Deficiencies of iron, vitamin B12, and folic acid are the most common nutritional causes of anemia. Although rare, severe deficiencies of several other vitamins and minerals, including vitamin A, vitamin B2, vitamin B6, vitamin C, and copper, can also cause anemia by various mechanisms. Rare genetic disorders can cause anemias that may improve with large amounts of supplements such as vitamin B1.

Taurine has been shown, in a double-blind study, to improve the response to iron therapy in young women with iron-deficiency anemia. The amount of taurine used was 1,000 mg per day for 20 weeks, given in addition to iron therapy, but at a different time of the day. The mechanism by which taurine improves iron utilization is not known.

Hemolytic anemia refers to a category of anemia in which red blood cells become fragile and undergo premature death. Vitamin E deficiency, though quite rare, can cause hemolytic anemia because vitamin E protects the red blood cell membrane from oxidative damage. Vitamin E deficiency anemia usually affects only premature infants and children with cystic fibrosis. Preliminary studies have reported that large amounts (typically 800 IU per day) of vitamin E improve hemolytic anemia caused by a genetic deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD) and anemia caused by kidney dialysis.

People with severe thalassemia who receive regular blood transfusions become overloaded with iron, which increases damaging free radical activity and lowers antioxidant levels in their bodies.        Some people with milder forms of thalassemia may also have iron overload.  Iron supplements should be avoided by people with thalassemia unless iron deficiency is diagnosed. Preliminary studies have found that oral supplements of 200 to 600 IU per day of vitamin E reduce free radical damage to red blood cells in thalassemia patients.      However, only injections of vitamin E have reduced the need for blood transfusions caused by thalassemia.

Test tube studies have shown that propionyl-L-carnitine (a form of L-carnitine) protects red blood cells of people with thalassemia against free radical damage.  In a preliminary study, children with beta thalassemia major who took 100 mg of L-carnitine per 2.2 pounds of body weight per day for three months had a significantly decreased need for blood transfusions.  Some studies have found people with thalassemia to be frequently deficient in folic acid, vitamin B12,  and zinc.    Researchers have reported improved growth rates in zinc-deficient thalassemic children who were given zinc supplements of  .5 to 90 mg per day, depending on age.    Magnesium has been reported to be low in thalassemia patients in some,    but not all,42 studies. A small, preliminary study reported that oral supplements of magnesium, 7.2 mg per 2.2 pounds of body weight per day, improved some red blood cell abnormalities in thalassemia patients.

Sideroblastic anemia refers to a category of anemia featuring a buildup of iron-containing immature red blood cells (sideroblasts). One type of sideroblastic anemia is due to a genetic defect in an enzyme that uses vitamin B6 as a cofactor. Vitamin B6 supplements of 50 to 200 mg per day partially correct the anemia, but must be taken for life.