Question

1. A) If 50% of ingested iron is not absorbed by the body and 75% of the iron in red blood cells is recycled, estimate how much iron must be ingested per day to maintain the iron content of the blood. Assume 25 mg iron / day is available for recycle. [2 points]

B) How much steak would you need to eat a day? How much spinach? [2 points]

Answer 1

Ans (A):

Suppose A mg of iron is to be ingested per day to maintain the iron content of the blood.

So, after ingestion, iron absorbed by the body = (A x 50)/ 100 = A/ 2 mg

Amount of iron recycled = (A/2) x (75/100) = 3A/ 8 mg

Assuming 25 mg iron/ day is available for recycle

Therefore, 3A/ 8 = 25

A = (25 x 8)/ 3 = 66.67 mg

So, Amount of iron that must be ingested per day = 66.67 mg

Ans (B): Based on recommended daily dietary intake:

• Approx. 50 - 80 g of steak/ meat will be needed to eat per day.
• Approx. 30 g of spinach will be needed to eat per day.