With age B12 absorption declines due to lack of inrinnsic factor in stomach lining helping its absorption . Take a lot of b12 supplements, food rich in B12. If needed injectable b12 will by pass stomach.

Hello there...., Foods rich in vitamin B-12 include: Eggs, Fortified foods, such as breakfast cereals, Milk, cheese and yogurt, Red and white meats and shellfish.... For milder cases of vitamin B-12 deficiency, treatment may involve changes to your diet and vitamin B-12 supplements in pill form or as a nasal spray. Your doctor may suggest vitamin B-12 injections, particularly if your vitamin B-12 deficiency is severe.