High doses of iron are definitely to be avoided. Iron may have a negative side. Higher blood levels have been correlated with increased risk of heart attacks. Iron surplus may aggravate hypersensitivity states. Storage of excess iron in body tissues is disease causing.
Ferrous sulphate is the cheapest iron supplement.
Iron preparations tend to be constipating. Unabsorbed iron tends to darken stool color. Iron may be taken with VM.C to enhance absorption, but copper intake may be impaired, and produce the same iron-deficiency effect. Iron supplements in the range of 10-30 mg per day may be desirable. Zinc Zinc is another mineral which has received increased attention recently.