Foods to Increase Red Blood Cells. Eating the right foods can help increase the number of red blood cells in your body. Here are a few of the ways you can eat your way to better blood cell health: 1  Iron. 2  Food rich in iron can help your body rebuild what it has lost.n that case, turning to supplements can help your body produce the red blood cells it needs. Here are a few options: 1  Iron. 2  This is a vital nutrient that your blood cells need to function properly. 3  Women need 18 mg and men need 8 mg of iron per day. 4  Vitamin B12.