Medical Bulletin 15/December/2025 - Video

Here are the top medical news for today:

Filtered coffee consumption linked to improved blood sugar and healthier HbA1c levels

Your morning coffee might be doing more for your health than just waking you up—it could also be helping stabilize your blood sugar. A new study published in npj Science of Food has uncovered how unsweetened filtered coffee may support long-term glycemic control by improving the composition of the gut microbiome. Using advanced genetic tools, researchers traced this connection through a causal pathway involving a specific gut bacterium called Veillonella, which produces propionic acid—an important compound linked to better insulin sensitivity.

Understanding the relationship between coffee and metabolism has long puzzled scientists. While previous observational studies suggested coffee reduces type 2 diabetes risk, clinical trials have been inconsistent, partly because they rarely accounted for differences in how people prepare their coffee—filtered or instant, sweetened or black. To resolve these contradictions, researchers from China and the United Kingdom used Mendelian Randomization (MR), a genetic method that infers cause-and-effect relationships from natural variations in people’s DNA.

The study combined data from two large genetic repositories—the UK Biobank, which includes more than 500,000 participants, and the MiBioGen Consortium, which profiles gut bacteria in about 18,000 individuals. Researchers analysed six coffee consumption patterns (including with sugar, milk, or artificial sweeteners) and tested their links to glycated haemoglobin (HbA1c), a reliable marker of average blood glucose levels over 8–12 weeks.

Among all coffee types tested, only genetically predicted unsweetened filtered coffee showed a direct, statistically significant link with lower HbA1c levels (Odds Ratio = 0.97; p = 0.04). When the team looked deeper, they discovered that filtered coffee was associated with higher genetic abundance of the bacterium Veillonella, known for producing propionic acid, a short chain fatty acid that helps regulate glucose metabolism. Mediation analysis revealed that Veillonella explained about 43% of coffee’s glycaemic benefit. In contrast, adding sugar or artificial sweeteners appeared to blunt these positive effects.

The researchers propose that brewing methods matter because filtration removes diterpenes while preserving beneficial chlorogenic acids and polyphenols, which may create a gut environment favoring propionate producing microbes. Though more experimental research is needed, the findings suggest a practical takeaway: when it comes to blood sugar control, unsweetened filtered coffee might be the smartest brew to choose.

REFERENCE: Cao, Z., An, Y., Du, Y., Xu, G., Wang, J., & Lu, Y. (2025). Different coffee consumption patterns affect HbA1c via propionic acid-producing gut microbiota. NPJ Science of Food. DOI – 10.1038/s41538-025-00655-w. https://www.nature.com/articles/s41538-025-00655-w

Family history of heart disease tied to early cardiac damage in adolescents: Study

Heart health may be more inherited than we think. A groundbreaking study of over 1,500 British adolescents has revealed that having parents with cardiometabolic diseases—such as hypertension, type 2 diabetes, or high cholesterol—can increase the risk of early heart damage in their children before they even reach adulthood. Published in the European Journal of Preventive Cardiology, the research was conducted by a global team from the University of Eastern Finland, the Universities of Bristol and Exeter, and Rutgers Robert Wood Johnson Medical School in the U.S.

The study drew on participants from the “Children of the 90s” birth cohort at the University of Bristol—a project that has tracked thousands of individuals from birth to adulthood. Specifically, 1,595 adolescents were monitored from age 17 to 24 through repeated echocardiography, a high-resolution imaging method that measures heart structure and function over time. One in three participants reported a parental history of cardiometabolic disease, making this the largest and longest-running echocardiography study in healthy youth worldwide.

At the start of the study, just 2.4% of all adolescents showed signs of left ventricular hypertrophy (LVH)—a form of heart muscle enlargement that signals early structural strain. By age 24, that number had nearly tripled to 6.5%. Among those with a family history of cardiometabolic disease, the rate quadrupled, compared with only a two-fold increase among those without family risk. Even after accounting for lifestyle factors like diet, physical activity, smoking, and body composition, a 20% higher odds of progressive heart damage remained for those with inherited risk.

Blood tests revealed that elevated glucose levels explained about 10% of this long-term relationship, linking subtle metabolic changes to structural heart changes. “Our findings confirm that heart disease risk begins earlier than we thought,” said study author Dr. Douglas Corsi. “Parents who manage their blood pressure, cholesterol, and blood sugar can pass on more than good habits—they can pass on healthy hearts.”

According to Dr. Andrew Agbaje of the University of Eastern Finland, adolescence represents a “critical preventive window.” Acting in the 20 years between early adulthood and midlife, he says, could significantly reduce premature heart attacks later on. The message is clear: family history isn’t destiny—but it’s a powerful warning to start heart care early.

REFERENCE: Corsi, D. R & Agbaje, A. O. (2025) Parents' History of Hypertension, Diabetes, and Dyslipidemia with Offspring Cardiac Damage - A 24-Year Longitudinal Study. European Journal of Preventive Cardiology. DOI: 10.1093/eurjpc/zwaf744. https://academic.oup.com/eurjpc/advance-article/doi/10.1093/eurjpc/zwaf744/8339954

Study finds vegan diet outperforms Mediterranean for weight loss, even with carbs

You don’t have to eat perfectly to lose weight—just ditch the animal products. A new analysis published in Frontiers in Nutrition suggests that a low-fat vegan diet promotes more weight loss than the Mediterranean diet, even when it includes refined grains and starchy foods like potatoes often considered “unhealthy.” The findings come from researchers at the Physicians Committee for Responsible Medicine, who found that swapping animal foods for plant foods—regardless of quality—had the greatest impact on body weight and metabolism.

The research builds on a previous randomized clinical trial that directly compared a low-fat vegan diet to a Mediterranean diet in 62 overweight adults over 16 weeks. Both diets featured fruits, vegetables, legumes, and grains, but the vegan plan excluded all animal products and added oils, while the Mediterranean plan emphasized fish, low-fat dairy, and olive oil. Participants switched between the two diets across two 16 week phases, separated by a short break, allowing each person to serve as their own control.

In the original trial, the vegan diet led to greater weight loss, improved body composition, and enhanced insulin sensitivity—and this new study reveals why. Using the plant-based diet index (PDI)—a tool that classifies foods by how “healthy” their plant origins are—scientists analyzed participants’ food logs and linked specific dietary patterns to weight changes. The index distinguishes between healthful foods (whole grains, fruits, and nuts) and unhealthful ones (refined grains, sweets, and potatoes).

Interestingly, those on the vegan plan saw the greatest rise not only in overall PDI scores but also in unhealthful plant-based diet index (uPDI) scores—because refined grains and potatoes replaced meat and dairy. This boost in plant-based eating, even from less than perfect foods, was the strongest predictor of weight loss. In contrast, participants on the Mediterranean diet showed no significant weight change despite “healthier” PDI scores.

Lead author Dr. Hana Kahleova explains, “Even when it includes less ideal plant foods, a vegan diet still outperforms other diets for weight management, simply because it eliminates animal fats and added oils.”

The takeaway? You don’t need to obsess over superfoods—just focus on shifting from animal to plant-based meals. Cutting out meat and dairy, even with some pasta or potatoes on your plate, can tip the scale toward better health and lasting weight loss.

REFERENCE: Hana Kahleova, Reagan Smith, Ilana Fischer, Haley Brennan, Tatiana Znayenko-Miller, Richard Holubkov, Neal D. Barnard. Plant-based dietary index on the Mediterranean and a vegan diet: a secondary analysis of a randomized, cross-over trial. Frontiers in Nutrition, 2025; 12 DOI: 10.3389/fnut.2025.1666807