Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans.
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The current recommended dietary allowance (RDA) for vitamin C for adult nonsmoking men and women is 60 mg/d, which is based on a mean requirement of 46 mg/d to prevent the deficiency disease scurvy. However, recent scientific evidence indicates that an increased intake of vitamin C is associated with a reduced risk of chronic diseases such as cancer, cardiovascular disease, and cataract, probably through antioxidant mechanisms. It is likely that the amount of vitamin C required to prevent scurvy is not sufficient to optimally protect against these diseases. Because the RDA is defined as "the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all healthy individuals in a group," it is appropriate to reevaluate the RDA for vitamin C. Therefore, we reviewed the biochemical, clinical, and epidemiologic evidence to date for a role of vitamin C in chronic disease prevention. The totality of the reviewed data suggests that an intake of 90-100 mg vitamin C/d is required for optimum reduction of chronic disease risk in nonsmoking men and women. This amount is about twice the amount on which the current RDA for vitamin C is based, suggesting a new RDA of 120 mg vitamin C/d. (+info)
Antiscorbutic activity of ascorbic acid phosphate in the rhesus monkey and the guinea pig.
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Rhesus monkeys fed an ascorbic acid-free, purified liquid diet, developed scurvy in 70 to 105 days as evidenced by loss of weight, anemia, bleeding gums, inflamed palate, diarrhea, and inability to stand. Oral administration of either 10 mg/kg body weight of ascorbic acid or an equimolar amount of the magnesium salt of 1-ascorbic acid phosphate cured all symptoms of scurvy. Similarly, oral administration of 1-ascorbic acid phosphate cured all symptoms of scurvy in the guinea pig and resulted in liver ascorbate levels equal to those of animals feed ascorbic acid. It is concluded that ascorbic acid phosphate is a readily available source of ascorbic acid activity in vivo. (+info)
Infant feeding in the 20th century: formula and beikost.
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The early years of the 20th century were notable for improvements in general sanitation, dairying practices and milk handling. Most infants were breast-fed, often with some formula feeding as well. Availability of the home icebox permitted safe storage of milk and infant formula, and by the 1920s, feeding of orange juice and cod liver oil greatly decreased the incidence of scurvy and rickets. Use of evaporated milk for formula preparation decreased bacterial contamination and curd tension of infant formulas. From 1930 through the 1960s, breast-feeding declined and cow's milk and beikost were introduced into the diet at earlier and earlier ages. Although commercially prepared formulas, including iron-fortified formulas replaced home-prepared formulas, few infants were breast-fed or formula fed after 4-6 mo of age. Iron deficiency was prevalent. From 1970 through 1999, a resurgence of breast-feeding was associated with a prolongation of formula feeding and an increase in usage of iron-fortified formulas. By the end of the century, formula feeding of older infants had largely replaced feeding of fresh cow's milk and the prevalence of iron deficiency had greatly decreased. (+info)
Ascorbate and phagocyte function.
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Scorbutic guinea pig neutrophils (PMN) were found to produce H2O2 and kill Staphylococcus aureus as well as control PMN, suggesting that ascorbate does not contribute significantly to phagocyte H2O2 production or bacterial killing. Total and reduced ascorbate contents of human PMN was observed to fall upon phagocytosis, whereas dehydroascorbate increased to a lesser extent. These observations are consistent with the view that ascorbate constitutes a functional part of the PMN's redox-active components and may thus function to protect cell constituents from denaturation by the oxidants produced during phagocytosis. (+info)
Will an orange a day keep the doctor away?
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An 80 year old man, who relied on a home based meals-on-wheels service was admitted to hospital with non-specific symptoms, but had clinical and biochemical evidence of scurvy. Subsequently, all new admissions (n=37) to the department over a three week period were assessed for evidence of undernutrition. It was found that 73% had hypovitaminosis C, with 30% having concentrations suggestive of scurvy. There were no significant associations between level of vitamin C and type of accommodation, food provision, or age. The commonest symptom associated with vitamin C deficiency was anorexia, but overall, there was a paucity of clinical signs associated with vitamin C deficiency. The possible associations of vitamin C deficiency in the elderly are discussed. (+info)
Bioavailability of a series of novel acylated ascorbic acid derivatives, 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids, as an ascorbic acid supplement in rats and guinea pigs.
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The bioavailability of a series of novel acylated ascorbic acid derivatives, 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-ascorbic acids (6-Acyl-AA-2G), as an ascorbic acid (AA) supplement was investigated in rats and guinea pigs. Oral administration of 6-Acyl-AA-2G to rats resulted in an increase in the plasma AA level. However, the intact form was not detectable in the plasma by high-performance liquid chromatography, indicating its hydrolysis through the process of absorption. After an intravenous injection to rats of 6-Octa-AA-2G as a representative derivative, the intact form rapidly disappeared from the plasma, being followed by a prolonged and marked elevation of the plasma AA level. Various tissue homogenates from guinea pigs were examined for their releasing activity of AA, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) and 6-O-acyl-AA from 6-Acyl-AA-2G. High activity was observed in the small intestine. These hydrolytic activities to AA and 6-O-acyl-AA were completely inhibited by castanospermine, an alpha-glucosidase inhibitor, and AA-2G was observed as the only resulting hydrolysate, suggesting the participation of alpha-glucosidase and esterase in the in vivo hydrolysis of 6-Acyl-AA-2G. 6-Octa-AA-2G was found to exhibit an obvious therapeutic effect in scorbutic guinea pigs from its repeated oral administration. These results indicate that 6-Acyl-AA-2G is a readily available source of AA activity in vivo, and may be useful as an effective pharmacological agent and as a promising food additive. (+info)
James Lind's Treatise of the Scurvy (1753).
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Lind is revered as the first doctor to conduct systematic clinical trials of potential cures for scurvy-trials in which oranges and lemons came out as decisive winners. The following paper argues that our modern understanding of scurvy and vitamin C has hindered our understanding of Lind's own conception of his work and of the place within it of his clinical trials. Lind conceived of scurvy not as a disease of dietary deficiency, but of faulty digestion. In the full context of his Treatise of the Scurvy, and of his own medical practice, the seeming decisiveness of the trials fades, to be replaced by a sense of Lind's bafflement at the nature of the disease to which he had devoted his career. (+info)
An unusual presentation of scurvy following head injury.
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We report an unusual clinical presentation of scurvy in a one and half year old child. The child presented with abrupt onset of peri-orbital ecchymoses and scalp hemorrhage following head injury. The child also had a history of temper tantrums and head banging. Our case did not have any of the typical clinical features of scurvy. The diagnosis was eventually confirmed radiologically and by observing a dramatic response to vitamin C therapy. It is important to remember that scurvy can present atypically i.e. without bleeding gums, painful limbs, pseudo-paralysis or scorbutic rosary. Scurvy should be kept as a differential diagnosis in a young child presenting with bleeding manifestations. Taking a detailed dietary history is of utmost importance in pediatric practice. (+info)