We have written before avoiding Alzheimer’s in many different ways, for example:

Alzheimer’s Causative Factors To Avoid

…and regular readers will also be aware of our dictum “what’s good for the heart, is good for the brain”, which is because the heart feeds the brain, with oxygen and nutrients, and also ultimately clears away detritus like beta-amyloid (associated with Alzheimer’s).

For much more detail on this, see: What’s Your Vascular Dementia Risk? ← includes actual numbers and a risk calculator tool and things like that

So, it’s no surprise of course that exercise is protective against dementia, and as per the above, typically the most important thing here is heart health, so getting regular cardiovascular exercise, such walking, running, or dancing is great. Cycling too. Things like that.

Beyond cardio

First, some background. A previous (2023) study concluded:

❝Among older adults, more time spent in sedentary behaviors was significantly associated with higher incidence of all-cause dementia. Future research is needed to determine whether the association between sedentary behavior and risk of dementia is causal.❞

Source: Sedentary Behavior and Incident Dementia Among Older Adults

We’re not going to go deeply into that paper, because our interest today is about the answer to that call of “future research is needed”, because a team of scientists have now delivered on that.

In terms of how recent this new research is, it was published today (at time of writing), in the Journal of the Alzheimer’s Association.

In it, Dr. Marissa Gogniat et al. examined the relationship between sedentary behavior and cognitive decline and neurodegeneration, in 404 adults aged 50+.

A note on “cognitive decline” and “neurodegeneration”: those two terms are often used interchangeably, because they are usually strongly associated with each other so if one goes up or down then so does the other, but technically:

• cognitive decline = a decline of cognitive abilities, as measured by cognitive performance tests
• neurodegeneration = physical degeneration of neural tissue, typically specifically in the brain, as measured by various physical markers of neurodegeneration (tests range from brain scans to blood markers to biopsies and more, but the point is that it’s all physical stuff)

While based on the one-line summary we gave (“examined the relationship between sedentary behavior and cognitive decline / neurodegeneration”), this can sound a bit like a “examined whether water is wet” study, but in fact it becomes interesting when physical exercise is controlled for, since they found:

❝Reducing your risk for Alzheimer’s disease is not just about working out once a day. Minimizing the time spent sitting, even if you do exercise daily, reduces the likelihood of developing Alzheimer’s disease.❞

~ Dr. Marissa Gogniat

Too vague? Here’s the less vague version:

❝In cross-sectional models, greater sedentary time related to a smaller AD-neuroimaging signature (β = -0.0001, p = 0.01) and worse episodic memory (β = -0.001, p = 0.003). Associations differed by APOE-ε4 status. In longitudinal models, greater sedentary time related to faster hippocampal volume reductions (β = -0.1, p = 0.008) and declines in naming (β = -0.001, p = 0.03) and processing speed (β = -0.003, p = 0.02; β = 0.01, p = 0.01).❞

In other words:

• Those are very significant findings, statistically speaking; the causal association cannot be reasonably denied without some strong new evidence for why
• Greater sedentary behavior is related to neurodegeneration and worse cognition.
• Sedentary behavior is an independent* risk factor for Alzheimer’s disease.
• Associations differed by APOE-ε4 carrier status in cross-sectional models.

*as in, the sedentary risk factor stands (so to speak) regardless of whether you exercise a lot

With regard to “Associations differed by APOE-ε4 carrier status in cross-sectional models.”, that’s a little complicated, as …

❝Interestingly, we only found a sedentary time x APOE-ε4 status interaction on occipital volume longitudinally (which did not survive correction for multiple comparisons) and no interactions on cognition. The significant effect on occipital lobe volume was driven by APOE-ε4 non-carriers, which does not align with our cross-sectional findings. APOE-ε4 carriers are thought to have accelerated gray matter volume loss, starting possibly in middle age. Therefore, while increased sedentary time may impact gray matter volume among APOE-ε4 carriers, this effect may be masked by the cumulative effect of APOE-ε4 on brain volume over the lifespan that is captured at baseline.❞

In other words: in all likelihood, having the APOE-ε4 mutation probably means it’s extra important for you to not be sedentary in your lifestyle, and (good news) being non-sedentary is probably disproportionately impactful for you in a positive way, but (bad news) the APOE-ε4 mutation causes such an increased risk already, that it’s difficult to 100% ascertain that statistically, without larger samples starting earlier in life.

You can read the paper in full here:

Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7-year period despite high levels of physical activity

“What if have to spend a lot of time sitting down?”

A valid question, relevant for many.

For this, check out:

Stand Up For Your Health (Or Don’t) ← our main feature on this also includes more things you can do if you must sit, to make sitting less bad!

Take care!

In fact, a plurality of ways:

Polyamines to the rescue

Polyamines are small molecules (by which we mean: small even by molecular standards) made of more than one amino acid. They occur naturally in our bodies, and in many of the foods we eat.

We’ve written about some polyamines before:

• Firstly: Spermidine For Longevity
• Recently: Spermine vs Alzheimer’s & Parkinson’s!

No, not all polyamines have sperm-themed names, but that’s just where several important ones were first identified. What can we say; apparently scientists just loved looking at that stuff in the 1800s!

Another important polyamine has the delightful name putrescine, whose name comes from…

The smell of death: evidence that putrescine elicits threat management mechanisms

Scientists (Dr. Nadja Gebert et al.) have identified why these polyamines and more should ideally form a good part of our diet.

Specifically, they found that after intestinal damage, the body increases its own polyamine levels, such as spermidine and putrescine to support protein homeostasis and regeneration. Upon testing further, they found that boosting the polyamine metabolism with dietary interventions and/or oral supplementation (which one might consider a dietary intervention in any case) restores regenerative capacity in aged intestinal cells.

In other words, the aging intestine remains capable of repair at the molecular level—it just needs the right molecular trigger to kick-start its regenerative capacity again.

And there’s more! Per the study authors,

❝By analyzing proteins and metabolites in intestinal tissue and conducting experiments to show how the intestine recovers after damage caused by 5-fluorouracil, we were able to determine that the reduced regenerative capacity of older intestinal cells is not an unavoidable effect of aging. Rather, it is directly related to a disruption in proteostasis.

Aging is not an irreversible process. If we understand how cells lose their balance—and how we can restore it—we may not be able to stop aging, but we can significantly mitigate its effects on our bodies.❞

You can read the paper in full, here: Polyamines sustain epithelial regeneration in aged intestines by modulating protein homeostasis

And if you’re wondering how to get more polyamines in your diet, then here you go:

Top 12 Food Sources Of Each Of The Most Important Polyamines

And if you’d rather go for a supplement-based approach then check out:

The Orchid That Renovates Your Gut (Gently) ← along with where to get it!

Want to learn more?

For a much more detailed overview of healing your gut, you might like this book that we reviewed a little while back:

Heal Your Gut, Save Your Brain – by Dr. Partha Nandi

Enjoy!