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Alzheimer’s Causative Factors To Avoid

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The Best Brains Bar Nun?

This is Dr. David Snowdon. He’s an epidemiologist, and one of the world’s foremost experts on Alzheimer’s disease. He was also, most famously, the lead researcher of what has become known as “The Nun Study”.

We recently reviewed his book about this study:

Aging with Grace: What the Nun Study Teaches Us About Leading Longer, Healthier, and More Meaningful Lives – by Dr. David Snowdon

…which we definitely encourage you to check out, but we’ll do our best to summarize its key points today!

Reassurance up-front: no, you don’t have to become a nun 😉

The Nun Study

In 1991, a large number (678) of nuns were recruited for what was to be (and until now, remains) the largest study of its kind into the impact of a wide variety of factors on aging, and in particular, Alzheimer’s disease.

Why it was so important: because the nuns were all from the same Order, had the same occupation (it’s a teaching Order), with very similar lifestyles, schedules, socioeconomic status, general background, access to healthcare, similar diets, same relationship status (celibate), same sex (female), and many other factors also similar, this meant that most of the confounding variables that confound other studies were already controlled-for here.

Enrollment in the study also required consenting to donating one’s brain for study post-mortem—and of those who have since died, indeed 98% of them have been donated (the other 2%, we presume, may have run into technical administrative issues with the donation process, due to the circumstances of death and/or delays in processing the donation).

How the study was undertaken

We don’t have enough space to describe the entire methodology here, but the gist of it is:

  • Genetic testing for relevant genetic factors
  • Data gathered about lives so far, including not just medical records but also autobiographies that the nuns wrote when they took their vows (at ages 19–21)
  • Extensive ongoing personal interviews about habits, life choices, and attitudes
  • Yearly evaluations including memory tests and physical function tests
  • Brain donation upon death

What they found

Technically, The Nun Study is still ongoing. Of the original 678 nuns (aged 75–106), three are still alive (based on the latest report, at least).

However, lots of results have already been gained, including…


A year into the study, in 1992, the “apolipoprotein E” (APOE) gene was established as a likely causative factor in Alzheimer’s disease. This is probably not new to our readers in 2024, but there are interesting things being learned even now, for example:

The Alzheimer’s Gene That Varies By Race & Sex

…but watch out! Because also:

Alzheimer’s Sex Differences May Not Be What They Appear


Based on the autobiographies written by the nuns in their youth upon taking their vows, there were two factors that were later correlated with not getting dementia:

  • Longer sentences
  • Positive outlook
  • “Idea density”

That latter item means the relative linguistic density of ideas and complexity thereof, and the fluency and vivacity with which they were expressed (this was not a wishy-washy assessment; there was a hard-science analysis to determine numbers).

Want to spruce up yours? You might like to check out:

Reading, Better: Reading As A Cognitive Exercise

…for specific, evidence-based ways to tweak your reading to fight cognitive decline.


While the dietary habits of the nuns were fairly homogenous, those who favored eating more and cooked greens, beans, and tomatoes, lived longer and with healthier brains.

See also: Brain Food? The Eyes Have It!

Other aspects of brain health & mental health

The study also found that nuns who avoided stroke and depression, were also less likely to get dementia.

For tending to these, check out:

Community & Faith

Obviously, in this matter the nuns were quite a homogenous group, scoring heavily in community and faith. What’s relevant here is the difference between the nuns, and other epidemiological studies in other groups (invariably not scoring so highly).

Community & faith are considered, separately and together, to be protective factors against dementia.

Faith may be something that “you have it or you don’t” (we’re a health science newsletter, not a theological publication, but for the interested, philosopher John Stuart Mill’s 1859 essay “On Liberty“ makes a good argument for it not being something one can choose, prompting him to argue for religious tolerance, on the grounds that religious coercion is a futile effort precisely because a person cannot choose to dis/believe something)

…but community can definitely be chosen, nurtured, and grown. We’ve written about this a bit before:

You might also like to check out this great book on the topic:

Purpose: Design A Community And Change Your Life – by Gina Bianchini

Want more?

We gave a ground-up primer on avoiding Alzheimer’s and other dementias; check it out:

How To Reduce Your Alzheimer’s Risk

Take care!

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