In this article, we are going to discuss some common questions that we get around the area of the microbiome, probiotics, and also gestational diabetes risk.
Can we change the gut microbiota positively during pregnancy and reduce the person’s risk of developing gestational diabetes? Or, if a person currently has gestational diabetes, can we improve their blood glucose level using probiotics to the point where they may not need to take insulin or any medications to control their blood glucose level during their pregnancy?
There’s recently been this onslaught of studies that have been conducted in either pregnant women or women with gestational diabetes where they’ve given the participants in those trials a probiotic supplement, and they’ve monitored their blood glucose level, insulin sensitivity, and the gestational outcomes as well.
The problem with some of these trials is that they’re very small and been provided in each individual trial with different probiotic supplements. They’re usually an attempt to “let’s just throw as many bacteria that we believe are beneficial as we can at these women in one dose and see what happens” and the problem is that it’s hard to interpret that information because each of the trials involved different species and some of the trials involved a number of different species within the trial.
If there is any beneficial effect of the probiotics? We don’t know which species was responsible and how much of that particular species is needed. It’s also possible that some of the provided species may even have a negative effect where they prevent the growth of other beneficial bacteria in the gut just by the mere presence in larger numbers. What these trials have found is that it seems to be an improvement in what we call insulin sensitivity in the women that took the probiotic supplements.
However, there was no subsequent improvement in blood glucose levels, so insulin sensitivity is not something that’s measured routinely in practice. It’s not really a patient-important endpoint unless it carries on to have a beneficial effect on the blood glucose level, which it didn’t in any of these trials.
That didn’t happen in those trials, so there may be some beneficial effects in improving insulin sensitivity, so women who’ve already got gestational diabetes may need less medication to control their blood glucose level. But we still can’t be sure of that because the trials were only undertaken in women who were not taking any medications for their gestational diabetes.
Another complicating factor is that many women who have gestational diabetes are put on a Metformin medication.
Metformin is a very good medication for improving insulin sensitivity, but the other side effect of Metformin is that it changes some of the composition of the gut microbiota in a positive way.
It encourages the growth of some beneficial species to higher levels, but we don’t know if the probiotics are having the effect or the Metformin. Now, in these trials, none of the participants were taking Metformin, but it’s another complicating factor in the day-to-day management of real-world gestational diabetes.
We don’t know which probiotic supplement, or even which species is beneficial.
Patients usually ask, “which probiotic — probiotic supplement would you recommend, or should I have.” and it’s an impossible sort of question to answer.
One of the things it would depend on is what the health outcome you’re trying to improve is? You certainly need to think about that before answering. But the other thing is that each of our gut microbiomes is very individualized as well.
The science isn’t there yet to say “based on these species,” and you probably wouldn’t even get a species-level analysis because we’re not at that level, we don’t have the technology to get down, to drill down to the species-level.
But even if you knew that “do we need more of these species or less of these species” – we don’t know those answers yet.
The bottom line is preventing gestational diabetes or managing gestational diabetes well, comes down to your overall health and your overall diet. Rather than taking probiotic supplements, we should be just focusing on improving gut health in general.
That’s where dietary guidelines come into play. It’s a variety of wholegrain cereals, fruits, and vegetables, reducing the saturated fat content of your diet and where possible to engage in physical activity. They’re all very good strategies for improving the health of your existing gut microbiota rather than adding a new species that we’re not sure about at this stage.