While there may be genetic reasons in some cases, most individuals requiring more Vitamin C usually exhibit much higher than average levels of other nutrients or factors that oppose Vitamin C, with Copper being at the top of the list. Lowering any Vitamin C antagonists, or adding a small amount of Nickel to one's daily dietary or nutritional regimen, considerably reduces the need for mega-doses of Vitamin C, while still achieving the same benefits.... Full Text

Manganese may help with some symptoms of Parkinson's disease such as muscle rigidity and twitching...
Research shows that phytosterols such as beta-sitosterol may help normalize the function of natural killer cells and T-helper lymphocytes...
Iron deficiency may be suspect with some forms of ADHD. 84% of children with ADHD were found to have abnormally low levels of ferritin...
A high intake of B Vitamins can trigger heart palpitations, HBP, major complications in patients with congestive heart disease...