I have received questions about this topic, so I will summarize what I discuss in The Asian Diet: Simple secrets for eating right, losing weight, and being well about probiotics.
Bacteria has gotten a bad name and is regarded by many as an enemy of good health. This is not always true. There are certain bacteria that we need for proper functioning and protection. For example, women's vaginas need a certain amount of bacteria to prevent the growth of yeast which leads to yeast infections. Our intestines harbor bacteria that help digest our food. When we take antibiotics, these intestinal bacteria get wiped out and can often cause intestinal problems such as diarrhea.
Probiotics are supplements that restore the good bacteria in our gut. Some people think that we should always be on this supplement. I disagree. I think that probiotics make sense when you are taking antibiotics. When your troops are under attack and being killed off, you need to supplement the troops. When there is no war, you don't have to keep sending in more brigades. Too much or too little of anything is not a good thing. I also worry that artificially regulating your bacteria levels too much can impair the body's ability to self-regulate.
So you might think "I am not taking antibiotics so I don't need probiotics". I hope that this is true, but antibiotics have infiltrated much of our food supply. Dairy, beef, pork, and poultry are often tainted with antibiotics because commercial over-production keeps the animals in disgustingly crowded pens which encourage the spread of disease. It is just like when people have been confined in Ghetto's in the past. Overcrowding breeds disease. So what do the industrial farms do? Do they recognize that overcrowding is damaging and provide the livestock with more space? No, the keep them in this unhygenic environment and shoot them up with antibiotics.
This is why is it so important to buy free-range, antiobiotic-free, dairy and meat products. Most of us have been ingesting probiotics unknowingly on a daily basis, so most of us could benefit from a course of probiotic supplementation. But I don't want people to be on these supplements too long. Fix the problem, then avoid the problem in the future. Though beware, that butter you put on your bread in the restaurant is probably not antibiotic-free. Nor are much of the dairy and animal products that you will be served in a restaurant. So periodic courses of probiotics may be necessary.
Eat well, be well. That is the lesson of The Asian Diet. To learn more about Asian wisdom and medicine, check out the website for my office, A Center for Oriental Medicine