4 Surprising Things That Age Your Brain (That No One Talks About)

And the simple fixes you can start today

In my experience, most people understand the brain health essentials: community, movement, sleep, a good diet and challenging your mind.

Today I wanted to share four lesser-known factors that profoundly impact how your brain ages - and what to do about it.

Note: I'm now including references at the bottom for further reading, with only key facts linked inline.

1. Brushing your Teeth

Forget the gut microbiome for a moment. Your mouth hosts over 700 species of bacteria - and they have a direct line to your brain through blood vessels and nerve pathways.

Research is now revealing just how much this bacterial-brain connection affects our cognitive health:

• People with chronic gum disease face 38% higher dementia risk

• Those with Alzheimer's and active gum infections decline 6 times faster

• Fewer teeth correlate with weaker memory tests and shrinkage of the brain’s memory regions.

Could this all be correlation? Maybe - but lab and tissue studies point the same way: the main gum bacterium (P. gingivalis) and its enzymes are found in Alzheimer’s brains, align with damaged brain proteins, and blocking those enzymes in infected mice reduces brain injury.

Bottom Line: Brush for two minutes, twice daily, and floss every day.

2. Protect your Hearing

Hearing loss doesn't just affect your ears.

Scientists now recognise it as a key modifiable risk factor for dementia. A pooled analysis of 8 studies (126,903 people overall) found hearing-aid use was associated with a 19% reduction in long-term cognitive decline.

How it works:

• Cognitive overload: Your brain works overtime to decode muffled speech, leaving less power for memory and thinking.

• Social withdrawal: Hearing problems can lead to isolation - disconnecting you from your friends and local community.

• Brain atrophy: If you don’t use it - you lose it. Less auditory input means key brain regions (including memory centres) shrink faster.

What to do: Protect your ears in loud environments. Think you have hearing loss? Try to get tested. Today's hearing aids are discreet, rechargeable, and adaptive - nothing like the bulky devices of the past.

3. Buying an Air Filter

Your environment shapes your cognitive health - the people you surround yourself with, your proximity to nature, and crucially, the air you breathe.

Air pollution infiltrates your brain through tiny particles that enter via your nose and bloodstream. Once inside, they activate three damaging mechanisms:

• The brain’s immune system (microglia) become chronically inflamed

• Oxidative stress damages neurons

• Alzheimer’s proteins (amyloid/tau) accumulate faster

Brain scans show the impact: key brain regions shrink and lose density, ageing your brain 1-2 years faster than normal.

Bottom Line: Buy a HEPA air filter and use it at home. The EPA's buying guide shows what specs to look for.

4. Chronic Daily Use of Benadryl

This doesn’t apply to most people who use antihistamines.

I’m specifically talking about first-generation antihistamines - the drowsy ones like Benadryl - taken daily for years.

As a doctor in memory clinic, I see this pattern constantly. Patients come in with memory and thinking problems, almost always using these medications to help with sleep. We stop the medication, and often within weeks they feel much better.

This research also backs this up:

• Studies show daily use of first-generation antihistamines for 3+ years is associated with an up to 54% increased dementia risk.

• Brain scans also show shrinkage in memory regions among users, likely because these drugs block acetylcholine - the exact neurotransmitter that Alzheimer's medications try to preserve.

Bottom line: If you're taking them nightly for sleep, talk to your doctor about alternatives. Don’t stop taking any medication your doctor has advised you to take!

Note: Please let me know in the comments if this was too much information, too little information, not explained well - I can’t improve if you don’t tell me!

Further Reading/ References

Oral health

1. Nadim R, et al. Influence of periodontal disease on risk of dementia: a systematic review and meta-analysis. Eur J Epidemiol. 2020;35:821–833. doi:10.1007/s10654-020-00648-x. SpringerLink

2. Ide M, et al. Periodontitis and Cognitive Decline in Alzheimer’s Disease. PLoS ONE. 2016;11:e0151081. doi:10.1371/journal.pone.0151081. PLOS

3. Newman-Norlund RD, et al. Exploring the link between tooth loss, cognitive function, and brain wellness in healthy aging. J Periodontal Res. 2024;59:1184–1194. doi:10.1111/jre.13280. PubMed

4. Nakamura H, et al. Brain atrophy in normal older adults links tooth loss and diet changes to future cognitive decline. npj Aging. 2024;10:20. doi:10.1038/s41514-024-00146-4. Nature

5. Dominy SS, et al. Porphyromonas gingivalis in Alzheimer’s disease brains: evidence for disease causation and treatment with small-molecule inhibitors. Sci Adv. 2019;5:eaau3333. doi:10.1126/sciadv.aau3333. PubMed

6. Borsa L, et al. Analysis of the link between periodontal diseases and Alzheimer’s disease: a systematic review. Int J Environ Res Public Health. 2021;18:9312. doi:10.3390/ijerph18179312.

Hearing Loss

1. Lin FR, Yaffe K, Xia J, et al. Hearing loss and cognitive decline in older adults. JAMA Intern Med. 2013;173(4):293-299. doi:10.1001/jamainternmed.2013.1868. PubMed

2. Lin FR, Ferrucci L, An Y, et al. Association of hearing impairment with brain volume changes in older adults. NeuroImage. 2014;90:84-92. doi:10.1016/j.neuroimage.2013.12.059. PubMed

3. Armstrong NM, An Y, Doshi J, et al. Association of Midlife Hearing Impairment With Late-Life Temporal Lobe Volume Loss. JAMA Otolaryngol Head Neck Surg. 2019;145(9):794-802. doi:10.1001/jamaoto.2019.1610. PubMed

4. Wang H-F, Zhang W, Rolls ET, et al. Hearing impairment is associated with cognitive decline, brain atrophy and tau pathology. EBioMedicine. 2022;86:104336. doi:10.1016/j.ebiom.2022.104336. PubMedThe Lancet

5. Lin FR, Pike JR, Albert MS, et al.; ACHIEVE Collaborative Research Group. Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial. Lancet. 2023;402(10404):786-797. doi:10.1016/S0140-6736(23)01406-X. PubMed

6. Yang Z, Ni J, Teng Y, et al. Effect of hearing aids on cognitive functions in middle-aged and older adults with hearing loss: A systematic review and meta-analysis. Front Aging Neurosci. 2022;14:1017882. doi:10.3389/fnagi.2022.1017882.

Air Pollution

1. Ultrafine particles can reach the brain via the olfactory nerve after inhalation (Oberdörster 2004). DOI: 10.1080/08958370490439597. CDC FTP

2. In humans, inhaled nanoparticles enter the bloodstream and accumulate at sites of vascular inflammation, supporting a hematogenous route to the brain (Miller 2017). DOI: 10.1021/acsnano.6b08551. PMC

3. Air pollution activates microglia and drives oxidative stress—key neurotoxic mechanisms implicated in neurodegeneration (Block & Calderón-Garcidueñas 2009). DOI: 10.1016/j.tins.2009.05.009. PMC

4. Higher ambient PM2.5 is associated with amyloid-PET positivity in older adults with cognitive impairment, linking pollution exposure to Alzheimer-type pathology (Iaccarino 2021). DOI: 10.1001/jamaneurol.2020.3962. PMC

5. Community cohort MRI: each 2 µg/m³ higher long-term PM2.5 associates with ~0.32% smaller total cerebral brain volume—approximately one year of brain ageing—and higher odds of covert infarcts (Wilker 2015). DOI: 10.1161/STROKEAHA.114.008348. PMC

6. Portable HEPA filtration (randomised, double-blind crossover; n=45) reduced indoor PM by ~60%, improved endothelial function (+9.4% reactive hyperemia index), and lowered CRP (–33%) in a woodsmoke-impacted community (Allen 2011). DOI: 10.1164/rccm.201010-1572OC.

Anti-histamines

1. Gray SL et al. Cumulative use of strong anticholinergics and incident dementia. JAMA Intern Med. 2015;175:401–407. DOI: 10.1001/jamainternmed.2014.7663. PubMed

2. Coupland CAC et al. Anticholinergic drug exposure and the risk of dementia: nested case–control study. JAMA Intern Med. 2019;179:1084–1093. DOI: 10.1001/jamainternmed.2019.0677. PubMed

3. Mur J et al. Association between anticholinergic burden and dementia in UK Biobank. Alzheimer’s Dement (N Y). 2022;8:e12290. DOI: 10.1002/trc2.12290. PubMed

4. Risacher SL et al. Anticholinergic use, cognition, brain metabolism, and atrophy in cognitively normal older adults. JAMA Neurol. 2016;73:721–732. DOI: 10.1001/jamaneurol.2016.0580. PMC

5. Ansotegui IJ et al. Fexofenadine clinical review (non-sedating, minimal CNS penetration). Ann Allergy Asthma Immunol. 2024;133:3–16. DOI: 10.1016/j.anai.2024.01.001. PubMed

6. Shamsi Z et al. Cetirizine and loratadine: no impairment on cognitive/psychomotor testing (vs promethazine). Eur J Clin Pharmacol. 2001;56:865–871. DOI: 10.1007/s002280000257. PubMed