MAKING NEW NEURONS AT ANY AGE

The Longevity Intelligence Briefing

The Neurogenesis Issue

Science-backed levers for a brain that keeps growing

---

Vol. 1 · Adult Brain Health · Spring 2025

Quick Takes

01

High-fat, high-sugar diets and chronic alcohol use actively suppress hippocampal neurogenesis — through inflammation, insulin resistance, and oxidative stress.

Zhao & Sabihi, 2026

02

A single daytime nap has been shown to restore hippocampal function and improve declarative learning in human subjects — the evidence is direct and compelling.

Ong et al., 2020

03

Intensive cognitive training and enriched environments can measurably increase hippocampal volume in as little as 12 weeks in older adults with mild cognitive impairment.

Fotuhi et al., 2016

Deep Dive

You Can Sculpt Your Own Brain. Here Is the Evidence.

More than a century ago, Santiago Ramón y Cajal wrote that any person could be "the sculptor of his own brain." The science of adult hippocampal neurogenesis is finally making that actionable.

"Superagers" — people who remain cognitively sharp well into very old age — show higher rates of hippocampal neurogenesis than average. The question worth asking is not whether this matters, but what we can do about it. Four converging domains of evidence point toward a surprisingly coherent answer.

"Any man could, if he were so inclined, be the sculptor of his own brain." — Santiago Ramón y Cajal

Diet and metabolism. The evidence here is unusually blunt: what we eat shapes whether new neurons are born and survive. Diets high in fat and sugar, chronic overnutrition, and alcohol or opioid exposure suppress neurogenesis through inflammation, oxidative stress, and insulin resistance.[1] Caloric restriction and intermittent fasting paradigms, by contrast, increase neurogenesis and elevate BDNF — the brain's primary growth factor — in animal models, with emerging human data suggesting improvements in hippocampal-dependent cognitive tasks.[2] From animal models, diets rich in polyphenols (blueberries, curcumin, resveratrol), omega-3 fatty acids, and sulforaphane from cruciferous vegetables enhance neurogenesis via BDNF upregulation and antioxidant pathways.[2]

Evidence strength Polyphenols + omega-3s: strong animal data; emerging human evidence for caloric restriction

Practical lever Mediterranean-style eating, time-restricted feeding, minimising ultra-processed food

Sleep and circadian health. Sleep deprivation impairs the proliferation and survival of newborn neurons in animal models; fragmented or short sleep correlates with reduced hippocampal volume in humans.[1] The glymphatic system — the brain's waste-clearance network — is most active during deep sleep, and disruption here likely compounds neurogenic suppression. Particularly striking: a controlled study found that a single daytime nap restores hippocampal function and improves declarative learning in human participants.[3] This is one of the few areas where the human evidence is both direct and practically implementable today.

· · ·

Stress, mood, and neuroinflammation. Chronic psychological stress, glucocorticoid excess, and neuroinflammation all suppress adult hippocampal neurogenesis and promote dendritic atrophy — documented primarily in animal models.[4] The honest caveat: we have stress-reduction practices with strong evidence bases (mindfulness, therapy, exercise), but none has been formally tested for neurogenic effects in humans. The mechanistic logic is sound; the direct human trial remains to be done.

Cognitive and social engagement. This is where the "use it or lose it" principle gets rigorous support. A 12-week personalised brain fitness programme in 127 older adults with mild cognitive impairment — combining cognitive training, neurofeedback, dietary coaching, fitness, and mindfulness — showed significant cognitive gains and, in the 17 participants who received MRI scans, 12 showed either reversal of hippocampal atrophy or increased hippocampal volume.[5] A separate 2022 memory-training study using episodic strategy training found relative hippocampal volume increases versus a no-training control, with effects persisting for weeks to months — though not clearly maintained at three years without continued practice.[6] Multimodal approaches combining brain stimulation, light therapy, music, gait training, and cognitive exercises have also shown enhanced neural activity in regions of interest in both young adults and older adults with MCI.[7]

Timeframe Measurable hippocampal changes documented within 12 weeks in multiple studies

Key implication Effects require continued practice — training is maintenance, not a one-time intervention

What makes this body of evidence unusual is its coherence. The same mechanisms — BDNF signalling, reduced inflammation, improved insulin sensitivity, glymphatic clearance — show up across all four domains. These are not independent levers. They appear to be parts of the same system.

References

1. Zhao Z, Sabihi SS. Dietary Bioactives and Physical Activity in the Regulation of Hippocampal Neurogenesis and Cognitive Decline. Food Sci Nutr. 2026.
2. Poulose SM, Miller MG, Scott T, Shukitt-Hale B. Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function. Adv Nutr. 2017.
3. Ong JL, Lau TY, Lee XK, van Rijn E, Chee MWL. A daytime nap restores hippocampal function and improves declarative learning. Sleep. 2020.
4. Opendak M, Gould E. Adult neurogenesis: a substrate for experience-dependent change. Trends Cogn Sci. 2015.
5. Fotuhi M, Lubinski B, Trullinger M, et al. A Personalized 12-week "Brain Fitness Program" for Improving Cognitive Function and Increasing the Volume of Hippocampus in Elderly with Mild Cognitive Impairment. J Prev Alzheimers Dis. 2016.
6. Memory-training study (episodic memory strategy training, young and older adults). 2022.
7. Oh W, Park H, Hallett M, You JSH. The Effectiveness of a Multimodal Brain Empowerment Program in Mild Cognitive Impairment: A Single-Blind, Quasi-Randomized Experimental Study. J Clin Med. 2023.