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Nutrition: supply, transport and evidence limits
Nutrients pass through absorption and regulated transport before brain use. Gut transmitter production is not a direct measure of brain synaptic supply.
Nutrition: supply, transport and evidence limits
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Diet provides substrates whose absorption, circulating handling and brain entry are regulated. The figure uses nutrient transport as a supported example, including large-neutral-amino-acid and glucose transport. It deliberately does not draw gut dopamine or serotonin travelling directly into brain synapses. Microbiome findings require separate evidence and cannot be treated as treatment efficacy or a reason to start supplements. This overview contains no individual nutritional diagnosis or intervention claim.
- Dietary inputs → Intestinal uptake: digestion / uptake
- Intestinal uptake → Blood and metabolism: circulation
- Blood and metabolism → Brain-barrier transport: transport
- Brain-barrier transport → Intracellular pathways: cellular use
What the diagram shows
Diet provides substrates whose absorption, circulating handling and brain entry are regulated. The figure uses nutrient transport as a supported example, including large-neutral-amino-acid and glucose transport. It deliberately does not draw gut dopamine or serotonin travelling directly into brain synapses. Microbiome findings require separate evidence and cannot be treated as treatment efficacy or a reason to start supplements. This overview contains no individual nutritional diagnosis or intervention claim.