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"Brain health" (dementia, Alzheimer's, etc.)

First of all, really love your series on diet heart studies - great idea to make a series, in order to for listeners to get an "overall" picture :) That said, I wonder where we are, diet-/nutrition-wise, regarding brain health, i.e., dementia (risk), cognition, etc.? There might be some signal in the noise regarding Omega-3, maybe cocoa/flavanols and others, but do we have a "status" here? Any significant evidence and/or possible mechanisms at play? Where should/could we, in your opinion, have a closer look maybe?

Maximum healthy BMI in lean individual

Sometimes I hear people write-off having a BMI of above 30 as the individual in question is lean and the BMI measurement doesn't take into account body composition. But, is there evidence to suggest any kind of upper limit, where even individuals with a 'healthy' composition would start experiencing worse outcomes?

What can we make of gut microbiome research?

Hello, Recently, gut microbiome research and its application in diet and lifestyle advice has been called into question due to stool samples lacking in their capability to represent the actual intestinal tract (https://www.nature.com/articles/s41586-023-05989-7). I'm now wondering what to believe of all the "science-backed" messages out in the dietetics/nutrition world about "eating to improve your microbiome" and its associations with disease. How do we interpret this new evidence - do we have to throw out previous research? Thanks :)

Fish contamination

How real are heavy metal and plastic contamination of fish? What are the effects?

Dietary iron-absorption enhancers

Hi gents, love your work. Do we need Dietary iron-absorption enhancers? I commonly hear dietitians say that you must eat vit c with non-heme iron foods, or you must avoid eating non-heme iron foods with calcium, phytates etc. But....does this actually impact iron status? Thanks!! - Paul