Any time a single nutrient is supplemented at excessive amounts, one is really dealing with a much more powerful drug-like effect. And although this has a greater potential to help a medical situation, it equally has the potential of making a particular medical condition worse, or even create new ones if inappropriately used. Supplementing above-RDA DRI amounts of Vitamin C will most certainly have a positive effect on people's general health, however the decision to megadose on Vitamin C - or any other nutrient - should at least be supported with some valid reasons or clinical evidence. In most cases, it is the synergistic effect of several similar nutritional compounds that yield the best results because of their more food-like attributes, and their lesser chance of provoking side effects... 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...