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Table 3 Studies of nutritional interventions involving individuals living with sickle cell disease in Africa

From: Nutritional perspectives on sickle cell disease in Africa: a systematic review

Authors and year of publication Location Ages No. of subjects Intervention Nutrient intervention type Design Outcome Comments
Afolabi et al., 2012 [85] Lagos State and Ogun State, Nigeria 15–48 years Not reported Seed oils from Solenostemon monostachyus, Ipomoea involucrate and Carica papaya plants Plant extract/ seed oil In vitro comparisons using blood from SCD patients; comparison groups were controls, cells treated with glutathione, and cells treated with a known anti-sickling plant extract • All plant extracts studied led to reduction in sickled red blood cells, reduction in Fe+ 2/Fe+ 3 ratios, and reduction in lactate dehydrogenase activity when compared with controls
• Individual extracts also showed varying improvements in hemoglobin concentration, sickle cell polymerization inhibition, and catalase activity
Some gender dependent differences were noted; specific bioactive compounds within each plant extract were not isolated
Imaga et al., 2013 [86] Lagos State, Nigeria 15–28 years 4 (2 treated, 2 controls) Oral ingestion for two weeks of a commercial product made from Cajanus cajan plant extract Plant extract/ seed oil Non-blinded in vitro comparison study • Treatment group reported to have anti-sickling effect, but no statistical analyses performed
• Treatment group reported to have increased fetal hemoglobin, but no statistical analyses performed
• No effect reported on packed cell volume, hemoglobin, or mean corpuscular hemoglobin
Statistical analyses lacking for main outcomes
Kaddam et al., 2019 [87] Khartoum, Sudan 5–42 years 47 Acacia Senegal (gum Arabic) supplementation as a lipid-lowering agent Plant extract/ seed oil Single-arm trial Treatment led to significantly decreased total cholesterol, triglycerides, and low-density lipoprotein; no effect on high-density lipoprotein Gum Arabic is a dried, gummy substance obtained from the acacia Senegal tree
Adegoke et al., 2013 [88] Ekiti State, Nigeria 1 year to “adolescent” (upper range not specified) 125 (65 treated, 60 controls) Oral ingestion for 6 months of freshly squeezed lime juice; dose was weight- dependent (range: 10–30 ml daily) Micronutrient Open label, randomized study • Treated group had significantly fewer pain episodes, febrile illness, and admission rate
• Treated group had significantly increased mean hematocrit
• No change in transfusion rate, organomegaly, or jaundice
Effect hypothesized to result from vitamin C, amino acids (especially phenylalanine) and flavonoids
Adegoke et al., 2017 [67] Ile-Ife, Nigeria Mean age
7 years
170 (95 treated, 75 controls) Oral ingestion for 3 months of vitamin D supplementation in children with SCD that had low 25-hydroxyvitamin D (25-OHD) levels Micronutrient Age- and gender-matched controlled study • Children with SCD and low 25-OHD levels had enhanced levels of pro-inflammatory cytokines
• Treatment with vitamin D in children with SCD that had low 25-OHD levels led to an improved pro-inflammatory cytokine profile
Effect hypothesized to result from anti-inflammatory influence of supplemental vitamin D
Daak et al., 2013 [89] Khartou, Sudan 2–24 years 128 (67 treated, 61 controls) Oral ingestion for 1 year of Omega-3 capsules containing EPA and DHA fatty acids; dose was weight-dependent Macronutrient Double-blinded, placebo-controlled, randomized study • Treatment group had improved primary outcome: significantly fewer clinical vaso-occlusive events
• Treatment group also had reduced severe anemia, reduced blood transfusions, reduced white blood cell counts, and reduced school absences due to disease
• No change in rates of stroke, sequestration crisis, or vascular necrosis
The study was not powered to detect changes in rates of stroke, sequestration crisis, or vascular necrosis
Cox et al., 2018 [90] Dar-es-Salaam, Tanzania 8–12 years (mean 10 years) 119 Oral ingestion of ready-to-use supplementary food (RUSF) with and without arginine and citrulline Macronutrient Double-blind, random order crossover trial • RUSF increased the global arginine bioavailability ratio and improved measures of endothelial function, and led to improvements in growth
• RUSF fortified with arginine and citrulline did not additionally increase the plasma global arginine bioavailability ratio or improve endothelial function
Arginine is the sole substrate of endothelial nitric oxide synthase and has been implicated in pathophysiology of SCD complications
Onalo et al., 2019 [91] Abu, Nigeria 5–17 years (mean 11 years) 68 (35 treated, 33 controls) Oral arginine therapy every 8 h until discharge in SCD patients hospitalized with severe vaso-occlusive events Macronutrient Double-blind, randomized, phenotype included placebo-controlled trial • Plasma arginine levels increased by 125% (arginine arm) vs 29% (placebo arm)
• 54% of children treated with arginine were discharged compared to 24% in placebo arm by day 5
• Arginine treatment appeared to ameliorate some measures of pain
• No significant differences in adverse events but arginine arm trended more towards vomiting compared to placebo
Arginine had previously been shown to have benefits in individuals with SCD in studies performed in the Unite States