Lets just say gut health is critical, healthy gut bacteria levels are a healthy gut. Consuming healthy bacteria is a long proven health strategy. Ages ago, probably about 10,000 years ago, before we were able to package probiotic microorganisms, fermented foods including beer, bread, wine, kefir, kumis, yogurt, and cheese were consumed for their nutritional and healing purposes.
To that end, pretty much all probiotics are good for you, we think. In a study , published in the Journal of Internal Medicine, it was shown that in women over 50, probiotics can halve risk of bone loss and dramatically decrease osteoporosis related fractures. So here's what we know so far:
1. Very few safety studies of probiotics have been carried out. Generally, health care providers don't warn people of risks, as we really don't know if there are any, and FDA says they can be regarded as generally safe (that's a real designation here is the link). In the Journal of Clinical Infectious Disease theoretical risks proposed include increasing the rates of systemic infections, disruption of normal metabolic activities, excessive immune stimulation in susceptible individuals, gene transfer and gastrointestinal side effects.
2. There are lots of studies of the various types of probiotics, both in healthy and sick individuals. Over 600 studies have been done, mostly looking at organisms from 6 genera: Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Enterococcus, and Bacillus. So look for those names if you are reading labels.
3. Although some people will report some complaints, you should have less diarrhea, gas and stool problems with probiotics. And the serious Clostridium difficile-associated diarrhea is less likely to occur in those receiving probiotics by 18%–20%.
4. Rare cases of blood fungal infections called fungemia have been reported. The most common probiotic strains in patients who consumed probiotics prior to symptom onset. The most commonly reported probiotics from these cases include types Saccharomyces or types of Lactobacilli.
5. Probiotics do increase the demand for oxygen in your intestinal track. In other words, they make your gut work harder. Exactly what that consequence would be for those with poor gut health or acute illness hasn't really been worked out. It may be that certain strains would be better at those times, but we just don't know yet.
6. Some bacteria have more gene resistance to antibiotics than others. That is true for the bacteria in probiotics lactic acid bacteria possess organs within themselves called plasmids that can give resistance to antibiotics such as tetracycline, erythromycin, or others.
7. Weight gain is associated with disordered gut health. Probiotics may affect the gut microbiota to modulate obesity, but to date the studies are not conclusive, and have not been linked to one particular type of probiotic strain. In studies using herbal weight loss medications, weight loss was enhanced with the Lactobacillus probiotics simulataneously given.
8. All probiotics are NOT created equally, and one probiotic strains can be expected to vary a bit and have a different effect than other probiotic strains, thus assume each product will have its own safety profile. That being said, if your bowel health isn't regulating, switching probiotics does make sense.