1. Globally, over 1.6 billion people are affected by iron deficiency, with the highest rates in preschool children and non-pregnant women being the most impacted group. 2. Iron deficiency can cause weakness, fatigue, poor concentration and skin, hair and nail problems. It decreases physical and mental abilities. 3. There are two types of iron - heme iron from meat which is easily absorbed and non-heme plant-based iron which is not. Heme iron supplements avoid common side effects from other iron supplements.