult volunteers) is unique in its immediate measurement of the plasma vitamins at the time of the clinical assessment (1971-1973). The complete mortality follow-up allows testing of several hypotheses regarding the molecular basis of cancerogenesis...

According to animal experiments, deficiency in vitamin E may be related to arterial lesions. In current cross-cultural epidemiology of middle-aged men representing 11 European populations with different mortality from ischemic heart disease (IHD) all principal antioxidant vitamins and selenium were compared in plasma. The vitamin E concentration within lipoproteins (alpha-tocopherol/cholesterol ratio) showed the most prominent correlation with IHD. This highly significant correlation seemed to be independent of the risk of coronary mortality attributable to hypercholesterolemia...

Aerobic metabolism entails the generation of reactive oxygen species. These include the superoxide anion radical, hydrogen peroxide, the hydroxyl radical, and singlet molecular oxygen. Further, organic alkoxyl or peroxyl radicals may be formed. In the pattern of antioxidant defense, some vitamins play a prominent role and have therefore received much attention recently in the study of the physiological or pathophysiological imbalance in the prooxidant/antioxidant equilibrium. Prooxidant states are sometimes also referred to as oxidative stress...

Criteria for epidemiological evidence of effects of elevated dosages of vitamins are basically the same as those for the evidence of effects of other exposures. Given the unambiguous classifications of both exposure and cases, they comprise strength, significance, specificity, and consistency of the statistical association, plausible time relationship as well as dose-effect relationship and consistency with other evidence. Today, the term epidemiological evidence usually refers to field experience, often to "observational," i...

Oral application of elevated dosages of vitamin B1, B6 and B12 have been found to improve target shooting in marksmen, recruited from a local pentathlon association, in two different studies. Study 1 was performed in an open controlled design, whereas in study 2 the group treated with B-vitamins was compared in a double-blind fashion with a placebo control group including 8 by 8 volunteers and 10 by 9 volunteers, respectively. The volunteers were randomly assigned to the groups. Performance quality was followed in both studies over a period of 8 weeks, while participants were continuously supplied with a combination of vitamins B1, B6 and B12 (Neurobion or Neurobion forte; E...

Water- and fat-soluble vitamins have a key function in many metabolic processes and are of special importance for athletic performance. The water-soluble vitamins thiamine, riboflavin, and pyridoxine as well as the fat-soluble vitamins beta-carotene, retinol, and alpha-tocopherol were determined by methods based on high-pressure liquid chromatography (HPLC) in serum or blood of non-athletes and athletes of different sports such as bodybuilders, cyclists, cross-country skiers, marathon runners, and swimmers...

Vitamins serve primarily as regulators of metabolic functions, many of which are critical to exercise performance. Depending upon the nature of their sport, e.g., strength, speed, power, endurance, or fine motor control, athletes may use megadoses of various vitamins in attempts to increase specific metabolic processes important to improved performance. Surveys have indicated that most elite athletes do take vitamin supplements, often in dosages greater than 50-100 times the United States Recommended Dietary Allowances...

A number of various mechanisms are prone to develop pain symptomatology. Among them infection, inflammation, degeneration, metabolic deviations, and traumas may be at the origin of complex reactions currently gathered under the terminology "rheumatism." For some time now, practitioners have introduced vitamins in the array of their antalgic supply; these were mainly vitamins of the B-group. Meanwhile research has enlarged knowledge about the oxidative mechanisms that are at the origin of inflammation, and has suggested the use of antioxidant substances, among them 9 vitamins...

Vitamin therapy for inborn errors of metabolism has been used in thiamin-responsive maple syrup urine disease, homocystinuria (pyridoxine-responsive cystathionine synthetase deficiency), disorders of vitamin B12 metabolism and defective methylmalonyl-CoA mutase, biotinidase and holocarboxylase synthetase deficiency, multiple acyl-CoA dehydrogenase deficiency, defective methylene tetrahydrofolate reductase and complex III deficiency (respiratory chain). The inherited defects lead either to alterations of the apoenzymes or to deficiencies of enzymes involved in the processing or reutilization of the vitamins...