A healthy gut typically contains large quantities and diversity of microorganisms which makes it both stable and resilient. Kefir gives you one of the highest diversity and concentration of live microorganisms in a probiotic. And more importantly, microorganisms from kefir are resident and not transient. This means that it stays in our bodies and doesn't just get expelled with body waste.
Kefir promotes better digestion. This means more nutrients are made available for the body in a form that is easier for the body to absorb and utilize.
Kefir contributes to better metabolism. This means more efficient access and storage of energy and more efficient synthesis and breakdown of tissues & cells.
Kefir contributes to a stronger immune system. This makes our bodies more resilient to sickness and infections.
Kefir contains a good amount of calcium. Calcium is needed for stronger bones & teeth and necessary for growth. The fermentation process makes the calcium easier for the body to absorb.
Kefir contains a good amount of protein. Protein is needed for creation of muscles and necessary for growth. The fermentation process makes the protein easier for the body to absorb.
Kefir influences increased secretion of good mood hormones. Kefir is also loaded with tryptophan (a.k.a. nature's Prozac) which helps you to be more relaxed and get a better night's sleep.