When genes controlling hemoglobin production are missing or altered, thalassemia occurs and is classified as alpha thalassemia or beta thalassemia. Hundreds of alpha globin and beta globin mutations have been identified in thalassemia, and the severity of the disease depends on which mutation or combination of mutations is present.
Mild forms of the disease may not need any treatment, but those with moderate to severe thalassemia may be treated with life-sustaining blood transfusions. Regular blood transfusions can influence iron deposition in body tissues and result in organ injury due to iron overload. Patients with non–transfusion-dependent thalassemia can also develop iron overload due to increased intestinal absorption of dietary iron.
In either case, iron overload can be managed with chelation therapy to remove excess iron from the body, although the risk for chelation toxicity exists. Non-transfused patients are encouraged to consume a diet that is nutrient-dense and moderately low in iron, which can be achieved by limiting foods that provide high amounts of iron, such as red meat and foods that are fortified with iron. A low-iron diet is generally not necessary for patients who receive transfusions and chelation therapy.
In addition to iron-related issues, patients with thalassemia are at risk for other morbidities due to poor nutritional status, and these can affect growth, bone mineralization and immune function. Preliminary findings based on data from a prospective, longitudinal cohort study published in 2012 showed surprising levels of nutrient inadequacy in patients with thalassemia who were receiving transfusions, especially as age increased. The authors suggested that registered dietitian nutritionists should promote healthful eating messages which encourage dietary sources of minerals and antioxidants, as opposed to providing diet instructions that solely focused on the avoidance of iron-rich foods.
Their rationale stemmed from the risk for nutrient deficiency when foods with iron are avoided, combined with the assessment of dietary intake, which in this case was obtained via food frequency questionnaire. For example, zinc status can be affected when iron-rich foods are avoided, and calcium, magnesium and vitamin D were concerns due to inadequate dairy consumption. However, many adolescent and adult participants reported taking a multivitamin/mineral and/or calcium and vitamin D supplements. Only vitamin B12, riboflavin, and selenium were obtained in adequate amounts from dietary sources by a majority of the participants. Therefore, increasing the intake of fruits, vegetables, and whole grains was also recommended, especially in regards to folate, due to its role in red blood cell metabolism.
A systematic review published in 2022 also supported the goal of optimizing dietary intake through nutrient-dense foods and appropriate use of supplements based on the prevalence of nutrient deficiencies assessed in the literature. The study identified deficiencies of vitamins A, C, D, selenium, and zinc as occurring most frequently. However, insufficient data were available to determine the status of several nutrients, including the vitamins B6, B12, K, niacin, thiamin, riboflavin, iodine, chromium, sodium and potassium. The authors also identified select nutrients that may require supplementation in high doses.
Therefore, due to the high risk for nutrient deficiencies and the influence being multi-factorial, nutritional assessment of patients with thalassemia by an RDN is recommended annually.
- National Heart Lung, and Blood Institute: What is Thalassemia? Accessed June, 17, 2022
- Escott-Stump, S. Thalassemias. In: Nutrition and Diagnosis Related Care, Ninth Edition. Chicago, IL: Academy of Nutrition and Dietetics; 2022:943-946.
- Fung, EB, Xu, Y, Trachtenberg, F et al. Inadequate dietary intake in patients with thalassemia. J Acad Nutr Diet. 2012; 112: 980–990.
- Goldberg EK, Lal A, Fung EB. Nutrition in Thalassemia: A Systematic Review of Deficiency, Relations to Morbidity, and Supplementation Recommendations. J Pediatr Hematol Oncol. 2022; 44: 1-11.
- Standards of Care Guidelines for Thalassemia. Northern California Comprehensive Thalassemia Center. UCSF Benioff Children's Hospital Oakland. 2012. Accessed June 17, 2022.
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