Characterization and antioxidant activity of flaxseed mucilage and evaluation of its dietary supplementation in improving calcium absorption in vivo

Calcium is an essential element for bone's strength and structure. Flaxseed mucilage (FM) is an economic bioactive component with potential prebiotic capability. FM promotes the growth of probiotic bacteria and it is added to fermented dairy products to increase the survivability of probiotic strains. Mucilage was extracted from flaxseed meal, as an industrial by-product, with or without ethanol precipitation (MEP and MWEP, respectively). Characterization, antioxidant, and chemical composition of the extracted mucilage were assessed. Plain milk as well as 100 mg/kg b. w of MWEP or MEP-fortified milk were administrated for 4 weeks to growing female rats fed a calcium-deficient diet to assess the role of mucilage, as a prebiotic, in calcium absorption, growth, and bone health. The free radical scavenging activity and the total reducing capability were greater in MWEP (72.4% and 17.53 mg/g, respectively) than in MEP (22.1% and 4.29 mg/g, respectively). Animals that received the mucilage-fortified milk showed an improvement in calcium absorption, which was reflected in the increase in the femur calcium and the improvement in bone health, which was evident through the histopathological findings of the bone tissues, and an improvement in bone growth, which was obvious through an increase in estrogen and insulin growth factor 1. It could be concluded that in addition to being a functional antioxidant made from industrial waste, flaxseed mucilage is also recommended to improve calcium absorption and bone health.