ascorbic-acid and Diseases-in-Twins

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Blood Chemical Analysis; Clinical Trials as Topic; Common Cold; Diseases in Twins; Female; Humans; Middle Aged; Placebos; Pregnancy; Twins, Monozygotic

We analysed self-reported cold data for 95 pairs of identical twins who took part in a double-blind trial of vitamin C tablets. One member of each twin pair took vitamin C and the other took a well matched placebo each day for 100 days. Vitamin C had no significant effect except for shortening the average duration of cold episodes by 19%.

Topics: Adolescent; Adult; Aged; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Diseases in Twins; Double-Blind Method; Female; Humans; Male; Middle Aged; Pregnancy; Time Factors; Twins, Monozygotic

Self-reported cold data have been analyzed for 95 pairs of identical twins aged 14-64 who took part in a double-blind trial of vitamin C tablets. One member of each twin pair took a tablet containing 1 g vitamin C and the other took a well-matched placebo each day for 100 days. In the total sample there was no effect of vitamin C in preventing colds. However, subdivision of the data showed a significant preventive effect of the placebo in the 51 pairs living together and an equal and opposite preventive effect of the vitamin C in the 44 pairs living apart. The placebo effect in the pairs living together may be attributed to the large proportion who wrongly perceived which treatment they were taking. The reduction of colds in the vitamin C group of the pairs living apart was about 20%. There were significant correlations between cold symptoms reported and the personality trait of neuroticism. No side effects of substantive changes in serum biochemistry could be attributed to the vitamin C dose.

Topics: Adolescent; Adult; Ascorbic Acid; Clinical Trials as Topic; Common Cold; Diseases in Twins; Double-Blind Method; Female; Humans; Male; Middle Aged; Pregnancy; Twins, Monozygotic

Metabolic studies were performed on two HLA identical 9 1/2-year-old twins with nephropathic cystinosis during 14 months' participation in a double-blind study to evaluate ascorbic acid treatment for cystinosis. Replacement therapy was identical in both children throughout the study except for the use of ascorbic acid. Leukocyte cystine content was markedly abnormal and elevated in both children prior to, during, and after the ascorbic acid study. We postulate that the lack of improvement in growth or chemical parameters in the twin treated with ascorbic acid was due to the ineffectiveness of ascorbic acid in decreasing intracellular cystine content.

Topics: Amino Acids; Ascorbic Acid; Child; Cystine; Cystinosis; Diseases in Twins; Double-Blind Method; Growth; Humans; Leukocytes; Male; Thyrotropin

Three different dosages of vitamin C, dependent on body weight, were administered to 44 school-aged monozygotic twins for five months using a double-blind, co-twin control study design. The mothers recorded daily observations of cold symptoms, and multiple biochemical, anthropometric, and psychological measurements were made at the beginning and end of the study. Paired comparisons showed no significant overall treatment effect on cold symptoms, but the response was not uniform in all sub-groups. Treated girls in the youngest two groups had significantly shorter and less severe illness episodes, and an effect on severity was also observed in the youngest group of boys. The seven treated twins in the latter group also grew an average of 1.3 cm more than their untreated co-twins during the five-minth period of the study.

Topics: Adolescent; Ascorbic Acid; Child; Clinical Trials as Topic; Common Cold; Diseases in Twins; Female; Growth; Humans; Male; Mental Processes; Motor Skills; Placebos; Pregnancy; Twins, Monozygotic

Topics: Ascorbic Acid; Common Cold; Diseases in Twins; Female; Genetic Variation; Genotype; Humans; Phenotype; Placebos; Pregnancy; Twins; Twins, Monozygotic

Topics: Ascorbic Acid; Diseases in Twins; Humans; Methemoglobinemia; Piperazine; Piperazines; Poisoning; Toxicology; Twins