Vitamin C dietary supplementation, are people who consume more vitamin C at lower risk for developing cancer, and if so, does an orally consumed supplement have the same benefit? Second, for people diagnosed with cancer, will large amounts of ascorbic acid administered intravenously treat the cancer, reduce the adverse effects of other treatments, and so prolong survival and improve quality of life? A 2013 Cochrane review found no evidence that vitamin C supplementation reduces the risk of lung cancer in healthy people or those at high risk due to smoking or asbestos exposure. A second meta-analysis found no effect on the risk
Vitamin B6 4-pyridoxic acid. Several studies have shown that 4-pyridoxic acid is undetectable in the urine of vitamin B-deficient subjects, making it a useful clinical marker to assess the vitamin B status of an individual. Other products of vitamin B metabolism excreted in the urine when high doses of the vitamin have been given include pyridoxal, pyridoxamine, and pyridoxine and their phosphates. A small amount of vitamin B is also excreted in the feces. The classic clinical syndrome for vitamin B deficiency is a seborrhoeic dermatitis-like eruption, atrophic glossitis with ulceration, angular cheilitis, conjunctivitis, intertrigo, and neurologic symptoms of somnolence, confusion, and