Iron deficiency, either through lack of iron in the diet or absorption issues, causes low ferritin, B-12 and iron levels, according to Mayo Clinic. Other vitamins, such as B-12, C, folate and zinc, assist in more efficie... More »

Low ferritin levels indicate iron deficiency, says MedicineNet. When iron levels are low, the body struggles to produce hemoglobin, a protein in red blood cells that allows them to carry oxygen, notes Mayo Clinic. This l... More » Health Medical Ranges & Levels

Causes of a low ferritin level include chronic bleeding in the digestive tract, heavy menstrual bleeding, iron-deficiency anemia and problems absorbing iron, explains MedlinePlus. Ferritin is a protein that stores iron i... More »

Causes of iron deficiency anemia, a condition where the body has low iron levels, include blood loss, insufficient iron in the diet, inability to absorb iron and pregnancy, according to Mayo Clinic. Lack of iron prevents... More »

The National Library of Medicine lists the normal B-12 level for a healthy adult as anywhere from 200 to 900 picograms per milliliter. Levels below 200 picograms per milliliter generally indicate a deficiency. Levels abo... More »

Causes of low iron in the blood, also known as iron deficiency anemia, include a lack of iron in the diet and blood loss during menstruation or as the result of a peptic ulcer, colon polyp or hiatal hernia, according to ... More » Health Medical Ranges & Levels

The Mayo Clinic says that iron levels measured in hemoglobin have a normal range of 13.5 to 17.5 grams of hemoglobin per deciliter of blood for men and 12.0 to 15.5 grams per deciliter for women. Normal hemoglobin iron l... More » Health Medical Ranges & Levels