Nutritional and functional values of microalgae (spirulina) naturally found in East Africa

Abstract

Sub-Saharan Africa has a higher prevalence of undernutrition, which is the underlying cause of stunting and underweight problems in children. Undernutrition is generally caused by insufficient intake of nutrients; in Africa, it’s mainly due to over-reliance on plant-based staple diets which contain inadequate amount of essential nutrients. Spirulina is a naturally abundant microalgae with great nutritional values and could be utilized to fortify diets to enhance human health. Therefore, this study evaluated nutrient content, bioavailability and safety of locally found Spirulina products, focusing specifically in East Africa, to enable possible food-based strategic interventions aimed at improving human nutrition in the region. A field survey was conducted to identify local Spirulina producers in East Africa and obtain samples. A total of 54 mice were used in evaluating the nutrient bioavailability and safety in vivo. A randomized control trial research design was used to select and allocate mice into treatment groups. Randomly grouped mice were separately fed three diets: control (basal), test (15% Spirulina powder blended with 85% basal diet) and standard (basal diet supplemented with standard nutritional supplements). The test and standard diets had equivalent nutrient content to enable direct comparison of results. Nutrients content analyses showed that a 100 g analyzed Spirulina samples contains 70 g protein, 82 mg iron, 84.5 mg zinc, 1302 mg calcium, 628 mg phosphorous, 27 𝜇g vitamin A, 246.8 𝜇g vitamin B9, 3.99𝜇g vitamin B12, 1.92 mg QE/g total flavonoid and 2.99 mg GAE/g total phenolic. The nutrients bioavailability from the control diet was statistically lower than those of test and standard diets, whose results were comparable. After the feeding experiment, mice had no significant differences in their serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), cystatin C and troponin I concentrations, indicating that the studied concentrations of control, test and standard diets had no adverse effect on critical organs (liver, heart, or kidney) of the mice. These results indicate the safety of Spirulina and reinforce its importance in reducing undernutrition in humans.