Medical Bulletin 22/August/2025 - Video

Here are the top medical news for the day:

Study Reveals How High Salt Diet May Lead to Brain Inflammation

A new study published in the journal Neuron reveals that a high-salt diet may cause brain inflammation, which in turn drives up blood pressure. Led by Masha Prager-Khoutorsky, associate professor in McGill University’s Department of Physiology, the research suggests that the brain—rather than just the kidneys—could be a key origin of hypertension.

Hypertension, or high blood pressure, affects about two-thirds of people over the age of 60 and is responsible for nearly 10 million deaths annually worldwide. Traditionally considered a disease of the kidneys and blood vessels, it is often asymptomatic but significantly increases the risk of heart attacks, strokes, and other serious health issues. However, up to one-third of patients fail to respond to standard medications—highlighting the need for a deeper understanding of alternative causes.

To simulate human eating patterns, researchers provided rats with water containing 2% salt—comparable to the sodium content in diets high in fast food, bacon, processed cheese, and instant noodles. This high-salt intake activated immune cells in a specific brain region, leading to inflammation and a spike in vasopressin, a hormone that raises blood pressure. The team used advanced brain imaging and modern laboratory techniques to observe these changes in real time.

“The brain’s role in hypertension has largely been overlooked, in part because it’s harder to study,” said Prager-Khoutorsky. “But with new techniques, we’re able to see these changes in action.”

The researchers opted to use rats rather than mice, as rats have salt and water regulation mechanisms that closely resemble those of humans, making the results more applicable.

The study offers crucial insight into the neurological basis of hypertension and could pave the way for brain-targeted therapies.

Reference: Gu, N., Makashova, O., Laporte, C., Chen, C. Q., Li, B., Chevillard, P. M., ... & Prager-Khoutorsky, M. (2025). Microglia regulate neuronal activity via structural remodeling of astrocytes. bioRxiv, 2025-02.

This Diet May Cut Risk of Cancer and Heart Disease Multimorbidity: Study

A new multinational study published in The Lancet Healthy Longevity has found that a plant-based diet is associated with a significantly lower risk of developing multiple chronic diseases, including cancer, diabetes, and cardiovascular conditions. The study, led by researchers from the University of Vienna in collaboration with the International Agency for Research on Cancer, France, and Kyung Hee University, Republic of Korea, analyzed data from more than 400,000 individuals aged 37 to 70 across six European countries.

The researchers drew on two major European cohort datasets—UK Biobank and the European Prospective Investigation into Cancer and Nutrition study—covering populations in the UK, Italy, Spain, Germany, the Netherlands, and Denmark. Their analysis revealed that individuals who adhered more closely to a healthy plant-based diet had a significantly lower risk of multimorbidity, a condition characterized by the coexistence of two or more chronic diseases.

Notably, the study found that in the UK Biobank cohort, those with higher adherence to a plant-based diet had a 32% reduced risk of developing multimorbidity compared to individuals with lower adherence. This association held true for both middle-aged individuals and those over the age of 60, highlighting the broad health benefits of this dietary pattern across age groups.

The healthy plant-based dietary pattern studied included high intakes of fruits, vegetables, whole grains, legumes, and plant-based alternatives like vegan sausages, with limited consumption of meat and processed animal products.

“You don’t have to cut out animal products entirely,” said Reynalda Córdova, lead author and nutritional epidemiologist. “Shifting towards a more plant-based diet can already have a positive impact.”

“Our study highlights that a healthy, plant-based diet not only influences individual chronic diseases but can also reduce the risk of developing multiple chronic diseases at the same time, in both middle-aged and older people,” added Córdova.

The authors concluded that public health interventions should promote predominantly plant-based diets as a preventive measure against multimorbidity linked to cancer and cardiometabolic diseases.

Reference: Plant-based dietary patterns and age-specific risk of multimorbidity of cancer and cardiometabolic diseases: a prospective analysis, Córdova, Reynalda et al. The Lancet Healthy Longevity, Volume 0, Issue 0, 100742

Too Much or Too Little Sleep Lead to Increased Risk of Mortality: Study Finds

A recent Korean study published in Scientific Reports reveals that prolonged sleep duration of more than eight hours is linked to increased risk of all-cause mortality—especially in men with regular sleep patterns and women with irregular ones. The research highlights the significance of both sleep duration and regularity as crucial factors in developing effective, personalized sleep health strategies.

Sleep is vital for maintaining physiological and psychological balance. Conducted by researchers from Hanyang University Medical Center, the study analyzed data from over 9,000 adults in the Korean Genome Epidemiology Study, spanning both rural and urban populations. Participants were grouped based on self-reported sleep duration (less than seven hours, seven to eight hours, or more than eight hours) and sleep regularity (regular or irregular). Researchers tracked their health outcomes over more than 15 years, examining all-cause mortality and major cardiovascular events.

The study recorded 1,095 deaths and 811 cardiovascular events. After adjusting for various health and lifestyle factors, findings showed that individuals sleeping more than eight hours per night had significantly higher mortality risk compared to those sleeping seven to eight hours. Interestingly, a non-significant trend toward increased mortality was also noted in those with short sleep duration. Irregular sleep patterns alone showed only a modest, non-significant increase in risk.

However, combined effects were more revealing. “Adults who consistently maintain a particular sleep-wake timing and sleep for seven to eight hours daily are at lower risk of all-cause mortality,” the researchers concluded. In particular, men with short irregular sleep or long regular sleep, and women with long irregular sleep, faced the highest risks.

These findings emphasize that sleep health interventions must consider not only sleep duration, but also regularity, age, and sex.

Reference: Park SJ. (2025). The impact of sleep health on cardiovascular and all-cause mortality in the general population. Scientific Reports.