Medical Bulletin 03/July/2026 - Video

Here are the top medical news for today:

Researchers Find Flavonoid-Rich Foods May Protect Against Inherited Breast Cancer Risk

A higher intake of flavonoid-rich foods may be linked to a lower risk of breast cancer, according to a new study published in npj Breast Cancer.

Researchers analyzed data from 93,271 women in the UK Biobank to examine whether the Flavodiet Score (FDS)—a measure of flavonoid-rich food consumption—was associated with breast cancer risk. Participants were followed for a median of 11.8 years, during which 3,110 women developed breast cancer.

The Flavodiet Score included 10 flavonoid-rich foods, such as tea, apples, oranges, grapes, berries, onions, sweet peppers, dark chocolate, grapefruit, and red wine. Researchers also performed additional analyses excluding red wine, and the results remained similar, indicating the association was not driven by alcohol intake.

Women in the highest FDS category had a 15% lower risk of developing breast cancer compared with those in the lowest category. Higher intakes of flavanones and proanthocyanidins—two flavonoid subclasses—were also linked to a reduced risk. Among individual foods, oranges and apples showed the strongest protective associations.

The study also examined genetic susceptibility using a polygenic risk score based on 168 breast cancer-related genetic variants. Women with a high genetic risk and a low flavonoid intake had the greatest likelihood of developing breast cancer. In contrast, those with high flavonoid intake had a lower risk, even among individuals with elevated genetic susceptibility, although no significant interaction between diet and genetics was identified.

Researchers noted that participants with higher flavonoid intake generally had healthier lifestyles, including greater physical activity and lower body weight. Because the study was observational, it cannot establish cause and effect. The authors say further research in more diverse populations and clinical trials is needed to confirm whether flavonoid-rich diets can help reduce breast cancer risk.

REFERENCE: Yang R, Xu YL, Wang Y, et al. (2026). Flavonoid-rich foods, genetic risk, and female breast cancer risk: a prospective cohort study. npj Breast Cancer. DOI: 10.1038/s41523-026-00989-y, https://www.nature.com/articles/s41523-026-00989-y

Researchers Link Gut Microbiome Modulation to Better Liver Cancer Immunotherapy Outcomes

A growing body of research suggests the gut microbiome may play a key role in determining how well people with advanced liver cancer respond to immunotherapy. A new review published in Cancer Biology & Medicine highlights how microbes in the gut and liver influence the tumor’s immune environment, potentially affecting treatment success and resistance in hepatocellular carcinoma (HCC), the most common form of liver cancer.

Although immune checkpoint inhibitors have improved outcomes for some patients, only a small proportion achieve long-lasting responses. Researchers from The Chinese University of Hong Kong reviewed recent evidence showing that the gut-liver axis—a communication network linking the intestine and liver—plays an important role in regulating anti-tumor immunity.

Healthy gut bacteria produce beneficial compounds such as short-chain fatty acids that help maintain immune balance. In contrast, microbial imbalance in HCC promotes harmful bacteria that generate inflammatory metabolites, including deoxycholic acid and quinolinic acid, which may encourage tumor growth and suppress immune defenses.

Researchers further highlighted microbial signatures linked to poor immunotherapy response. Some bacteria appear to disrupt tryptophan metabolism, reducing beneficial metabolites and weakening the activity of CD8+ T cells, which are essential for destroying cancer cells.

The authors suggest that the gut microbiome is more than a biomarker—it may actively shape treatment outcomes. This opens the possibility of improving immunotherapy through microbiome-targeted strategies such as probiotics, high-fiber diets, or fecal microbiota transplantation (FMT).

Several clinical trials are already investigating these approaches, including studies combining FMT with immunotherapy in patients who previously failed treatment. While further research is needed, scientists believe modifying the gut microbiome could eventually help identify likely responders, overcome treatment resistance, reduce immune-related side effects, and improve outcomes for people with advanced liver cancer.

REFERENCE: Wu, M., et al. (2026). How the gut microbiome affects the immunotherapy response in hepatocellular carcinoma. Cancer Biology & Medicine. DOI: 10.20892/j.issn.2095-3941.2025.0761. https://www.cancerbiomed.org/content/early/2026/04/10/j.issn.2095-3941.2025.0761

Scientists Discover Vitamin C's Unexpected Role in Supporting Brain Health

Higher blood levels of vitamin C may be associated with healthier brain structure and stronger brain connectivity in older adults, according to a study published in PLOS One. While the findings do not prove that vitamin C prevents cognitive decline, they add to growing evidence that nutrition may influence brain health during aging.

Researchers from Hirosaki University in Japan analyzed data from 2,044 adults aged 64 years and older. Participants underwent magnetic resonance imaging (MRI) scans and provided blood samples to measure plasma vitamin C levels. The team examined gray matter volume, white matter volume, and connectivity within the brain's default mode network (DMN), which plays a key role in memory, attention, and other cognitive functions.

After accounting for factors such as age, education, and physical activity, the researchers found that participants with lower vitamin C levels tended to have reduced gray matter volume and weaker connectivity within the DMN. Gray matter contains most of the brain's nerve cell bodies and is essential for processing information, while the DMN helps coordinate higher-order thinking and memory-related activities.

The researchers suggest that maintaining adequate vitamin C levels may help preserve brain structure and function as people age. However, they caution that the study was observational and cannot determine whether low vitamin C directly causes these brain changes. Other lifestyle and health factors could also contribute to the observed associations.

Although more research is needed, the findings support the idea that everyday dietary habits may play an important role in healthy brain aging. A balanced diet that provides sufficient vitamin C could potentially contribute to maintaining brain health, but clinical trials will be required to determine whether increasing vitamin C intake can directly reduce age-related cognitive decline.

REFERENCE: Haruka Nagaya, Keita Watanabe, Tomohiro Shintaku, Miho Sasaki, Jusei Kudo, Sera Kasai, Yuka Ishimoto, Kana Saito, Shuichi Matsuhashi, Taiki Koshiishi, Mizuki Imura, Amo Ozawa, Saaya Mori, Daisuke Watanabe, Shin Shukunobe, Tatsuro Sasaki, Soichiro Tatsuo, Shinya Kakehata, Tatsuya Mikami, Daichi Kokubu, Yusuke Ushida, Shingo Kakeda. Plasma vitamin C levels are associated with brain structural networks on MRI: A large cohort study. PLOS One, 2026; 21 (6): e0348504 DOI: 10.1371/journal.pone.0348504