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Food sources: Proteins in foods from animal and plant sources typically contain about 40-60 mg/g Val. Dietary supplements containing crystalline valine, often in combination with other amino acids, are commercially available.
Nutrition Summary
Function: The essential amino acid L-valine (Val) is required for protein synthesis. It is also used as an energy fuel; its complete oxidation requires thiamine, riboflavin, niacin, vitamin B6, vitamin B12, pantothenate, biotin, lipoate, ubiquinone, magnesium and iron.
Food sources: Proteins in foods from animal and plant sources typically contain about 40-60 mg/g Val. Dietary supplements containing crystalline valine, often in combination with other amino acids, are commercially available.
Requirements: Adults are considered to require at least 20 mg/kg per day (Young and Borgonha, 2000).
Deficiencies: Chronic deficiency of Val of all essential amino acids or lack of protein can lead to growth impairment, loss of muscle mass and organ damage.
Excessive intake: Excessive intake of protein and mixed amino acids (more than three times the recommended daily intake or 2.4 g/kg) is thought to increase the risk of glomerulosclerosis and accelerate osteoporosis.
Stuart H. Orkin, MD, Nathan and Oski Infant and Pediatric Hematology and Oncology, 2015
Sickle cell trait is the term used to describe heterozygous carriers of the HbS mutation. Sickle cell trait is estimated to affect as many as 3 million Americans and hundreds of millions worldwide,732 but is not usually associated with increased morbidity or mortality under normal physiological conditions. 733-737 No associated anemia, abnormal erythrocyte morphology, or decreased cell viability. Most people have an HbS of about 40% and an HbA of about 60%; however, comorbidity alpha-thalassemia can reduce the HbS score to 28% to 35%. 738 Decreased HbS levels are also seen in patients with iron 739 and folate 740 deficiencies. The growth, behavior, educational achievement, and pregnancy risks of children with sickle trait are completely normal. 741-743 Patients diagnosed with sickling features but with a clinical and laboratory phenotype consistent with a prominent sickling phenotype should be considered for a molecular globin diagnosis to ensure accuracy of diagnosis.744,745
However, under certain extreme conditions, individuals with sickle cell trait may develop sickling and even die. These include severe pneumonia, unpressurized 746 flying and high-altitude exercise. 747,748 The risk of sickle cell trait in routine commercial aviation is overstated. 749 Sickle cell features have been associated with medical complications 750 including loss of the ability to concentrate urine (hypouria) 751 papillary necrosis with persistent hematuria 452 and rare renal medullary carcinoma 469 . Sickle cell trait may be a risk factor for end-stage renal disease; however, data are conflicting. 750,752,753 Under extreme conditions such as high altitude, severe left upper quadrant pain associated with splenic infarction may occur. 754 Sickle cell trait is associated with increased risk of venous thromboembolism. 755 Women with sickle cell trait were at increased risk for preeclampsia; however, their infants had a slight decrease in gestational age and birth weight and no increase in infant mortality. 756 Traumatic hyphema with sickle features is a medical emergency because HbAS Sickle RBCs mechanically obstruct aqueous humor outflow and raise intraocular pressure under hypoxic conditions in the anterior chamber. 757,758 Careful general anesthesia does not pose significant risk to individuals with sickle features, 759,760 but tourniquet surgery 728 and deep hypothermia should be avoided.