Nutritional support in sickle cell anemia: theoretical considerations.

Despite the clinical diversity of sickle cell anemia (HbSS) this autosomal recessive disorder, often characterized by a 6- to 20-fold increase in destruction rates of the red blood cells (RBC) without a corresponding increase in synthesis, is essentially a chronic hypermetabolic condition. The stress of HbSS produces caloric inefficiency and a marked increase in resting metabolic rate. Nitrogen metabolism is set at a higher than normal dietary intake, and data are still incomplete regarding the possibility that this genetic disorder may have special amino acid requirements. The physiologic needs for most vitamins and essential mineral elements are increased because of the elevated dietary requirements for energy and nitrogen. Many of these micronutrients, especially α-tocopherol, ascorbic acid, retinol, zinc, and selenium, are free radical scavengers, and thus play crucial roles in retarding premature aging of RBCs caused by peroxidation of the membrane. Evaluation of the dietary requirements of the HbSS victim must also take into account the variable, often age-related, increase in nutrient losses after functional impairment in organs, such as the kidneys, which are usually elicited by repeated vaso-occlusive insults.