Development Of Special Diet For The Elderly People Based On Gut Microbiota Regulation

As life expectancy is increasing,there has been a subsequent increase in the aging population.Exploring novel methods by adjusting diet structure to improve the lifespan and quality of life of the elderly people has thus become a hotspot in research.Dietary protein is essential for the elderly people.Although experts recommend that the aging population should eat more protein,a high-protein diet may increase the burden on elderly people with degraded digestion and absorption.Due to the decrease of protein digestion and absorption ability,the entry of undigested protein into the colon resulted in the increase of the abundance of proteolytic bacteria.In addition,the decline of oral and esophageal function will also make the elderly people avoid intaking fiber-rich foods,resulting in gut microbiota fermentation to proteins,amino acids and other substrates.Therefore,based on the reasons for the changes of gut microbiota of the old people,this paper aims to explore the effects of high protein or moderately hydrolyzed protein diet on gut microbiota and determine the proteins that can regulate gut microbiota and improve physiological function.Then in vitro fecal microbiota fermentation experiment was used to explore the regulatory effect of different dietary factors on aging gut microbiota,and to confirm the dietary factors in the special food.Finally,the design and clinical evaluation of thie special food for the elderly people were carried out.(1)To analyze the effect of different content and form of protein on the physiological function of aging mice,C57BL/6J female aged mice were used.The animal experiment was to study the effects of normal or high protein,whole protein or hydrolyzed protein and pure soy protein or whey protein diet on bone,muscle health and gastrointestinal function.The results showed that the hydrolyzed protein with a normally recommended protein energy supply ratio of 14.7% was helpful to maintain body weight,bone and muscle health,while the small intestinal structure and function were damaged,and the level of serum pro-inflammatory factors was increased in the increased protein energy ratio group.The relative abundance of conditional pathogenic bacteria(Streptococcus and Peptococcus)increased in gut microbiota of mice fed with whole protein,while the relative abundance of Bifidobacterium decreased.The entry of undigested and absorbed proteins into the colon caused adverse changes in gut microbiota and made the aging body unhealthy.To sum up,hydrolyzed whey protein and soybean peptide with a normally recommended protein energy supply ratio of 14.7% are suitable for aging body.(2)Screening of indigestible functional dietary factors that can adjust the structure and species composition of aging gut microbiota.The food-derived dietary factors were selected to replace the carbon source in the culture medium.The fermentation experiment of fecal bacteria in vitro was carried out to screening the dietary factors that can make the fermented fecal microbiota tend to that of young people.Based on the characteristic importance score of random forest model,the top bacteria were selected as the difference between the elderly and young people.The results showed that the bacterial polysaccharides with the main structure of ?-glucan increased the content of short-chain fatty acids(SCFAs)in the fermentation broth.There was no significant difference in Beta diversity between fermented microbiota after adding eight dietary factors and fermented feces microbiota of young people.In addition,most dietary factors increased the abundance of beneficial bacteria(Bifidobacterium,Parabacteroides,Bacteroides,Faecalibacterium,et al.)and reduced the abundance of harmful bacteria(Fusicatenibacter,Dorea,Escherichia-Shigella,et al.).To sum up,ganoderma lucidum polysaccharides and auricularia auricula polysaccharides as well as fructo-oligosaccharides are more effective in regulating the structure and species composition of gut microbiota in the elderly people,which can be added to the special food.(3)Design and clinical evaluation of special food for the elderly were carried out.Based on the protein and dietary factors determined by previous experiments,combined with the existing fully nutritious formula food and the national standard for special foods,this special food for the elderly people was designed.The elderly volunteers were recruited for a two-month clinical trial.The results showed that the special food reduced the fat content,increased the muscle content,improved the exercise ability and upper limb strength.The special food also promoted gastrointestinal peristalsis,alleviated the defecation problems,and increased the contents of anti-inflammatory factors in serum and SCFAs in feces.In addition,this food decreased the abundance of bacteria associated with disease(Ruminococcus),and increased the abundance of bacteria associated with SCFAs production(Anaerostipes,Roseburia,et al.),antiinflammatory(Faecalibacterium,et al.),mobility improvement,and maintenance of bone health(Bifidobacterium).To sum up,the special food for the elderly people designed in this experiment improves the gastrointestinal dysfunction and muscle atrophy by regulating the gut microbiota,and maintains the health of the aging body.