However, the potential heart benefit of giving blood should be yet another encouragement to donate. Women donators showed a very small benefit. The study supports the iron hypothesis , which suggests that women are protected from hardening of the arteries because they have lower body stores of iron than men, through menstrual blood loss. Stored iron may interact with cholesterol to help harden arteries. Blood donation appears to help give men the iron lowering benefits enjoyed by women.
Women have half the iron stores and half the heart attacks of men.