Medical Bulletin 28/November/2025

The findings were published in the Journal of Physiology.

Sitting for long hours may seem harmless but seriously harms your cardiovascular health. Research shows that prolonged sitting reduces blood flow and vessel function, leading to higher blood pressure, increased cholesterol, and insulin resistance. This creates a cascade of metabolic problems, including obesity and heightened risk of heart disease, stroke, and type 2 diabetes. Even among those who exercise regularly, sitting more than 10 hours a day sharply raises the likelihood of heart failure and cardiovascular death.

In this innovative study, 40 healthy young men with varying fitness levels participated in a two-hour sitting trial. Before sitting, they consumed either a high-flavanol cocoa drink or a low-flavanol version. Researchers measured key indicators of vascular health, including flow-mediated dilatation (FMD) in arm and leg arteries, blood pressure, blood flow, and muscle oxygenation both before and after sitting.

Results revealed striking differences: men who drank low-flavanol cocoa experienced significant declines in artery elasticity (FMD), increased diastolic blood pressure, reduced blood flow, and lower muscle oxygen levels—effects linked to higher risks of cardiovascular disease. Interestingly, these detrimental changes occurred in both fitter and less-fit individuals, indicating that physical fitness alone does not protect against sitting-induced vascular damage.

Conversely, participants consuming the high-flavanol cocoa drink maintained stable vascular function, with no significant drop in artery elasticity or muscle oxygenation. This is the first study to demonstrate that flavanols effectively prevent sitting-induced vascular dysfunction regardless of fitness levels.

The study’s lead author, Dr. Catarina Rendeiro, emphasized that incorporating high-flavanol foods and drinks during long sitting periods could help reduce cardiovascular risks associated with sedentary lifestyles. She recommends pairing such dietary habits with regular activity breaks—standing or walking—to further enhance vascular health.

REFERENCE: Alessio Daniele, Samuel J. E. Lucas, Catarina Rendeiro. Dietary flavanols preserve upper‐ and lower‐limb endothelial function during sitting in high‐ and low‐fit young healthy males. The Journal of Physiology, 2025; DOI: 10.1113/JP289038

Research reveals People with this blood type may have higher fatal liver disease risk

Your blood type may reveal more than just transfusion compatibility—it could signal your risk for certain liver diseases. A new study published in Frontiers in Medicine shows that people with blood type A are more prone to autoimmune liver diseases, where the immune system mistakenly attacks the liver, potentially causing long-term damage. Autoimmune hepatitis, which attacks liver cells, is especially linked to blood type A.

Autoimmune hepatitis is a condition where the body’s immune system mistakenly attacks its own liver cells, causing inflammation and damage. Normally, the immune system defends against harmful invaders like viruses and bacteria, but in this disorder, it targets healthy liver tissue instead. This ongoing attack leads to swelling and irritation, which, if left untreated, can cause scarring and eventually liver failure.

On the other hand, individuals with blood type B appear to have a lower risk, particularly for primary biliary cholangitis (PBC), a chronic disease that damages bile ducts and can lead to liver failure. The study analyzed data from over 1,200 people, including 114 patients with autoimmune liver conditions, finding the highest incidence among blood type A, followed by O, B, and AB groups. Blood type is determined by specific antigens on red blood cells, dividing people into A, B, AB, and O groups, each with positive or negative subtypes.

While having blood type A doesn’t guarantee liver disease, it is a factor to consider if you experience unexplained symptoms like fatigue or joint pain. Experts recommend regular liver function check-ups, a healthy diet rich in whole grains, fruits, vegetables, legumes, nuts, and unsaturated fats like olive oil, along with avoiding alcohol to minimize liver damage—especially in PBC. Calcium and vitamin D supplements can support bone health, since liver disease can increase osteoporosis risk. Smoking cessation and physical activity are also advised to maintain overall liver and bone well-being.

This study sheds light on the complex relationship between genetics and liver health, encouraging personalized monitoring and lifestyle adjustments to protect those at higher risk. More research is needed to fully understand these links across diverse populations.

REFERENCE: Hong,Yi; Mu,Shijie; Wang,Lin; Association between ABO blood group system and autoimmune liver disease; Frontiers in Medicine; 2025; Volume 12 – 2025; https://doi.org/10.3389/fmed.2025.1696577

High glycemic index diets may raise lung cancer risk, study finds

A surprising new study published in the Annals of Family Medicine reveals an unexpected link between dietary carbohydrates and lung cancer risk, focusing on two key measures: glycemic index (GI) and glycemic load (GL).

The glycemic index (GI) rates how fast a carbohydrate food raises blood sugar on a scale from 0 to 100. Glycemic load (GL) goes a step further by also considering the amount of carbs eaten, showing how much the food actually affects blood sugar.

The study analyzed data from over 101,000 adults enrolled in the U.S. National Cancer Institute’s Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial starting in the 1990s. Participants completed detailed diet questionnaires and were followed for roughly 12 years to monitor lung cancer incidence. Researchers classified participants by their dietary GI and GL, carefully adjusting for smoking and other risk factors to isolate the diet-cancer relationship.

Findings revealed a paradox: people consuming diets with the highest glycemic index had a 13% increased risk of lung cancer compared to those with the lowest GI. This elevated lung cancer risk was observed for both non–small cell and small cell lung cancers. Surprisingly, however, those with the highest glycemic load diets had about a 28% lower risk of lung cancer overall, mainly driven by reduced non–small cell lung cancer risk, with no clear association for small cell types.

These results suggest that not all carbs impact lung cancer risk equally. Diets rich in low-GI, high-quality carbohydrates—such as fruits, vegetables, and whole grains—may help reduce lung cancer risk, while frequent consumption of high-GI foods like refined sugars could elevate it.

While further research is warranted to understand underlying mechanisms, this study encourages thoughtful carbohydrate choices as part of lung cancer prevention strategies, reinforcing a diet emphasizing nutrient-rich, low-GI foods for long-term health.

REFERENCE: Wang, J., et al. (2025) Dietary Glycemic Index, Glycemic Load, and Risk of Lung Cancer: A Population-Based Cohort Study. Annals of Family Medicine. DOI: 10.1370/afm.250132. https://www.annfammed.org/content/23/6/524