Medical Bulletin 27/March/2026

Here are the top medical news for today:

Can Collagen Supplements Improve Skin Health and Reduce Signs of Aging? New Research Explain

Skin aging is strongly linked to the gradual loss and degradation of collagen, a key structural protein that maintains skin firmness, elasticity, and hydration. Collagen accounts for nearly 30% of total body protein and is a major component of the extracellular matrix that supports skin cells.

A review in Food, Nutrition and Health examines what these compounds do for the skin, drawing on clinical studies to highlight both their potential and important limitations.

With aging, both intrinsic factors (natural aging) and extrinsic factors such as ultraviolet (UV) radiation accelerate collagen breakdown. This leads to reduced elasticity, dryness, wrinkles, and uneven pigmentation.

Collagen peptides, derived from the enzymatic breakdown of collagen, have gained attention as a dietary supplement for improving skin health. Due to their low molecular weight, these peptides are more easily absorbed in the body compared to native collagen.

Research suggests they may stimulate collagen production, enhance skin hydration, and improve elasticity. They are also believed to reduce oxidative stress and inhibit matrix metalloproteinases (MMPs), enzymes responsible for collagen degradation.

Preclinical and small clinical studies indicate that collagen peptides may support fibroblast activity, promote extracellular matrix repair, and increase the production of important skin components such as hyaluronic acid and elastin.

Some evidence also suggests protective effects against UV-induced damage and inflammation. However, results across studies are inconsistent, with variations in dosage, duration, and peptide sources.

Oral supplementation, typically at doses of 2.5–5 grams per day, shows the most consistent benefits, while topical applications remain less effective due to limited skin penetration. Despite promising findings, long-term safety data and large-scale human trials are still lacking.

Overall, collagen peptides offer potential as a supportive strategy for skin aging, but further robust research is needed to confirm their long-term effectiveness and optimal use.

REFERENCE: Chen, K., Ma., D., Yang, X., et al. (2026). The effects and mechanisms of collagen peptides for alleviating skin ageing. Food, Nutrition and Health. DOI: https://doi.org/10.1007/s44403-026-00046-3. https://link.springer.com/article/10.1007/s44403-026-00046-3

Study Reveals Metformin’s Hidden Brain Pathway After Six Decades of Use

A new study from Baylor College of Medicine, published in Science Advances, reveals that Metformin may lower blood sugar through an unexpected brain-based mechanism, challenging long-held assumptions about how the drug works.

For more than six decades, metformin has been the first-line therapy for Type 2 Diabetes, mainly believed to act by reducing glucose production in the liver and influencing gut metabolism. However, researchers led by Makoto Fukuda investigated whether the brain—known to regulate whole-body energy balance—also contributes to its effects.

The team focused on Rap1, a molecule found in the Ventromedial Hypothalamus, which plays a critical role in glucose regulation. Using genetically engineered mice lacking Rap1 in this region, researchers found that low-dose metformin no longer reduced blood glucose levels.

In contrast, other treatments such as insulin and GLP-1 receptor agonists remained effective, highlighting the specific importance of Rap1 in metformin’s action.

To further confirm the brain’s role, scientists delivered extremely small amounts of metformin directly into the brain. Even at doses thousands of times lower than oral administration, the drug significantly lowered blood sugar.

The study also identified SF1 neurons as key mediators. Metformin increased their electrical activity—but only when Rap1 was present—demonstrating that this signaling pathway is essential.

These findings show that the brain is highly sensitive to metformin, requiring much lower concentrations than the liver or gut.

This discovery opens the door to developing more precise, brain-targeted therapies for diabetes. It may also help explain metformin’s broader benefits, including potential effects on brain aging, though further research is needed.

REFERENCE: Hsiao-Yun Lin, Weisheng Lu, Yanlin He, Yukiko Fu, Kentaro Kaneko, Peimeng Huang, Ana B. De la Puente-Gomez, Chunmei Wang, Yongjie Yang, Feng Li, Yong Xu, Makoto Fukuda. Low-dose metformin requires brain Rap1 for its antidiabetic action. Science Advances, 2025; 11 (31) DOI: 10.1126/sciadv.adu3700

Excessive Dietary Sodium Intake Linked to Increased Risk of New-Onset Heart Failure: Study

A new report from Vanderbilt Health highlights excessive sodium intake as a significant and independent risk factor for developing Heart Failure.

Published in Journal of the American College of Cardiology: Advances, the study underscores the urgent need to address dietary salt consumption, particularly in high-risk populations.

Researchers analyzed data from over 25,300 participants in the Southern Community Cohort Study, which primarily includes Black and low-income individuals from the southeastern United States. T

he findings revealed that average daily sodium intake in this group was approximately 4,200–4,269 milligrams—nearly double the recommended limit of 2,300 milligrams. This elevated intake was associated with a 15% higher risk of new-onset heart failure.

Importantly, this increased risk was found to be independent of other contributing factors such as overall diet quality, calorie intake, high blood pressure, and lipid levels.

According to lead researcher Deepak Gupta, even modest reductions in sodium consumption could significantly lower the burden of heart failure in vulnerable populations.

However, reducing salt intake is not straightforward. Structural challenges—such as limited access to fresh, healthy foods, inadequate transportation, and socioeconomic barriers—make it difficult for many communities to adopt low-sodium diets.

These findings highlight the need for comprehensive public health strategies that go beyond individual behavior change.

The study also estimates that reducing sodium intake to around 4,000 milligrams per day could decrease heart failure cases by 6.6% over a decade.

Overall, the research reinforces the critical role of dietary sodium in cardiovascular health and the importance of population-level interventions.

REFERENCE: Dupuis, L., et al. (2026). Dietary Sodium Intake and Risk of Incident Heart Failure in the Southern Community Cohort Study. JACC: Advances. DOI: 10.1016/j.jacadv.2026.102651. https://www.jacc.org/doi/10.1016/j.jacadv.2026.102651