Small intestine- finally break down our food & absorb nutrients into our body; good bacteria are essential in producing enzymes to efficiently break down food.
Large intestine- absorb water, vitamins, and glucose into our bloodstream and store & secrete waste from our body. With imbalanced nutrition (e.g., consuming too much protein, fat, and carb compared to fibre-rich food), this waste will build up as a chronic dunk and prevent nutrition from being fully absorbed. They are also food for the harmful bacterias to feed on, ferment and make us gassy, producing toxins in our body and affecting other health issues, our mood, and sleep. On the other hand, if you have well-balanced good bacteria, they can help break down remaining nutrients, produce vitamins by fermentation and fully secrete waste with regular bowel movements.
A well-balanced microbiome is the key to good gut health, which benefits your overall health.