Probiotics: What we know (for now)

Probiotics are being added to everything and being touted as a big benefit to our general health and well being. Infant formulas now contain probiotics and many designer yogurts have added them. You can buy them as a supplement at the drug store as well, and evidence suggests that they have an important role to play in certain conditions.

Probiotics are bacteria that normally colonize our intestinal tract and aid in digestion and modulate the gut immune response. Of all the cells in the human body, 80 percent of them are foreign bacteria that colonize us and we live symbiotically with. Given this fact, it makes sense that if the gut balance or microbiome is off kilter, it could have effects on both digestion and gut immunity.

The challenges we face today are that we don’t know what the optimal balance is for any given person; in fact our own genetics interact with those of our colonizing bacteria, so what may be optimal balance for one person wouldn’t be optimal for someone else.

Research into the role supplemental probiotics can play in our health and medicinally when ill is limited, but there is some. Here’s a summary of what probiotic supplements seem to help and what they don’t:

• Antibiotic-induced diarrhea: Probiotics clearly help. If you’ve had diarrhea in the past while on antibiotics, it works best to start the probiotics before any diarrhea appears. To work, you need to give 100 billion cfu/day of lactobacillus GG or S. boulardii to work. These are found in Culturelle and Lactinex among others. These are readily available at the drug store, but you may need to ask the pharmacist to help you find them.
• Viral-induced diarrhea: Probiotics may decrease the duration of the illness. Same doses and types for the antibiotic induced diarrhea.
• Recurrent C. diff diarrhea: Probiotics may help. This is most relevant in the hospital setting or for children who are in an institutional setting, as C. diff is really rare in children otherwise.
• Irritable bowel syndrome: Mixed evidence but probiotics may help. In this case, a specific combo probiotic called VSL#3 worked the best at reducing symptoms.
• Ulcerative Colitis: VSL#3 seemed to offer some benefit in high doses of four packets daily. Other probiotics didn’t have much benefit. No clear benefit was seen with any probiotic supplements in patients with Crohn’s disease.
• Infant eczema: Maybe if the infant is less than 12 months old. In this case, using the lactobacillus GG or S. boulardii doses for diarrhea (see above) makes sense. Interestingly probiotic supplements given proactively don’t seem to prevent eczema from occurring even though supplements may decrease severity once it is there.
• Asthma prevention: No benefit has been seen in using probiotic supplements.
• Common cold: Probiotic supplements may help decrease the duration of the common cold in children in daycare and fewer days of work and daycare are missed when infants are on probiotics.
• Infant colic: Probiotics are worth a try. Lactobacillus reuteri found in BioGaia brand has been shown to decrease duration of crying for infants with colic.

Research continues, of course, and in general my rule of thumb is that if a supplement is going to do no harm and has been shown to have potential benefits, it is worth using. I routinely recommend probiotics for kids on antibiotics, children with diarrhea, and infants in day care. After attending the conference where this was all reviewed, I will now suggest more colicky infants try them as well as infants with eczema.

As far as everyone taking them daily as a health maintenance plan, there isn’t enough data to suggest that there are benefits to daily supplementation outside other than infants in daycare.