I've done a ton of reading. I don't disagree with anything said above but I will add a little:

• I've read that the types of probiotics found in good quality yogurt are helpful but do not normally colonize the gut; if you stop eating yogurt, the benefits gradually fade.
• Both types of kefir, dairy and water, have MANY more types of probiotics than yogurt. There is some evidence that kefir can change the gene expression of gut flora in positive ways and there is some evidence that some of the kefir probiotics can colonize the gut.
• I read of a research study in which scientists were amazed that kefir made in unsanitary conditions by pastoral peoples didn't contain any "dangerous" bugs. They actually injected a batch of kefir with pathogens and 3 days later (I think that was the interval) the bad bugs were gone, apparently killed.

Now my anecdotal experience. As Anonymous Chump said, when I started drinking water kefir I was very careful and drank only a tablespoon full for the first few days. Even so, I definitely felt changes going on in my gut. I now drink a small amount of first-brew and 1 or 2 bottles of carbonated water kefir every day.

One year ago, I could not eat ice cream or yogurt; even trace amounts of yogurt upset my stomach in a fairly violent way. This Christmas, I ate a pint of ice cream on several different days with no symptoms; I now eat 1/2 a cup of home-made lively yogurt every day with no symptoms.

I can only conclude that some of those bugs are making it through my stomach! Actually, I can't speak for dairy kefir but water kefir is a watery liquid and if you drink it on an empty stomach it doesn't spend much time there and acid/bile levels should be at their lowest.

This is what I've learned from word-of-mouth: Plenty of them die, but some of them make it. They're hearty little bugs, and they also reproduce very fast (as all bacteria do). So even if only a few make it, they can quickly populate your gut from the luckiest/toughest survivors.

Commercial strains of probiotics aren't as tough; they're living in processed foods and/or have been heavily processed themselves, and so are weak by the time you bring them home and eat them. That's why probiotic supplements need help in the form of encapsulation. I've also read that commercial yogurts and kefirs often cannot deliver on the promised probiotics because the bugs just cannot survive.

I don't have actual research links. But I know that kefir is doing something in there -- when I drink too much at once, I sure know it. Some pretty epic bacterial battles occur when I send in a ton of troops!

Edit to provide an interesting quote from Wikipedia:

"Both kefir and yogurt improve lactose digestion simply because some of the bacterial cells give up their lives in the intestinal tract, release their enzymes and digest the lactose. It's a one-shot deal. However, kefir has additional microorganisms that may be able to colonize the intestines and benefit health further by protecting the intestine against disease-causing bacteria." -ScienceDaily. 2003-05-30.

...so they are making it to your intestinal tract, but most of them die there; however, kefir has so many types of bacteria that some types just might take up residence and keep helping you out.

Fun fact: Babies are born with sterile guts, and slowly build up their gut flora via their digestive tracts by interacting with their world, be it going through the birth canal, nursing, licking and sticking random objects in their mouths, etc.

So, through the mouth is the normal route by which we alter and supplement the critters in our gut. Like others have said, I think it is a numbers game, and if you have that kefir on a regular basis, a certain amount will make it through the stomach acid gauntlet and start to colonize.

this is my own theory

ever added an acidic liquid to milk? the milk curdles. in fact, my mom once told me when milk gets to the stomach, it turns into pieces of semi-solid jellies, as she had seen me vomiting up the stuff as that (i vomited alot as a kid). and as i recall, i once added lemon juice to milk and it become a little jell-like. so here's my theory: fermented milk goes into stomach, meets stomach acid, curdles and forms semi-solid pockets of jellies which contain the probiotics, and due to the fact that the stomach only churns the pockets never get damages and the probiotics never get released until somewhere in the intestine with other digestive juices added to the mix. what do u guys think of this theory?

"These bacteria are not highly acid-and bile-resistant, with only 15% surviving the passage through the stomach and about 1% reaching the large intestine, 70 where they fail to colonize"

link text

link text

"The term probiotic refers to live microorganisms that reside in the gastrointestinal tract and have beneficial effects on the host (De Simone et al. 1991; Lee and Salminen 1995). More than four hundred species of bacteria are estimated to survive in the gastrointestinal tract and these endogenous bacteria comprise the intestinal microflora. Even more species may be present but not culturable by the traditional plate count methods. After passage through the stomach and the small intestine, some probiotics survive and become established transiently in the large bowel. In order to survive in and colonize the gastrointestinal tract, probiotic bacteria need to express high tolerance to acid and bile and to have the ability to adhere to intestinal surfaces (Lee and Salminen 1995; Kirjavainen et al. 1998; Fujiwara et al. 2001)."

Dr. Mercola's site states that most of the probiotics make it through and do not need encapsulation if they come from a good food source or a good pharma source.

Has anyone ever heard of h. Pylori? It's the bacteria that causes most stomach ulcers. It's a relatively recent discovery that the stomach is not actually a sterile environment. There are bacteria that can live and even thrive in the stomach. I wouldn't be surprised if more bacteria than we thought are able to pass through alive.

I heard its a myth probiotics not making it through gut. new studies show that probiotic count is passed down from the mother to the child. Mother with low probiotic count = baby with low probiotic count and mother with high probiotic count= baby with high probiotic count. Not sure if its cell memory. But there is a link with kefir and dna and changing dna and also NKC ( natural killer cells ). Also certain species have difficult time through the gut but not all of them. google in vitro selection of probiotics.

probiotics are "killed" by chlorine chemicals processed foods etc..

Probiotics are food for good bacteria.

"For example, one expert claims that stomach acid kills 99.9 percent of lactobacillus and bifidobacteria, which are probiotics in yogurt. Another says these probiotics are among the few that do survive the stomach. Then a UCSF study finds probiotics that don't even need to be alive to have an effect, since they have an immunostimulative role (like dead viruses used for a vaccine)."

unique healing on youtube has good sound info she doesnt really push product and has healed herself of incurable diseases with probiotics etc. she just says massive probiotics for 3 years and bentonite clay to mitigate until healed.. has an herbal product thats cheaper than buying probiotic. I tried it its good, I just cant do all the herbs and well kefirs cheap baby. I dont agree with her that there are not enough probiotics in kefir and it would take 10 years to heal the gut on kefir alone .. but until I get labs done on my kefir I will take probiotics ( good cheap source custom probiotics dot com )

https://www.youtube.com/watch?v=PpPeAa74yNs

what I am interested in is getting a lab culture done on my kefir, not the grains. When its done I will post it.

I am adding a study here as it supports cfu count in kefir and well one never knows if this study will " disappear" J Food Sci. 2012 Aug;77(8):M425-33. doi: 10.1111/j.1750-3841.2012.02805.x. Investigation on culturable microflora in Tibetan kefir grains from different areas of China. Gao J, Gu F, Abdella NH, Ruan H, He G. Source

College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China. Abstract

Four samples of Tibetan kefir grains (TK-ZJUJ 01-04) from Tibet and surrounding areas were investigated via phenotypic and genotypic methods to compare and analyze the diversity of culturable microflora among different origins. As a result, 4 genera of microorganisms from TK-ZJUJ01: Bacillus subtilis (2.9 × 10(7) cfu/mL), Lactococcus lactis (8.2 × 10(7) cfu/mL), Kluyveromyces marxianus (3.0 × 10(6) cfu/mL), Saccharomyces cerevisiae (9.0 × 10(6) cfu/mL); 4 genera from TK-ZJUJ02: Lactobacillus kefiri (1.0 × 10(8) cfu/mL), Pichia kudriavzevii (5.0 × 10(6) cfu/mL), K. marxianus (1.9 × 10(7) cfu/mL), Kazachstania unispora (6.2 × 10(7) cfu/mL); 6 genera from TK-ZJUJ03: Leuconostoc lactis (4.6 × 10(7) cfu/mL), L. lactis (3.0 × 10(7) cfu/mL), Lactobacillus plantarum (3.0 × 10(7) cfu/mL), K. unispora (3.0 × 10(6) cfu/mL), K. marxianus (2.0 × 10(6) cfu/mL), (1.7 × 10(7) cfu/mL); and 4 genera from TK-ZJUJ04: L. plantarum (1.8 × 10(7) cfu/mL), Acetobacter fabarum (5.0 × 10(6) cfu/mL), K. unispora (6.2 × 10(7) cfu/mL), Pichia guilliermondii (6.2 × 10(7) cfu/mL) were identified. Yeasts like P. kudriavzevii and P. guilliermondii isolated in this study were the first time reported in Tibetan kefir grains. For TK-ZJUJ 01-03, lactic acid bacteria were the major microorganisms, which accounted for more than 50% of all the microbial population, while for TK-ZJUJ04, the largest microbial group was yeasts which accounted for more than 50%. In a word, study of diversity and composition of microflora provided us theoretical foundation for further investigation and application of Tibetan kefir grains. PRACTICAL APPLICATION: This is the basic research in order to develop and industrialize a new kind of yogurt starter which is naturally formed microbiota with both lactic acid yeast...

google this; " COMPARATIVE STUDY OF KEFIR LACTICMICROFLORA " , there is a cfu graph provided for lab culture done on romanian kefir grains

Has anyone ever heard of h. Pylori? It's the bacteria that causes most stomach ulcers. It's a relatively recent discovery that the stomach is not actually a sterile environment. There are bacteria that can live and even thrive in the stomach. I wouldn't be surprised if more bacteria than we thought are able to pass through alive.

I have read that both water kefir and kombucha are very acidic. My question is: do they have an acid producing effect on the system? I have found this website extremely helpful in case some people have not seen it: www.yemoos.com

I have a question. I just read that Kombucha can kill and has killed people. They get lactic acidosis or liver failure and get seriously sick and some have died. Is that true? I am very worried because my son has recently started taking Kombucha and got very sick. The doctors don't know what it is....a stomach ulcer, acid reflux but my son says it's not hearburn.....that the pain is under his ribs and in his chest...since he stopped taking the kombucha, the pain has subsided. He has had blood tests and we are waiting for the results.

Karen,

It could potentially be a die off reaction of other bacteria or yeast. This is actually fairly common.

If kefir doesnt get by the stomach acid to some extent then why does my gut start responding so favorably to its ingestion? Im convinced regular consumption is key.

I make my own milk and water kefir x2yrs. I wonder how drastically mine would differ from the strains found in the tibetan kefir study. I would assume the makeup of yeasts would be vastly differing. Anyone have any thoughts on that?