Last fall, two studies showed that probiotics may not work as well in kids who have “tummy bugs” as we had previously thought.

I am defining acute gastroenteritis here – that’s the term we docs use to describe a tummy bug – as that all-too-common few days of vomiting and loose stools/diarrhea your kids pick up at school.

In the studies (which were actually pretty good ones), two large groups of children (one study had 971, another had 886) were randomly selected to take five days of mostly Lactobacillus rhamnosus or Lactobacillus helveticus, two common probiotics we recommend for kiddos this age, if they walked into certain U.S. or Canadian ERs with symptoms of gastroenteritis. Another group was assigned a fake/placebo.

The studies seemed pretty fair. Their poops were tested and found to have similar germs (viruses vs bacteria vs no cause found). Similar numbers in each group had gotten antibiotics or vomiting medicines. Neither study was run by a corporation – they were publicly funded.

After 14 days, participants were given a survey to see how their symptoms were doing. I’ll spare you the details – the probiotic group didn’t feel any better than the placebo group in both studies.

What does this mean? Well. Probiotics may not be beneficial to our kids when it comes to tummy bugs. But, let’s remember our critical thinking skills when we read medical studies –

• They only tested two types of probiotics.
• They only tested a five-day course of it.
• These studies were done on one age group only: 3 months to 4 years.

Probiotics have, in other studies, been proven to be beneficial in helping other ailments! Like colic, irritable bowel syndrome, chronic constipation, and even preventing necrotizing enterocolitis in premature babies. So let’s not give up on them yet.

But I do think this is enough evidence to prove that probiotics likely wont help your kids tummy bug. If you have questions, talk to your pediatrician about other ways probiotics can help.

But, here goes …

Our intestines are full of bacteria that help us to break down food products and whose function has an effect on immunity and possibly allergies. These bacteria can be called “probiotic” organisms.

1.What are probiotic/prebiotic supplements?

Probiotic bacteria can be given as a supplement which can be mixed in with foods, beverages or given as a supplement (similar to a vitamin).

Prebiotics are substances which, when ingested, help to increase the number of probiotic bacteria in the colon. Prebiotics are typically small chains of sugars that humans cannot digest or use. They can be ingested in beverages or nutritional supplements and are even added to some formulas.

2.Are they safe?

Studies suggest that the use of probiotics is safe in healthy infants and children. However, some patients might be at risk:

Children who have abnormal immune systems such as ill preterm babies or children with implanted catheters (or other medical devices) should consult with their doctor because infections have occurred as a result of giving probiotics in these groups. Studies have also shown that adding prebiotics to infant formula is safe.

3.What conditions do they work for?

Infectious diarrhea (stomach bugs)

Some evidence suggests taking probiotics might prevent cases of infectious diarrhea, particularly in day care centers, but the effect is very small. It would take about seven kids taking the probiotic daily to prevent just one case of diarrhea, thus I don’t recommend use of probiotics to prevent diarrhea.

Once diarrhea has started, there’s pretty good evidence that starting probiotics may decrease the time of a child having diarrhea by as much as 40 hours. So it would seem good to provide probiotics at the first sign of infectious diarrhea. The effect was greatest with a probiotic known as Lactobacillus rhamosus GG (LGG).

Antibiotic associated diarrhea

Diarrhea is a common side effect with children who are taking antibiotics. Studies have shown that taking may decrease the child’s risk of developing diarrhea. Once again, the effect is small as it takes seven kids taking the probiotic to prevent one episode of antibiotic associated diarrhea. However, because it only requires the child to take the probiotic during the course of the antibiotic, this seems like a reasonable approach. Treating antibiotic associated diarrhea once it has already started does not appear to be helpful.

4.What conditions might they work for?

Eczema and allergies

Studies have been mixed on the use of probiotics for both prevention of and treatment for allergic diseases (including eczema). One of the major problems is that these diseases often are difficult to study because they are difficult to define and assessment for improvement is often subjective.

Colic

Some early data suggested that probiotics might be helpful for infants with colic. This is also very difficult to study as definitions for colic are wide and varied. It’s hard to even know if colic is a real, definable illness or just a baby that cries a lot. Further information and studies would be necessary in order to fully recommend probiotic use.

5.What’s next?

As we learn more about the normal bacteria that live in our intestines and how variation of the amount and type might contribute to disease, I’m hopeful that we’ll continue to see conditions for which probiotics are safe and effective.