In low calcium situations and a disposition for high stomach acid, supplementing larger amounts of Vitamin C can be a problem not only for those with a sensitive stomach, but also for calcium uptake since too much acid results in calcium loss. While some types of 'Buffered C' such as Calcium Ascorbate help in milder cases, Sodium Ascorbate would be another option in more severe cases, provided there is no sodium sensitivity, or a history of kidney disease... Full Text