Effect of iron depletion on cardiovascular risk factors: studies in carbohydrate-intolerant patients

Controversy surrounds the role of iron (Fe) in atherosclerosis (ASCVD), mainly due to the inaccuracy of assessing body Fe stores with serum ferritin and transferrin saturation. Quantitative phlebotomy was used to test whether or not (a) Fe stores are increased in individuals at high risk for ASCVD and (b) Fe depletion to near-deficiency (NID) levels is associated with reduction of risk factors for ASCVD. Thirty-one carbohydrate-intolerant subjects completed the study. Fe stores were within normal limits (1.5 +/- 0.1 g). At NID, a significant increase of HDL-cholesterol (p < 0.001) and reductions of blood pressure (p < 0.001), total and LDL-cholesterol (p < 0.001), triglyceride (p < 0.001), fibrinogen (p < 0.001) and glucose and insulin responses to oral glucose loading (p < 0.001) were noted, while homocysteine plasma concentration remained unchanged. These effects were largely reversed by a 6-month period of Fe repletion with reinstitution of Fe sufficiency. Thus, although individuals at high risk for ASCVD are not Fe-overloaded, they seem to benefit, metabolically and hemodynamically, from lowering of body Fe to levels commonly seen in premenopausal females.