Spirulina as a daily nutritional supplement of young pre-school Cambodian children of deprived settings: a single-blinded, placebo-controlled, cross-over trial

BACKGROUND: Spirulina (SP) is widely used as a nutritional supplement to enhance child nutrition in low-income countries. We assessed Spirulina’s efficacy of the current dose supplied by institutions in Cambodia on improving growth and anemia in a cross-over randomized controlled trial in preschool underprivileged children from similar settings. METHODS: Preschool children cared by a not-for-profit institution were randomly and blindly allocated (2 to 1) to spirulina or placebo: 100 g in total, given in 2 g per day. After 5 weeks of wash-out, participants were crossed-over to the other group. Anthropometric gain and selected hematological data (blood cell count, ferritin, and C-reactive protein) were assessed at each phase. RESULTS: A total of 179 children completed the trial, 149 (83.2%) completed all the anthropometrics, and 99 (55.3%) all hematological measures. Mean BMI was 14.18 (95%CI: 14.00–14.37) and 31(20.8%) children had thinness. Mean blood hemoglobin was 11.9 g/dL (95%CI: 11.8–12.1). The weight gain of the SP group showed a modest higher trend compared to placebo (0.63 kg; 95%CI: 0.54–0.72 and 0.46 kg; 95%CI: 0.33–0.58, respectively; p = 0.07). Height increased similarly in both groups. The number of anemic children decreased by 6 (6.06%) and 11 (11.11%) on Placebo or SP, respectively (p = 0.004). Tolerance was good. CONCLUSION: SP may be recommended to improve childhood anemia. The analysis of the usual daily dose (2 g) provided by organizations in Cambodia shows a tendency to improve weight gain in the group supplemented with SP very close to significance, but no trend in height. Increased doses and longer supplementation should be evaluated further. TRIAL REGISTRATION: The study was retrospectively registered at ISRCTN under number 11696165 on 12/12/2018. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03766-5.