Concern about the use of iron-especially inorganic iron in supplementation has increased. Indians generally get plenty of iron, and supplementation of this nutrient may create an iron overload, which has been associated with increased risk of heart disease in males. There is some concern iron supplementation may actually increase oxidative stress.
Manganese taken in supplementation is very safe, although there are reports of people who develop manganese toxicity from their environment. This is usually seen in those who mine manganese or are exposed to high levels in the environment. These individuals may begin to hallucinate and become very irritable.