Iron-rich foods, such as lentils, pumpkin seeds, beans, dates, longans, grains, nuts, and green, leafy vegetables can help to ensure you meet the requirements for blood donation. Having a diet rich in Vitamin C can also help as it increases the absorption of iron in your body. 

Taking iron supplements a week before your scheduled donation can also make a difference. 

At the same time, avoid drinking tea/coffee/caffeine-rich drinks 1 hour before and after food, as caffeine can reduce the absorption of iron by more than 80%.