This post is part of my ongoing discussion on digestion. But in talking about kefir, the benefits of kefir may start with digestion but extend throughout the entire body. I truly believe that kefir is one of the most beneficial beverages/foods to consume in the diet. Dairy kefir is a cultured, lacto-fermented beverage/food that is teeming with health benefits. Kefir is rich in beneficial bacteria and yeasts, phosphorus, vitamin K, biotin, folic acid, mineralsand enzymes. Plus kefir is low in lactose. Kefir is akin to plain yogurt as they share a somewhat sour taste but kefir contains both beneficial bacteria and yeasts whereas yogurt only contains beneficial bacteria. One of my research articles listed 56 different strains of beneficial organisms and microflora! Compare that to the yogurt you bought at the grocery store that may contain 3 different strains.
The beneficial microflora contained in kefir have multiple purposes. Kefir assists in keeping the digestive tract balanced and healthy. The digestive tract is home to approximately 400 different species of organisms with a population of about 100 trillion. Yes, that's 100,000,000,000,000! Without these microflora, problems arise. As 70-80% of your immune system is located in your digestive tract, maintaining a proper balance in the gut is vitally important for general health. Factors negatively affecting digestive health include stress, disease, poor nutrition, toxins, and medications. 
Kefir is gaining popularity in health food stores and there are more brands available than ever before. Most advertise having 10 different strains of microflora. I caution you to watch the sugar content in some flavors as it can be quite high. If you are buying your kefir, I recommend the plain, whole milk version. However, if you want more bang for your kefir buck, I recommend making your own. It's remarkably simple. I've been making my own for a few years now and am drinking some as I speak! There are many different tutorials online for guidance or more indepth information.
Some of the sites I like are:
http://www.culturedfoodlife.com/www.kefirlady.com
http://www.culturesforhealth.com/
http://gnowfglins.com/
http://nourishedkitchen.com/
Because kefir is so easy to make, I recommend making your own as it confers more healthy organism than the store bought versions. Additionally the store bought versions are made differently than homemade versions. I normally have extra kefir grains available so if you need some, let me know.
