Konjac oligosaccharides promote calcium absorption and bone health in growing mice

Abstract

Childhood and adolescence are critical periods for rapid bone mass accumulation and the achievement of peak bone mass. However, low-calcium diets disrupt bone metabolism, and traditional inorganic calcium supplements, such as calcium carbonate, have certain limitations in bioavailability and in their effects on bone mass. Prebiotics can improve skeletal health, but the mechanism of action of konjac oligosaccharides (KOS) in calcium-deficient growing mice remains insufficiently explored. This study aimed to investigate the effects of KOS on bone health in mice subjected to a low-calcium diet during growth, as well as its potential mechanisms. A low-calcium juvenile mouse model was established, with interventions including calcium carbonate alone or in combination with KOS. After six weeks, supplementation with 8% KOS significantly enhanced calcium absorption, reduced serum PTH, ALP, TRAP-5b, and CTX-1 levels, increased serum OCN and P1NP levels, and improved bone mineral density, trabecular structure, and bone strength. Meanwhile, KOS markedly modulated the gut microbiota composition in hypocalcemic mice, increasing the abundance of beneficial bacteria such as Bifidobacterium, Lactobacillus, and Bacteroides, while decreasing the proportion of potentially harmful bacteria. It also significantly lowered cecal pH and increased cecal content weight. Compared with the reference compound, inulin, KOS exhibited similar but more pronounced effects on promoting bone formation and regulating the microbiota. This study confirms the bone health-promoting effects of KOS in calcium-deficient mice during growth, providing experimental evidence for the development of KOS-calcium composite dietary supplements.