Not all probiotics are created equal and picking the right ones can be all important to seeing changes in your health. So here are some things to look for when making your purchases of quality probiotics:
1) Make sure there is some sort of guarantee that the microbes are live. Probiotics are meant to deliver live critters to your gut; dead critters don't count. Some companies say "live at manufacturing" and don't guarantee what will be there when the product gets to you. Others promise live microbes, while some ignore the issue altogether. If they ignore the issue, I'd be inclined to ignore the manufacturer and buy elsewhere. Read the fine print on the label. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153040/
2) The human body carries about 100 trillion microorganisms in its intestines, a number ten times greater than the total number of human cells in the body. So if you want to to change your gut flora you need LOTS of critters~the more the better. Looks for probiotics that have billions and billions of units. Manufacturers generally referred to them as Colony Forming Units, or CFU.
3) The current state of science says that we have as many as 1000 different strains in our guts, so look for probiotics that have a large variety of strains. Again, read the label. The more strains the better. In advanced probiotics, we'll talk about how different strains of bacteria affect different aspects of the body, and how bacteria become personalized, but for this primer, think the more strains the better.
4) Look for probiotics that also contain PRE biotics. Prebiotics set the stage to allow microbial colonies to flourish.
Now let's apply what we've learned:
Procter & Gamble sells a product called Align. It contains only ONE strain of microbe. Here's the information from the Align website.
Bifidobacterium infantis 35624 (Bifantis)
Colony-forming units (CFU): Contains 1 x 109 (1 billion) (4 mg) live bacteria/CFU when manufactured, and provides an effective level of bacteria (1 x 107 CFU)
It claims to be the "#1 doctor recommended probiotic." My guess would be that is because P&G, as a Fortune 500 company, has the marketing budget equal to the GPD of some small countries. Considering what we've learned, spending $35 for a package of 42 capsules of Align, would not be a good use of your money, no matter what the P&G marketers would tell you. It has only one strain. In the scheme of things 1 billion CFUs ain't a whole lot and won't put a dent in changing your gut flora and there are no pre biotics included.
As far as which are good probiotics to buy, I'm going to stay away from recommendations lest readers think I'm getting paid to write these blogs. Plus, I think you are better off doing some homework and picking brands that suit you.
But if you aren't inclined to do your own research, Amazon best sellers can be a good place to start.