Strontium is of great significance to human health and participates in various physiological functions and biochemical effects. It has great prospects in the development of health products and natural medicines. Strontium not only has a protective effect on bone diseases, dental caries and cardiovascular diseases, but also maintains reproductive health. In addition, more and more studies have confirmed that strontium also has many functions such as anti-inflammatory, antioxidant, anti-adipogenesis, anti-cancer, anti-diabetes, pro-angiogenesis and heart protecting functions. In order to provide a theoretical basis for the development of strontium rich foods and the application of strontium in nutrition, this paper reviews the relationship between strontium and calcium, the safety of strontium, and its safety threshold and major physiological functions.

Short chain fatty acid (SCFA), a class of fatty acids with six or less carbon atoms, have important physiological functions for human health. As metabolites of the intestinal flora, SCFA can maintain intestinal health. Furthermore, accumulating research has proved that SCFA have many functions such as maintaining brain and bone functions, participating in regulating the immune response, antibacterial and antitumor activity, and alleviating obesity and diabetes. In this paper, recent literature on the production, absorption and functions of SCFA in the body are reviewed to provide a theoretical reference for the research and application of SCFA in nutrition.

As global aging intensifies, the incidence of age-related bone metabolic disorders, such as osteoporosis, continues to climb. Seeking safe and effective therapeutic interventions is of utmost importance. The modulation of bone metabolism by the gut microbiota and their metabolites has emerged as a focal area of research. Short-chain fatty acids (SCFAs), including acetic, propionic, and butyric acids, exert regulatory effects on bone formation and resorption through the gut-bone axis. Furthermore, SCFAs play positive roles in maintaining bone homeostasis and contribute to the alleviation of inflammatory bone loss. This review synthesizes the current knowledge about the mechanism by which SCFAs regulate bone metabolic homeostasis via endocrine pathways, immune modulation, and enhanced nutrient absorption, hoping to provide a scientific foundation for the prevention and treatment of metabolic bone diseases in the elderly.

In order to analyze the effects of regions and seasons on the lactoferrin content in raw milk produced by healthy dairy cows in the major dairy-producing areas of China and to explore the difference in lactoferrin content in raw milk in China, a total of 164 raw milk samples were collected in four seasons from the six major dairy-producing areas in China and analyzed for their lactoferrin contents by ultra-high performance liquid chromatography (UPLC). The results showed that there was no significant difference in lactoferrin content in raw milk samples from North China, South China, Southwest China, Northeast China, Northwest China, and East China. The lactoferrin content of raw milk collected in autumn and winter was significantly higher than that in spring and summer. This study revealed the regional and seasonal differences in lactoferrin content in raw milk.