Medical Bulletin 04/ April/ 2024

Gut microbiome contributes differently to obesity onset in men and women, finds study

A new research being presented at this year's European Congress on Obesity (ECO) identified changes in the composition of gut bacteria that may play a key role in the onset and development of obesity, with differences in men and women, which might affect the metabolism of different nutrients and therefore the presence of bioactive molecules in the gut that influence the development of metabolic disease.

The gut microbiota consists of a complex community of microorganisms (bacteria, viruses, fungi and protozoa) which inhabit the gastrointestinal tract. Disruption in this community significantly affects metabolic health and influences the risk of certain diseases, including obesity. However, it is still unclear which species represent a greater or lesser likelihood of developing obesity, as well as the impact of these species on our metabolic health.

In the study, researchers analysed metagenomic and metabolomic data from a Spanish population to understand how gut microorganisms contribute to obesity development. They examined fecal metabolites, produced by gut bacteria during food metabolism, impacting health. The study included 361 adults, classified based on obesity levels. .Genetic microbiota profiling was done to identify the different types, composition, diversity, and relative abundance of bacteria present in stool samples of the participants.

The results revealed that individuals with a higher obesity index had lower levels of C. minuta, associated with health. In men, higher abundance of P. helcogenes and C. canadensis correlated with increased BMI, fat mass, and waist circumference. Conversely, in women, higher levels of P. micans, P. brevis and P. sacharolitica predicted higher BMI, fat mass, and waist circumference, but not in men.

“Gut microbiome composition, specifically higher levels of the Christensenella minuta bacterium, appeared to protect against obesity. Whereas the species that influence the risk of developing obesity appear to be different between the sexes and interventions to help prevent an obesity-favourable microbiome may need to be different in men and women. Further research is needed to better understand when the switch to an obesity favorable gut microbiota may take place, and therefore the right timing for possible interventions," said Dr Paula Aranaz, lead author from the Centre for Nutrition Research at the University of Navarra in Spain.

“Our findings reveal how an imbalance in distinct bacterial groups are likely to play an important role in the onset and development of obesity, with considerable differences between the sexes, which might affect the metabolism of different bioactive molecules present in the metabolome that influence the development of metabolic disease."

Reference: European Association for the Study of Obesity; European Congress on Obesity (ECO 2024)

Association between Menopause and heart health

According to new research presented at the American College of Cardiology’s Annual Scientific Session, a woman’s cardiovascular risk can rise sharply after she goes through menopause, quickly catching up to men of a similar age and health profile.

Heart disease is the leading cause of death in both men and women, but women’s cardiovascular risk has traditionally been undertreated because women tend to develop heart disease at an older age than men and may experience different and sometimes more subtle symptoms. After menopause, women have much less estrogen and shift to a more testosterone-heavy profile. This affects the way the body stores fat, where it stores fat and the way it processes fat; it even affects the way the blood clots. And all of these changes increase the risk of developing heart disease.

In the study, post-menopausal women underwent heart scans to assess their CAC score, indicating plaque buildup in heart arteries. Researchers analyzed data from 579 women on statins, comparing CAC changes with matched men. Women with baseline CAC levels of 1–99 and 100–399 showed significantly higher CAC increases compared to men. No significant difference was observed for baseline CAC levels of 400 or higher.

The findings suggested that plaque buildup is accelerated in post-menopausal women compared to men, indicating that many women experience a steep rise in the risk of heart problems, which may be related to the drop in estrogen that women experience during menopause.

“This is a unique study cohort of only post-menopausal statin users that signals that post-menopausal women may have the risk of heart disease that is on par with males. Women are underscreened and undertreated, especially post-menopausal women, who have a barrage of new risk factors that many are not aware of. This study raises awareness of what those risk factors are and opens the door to indicating the importance of increased screening for coronary artery calcium (CAC),” said Ella Ishaaya, MD, an internal medicine physician at Harbor-UCLA Medical Center in Torrance, California, and the study’s lead author.

Reference: “CAC Progression in Men and Women: Is There an Inflection at Menopause?” AMERICAN COLLEGE OF CARDIOLOGY; MEETING: American College of Cardiology's Annual Scientific Session

How is metabolic profile linked to disorders?

According to a study published in the journal JAMA Network Open, biomarkers of lipid, apolipoprotein, and carbohydrate metabolism have been suggested to be associated with the risk for depression, anxiety, and stress-related disorders, but results are inconsistent.

Depression, anxiety, and stress-related disorders affect around one-third of individuals. Research suggests that metabolic dysregulation, including lipid and glucose abnormalities, may contribute to their development by triggering inflammation. This inflammation, involving immune cells and cytokines, is associated with these disorders.

The study analysed data from 2,11,200 participants aged 16 years and older from the AMORIS cohort. Participants included healthy individuals undergoing routine health screenings in the workplace and those with health conditions referred for testing by physicians. They were free of mental disorders at baseline and had at least one measurement for the biomarkers studied.

The results showed that during a mean follow-up time of 21 years, a total of 16,256 participants were diagnosed with depression, anxiety, or stress-related disorders. Among these, 9,725 were diagnosed with depression, 7,582 were diagnosed with anxiety, and 4,833 were diagnosed with stress-related disorders. A total of 3,128 participants were diagnosed with both depression and anxiety, whereas less than 1% were diagnosed with both depression and stress-related disorders or with both anxiety and stress-related disorders. Only 984 participants had received all 3 diagnoses.

The findings suggested that compared with low or normal levels, high levels of glucose and TGs were associated with a higher risk of depression, anxiety, and stress-related disorders, whereas a high level of HDL-C was associated with a lower risk. In addition, these biomarkers showed different levels between individuals who developed depression, anxiety, or stress-related disorders and those not developing such during many years before diagnosis.

Reference: Charilaos Chourpiliadis, MD; Yu Zeng, MSc; Anikó Lovik, PhD; et al; Metabolic Profile and Long-Term Risk of Depression, Anxiety, and Stress-Related Disorders; Journal: JAMA Network Open; doi:10.1001/jamanetworkopen.2024.4525