Medical Bulletin 25/August/2026 - Video

Here are the top medical news for today:

Research Finds Common Vitamin Linked to 13% Better Brain Performance

Higher vitamin D supplement intake was associated with better cognitive performance in older adults with mild cognitive impairment and sleep disturbances, according to researchers at Emory University.

The preliminary study, published in Sleep Medicine, examined 54 adults with sleep problems and mild cognitive impairment (MCI), a condition involving subtle changes in memory and thinking that can precede dementia.

Participants who reported taking 5,000 IU or more of vitamin D daily scored more than 13% higher on the Montreal Cognitive Assessment (MoCA) than those who did not take vitamin D, even after researchers adjusted for other factors.

The MoCA is a commonly used screening tool that assesses memory, attention, language and other thinking abilities. Researchers did not observe similar cognitive benefits among participants taking lower daily amounts of vitamin D.

The study also examined whether the type of vitamin D mattered. Cognitive performance was similar among participants taking vitamin D2 and those taking vitamin D3, suggesting that the observed association was not specific to one form of the supplement.

Researchers highlighted the potential importance of addressing modifiable factors during MCI, when cognitive changes may be emerging but before dementia has fully developed. Sleep disturbances are also common in people with cognitive impairment and Alzheimer's disease, and previous research has linked vitamin D deficiency with problems such as insomnia and nighttime awakenings.

However, the researchers emphasized that the findings are preliminary and do not show that high-dose vitamin D prevents or treats dementia. The study was small and based on reported supplement use, so larger and longer-term studies are needed to determine whether vitamin D supplementation directly improves cognitive function.

Importantly, 5,000 IU per day is a high supplemental dose, and people should not start taking this amount without medical guidance, as excessive vitamin D can cause harmful calcium buildup and other complications.

REFERENCE: Sirui Zhou, Paul Sudeshna, Lynn Marie Trotti, Donald Bliwise, Victoria Pak. Vitamin D supplement intake is associated with better cognition in persons with sleep disturbance and mild cognitive impairment. Sleep Medicine, 2026; 146: 108960 DOI: 10.1016/j.sleep.2026.108960

Type 2 Diabetes Differs Across Weight Profiles, Study Challenges One-Size-Fits-All Approach

Type 2 diabetes may develop through two fundamentally different biological pathways depending on a person's body weight, suggesting that treatment could eventually need to be tailored to the underlying cause rather than using the same approach for everyone, according to a study published in Diabetologia.

Researchers from Amsterdam UMC and the University of Ghana analyzed data from more than 3,300 adults with type 2 diabetes to examine how body composition relates to the mechanisms behind the disease.

The study found that in people with a higher BMI, type 2 diabetes was primarily driven by insulin resistance, in which the body's cells become less responsive to insulin. In people with a lower BMI, however, diabetes was more often linked to the pancreas producing insufficient insulin.

Despite these differences, patients are generally treated with similar medications, including drugs such as metformin and sulfonylureas. Researchers say treatments that primarily target insulin resistance may be less effective for people whose diabetes is driven mainly by inadequate insulin production.

The findings also revealed differences in diabetes-related complications. People with lower BMI were more likely to experience diabetic retinopathy and stroke, while those with higher BMI more often had high blood pressure and cardiovascular disease. Chronic kidney disease occurred at similar rates across the groups. Researchers found that body fat explained much of the variation in these outcomes, supporting the possibility that type 2 diabetes may represent biologically distinct forms rather than a single disease process.

The study also highlights factors beyond excess weight that may contribute to diabetes. Researchers noted that experiences such as malnutrition or low birth weight may affect pancreatic development and the body's ability to produce insulin later in life.

The researchers are calling for targeted clinical trials to determine whether treatments should be selected according to the biological mechanism driving diabetes. They emphasize that more research is needed before changes to current treatment guidelines can be recommended.

REFERENCE: Esmail, S., Hayfron-Benjamin, C., Darko, S.N. et al. Divergent complication patterns of type 2 diabetes in African individuals who are lean versus overweight or obese: a multi-cohort analysis. Diabetologia (2026). https://doi.org/10.1007/s00125-026-06830-2

Yeast-Based Supplement May Enhance Immune Response Against Cancer: Study

A yeast-based dietary supplement may help restore cancer-fighting immune activity impaired by obesity, according to a preclinical study by researchers at Trinity College Dublin and University College Dublin.

The study, published in Cell Reports, found that yeast beta-glucan strengthened immune responses against cancer in obese mice by changing how immune cells develop in the bone marrow.

Researchers fed mice standard or high-fat diets supplemented with yeast beta-glucan for four to 12 weeks before exposing them to different types of cancer cells, including colorectal, skin and breast cancer.

The supplement appeared to trigger trained immunity, a process in which early immune cells in the bone marrow undergo long-lasting changes that allow the body's innate immune system to respond more effectively to future threats.

In obese mice, which can develop impaired immune responses that make it harder to fight tumors, yeast beta-glucan restored aspects of anti-tumor immune activity. The researchers also found that the supplement reversed immune memory defects that persisted even after the animals lost weight.

According to the researchers, this is the first evidence that dietary consumption of yeast beta-glucan can induce trained immunity by reprogramming bone marrow stem cells. Previous studies had produced similar effects using injections rather than dietary supplementation.

The findings are potentially important because obesity can cause long-lasting changes in immune function, and some of these changes may remain even after weight loss. Strengthening innate immunity could potentially improve the body's ability to respond to tumors, infections and vaccines.

However, the findings are limited to laboratory mice, and it is not yet known whether the same immune benefits occur in humans. Clinical trials will be needed to determine whether yeast beta-glucan can safely enhance anti-cancer immunity or complement treatments such as chemotherapy and immunotherapy.

REFERENCE: Anna E. Ledwith, et al.; Yeast β-glucan supplementation supports immunometabolic anti-tumor responses and reverses obesity-induced dysfunction via trained hematopoiesis. Cell Reports, 2026; 45 (7): 117648 DOI: 10.1016/j.celrep.2026.117648