Medical Bulletin 12/March/2026

Here are the top medical news for today:

Popular Pre-Workout Supplements Linked to Increased Risk of Sleep Loss: Study

A new study suggests that popular pre-workout dietary supplements may significantly disrupt sleep among teenagers and young adults. The research, based on data from the Canadian Study of Adolescent Behaviors, found that young people who used these supplements were more than twice as likely to report extremely short sleep durations compared with non-users.

Pre-workout supplements are widely marketed to boost energy and improve exercise performance. Popular brands are commonly used by teenagers and young adults seeking enhanced workout results. However, these products often contain high levels of caffeine and stimulant-like ingredients, which may interfere with normal sleep patterns.

The study analyzed data from participants aged 16 to 30 years. Researchers found that individuals who had used pre-workout supplements within the previous year were significantly more likely to report sleeping five hours or less per night. This level of sleep is considered insufficient for healthy development and daily functioning. Health experts typically recommend 8–10 hours of sleep for adolescents and 7–9 hours for young adults.

Lead researcher Kyle T. Ganson from the University of Toronto noted that many pre-workout supplements contain between 90 and over 350 milligrams of caffeine per serving. For comparison, a can of cola contains about 35 milligrams, while a typical cup of coffee contains around 100 milligrams. Such high stimulant doses can remain active in the body for hours, making it harder to fall asleep.

Researchers say inadequate sleep during adolescence and young adulthood can affect mental health, academic performance, and physical development. They recommend that healthcare professionals discuss supplement use with young people and advise avoiding stimulant supplements 12–14 hours before bedtime.

The findings also highlight the need for greater awareness and stronger regulation of dietary supplements, as many young consumers may underestimate their potential health effects.

REFERENCE: Kyle T. Ganson, Alexander Testa, Jason M. Nagata. Use of pre-workout dietary supplements is associated with lower sleep duration among adolescents and young adults. Sleep Epidemiology, 2025; 5: 100124 DOI: 10.1016/j.sleepe.2025.100124

Study Finds Postbiotics Could Aid PCOS Treatment via Microbiome Restoration

A growing body of research suggests that the gut microbiome may play an important role in Polycystic Ovary Syndrome (PCOS), a common endocrine disorder affecting women of reproductive age. A recent review published in ACS Nutrition Science highlights the potential of postbiotics as a complementary approach for managing the condition.

PCOS is characterized by hormonal imbalance, particularly elevated androgen levels, along with ovulatory dysfunction and polycystic ovarian morphology. Many women with PCOS also experience metabolic issues such as Insulin Resistance, weight gain, acne, infertility, and excessive hair growth. Researchers believe that both genetic and environmental factors contribute to the development of the disorder.

Recent studies have linked PCOS with disturbances in the gut microbiome. Women with PCOS often show signs of gut dysbiosis, an imbalance between beneficial and harmful gut bacteria. Beneficial microbes such as Bifidobacterium and Lactobacillus may decline, while potentially harmful bacteria like Escherichia coli and Staphylococcus aureus may increase. This imbalance can promote inflammation, disrupt metabolism, and worsen insulin resistance.

Postbiotics—bioactive compounds produced by beneficial bacteria—are emerging as a potential therapeutic tool. These compounds include Short Chain Fatty Acids (SCFAs) such as butyrate and acetate, which help regulate inflammation, maintain the intestinal barrier, and improve metabolic health. Reduced SCFA production due to gut dysbiosis may increase intestinal permeability and allow bacterial toxins to enter the bloodstream, triggering inflammation.

Preliminary evidence suggests that postbiotics may help improve insulin sensitivity, regulate glucose metabolism, reduce inflammation, and lower androgen levels. These effects could potentially reduce the risk of complications such as Type 2 Diabetes and cardiovascular disease in women with PCOS.

REFERENCE: Pathak, V. A., Kshirsagar, S. J., Deokar, G. S., et al. (2026). Therapeutic Application of Postbiotics in the Management of Polycystic Ovarian Syndrome. ACS Nutrition Science. DOI: https://doi.org/10.1021/acsnutrsci.5c00042. https://pubs.acs.org/doi/10.1021/acsnutrsci.5c00042

Scientists Identify How Exercise May Help Protect Brain From Alzheimer’s

A new study suggests that exercise may help protect the brain from Alzheimer's Disease by strengthening the Blood-Brain Barrier, a critical structure that shields the brain from harmful substances circulating in the bloodstream. The research, conducted by scientists at the University of California, San Francisco, was published in the journal Cell.

Previous studies had shown that physical activity increases levels of a protein called Glycosyl-phosphatidylinositol-Specific Phospholipase D1 (GPLD1) in the blood. This protein is associated with improved brain health and reduced cognitive decline. In the new study, researchers discovered how GPLD1 helps protect the brain by regulating another molecule called Tissue-Nonspecific Alkaline Phosphatase (TNAP).

TNAP normally helps maintain the permeability of the blood-brain barrier during stressful conditions. However, with aging, TNAP can accumulate in the cells of the barrier and impair its function. The researchers found that GPLD1 helps remove or “prune” excess TNAP from these cells, thereby strengthening the barrier and reducing inflammation in the brain.

Experiments in mice supported this mechanism. Young mice engineered to have higher TNAP levels in their blood-brain barrier developed cognitive decline similar to older animals. Conversely, older mice engineered to have lower TNAP levels showed fewer leaks in the barrier, reduced inflammation, and improved cognitive performance.

In mouse models of Alzheimer’s disease, increasing GPLD1 levels or reducing TNAP was also associated with fewer deposits of Amyloid Beta, a hallmark protein linked to Alzheimer’s pathology.

Although the study was conducted in mice, the findings suggest that exercise-triggered biological processes may help protect the aging brain. Researchers hope that understanding this mechanism could eventually lead to therapies that mimic the brain-protective effects of exercise, especially for individuals who are unable to engage in regular physical activity.

REFERENCE: Bieri, Gregor et al.; Liver exerkine reverses aging- and Alzheimer’s-related memory loss via vasculature; Cell, Volume 189; DOI: 10.1016/j.cell.2026.01.024