High dose riboflavin may increase the risk of magnesium deficiency. Vitamin B6 and magnesium deficiencies are similar and supplementation with one or the other is helpful. Vitamin B6 increases cell membrane transfer and utilization of magnesium. Iron may accelerate the development of manganese deficiency. Caffeine increases urinary excretion and calcium increases fecal excretion.
Vitamin D enhances phosphorus absorption.
Caffeine increases urinary excretion and potassium deficiency may be refractory to treatment in the presence of magnesium deficiency. Inorganic selenium is ineffective in various in vitro experiments against selenium deficiency and can interact with glutathione to form free radicals. This usually lessens after 3 days and may disappear at higher doses. Decrease by taking niacin with meals, raising dosage slowly, or taking 300mg aspirin 15 - 30 minutes before ingestion of niacin. Can raise uric acid levels by competing with uric acid for renal excretion.