Constipation or constipation is the alteration of the intestinal habit to defecate or the feeling of not being able to defecate completely in which bowel movements could intervene infrequently.
A large percentage of the population suffers from an intestinal disorder that makes it difficult to defecate normally in terms of frequency and complete emptying, this could be caused by various external or internal factors of the body that hinders normal intestinal transit causing symptoms such as:
- Stomach pain
- Changes in the consistency of stool movements (hard or compact stools)
- Defecatory effort, that is, pushing a lot to be able to defecate.
Certain external factors that can increase the risk of constipation are changes in diet, absence or little consumption of fiber, sedentary lifestyle, low fluid intake, abuse in the use of medications, decrease in body minerals such as calcium, magnesium, potassium and iron and gastrointestinal disorders such as irritable bowel with predominance.
All these factors mentioned above can be modified, starting with changing the lifestyle. Including a daily diet based on functional foods to which curative or preventive action is attributed depending on the case, with healthy benefits in which probiotics are included.
Probiotics are those foods that have been inoculated by non-pathogenic live microorganisms that when included in the diet gives various benefits, among the most prominent as the development of intestinal bacterial flora.
Fermented milks are functional probiotic foods obtained by reducing the pH of milk through lactic fermentation by achieving an environment suitable for the proliferation of these microorganisms.
Fermented milks include the famous, milk kefir, a product obtained from lactic fermentation with cultures of bacteria such as Lactobacillus, Bifidobacterium, Streptococcus and Sasharomycces.
Already exposed everything above, now we will break down in knowing how the consumption of milk kefir is related and its effect on constipation.
Can milk kefir cure constipation?
There are several scientific studies with animal and human models where evidence shows the relationship regarding the consumption of milk kefir and its effect on improving constipation.
Supplementation with Lactobacillus kefiranofaciens was shown to be effective in treating constipated rats where there was an improvement in fecal moisture and wet stool weight. This is important considering that the reduction of volume (liquid) in the body can produce hard and compact stools causing constipation. 
Although there are inconsistent studies on the effectiveness of the effect of a single probiotic strain as therapy for people suffering from this condition, there are scientific studies with infants between the ages of 4 to 16 years where they used a daily mixture of certain specific bacterial strains containing Lactobacillus and Bifidobacterium, in which the results were positive for frequent bowel movements. 
As explained at the beginning of this reading, kefir granules contain these same bacteria that can help improve intestinal transit, improving the change of stool movements and also prevent constipation.
Although the number of clinical trials is very scarce in humans, there are still few studies in healthy people where they evaluated the effect of two bacterial probiotic strains such as Lactobacillus gasseri and Lactobacillus coryniformis, in fecal studies where they gave very favorable results in terms of increased fecal frequency, humidity, and adequate stool weight. 
Finally, we have this study conducted in people with chronic constipation, where it is established that the consumption of kefir improves the symptoms of constipation, and also the same results suggest that kefir increases intestinal satisfaction scores and accelerates colonic transit. 
In short, while much research is still needed to secure the facts in a categorical way, it could be said that the consumption of milk kefir will potentially improve the symptoms of constipation.
How can kefir probiotics help improve constipation?
In the digestive tract and other parts of the body we have billions of bacteria, especially in the colon in which they live mostly, approximately 400 species of bacteria that in a healthy body coexist symbiotically fulfilling some specific and vital functions for the human body, the most important being Lactobacillus and Bifidobacterium (so far).
Within these specific and vital functions in the human body, there is the regulation of serotonin at the gut-brain level. Serotonin is a very important neurotransmitter that plays a great role in neurological disorders and intestinal diseases. 
There are scientific studies where he explains that there is a close relationship in the intestinal microbiota and at the neuronal level, a bidirectional communication in response to various external etiologies such as different emotions, stress, release of hormones, digestion, the type of immune system, among others.
80% of our immune system is in the intestine, specifically in the intestinal cells, but its alteration affects our defenses, and these are captured by sensors or cellular receptors of the immune system, such as the «danger sensory» proteins so called to understand it better or with its scientific name such as TRL2.
When harmful microorganisms abound compared to the beneficial microorganisms of the intestinal bacterial flora, this sensory protein (TRL2) will decrease the production of serotonin at the mucosal level consequently affecting the muscles of the intestine decreasing its mobility hindering the passage of feces throughout the colon until its expulsion.  
The TRL2 will recognize the quantity and quality of the intestinal flora, depending on these levels will condition the production of serotonin. 90% of serotonin in the body is found in the intestinal mucosa where it probably influences motor activity, that is, the part that is responsible for stimulating the movements of the intestinal muscles.  
Previously it was explained that one of the causes of constipation or constipation are infrequent bowel movements, this is where probiotics act, which can act to prevent constipation, and milk kefir are included in the formula.
Milk kefir is more than a probiotic, since it has a varied and complex microbial composition of different species of yeasts, lactic acid bacteria, acetic acid bacteria, mycelial fungi and all these elements are covered by kefiran. 
Kefiran is an exopolysaccharid obtained during lactic fermentation that apparently protects the microbiota within the kefir grains. This polysaccharide is mainly produced by the bacterium Lactobacillus Kefiranofaciens and gives these probiotic numerous beneficial properties such as essential amino acids for intestinal motor regulation. 
The probiotic effect of milk kefir will predominate in the ability to regenerate and repopulate the intestinal microbiota, providing the appropriate quantity and quality of beneficial bacteria against those that are not and thus stimulate the production of serotonin through the uptake of TRL2 receptors in order to make bowel movements more frequent and prevent constipation.
Another important effect of milk kefir to improve constipation is the contribution of essential amino acids such as tryptophan, which is key in the nervous system. Tryptophan promotes the synthesis of serotonin as a neurotransmitter and motor regulator of the intestine.
In summary, the probiotics present in kefir will have an effect on improving intestinal imbalances that cause constipation. In addition, its neurological effect could help improve bowel movement to promote fecal evacuation.
How to maximize the effects of milk kefir to improve constipation?
To improve constipation the individual must meet the physiological needs of nutrients that are required daily, in this case we talk about milk kefir that has all the nutritional and essential requirements to improve the symptoms of constipation according to various studies.
In order to maximize these probiotic effects, it is necessary to carry out a good diet based on vegetables such as artichoke, asparagus, leek, onion, garlic, banana and wheat, which contain fructooligosaccharides and manage to reach the lower tract of the colon as selective substrates of high quality for the proper functioning of probiotics.
Among this functioning we have a better absorption of nutrients, increasing the amount of beneficial bacteria Bifidobacterium and Lactobacillus, increasing the amount and frequency of bowel movements, and finally, producing short-chain fatty acids that possibly influence to stimulate bowel movements.
A fiber-based diet is important to include along with the consumption of milk kefir to enhance the effects of this probiotic and improve intestinal transit, since foods rich in fiber are considered prebiotics.
Another way to help enhance these effects of kefir is to ensure that the fermentation process is carried out at a temperature of 20 to 25 ° C for about 24 hours to achieve the right quantity and quality of microorganisms of Lactobacillus and its species. 
During the process of making kefir it is preferable to do it in an artisanal way so that one can control the necessary fermentation time and achieve the desired effect to improve constipation.
Another important aspect is to use this product with the intake of plenty of liquids especially water when we use kefir as a laxative and thus help increase the moisture of the stool.
What would be the recommended dosage of milk kefir to prevent constipation?
Regarding the dose will depend on each person in terms of the condition that is, there are studies where they refer to the consumption of a cup a day for an adult who is in good health in which it may be enough as breakfast or dinner. Now in conditions of pregnancy, older adults, adolescents, infants suggest up to two cups a day equivalent or half a liter. 
It is important to mention that if we want to know the amount of a cup in ml, this may vary slightly depending on the type of cup, but in order not to cause confusion, we will mention the amount of a standard cup that is 250 ml.
In people with diseases it is indicated according to the different studies to increase the doses, until ingesting a liter a day distributed during the day, followed by a healthy diet, although in my opinion, it seems to me an excessive amount considering that it is a product based on milk.
Now you can start with a minimum dose of approximately 180 ml and gradually increase to tolerance if you are a healthy person and what you want is to prevent constipation. 
What is certain is that if you want to get the benefits of kefir, consumption has to be regular and incorporate it into your daily diet to get the desired benefits.
Can milk kefir be used as monotherapy in constipation?
It is important to clarify that milk kefir is of great help to the body for the various benefits it offers, however, constipation has a wide variety of external factors that are also involved or associated.
For this reason, probiotics are used as an alternative therapy in combination with other treatments that are necessary and indicated by your health professional to alleviate the different conditions that the person encounters.
The important thing is always to adopt good eating habits, that is, a balanced diet based on raw materials fundamentally, complemented with physical exercises and adequate hydration.
Following these suggestions, there is a high potential to prevent constipation and improve living conditions in terms of comfort and nutrition in our body.
Can kefir milk cause constipation?
Milk kefir does not cause constipation since milk is a food substrate that provides the glucose necessary to start the fermentation of kefir granules through the different microorganisms mentioned above.
There are even human studies where they mention that ingesting fermented milk with kefir granules on constipation in patients with neurological disorders improves evacuatory frequency, consuming 2g of kefir with each meal for 12 weeks, according to their results there were individuals who improved constipation levels while in others there was no difference. 
Depending on the condition that the person is, consuming fermented milk will not cause constipation, so you can drink this drink quietly and in turn will help improve the symptoms of constipation or prevent it.
Even if you have some insecurity to drink fermented milk in case you are lactose intolerant or allergic to dairy products, you can consume kefir by replacing milk with water and adding sugar to the preparation so that fermentation is achieved and ready. You will have the same beneficial properties of kefir to improve constipation.
I hope your doubts have dissipated and you have more clarity about the consumption of milk kefir to relieve constipation. As always, we leave you with very interesting, related articles that I am sure you will love.