Medical Bulletin 21/ November/ 2024

The number and type of microbes present in the saliva of pregnant women differ according to whether they are experiencing life stress and symptoms of anxiety, depression and post-traumatic stress disorder (PTSD), finds a study published in the open access journal BMJ Mental Health.

The study included 224 pregnant women enrolled in the Michigan Prenatal Stress Study assessed for recent stresses and mental health symptoms during their second trimester. Women were asked to provide saliva samples during the week of their assessments. The results showed the oral microbiome varied with whether women had reported life stress, anxiety, depression or post-traumatic stress disorder (PTSD) symptoms during the assessments.

Oral microbiomes of women with high levels of post-traumatic stress disorder symptoms showed high beta diversity, which means the specific microbe species in their saliva notably differed from the species found in women with low post-traumatic stress disorder symptoms.

Specific stress and mental health traits were also associated with high levels of certain microbe species. Women who had experienced recent life stress had a greater abundance of species in the phylum Proteobacteria, while Spirochaetes was more abundant in women with high levels of depression symptoms. Greater numbers of Dialister species and species in the phylum Firmicutes were seen in women with levels of anxiety and depression symptoms, and species in the genus Eikenella were elevated in women with high anxiety, depression or post-traumatic stress disorder.

22 potential covariates were investigated to see whether they influenced changes in the microbiome. This analysis revealed that cigarette smoking could explain 7.2% of the variance seen in oral microbiomes, dental problems could explain 3.1%, intimate partner violence could explain 4.1% and unplanned pregnancy could explain 2%.

A new study that investigates low-dose ketamine (LDK) as an adjunct to morphine for treating acute pain has been published in the Academic Emergency Medicine (AEM), the peer-reviewed journal of the Society for Academic Emergency Medicine (SAEM).

The study highlights the potential of low-dose ketamine as a valuable tool in pain management, providing a safe and effective option for emergency medicine physicians managing acute pain.

Pain remains one of the most common and challenging complaints among patients presenting to the emergency department (ED). For individuals with opioid tolerance, achieving effective pain relief can be particularly difficult, as they often require higher doses of opioids, which increases risks of hyperalgesia and withdrawal symptoms. In their randomized, placebo-controlled trial, lead author Stine Fjendbo Galili, MD, and colleagues explored the effectiveness of low-dose ketamine as an adjunct to morphine in a diverse emergency department population with varying levels of opioid use. The study demonstrated that a single dose of 0.1 mg/kg of ketamine provided significant reductions in pain scores for 30 minutes compared to a placebo.

The study concluded that low-dose ketamine may be an effective short-term adjunct analgesic to morphine for managing acute pain, offering relief to both opioid-tolerant and opioid-naïve patients.

Reference: Galili, S. F., Bech, B. H., Kirkegaard, H., Ahrensberg, J., & Nikolajsen, L. (2024). Low‐dose ketamine as an adjunct to morphine: A randomized controlled trial among patients with and without current opioid use. Academic Emergency Medicine.

The World Institute of Kimchi, South Korea, has been publishing a series of articles on the anti-obesity effects of kimchi in international journals. These articles, based on research studies on the subject, indicate that the regular consumption of kimchi, a traditional Korean fermented food, is effective in reducing body fat and may serve as a promising dietary strategy to combat obesity.

A research study, published in Journal of Functional Foods, focused on the anti-obesity effects of kimchi and its impact on gut microbiomes. This study investigated the changes in anthropometric measurements, blood biomarkers, and gut microbiomes of 55 overweight adults, comprising both males and females, with a BMI ranging from 23 to 30 kg/m². The participants consumed 3 kimchi capsules per meal for 3 months. The kimchi capsules contained kimchi powder produced by freeze-drying cabbage kimchi fermented at 4℃ for 2 weeks. The research team analyzed the changes in the body fat composition of the participants and found that the group that consumed kimchi showed a 2.6% decrease in body fat, but the control group that did not take the kimchi capsules exhibited a 4.7% increase in body fat, showing a statistically significant difference between the two groups.

Further, the analysis of the microbiomes of the participants revealed that kimchi consumption resulted in an increase in the abundance of the beneficial gut bacterium, Akkermansia muciniphila*, and a reduction in the number of Proteobacteria, which are associated with obesity.

The successful completion of this clinical trial on the body fat-reducing effects of kimchi indicates that a steady consumption of kimchi is effective in alleviating obesity symptoms through the modulation of the gut microbiota.

Reference: Lee, W., Kwon, M. S., Yun, Y. R., Choi, H., Jung, M. J., Hwang, H., ... & Hong, S. W. (2024). Effects of kimchi consumption on body fat and intestinal microbiota in overweight participants: A randomized, double-blind, placebo-controlled, single-center clinical trial. Journal of Functional Foods, 121, 106401.

According to a study published in open access format by the Nature group journal Nutrition & Diabetes, consuming more than 45% of our daily calorie intake after 5 p.m. is associated with an increase in glucose levels, with the harmful consequences that this has for health, regardless of the individual's weight and body fat.

"Maintaining high levels of glucose over long periods of time can have implications including a higher risk of progressing to type 2 diabetes, an increase in cardiovascular risk due to the damage that high glucose levels do to blood vessels, and increased chronic inflammation, which aggravates cardiovascular and metabolic damage," said Díaz Rizzolo, postdoctoral researcher and member of the Faculty of Health Sciences at the University of Columbia.

The study included 26 participants between the ages of 50 and 70 who were overweight or obese, and had prediabetes or type 2 diabetes. The participants' glucose tolerance levels were compared, and they were divided into two groups: early eaters, who consumed most of their daily calories before the evening, and late eaters, who consumed 45% or more of their calories after 5 p.m. The two groups consumed the same amount of calories and the same foods during the day, but did so at different times. The participants used a mobile app to record their meals in real time.

The main finding of the study is that the late eaters had a poorer tolerance of glucose, regardless of their weight or the composition of their diet. It also found that they tended to eat larger amounts of carbohydrates and fats during the evening.

Díaz Rizzolo explained that "the body's ability to metabolize glucose is limited at night, because the secretion of insulin is reduced, and our cells' sensitivity to this hormone declines due to the circadian rhythm, which is determined by a central clock in our brain that is coordinated with the hours of daylight and night."

Reference: Díaz-Rizzolo, D.A., Santos Baez, L.S., Popp, C.J. et al. Late eating is associated with poor glucose tolerance, independent of body weight, fat mass, energy intake and diet composition in prediabetes or early onset type 2 diabetes. Nutr. Diabetes 14, 90 (2024). https://doi.org/10.1038/s41387-024-00347-6