Siobhan Mitchell, PhD
esiobhanmitchell.bsky.social
Siobhan Mitchell, PhD
@esiobhanmitchell.bsky.social
I'm a neuroscientist with a special focus on nutrition, metabolism and mitochondria. Always happy to chat about brain aging (or any kind of aging), great books to read, travel, food and writing.

https://sciprofiles.com/user/publications/865800
We often hear someone saying they're cranky due to low blood sugar. But most research shows there's no correlation of mood and blood glucose...

A new study has a new twist--some people can sense low blood glucose-- but only via hunger which manifests as poor mood.
www.thelancet.com/journals/ebi...
Glucose levels are associated with mood, but the association is mediated by ratings of metabolic state
We conclude that hunger-related mood shifts depend on conscious sensing of the body's internal state instead of acting subconsciously. Our study highlights the relevance of considering the self-report...
www.thelancet.com
February 2, 2026 at 6:13 PM
🧪Are high protein diets really better for aging?

Protein restriction in mice improves mitochondria quality control via AMPK signalling. This enhanced cardiovascular health by maintaining ATP production.

onlinelibrary.wiley.com/doi/10.1111/...
Dietary Protein Restriction Ameliorates Cardiac Inflammaging via AMPK‐ULK1‐Mediated Mitochondrial Quality Control
Dietary protein restriction protects the aging heart in the context of obesity by limiting mitochondrial DNA leakage and suppressing cGAS–STING-driven inflammation. Through AMPK–ULK1-dependent mitoph....
onlinelibrary.wiley.com
February 1, 2026 at 8:36 AM
🧪A recent study showed that mortality is tied to APOE4, which raises risk of Alzheimer's ~88% www.thelancet.com/journals/lan...

to decrease Alzheimer's risk (APOE4):

-maintain insulin sensitivity
-exercise regularly
-take care of your mitochondria via mitoquinol: pubmed.ncbi.nlm.nih.gov/41502301/
Long-term effects of APOEε4 on mortality
The apolipoprotein E (APOE) gene plays a critical role in neurodegenerative diseases,1,2 cardiovascular diseases,2 and longevity.3 Nucleotide polymorphisms give rise to three alleles of APOE, namely A...
www.thelancet.com
January 19, 2026 at 12:55 AM
Reposted by Siobhan Mitchell, PhD
WELL NOW, would you look at that?

A massive, 26-YEAR-LONG study of MORE THAN 2.4 MILLION people in Sweden found found NO EVIDENCE to support a causal link between acetaminophen (the API in Tylenol) use during pregnancy and increased risk of autism, ADHD, OR intellectual disability in children.
January 18, 2026 at 5:00 PM
Reposted by Siobhan Mitchell, PhD
Phase 2 trial: ICP-332, a TYK2 inhibitor, showed safety and efficacy for moderate-severe AD in 18-75yr olds across 19 centers in China. PMID:41533373, JAMA Dermatol 2026 https://doi.org/10.1001/jamadermatol.2025.5295 #Medsky #Pharmsky #RNA #ASHG #ESHG 🧪
https://doi.org/10.1001/jamadermatol.2025.5295
No description available
doi.org
January 16, 2026 at 3:10 AM
Reposted by Siobhan Mitchell, PhD
RESEARCH | L Casanueva Reimon, SM Steculorum et al. (CECAD)

Non-nutritive sensory components of high-fat diet, such as bacon flavor, are sufficient to impair metabolic health in mice 🧪
Fat sensory cues in early life program central response to food and obesity - Nature Metabolism
Non-nutritive sensory components of high-fat diet, such as bacon flavour, are sufficient to impair metabolic health in offspring in mice.
dlvr.it
January 11, 2026 at 6:06 PM
Reposted by Siobhan Mitchell, PhD
A feature in Nature examines what could come in science before 2050, including nuclear fusion and people on Mars. 🧪
Science in 2050: the future breakthroughs that will shape our world — and beyond
Nuclear fusion. People on Mars. Artificial general intelligence. These are just some of the advances that could come by the mid-century mark.
go.nature.com
January 11, 2026 at 11:21 PM
Reposted by Siobhan Mitchell, PhD
✨Please share! My newsletter is out.

🤒"Ridiculous numbers of Flu" now
💊Combo (antivirals + anti-inflammatory) for Long COVID
💉RFK Jr changes Childhood Immunization Schedule w/o data
👶NY free childcare for all 2 year olds

& much more buff.ly/L0LgQG6

#medsky #pedsky 🛟😷🧪
January 12, 2026 at 1:17 AM
🧪Super-innovative mitochondria function blood test has been developed to show possible Alzheimer's risk !

Mitochondrial function was tested via mitochondria size, membrane potential, apoptosis, oxidative stress.

It correlated to worse cognition and APOE4
pmc.ncbi.nlm.nih.gov/articles/PMC...
A blood based mitochondrial functional index biomarker for Alzheimer's disease
Alzheimer's disease (AD) pathology is complex and involves mitochondrial dysfunction. There are emerging therapies targeting mitochondrial function in clinical trials for AD. This highlights the need for biomarkers that measure mitochondrial ...
pmc.ncbi.nlm.nih.gov
January 12, 2026 at 3:31 AM
Why your vitamin D supplements might not be working

This study showed that sufficient magnesium helped improve vitamin D levels (including optimising levels that are too high )

Another reason to ensure good #magnesium intake!

www.sciencedaily.com/releases/202...
Why your vitamin D supplements might not be working
A randomized trial from Vanderbilt-Ingram Cancer Center reveals that magnesium may be the missing key to keeping vitamin D levels in balance. The study found that magnesium raised vitamin D in people ...
www.sciencedaily.com
December 31, 2025 at 7:37 AM
As 2025 draws to a close and we focus on getting ready for 2026, here's my op ed in the NZ Herald on how to address 'holiday hangover'

It's got tips on
🧪diet
🧪lifestyle
🧪dealing with stress

www.thepost.co.nz/nz-news/3609...
How the ‘holiday hangover’ hits women – and how they should respond
OPINION: My hope is that if women understand this, they will be kinder on themselves and lean into rest.
www.thepost.co.nz
December 30, 2025 at 7:48 PM
Reposted by Siobhan Mitchell, PhD
Top #Altmetric 2025: 🥈🧪

C Matute et al (UPV/EHU, ES) report that the MRI signal used as surrogate of myelin content is significantly reduced after marathon running, but fully recovered within two months.
Reversible reduction in brain myelin content upon marathon running - Nature Metabolism
Using magnetic resonance imaging on marathon runners, Ramos-Cabrer, Cabrera-Zubizarreta et al. report that the signal detected as a surrogate of myelin content is significantly reduced after exercise, but fully recovered within two months.
bit.ly
December 18, 2025 at 6:31 PM
Reposted by Siobhan Mitchell, PhD
If you need a happy science story today - another piece how male dolphins who bond better with their mates* age slower

@aunz.theconversation.com piece by @liviagerber.bsky.social @kjpeters.bsky.social and Lee Rollins

*Aussie dolphins, so the Aussie meaning of mates
🐳🦑🧪
Friendship is magic: male dolphins with close friends age more slowly
Like friendship itself, the slower ageing is more than just skin deep.
theconversation.com
December 16, 2025 at 11:00 PM
🧪Theobromine (the main psychoactive in #cocoa) is associated with slower aging

Years ago, I published on how #theobromine improves mood and blood pressure, so nice to see these benefits extend to #aging as well (bring on the #hotchocolate)

www.aging-us.com/article/2063...
Theobromine is associated with slower epigenetic ageing | Aging
Aging | doi:10.18632/aging.206344. Ramy Saad, Ricardo Costeira, Pamela R. Matías-García, Sergio Villicaña, Christian Gieger, Karsten Suhre, Annette Peters, Gabi Kastenmüller, Ana Rodriguez-Mateos, Cri...
www.aging-us.com
December 16, 2025 at 10:03 PM
For all those interested in #healthaging and #mitochondria check out my appearance on the Balancing Act with Montel Williams and Olga Villaverde

Graceful Aging: Nourishing Health at the Cellular Level thebalancingact.com/graceful-agi...
Graceful Aging: Nourishing Health at the Cellular Level - The Balancing Act
MitoQ offers breakthrough mitochondrial supplements to support vitality, cellular longevity, and whole-body health.
thebalancingact.com
December 10, 2025 at 10:54 PM
Reposted by Siobhan Mitchell, PhD
💥CONTAM CALENDAR GIVEAWAY💥

Here's your chance to win a ContamCalendar 2026! 🗓️🍄🦠

Just follow @contamclub.bsky.social and repost this post to enter the competition

Winner will be randomly selected from Bluesky or Twitter on Wednesday @ 6pm UTC
November 24, 2025 at 4:12 PM
Reposted by Siobhan Mitchell, PhD
New research identifies a unique T-helper cell subset that increases with age and may help clear senescent cells — a potential lever for slowing biological aging.
At AGE, we champion discoveries that reveal how the immune system shapes longevity.
www.sciencedaily.com/releases/202...

#AgingResearch
November 30, 2025 at 6:42 PM
🧪The average cell uses 10 billion ATP per day
🧪Each ATP needs to be recycled from ADP 1000 times per day.
🧪Because the body cannot store ATP, the mitochondria must make more continually (especially for the brain which use 70% of our ATP).
🧪Our cells have 250 g of ATP, about 4.25 watts
Mitochondria—Fundamental to Life and Health
An official website of the United States government
pmc.ncbi.nlm.nih.gov
November 21, 2025 at 1:54 AM
Reposted by Siobhan Mitchell, PhD
GLP-1s are being studied for a wide range of conditions. Now, scientists will test whether their anti-inflammatory properties can help alleviate symptoms of #LongCovid. @wired.com @emilymullin.bsky.social
www.wired.com/story/weight...
Weight-Loss Drug Zepbound Is Being Tested as a Treatment for Long Covid
GLP-1s are being studied for a wide range of conditions. Now, scientists will test whether their anti-inflammatory properties can help alleviate symptoms of long Covid.
www.wired.com
November 14, 2025 at 6:22 PM
Reposted by Siobhan Mitchell, PhD
For what its worth, the blue plaque crediting Watson and Crick was replaced a few years back with one that gives proper credit because people kept adding Franklin's name to it.

newn.cam.ac.uk/newnham-news...
Revised plaque acknowledges Franklin’s DNA role
A blue plaque which commemorates the celebration by Francis Crick and James Watson of the discovery of the structure of DNA in 1953 has been updated to acknowledge the contribution of Newnham alumna R...
newn.cam.ac.uk
November 9, 2025 at 10:00 AM
🧪 Wearing your heart (and your age) on your wrist

Cool new study shows that an Apple watch can act as a biological aging clock.

This study predicted cardiovascular, diabetes, and other diseases of aging all through that pulsing green light on your wrist.
www.nature.com/articles/s41...
A wearable-based aging clock associates with disease and behavior - Nature Communications
Biomarkers of aging play a vital role in understanding human longevity, but can be inconvenient or invasive to collect. Here, the authors develop an aging clock using consumer wearable photoplethysmog...
www.nature.com
November 5, 2025 at 3:39 AM
Younger adults are reporting higher levels of memory problems.

The authors state that economic hardship may be a cause

I wonder if growing rates of obesity at younger ages might play a role (I recently published how losing just 5% of body weight can improve cognition).
dx.doi.org/10.1212/WNL....
Rising Cognitive Disability as a Public Health Concern Among US Adults | Neurology
Background and ObjectivesCognitive disability—defined by the Behavioral Risk Factor Surveillance System (BRFSS) as serious difficulty concentrating, remembering, or making decisions because of a physi...
dx.doi.org
November 3, 2025 at 2:04 AM
Reposted by Siobhan Mitchell, PhD
excited to read this preprint from rabinowitz lab- how does the body decide which nutrients are burned, and how can this go wrong in T2 diabetes?
www.biorxiv.org/content/10.1...
Competitive catabolism in systemic metabolic homeostasis
Systemic metabolic homeostasis maintains circulating nutrient concentrations within physiological ranges. Insulin is central to this process, lowering circulating levels of glucose, free fatty acids, ...
www.biorxiv.org
October 31, 2025 at 7:40 PM
Huge paradigm shift!

The brain does use fat, this is big news in the neuroscience world, since for decades it was thought that the brain used exclusively glucose or ketones.

Why did this take so long to figure out? Because neurons don't use this fuel all the time
www.nature.com/articles/s42...
Triglycerides are an important fuel reserve for synapse function in the brain - Nature Metabolism
Kumar et al. show that under glucose-depleted conditions, neurons can use fatty acids as an alternative source of energy to support synaptic function.
www.nature.com
October 27, 2025 at 8:37 PM
Reposted by Siobhan Mitchell, PhD
A tale of two organelles: #Mitochondria and #lysosomes
Activated cell states → ↑ mitochondria vs. resting cell states. These mitochondria have more dense cristae, suggesting they are an important part of regulatory T cell activation during #inflammation. bit.ly/4qLclsH bit.ly/3LdvLWx
Mitochondrial and lysosomal signaling orchestrates heterogeneous metabolic states of regulatory T cells
Mitochondrial and lysosomal signaling orchestrates Treg cell metabolic states and functional fitness.
bit.ly
October 27, 2025 at 7:27 PM