Can probiotics treat gestational diabetes? (+Week 1)
The takeaway
Week 1 of the Microbiome Diet resulted in gut happiness, decreased fasting blood glucose, improved bowel movements, weight loss and a chance to try new recipes.
Cravings were challenging, but also presented an opportunity to practice mindfulness
Studies show mixed results for using probiotics to reduce fasting blood glucose and improve insulin resistance in GDM.
Read on for details!
The microbiome diet aims to accomplish two major goals.
Reduce inflammation by eliminating reactive/allergenic foods AND limit the growth of harmful gut bacteria by eliminate grains, dairy, legumes, eggs, potatoes/sweet potatoes, processed sugar, processed foods, soy and corn.
Nourish the body with nutrient-dense food, heal the gut and promote the growth beneficial bacteria by eating high quality meats, lots of veggies including those high in prebiotic fiber, fruits, nuts, seeds, and fermented veggies like sauerkraut and kimchi.
Many people ask what I eat while on this diet. For breakfast we ate veggie-and-ground turkey skillets, nut-and-seed granola with berries and homemade almond milk, and chia seed pudding with nuts and berries. Lunches and dinners were chicken or meatball soups with lots of veggies, a beer beef stew, spaghetti squash topped with meaty red sauce or chicken and veggies, and salmon with cauliflower rice and asparagus. Snacks were veggies dipped in sunflower seed butter, fruit with nuts, and fresh sauerkraut. I eat 3 meals and 3 snacks; my husband eats 3 meals and 1 or 2 snacks.
What changes occurred during the first week?
Overall gut happiness. After the first day, both my husband and I felt better. We described the feeling as “lighter.” My whole belly felt less swollen. Our stomachs just felt better. I vividly remember experiencing this while doing the Microbiome Diet last time and it quite eye opening. Many times, after eating, I would realize that my gut actually felt good. Which made me realize that more often than not, my gut didn’t actually felt crampy or bloated after eating. This was both alarming and groundbreaking for me. I can’t believe I forgot that feeling! Experiencing it provides pretty solid motivation to continue on this adventure.
Decreased fasting blood glucose. My fasting blood glucose dropped about 6 points from 91.8 (using 10 measurements 1/16-2/26) to 85.6 (using 5 measurements 3/1-3/5). The ideal is below 90. Previously, 7 of the 10 measurements I took were over 90. In the last week, 1 of 5 measurements was over 90. I attribute the lower numbers to reducing the amount of carbs I ate and eating healthier overall. I definitely still have to be careful about eating too many carbs in my before-bed snack, but my numbers are trending in the right direction.
Changes in bowel movements. This wouldn’t be a gut microbiome-focused blog if I didn’t discuss my bowel movements. Yep, I know it’s probably TMI so I won’t go into detail, but suffice it to say that they improved in frequency and consistency. I chalk this up to more veggies (fiber and water) and less grains, sugar and processed food (binders). On the other hand, my husband’s worsened. He tends to do fine with dairy and moderate amounts of grains, so our dietary changes may not benefit him as much as me.
Weight loss. I lost 4% of my body weight, which was not a goal; in fact, I consciously ate generous portions and snacked whenever I felt hungry to provide adequate prenatal nutrition. Granted, I had gained more than twice what is recommended during the first trimester so it’s possible my body was happy to shed the extra weight. But I attribute much, if not all, of it to water weight. For me, eliminating grains and sweets really cuts down on bloating and inflammation.
Craving control/mindfulness. We dramatically changed our diets experienced so naturally we experienced cravings this week. Generally, we limit non-compliant foods in our house, but there will always be meals and celebrations with friends and family that feature such foods. Our strategies included the following.
Filling up on healthy foods, and also recognizing that we were full and wouldn’t enjoy the indulgence anyway
Enjoying the aromas (while baking breakfast cookies)
Substituting with a compliant treat, like apple cinnamon tea or an almond milk Dandy blend latte, a handful of berries, cocoa nibs or compliant granola
Focusing on the conversation rather than the food we chose not to eat
And sometimes, when it was really tough, distance from the food worked (like literally moving away after a very tempting dinner that included beer and bread, followed with cookies, ice cream and after-dinner drinks).
Trying new recipes. All of our breakfasts are new-ish or variations of something else we’ve eaten. I will share these recipes next week after I work out a few kinks!
Let's move onto current research discussing the use of probiotics to treat gestational diabetes.
Last week I discussed a study that showed that administering probiotics along with dietary counseling starting in the first trimester of pregnancy reduced the incidence of gestational diabetes mellitus (GDM) by 60%, when compared with dietary counseling alone or no intervention [1]. Unfortunately, I cannot find any other studies that evaluate probiotics to prevent GDM, but I will discuss a few studies that assess probiotic interventions as supplemental treatment for GDM.
In these studies, after women are diagnosed with GDM, a host of measurements are taken, including fasting blood glucose, weight, insulin resistance and insulin sensitivity. The women are given either probiotics or placebos that they will take for 6-8 weeks (depending on the study). They received standard dietary counseling and support, but were excluded from the study if they required medications like insulin or metformin.
These results are pretty mixed. The first 2 studies include 124 women and report a statistically significant decrease in fasting blood glucose in the probiotic group compared to placebo; whereas the other 3 studies report no difference for 321 women. Three studies involving 206 women showed decreased insulin resistance in the probiotic group compared to placebo, whereas the other 2 showed no difference in 239 women. The evidence does not support a strong or consistent effect of probiotics improving fasting blood glucose or insulin resistance in women with GDM.
As we often see, there are several caveats that complicate comparison between these studies. The diagnosis criteria for GDM differed across many of these studies so while all studies assess gestational diabetics, their definition of GDM differs slightly. This may influence the overall effect of probiotics because the women have different starting points.
Also, the probiotics varied in species and dose. Different species of probiotic bacteria may influence gut health differently, and the ideal dose is unknown. The outcomes may have been different if the interventions lasted longer than 6 or 8 weeks. A study that analyzed 17 trials of probiotic interventions in normoglycemic, Type 2 diabetic, and gestational diabetic individuals showed lower fasting glucose and improved insulin resistance in interventions lasting longer than 8 weeks and using probiotics that contain multiple species, but showed no association between dose and benefit [7].
Lastly, the studies didn’t report on any changes in the gut microbiota of the participants, so we don’t know if any of the changes that did occur correlated with a shift in the gut microbiome.
How might probiotics affect fasting plasma glucose or insulin resistance? Probiotics may suppress proinflammatory pathways [8] and may provide antioxidant properties that reduce oxidative stress [7].
Probiotic bacteria are known to produce short chain fatty acids (SCFAs) as a byproduct of fermentation of dietary fiber. SCFAs have many effects, including:
regulating leptin and ghrelin, hormones which regulate appetite, energy intake and expenditure [9];
increase insulin sensitivity [10], and
reducing gastrointestinal permeability, which can decrease the amount of circulating endotoxin [11]. Endotoxin stimulates proinflammatory immune pathways in the body, leading to chronic, systemic inflammation which causes hyperglycemia and insulin resistance [12, 13].
Indeed, one of these studies showed reduced inflammatory markers after probiotic intervention in women with GDM [4].
The evidence for using probiotics to reduce fasting blood glucose levels and insulin resistance in GDM isn’t particularly compelling. However, the mechanism leading to diabetes in GDM may not allow for the benefits of probiotics to overcome the symptoms. In GDM, hormones from the placenta interfere with the body’s ability to use insulin properly. Meanwhile, the pancreas is unable to produce adequate insulin to maintain proper blood sugar levels. This causes insulin resistance, which notably goes away after pregnancy. Still, I think larger studies looking at longer interventions with more probiotic species will help us fully understand whether probiotics are part of an effective treatment strategy for GDM.
Do you take probiotics? Are you using them with blood sugar control in mind? I'd love to hear about your experience!
References
Luoto, R., et al., Impact of maternal probiotic-supplemented dietary counselling on pregnancy outcome and prenatal and postnatal growth: a double-blind, placebo-controlled study. Br J Nutr, 2010. 103(12): p. 1792-9.
Karamali, M., et al., Effects of probiotic supplementation on glycaemic control and lipid profiles in gestational diabetes: A randomized, double-blind, placebo-controlled trial. Diabetes Metab, 2016. 42(4): p. 234-41.
Dolatkhah, N., et al., Is there a value for probiotic supplements in gestational diabetes mellitus? A randomized clinical trial. J Health Popul Nutr, 2015. 33: p. 25.
Jafarnejad, S., et al., Effects of a Multispecies Probiotic Mixture on Glycemic Control and Inflammatory Status in Women with Gestational Diabetes: A Randomized Controlled Clinical Trial. J Nutr Metab, 2016. 2016: p. 5190846.
Lindsay, K.L., et al., Impact of probiotics in women with gestational diabetes mellitus on metabolic health: a randomized controlled trial. Am J Obstet Gynecol, 2015. 212(4): p. 496 e1-11.
Nabhani, Z., et al., The effects of synbiotic supplementation on insulin resistance/sensitivity, lipid profile and total antioxidant capacity in women with gestational diabetes mellitus: A randomized double blind placebo controlled clinical trial. Diabetes Res Clin Pract, 2018. 138: p. 149-157.
Ruan, Y., et al., Effect of Probiotics on Glycemic Control: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials. PLoS One, 2015. 10(7): p. e0132121.
Laitinen, K., et al., Probiotics and dietary counselling contribute to glucose regulation during and after pregnancy: a randomised controlled trial. Br J Nutr, 2009. 101(11): p. 1679-87.
Kellow, N.J., et al., Effect of dietary prebiotic supplementation on advanced glycation, insulin resistance and inflammatory biomarkers in adults with pre-diabetes: a study protocol for a double-blind placebo-controlled randomised crossover clinical trial. BMC Endocr Disord, 2014. 14: p. 55.
Tilg, H., Obesity, metabolic syndrome, and microbiota: multiple interactions. J Clin Gastroenterol, 2010. 44 Suppl 1: p. S16-8.
Jayashree, B., et al., Increased circulatory levels of lipopolysaccharide (LPS) and zonulin signify novel biomarkers of proinflammation in patients with type 2 diabetes. Mol Cell Biochem, 2014. 388(1-2): p. 203-10.
Cani, P.D., et al., Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes, 2007. 56(7): p. 1761-72.
Taylor, B.L., et al., Effect of Probiotics on Metabolic Outcomes in Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients, 2017. 9(5).
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