In a first study of its kind, researchers at the UC Davis School of Medicine found that probiotics significantly improved symptoms of pregnancy-related nausea, vomiting, and constipation. The results were published in the journal nutrient.
Nausea and vomiting affect around 85% of pregnancies and can significantly affect the quality of life, especially in early pregnancy.
“The cause of nausea and vomiting during pregnancy is still unknown. Various theories have been put forward, but none of them are conclusive,” said Albert T. Liu, first author of the study and professor of obstetrics and gynecology.
“Nausea, vomiting, and constipation during pregnancy can seriously affect a patient’s quality of life. Once nausea and vomiting progress through pregnancy, they can be difficult to control and sometimes the patient even has to be hospitalized,” said Liu.
Probiotics are known as “beneficial bacteria”. They are found in foods like yogurt, kimchi, kefir, sauerkraut, and tempeh. Probiotics are also available as dietary supplements. According to the National Center for Complementary and Integrative Health, probiotics or prebiotics were the third most popular nutritional supplement for adults, along with vitamins.
Probiotics are designed to support the community of various microbes, often referred to as the “gut microbiome”, found in the gastrointestinal tract.
During pregnancy, hormones like estrogen and progesterone increase, which leads to many physical changes. These increases can also alter the gut microbiome, which is likely to affect the functioning of the digestive system and cause undesirable symptoms such as nausea, vomiting, and constipation.
The researchers wanted to find out whether supplementation with a probiotic could be beneficial for gastrointestinal function during pregnancy.
The study lasted 16 days. A total of 32 participants took one probiotic capsule twice a day for six days and then took two days off. Then they repeated the cycle.
The probiotics were available over the counter and mostly containedLactobacilli., some kind of good bacteria. Each capsule contained approximately 10 billion live cultures at the time of manufacture.
During the duration of the study, the participants made 17 daily observations of their symptoms, so that the researchers were able to statistically evaluate a total of 535 observations.
The researchers found that taking the probiotic significantly reduced nausea and vomiting. Nausea hours (the number of hours that participants felt nauseous) were reduced by 16% and the frequency of vomiting was reduced by 33%. The use of probiotics also significantly improved symptoms related to quality of life, such as fatigue, loss of appetite, and difficulty maintaining normal social activities, as assessed on questionnaires.
Probiotics have also been found to significantly reduce constipation.
“Over the years I have observed that probiotics can reduce nausea and vomiting, and relieve constipation. It is very encouraging that the study has proven this, ”said Liu. “Probiotics also helped many of my other patients who didn’t take part in the study,” Liu said.
New evidence of gut microbes and by-products
Participants also contributed faecal samples before and during the study. The samples were analyzed to identify the type and number of microbes and the various by-products of digestion.
This enabled the researchers to investigate whether biomarkers in the stool samples corresponded to increased nausea and how the probiotics affected the participants who started the study with different initial biomarkers.
One finding was that low levels of bacteria that carry an enzyme called bile salt hydrolase, which makes bile acid to take in nutrients, has been linked to more pregnancy-related vomiting. Probiotics increase bacteria producing bile salt hydrolase, which could explain why the supplements reduced nausea and vomiting.
Another finding was that there was a high level of intestinal microbes Akkermansia and A. muciniphila at the start of the study were associated with increased vomiting. The probiotic significantly reduced the amount of these particular microbes and also reduced vomiting. That suggests Akkermansia and A. muciniphila can be reliable biomarkers that can predict vomiting in pregnancy.
Another finding was that vitamin E levels increased after taking probiotics. Higher vitamin E levels were associated with low levels of vomiting.
“This research provides important insights into the influence of intestinal microbes on gastrointestinal function during pregnancy. Our gut microbiota explains why we are what we eat and why bacteria-made metabolites and products have a huge impact on our health, “said Wan. “They affect the gastrointestinal tract as well as skin health and neurological function.”
Although the results are fascinating, the researchers caution that due to the small sample size, further studies are needed to confirm the effects of the probiotics.
“Our previous work has shown the benefits of probiotics in preventing liver inflammation. The current study may be one of the first to show the benefits of probiotics in pregnancy,” said Wan. “It would be interesting and important to continue testing whether probiotics can reduce nausea and vomiting caused by chemotherapy in cancer patients.”
Other authors on this study include Shuai Chen from the Department of Public Health Sciences and Prasant Kumar Jena, Lili Sheng and Ying Hu from the Department of Pathology and Laboratory Medicine at the University of California, Davis.