Hello and welcome to HCM,Hemoglobin
level of 12.4 gm% is not bad for you at 71 years of age.
However, if you want to increase the hemoglobin level, you need to take iron rich foods.
Iron rich foods include green leafy vegetables, fruits like apples, cheese, etc.
Increase the uptake of these food items and get your hemoglobin checked after few months. Get peripheral blood film examination along with hemoglobin estimation.
Since, you are not anemic there is nothing to worry.
Thanks and take care
Dr Shailja P Wahal