Microalgae in Human Nutrition and Health
Microalgae-derived minerals are emerging as sustainable nutrient sources for humans; however, knowledge of their bioaccessibility and bioavailability remains limited. This study systematically evaluated mineral (Fe, Ca, Zn, Mg, Cu, Mn, P, K), carbon (C), and nitrogen (N) content and their bioaccessibility from 9 microalgae samples using standardized INFOGEST 2.0 in vitro digestion, combined with a human intestinal epithelial (Caco-2) cell model for iron bioavailability assessment. Total mineral content varied notably (Fe, 72.1–3120.9 mg/kg; Ca, 516.9–24,146.3 mg/kg; Zn, 12.1–282.1 mg/kg; Mg, 379.2–15,245.9 mg/kg). Mineral bioaccessibility exhibited a wide variability; for instance, Fe bioaccessibility ranged from 0.5 % in Tetraselmis chuii to 83.4 % in green Chlorella vulgaris. The bioaccessibility of Ca (0–82.3 %), Zn (51.9–62.2 %), Cu (7.5–89.8 %), Mg (68.0–92.2 %), Mn (6.75–84.3 %), P (9.7–100 %), and K (91.1–100 %) also showed large interspecies differences, similar for C (12.4–78.1 %) and N (39.5–93.8 %). The iron bioavailability of Arthrospira platensis and unlysed Haematococcus pluvialis is the highest, comparable to that of FeSO4. Tetraselmis chuii and Dunaliella salina exhibit relatively lower bioavailability; however, their levels remain higher than those found in conventional foods. This study demonstrates the potential of microalgae as an innovative and sustainable food source, offering highly bioaccessible minerals and bioavailable iron for human nutrition. It emphasizes the necessity of evaluating both bioaccessibility and bioavailability to accurately assess the nutritional value of microalgae-derived minerals, thereby informing future dietary applications and nutritional strategies in food science. See more in Gao et al., 2026: external page https://doi.org/10.1016/j.crfs.2026.101302
Iron-deficiency anemia is a major global health issue impacting approximately 1 billion people worldwide. Microalgae are sustainable and iron-rich resources; however, comprehensive studies on the bioaccessibility and bioaccumulation of microalgae-derived iron are limited. This study assessed these factors using three different microalgae species (Arthrospira platensis, Galdieria sulphuraria, and Chlorella vulgaris) grown under autotrophic, heterotrophic, and mixotrophic conditions using both standard (all modes) and iron-enriched media (autotrophic mode only). With the standard medium, the highest levels of iron bioaccumulation were observed under autotrophic conditions for A. platensis (563.4 mg/kg) and C. vulgaris (326.5 mg/kg), whereas G. sulphuraria reached its peak accumulation (238.9 mg/kg) under mixotrophic conditions. Heterotrophic mode yielded superior bioaccessibility results (66.9% for G. sulphuraria and 76.3% for C. vulgaris) compared to autotrophic cultivation (18.4%, 39.8%, and 41.8% for A. platensis, G. sulphuraria, and C. vulgaris, respectively). Increased iron concentrations in the culture medium resulted in substantial enhancements in iron bioaccumulation, particularly for G. sulphuraria. A 7.6-fold increase (up to 1,472.4 mg/kg) was achieved with a 150-fold iron concentration in the medium under autotrophic conditions. However, this increase in biomass iron content was accompanied by a relative decline in bioaccessibility, from 36.8% to 17.1%. The maximum amount of absolute bioaccessible iron (251.6 mg/kg) was found in G. sulphuraria cultivated autotrophically, which considerably exceeds the levels typically found in conventional foods. This study systematically evaluated the bioaccessibility and bioaccumulation of iron in various microalgae species, highlighting their potential as sustainable, innovative, highly bioaccessible, and iron-rich sources for addressing iron-deficiency anemia. See more in Gao et al. 2026: external page https://doi.org/10.1016/j.biortech.2025.133567