Medical Bulletin 31/January/2026

Researchers analyzed data from 8,320 Brazilian university graduates in the CUME+ study. Participants reported their dietary intake via food frequency questionnaires, which included 144 food items. Using existing literature, the team estimated melatonin content for 119 items, identifying coffee, lentils, beans, and rice as the main sources. Average daily melatonin intake was approximately 25,500 ng, with men consuming slightly more than women. Higher melatonin intake also correlated with healthier dietary patterns, including more fiber and carbohydrates, and lower protein, cholesterol, and saturated fat consumption.

Health outcomes examined included obesity, depression, type 2 diabetes, metabolic syndrome, hypertension, dyslipidemia, obstructive sleep apnea, and sleep duration. The study found no significant links between dietary melatonin and conditions like diabetes, hypertension, metabolic syndrome, sleep duration, or sleep apnea. However, moderate melatonin intake was inversely associated with obesity and depression. Interestingly, the strongest benefits appeared in intermediate intake levels rather than the highest, suggesting that balance matters.

While this study cannot prove cause and effect due to its cross-sectional design, the findings support the idea that melatonin-rich foods could play a role in metabolic and neurobehavioral health, potentially through anti-inflammatory or regulatory pathways.

Incorporating beans, lentils, rice, and coffee into daily meals may be a practical, enjoyable way to naturally support weight management and mood, highlighting diet as a subtle yet powerful tool in promoting overall wellbeing.

REFERENCE: Zanirate GA, Bressan J, Leal ACG, Pimenta AM, Hermsdorff HHM (2026). The Content of Dietary Melatonin in 119 Food Items and Its Relationship With Chronic Diseases, Results of the CUME+ Study. Journal of Human Nutrition and Dietetics, 39(1), e70193. DOI: 10.1111/jhn.70193, https://onlinelibrary.wiley.com/doi/10.1111/jhn.70193

Study Finds Certain Food Preservatives Potentially Associated with Cancer

Could your packaged snacks be quietly raising cancer risk? A major long-term study from France, published in The BMJ, suggests that regularly consuming certain food preservatives may slightly increase the risk of developing cancer. These additives, widely used in processed foods and drinks to extend shelf life, have long raised safety questions, but real-world evidence linking them to cancer has been limited—until now.

The NutriNet-Santé study followed 105,260 cancer-free adults aged 15 and older (average age 42; 79% women) for an average of 7.5 years. Participants recorded detailed 24-hour dietary intake, allowing researchers to track exposure to 17 common preservatives—including citric acid, potassium sorbate, sodium nitrite, potassium nitrate, and acetic acid—and monitor subsequent cancer diagnoses. During follow-up, 4,226 participants developed cancer, including breast, prostate, and colorectal cancers.

Overall, most preservatives showed no association with cancer. However, higher intakes of certain non-antioxidant preservatives—potassium sorbate, potassium metabisulfite, sodium nitrite, potassium nitrate, and acetic acid—were linked to increased risks. For example, potassium sorbate was associated with a 14% higher overall cancer risk and a 26% higher risk of breast cancer. Sodium nitrite intake corresponded to a 32% higher prostate cancer risk, while potassium nitrate and acetic acid were tied to elevated overall and breast cancer risks. Among antioxidant preservatives, only sodium erythorbate showed a small association with higher cancer incidence.

Researchers caution that the study cannot prove causation and that other factors may contribute. Still, the large sample size, detailed dietary tracking, and long follow-up provide valuable insights. Potential biological mechanisms include immune and inflammatory changes triggered by certain preservatives.

The findings highlight the importance of reducing unnecessary preservative intake and favoring freshly prepared, minimally processed foods. They also call for a re-evaluation of regulatory safety limits, labeling transparency, and monitoring practices for food additives, balancing preservation benefits with long-term health risks.

REFERENCE: Anaïs Hasenböhler, Guillaume Javaux, Marie Payen de la Garanderie, Fabien Szabo de Edelenyi, Paola Yvroud-Hoyos, Cédric Agaësse, Alexandre De Sa, Inge Huybrechts, Fabrice Pierre, Marc Audebert, Xavier Coumoul, Chantal Julia, Emmanuelle Kesse-Guyot, Benjamin Allès, Valérie Deschamps, Serge Hercberg, Benoit Chassaing, Bernard Srour, Mélanie Deschasaux-Tanguy, Mathilde Touvier. Intake of food additive preservatives and incidence of cancer: results from the NutriNet-Santé prospective cohort. BMJ, 2026; 392: e084917 DOI: 10.1136/bmj-2025-084917

‘Evening People’ Found More Likely to Have Poor Cardiovascular Health

THUMB: Are You a Night Owl? Check Your Heart

Are Night Owls at Higher Risk for Heart Problems? New Study Suggests They Might Be! Middle-aged and older adults who are more active in the evenings may have poorer cardiovascular health than their daytime-active peers, according to new research published in the Journal of the American Heart Association.

The study analyzed health data from over 300,000 adults in the UK Biobank to explore how chronotype—whether someone is naturally a “morning person” or “evening person”—affects heart health.

Participants self-reported their chronotype: about 8% were “definitely evening people” (night owls), 24% were “definitely morning people” (early birds), and 67% were intermediate types. Cardiovascular health was assessed using the American Heart Association’s Life’s Essential 8™ metrics, which include diet, physical activity, sleep, smoking, and clinical measures like cholesterol, blood sugar, blood pressure, and weight.

Key findings included:

• Night owls had a 79% higher prevalence of poor overall cardiovascular health compared to intermediate types.

• They faced a 16% higher risk of heart attack or stroke over a median 14-year follow-up.

• Women night owls were particularly affected, showing lower cardiovascular health scores than men with the same chronotype.

• Poor habits like smoking and inadequate sleep largely explained the increased risk.

• Morning people had slightly better outcomes, with a 5% lower prevalence of low cardiovascular health scores compared to intermediate types.

Evening chronotypes often experience circadian misalignment, meaning their internal body clocks don’t align with natural day-night cycles or typical daily schedules, which can influence behaviors affecting heart health.

Experts emphasize that night owls aren’t doomed—many risks are modifiable through lifestyle changes. Aligning medication timing, improving sleep habits, and reducing smoking can help evening types protect their cardiovascular health.

The study’s limitations include a mostly White, generally healthy cohort and reliance on self-reported chronotype at a single time point, which may limit generalizability.

REFERENCE: Kianersi, Sina, Potts, Kaitlin S., Wang, Heming, Sofer, Tamar, Noordam, Raymond; Chronotype, Life’s Essential 8, and Risk of Cardiovascular Disease: A Prospective Cohort Study in UK Biobank; Journal of the American Heart Association; doi: 10.1161/JAHA.125.044189; https://doi.org/10.1161/JAHA.125.044189