November 2025 – NatWonk – Dr Bier’s Research Reviews

Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes

November 28, 2025

Comment: It’s Thanksgiving, and I figured it would be fun to see if there was any actual research on turkey and sleepiness. There isn’t, but I came across this interesting study showing that tryptophan is associated with both improved sleep and decreased depression symptoms. Despite it’s reputation, turkey is actually about equivalent in tryptophan to […]

Cardiac Troponins and Cardiovascular Disease Risk Prediction: An Individual-Participant-Data Meta-Analysis

November 26, 2025

| No Comments

| Cardiovascular Health

📝Comment: This meta-analysis represents the highest level of evidence for a prognostic biomarker, using Individual-Participant-Data (IPD) analysis across 15 high-quality prospective cohorts. While the absolute increase in risk prediction (C-index) is modest, high-sensitivity troponins are an independent prognostic factor for cardiovascular disease that provide greater predictive gains than traditional inflammatory markers like C-reactive protein (CRP), […]

High-Sensitivity Cardiac Troponin I for Risk Stratification in Older Adults

November 26, 2025

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| Cardiovascular Health

Comment: Although we are all used to seeing troponin used to rule in or out a heart attack, this study shows it can be used for prognostic chronic risk stratification. It shows there is a population of older, asymptomatic people who, despite having no history of MI or overt CVD, are walking around with a […]

Diet and Risk for Incident Diverticulitis in Women : A Prospective Cohort Study

November 25, 2025

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| Miscellaneous

Comment: A more recent study, this one was in women and showed that nuts and this time seeds are perfectly safe for diverticulitis. Corn actually decreased the risk. Summary: 🎯 Clinical Bottom Line This large prospective cohort study provides compelling evidence to refute the historical dogma that women should avoid “particulate” foods—specifically nuts, seeds, corn, […]

Nut, corn and popcorn consumption and the incidence of diverticular disease

November 24, 2025

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| Miscellaneous

Comment: Not only do nuts not increase incidence, but they actually decrease the incidence. Another example of ‘logical’ thinking that was wrong on testing, but still endures. One of my favorite quotes ever, from the lead researcher, in that it underlines so much of medical thinking:“It is not exactly clear where this idea came from […]

A Randomized Clinical Trial Evaluating Vitamin D Normalization on Major Adverse Cardiovascular-Related Events Among Acute Coronary Syndrome Patients: The TARGET-D Trial – Conference Abstract Only

November 22, 2025

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| Cardiovascular Health

Comment: I don’t usually review abstracts, but I think this is interesting enough that it’s worth posting at the very least to mark the dosing strategy, which finally mimics what we do clinically. The most compelling takeaway from the TARGET-D trial isn’t just the reduction in recurrent Myocardial Infarction (MI), but how they achieved it: through […]

Hormonal Contraceptive Formulations and Breast Cancer Risk in Adolescents and Premenopausal Women

November 21, 2025

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| Cancer

Comment: This massive Swedish cohort study serves as a critical update for anyone managing contraception. While the absolute risk remains low—approximately 1 extra case per 7,752 users per year—the relative increase in breast cancer risk is substantial, driven largely by specific hormonal components. The overall Hazard Ratio of 1.24 suggests a 24% increase in relative […]

Higher vitamin B12 from mid- to late life is related to slower rates of cognitive decline

November 17, 2025

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| Neurological & Cognitive Health

Comment: It’s not like using B12 is a shocking new concept – it’s commonly used for brain and memory issues. This study adds that measuring serum B12 alone isn’t sufficient. The protective association was driven by the composite score, not standard cobalamin levels. To truly ensure our patients are utilizing B12 for neuroprotection, we must […]

A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D

November 16, 2025

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| Miscellaneous

Comment: This one’s a bit of a favorite, as I don’t think anyone who measures vitamin D serum levels in clinical practice believes the IOM suggested dose could possibly be accurate. Here the authors point out a statistical mistake that was made and reassesses the same data to come to extrapolate to a far higher […]

Letter to Veugelers, P.J. and Ekwaru, J.P., A statistical error in the estimation of the recommended dietary allowance for vitamin

November 16, 2025

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| Miscellaneous

Comment: This is a graph that I keep close at hand as I share it with patients very frequently. It shows how diverse the requirements are to achieve adequate serum vitamin D levels, and how the actual supplementation level to get most people into target range is far higher than the IOM recommendations, which were […]