Olive Oil and Memory

I know better than to glance at scientific studies and say "Oh, that's what the Gemara says!" Nine times out of ten it doesn't mean anything, especially when it comes to segulos and refu'os, where it's so hard to know when the Gemara is being literal and when it's being symbolic. I learned my lesson when I tried to convince Dr. Barry Simon, a professor at CalTech, that the weightlessness and immeasurabllity and "above time" (See Rogatchover Shemos 16:33 and Teshuvos II 28) nature of the Aron follows from the association of gravity and spacetime. He basically told me to stick to things I understand. But sometimes it's interesting to speculate about commonalities and ancient wisdom.

Horyos 13b:

חמשה דברים משיבים את הלימוד פת פחמין וכל שכן פחמין עצמן והאוכל ביצה מגולגלת בלא מלח והרגיל בשמן זית והרגיל ביין ובשמים והשותה מים של שיורי עיסה ויש אומרים אף הטובל אצבעו במלח ואוכל הרגיל בשמן זית מסייע ליה לרבי יוחנן דאמר רבי יוחנן כשם שהזית משכח לימוד של שבעים שנה כך שמן זית משיב לימוד של שבעים שנה:

והרגיל ביין ובשמים:  מסייע ליה לרבא דאמר רבא חמרא וריחני פקחין:

והטובל אצבעו במלח:  אמר ר"ל ובאחת כתנאי ר' יהודה אומר אחת ולא שתים רבי יוסי אומר שתים ולא שלש וסימניך קמיצה 

Rashi

פת פחמין. פת האפוי בגחלים: 

של שיורי העיסה. שנשתיירה מלישה:

So there you have a Gemara that says that olive oil is beneficial for memory. 

As I said, this certainly can be an unscientific association with the Menora, as the Maharal says in his Chidushei Agados, and not meant to be either descriptive or prescriptive. Even if it is meant literally, it could be a segula, not science.

פירוש, כי השמן זית מיוחד לחכמה ושכל, מפני שממנו האור אשר השכל דומה לו, והזיתים אשר הוא נושא אל השמן, שבתוך הזית הוא שמן, מוכן לשכחה, כי השמן הוא נבדל מן הזית, ומפני שהשמן נבדל מן הזית הוא נבדל לגמרי, שזהו מיוחד לאור ולשכל, והנושא אשר [השמן] יוצא ממנו, כי הנושא אשר השכל עומד בו הוא חמרי, והוא משכח השכל כאשר הוא מוטבע בו. לכך כאשר אוכל הזתים הוא משכח תלמודו, כאלו השמן מוטבע בגוף הזית. וכאשר אוכל השמן שהוא בפני עצמו והוא נבדל מן הזית, הוא יפה לחכמה, כי הוא אור לגמרי, [והזית אשר השמן יוצא] ממנו הוא הפך זה, שהוא מסוגל אל הפך החכמה, לכך הוא מסוגל [לשכחה]. 

The reason this came up is this study in Annals of Clinical and Translational Neurology. Here's the intro to the article, in case the link doesn't work:

Extra-virgin olive oil ameliorates cognition and neuropathology of the 3xTg mice: role of autophagy

Authors

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• First published: 21 June 2017

Objective

Consumption of extra virgin olive oil (EVOO), a major component of the Mediterranean diet, has been associated with reduced incidence of Alzheimer's disease (AD). However, the mechanisms involved in this protective action remain to be fully elucidated.

Methods

Herein, we investigated the effect of daily consumption of EVOO on the AD-like phenotype of a mouse mode of the disease with plaques and tangles.

Results

Triple transgenic mice (3xTg) received either regular chow or a chow diet supplemented with EVOO starting at 6 months of age for 6 months, then assessed for the effect of the diet on the AD-like neuropathology and behavioral changes. Compared with controls, mice receiving the EVOO-rich diet had an amelioration of their behavioral deficits, and a significant increase in the steady state levels of synaptophysin, a protein marker of synaptic integrity. In addition, they had a significant reduction in insoluble Aβ peptide levels and deposition, lower amount of phosphorylated tau protein at specific epitopes, which were secondary to an activation of cell autophagy.

Interpretation

Taken together, our findings support a beneficial effect of EVOO consumption on all major features of the AD phenotype (behavioral deficits, synaptic pathology, Aβ and tau neuropathology), and demonstrate that autophagy activation is the mechanism underlying these biological actions.

The study is also cited in this article in Newsweek . The article ends by saying that the next step is to see whether olive oil ameliorates existing dementia or only prevents it. According to the Gemara, it even cures it - משיבים את הלימוד. It is protective and repairative.

Extra virgin olive oil is the key ingredient of the Mediterranean diet that protects the brain from Alzheimer’s disease and cognitive decline, scientists have discovered.
The health benefits of the Mediterranean diet—rich in plant-based foods, olive oil and fish—have long been known. It reduces the risk of heart disease and stroke, and leads to a lower risk of dementia.
A team of scientists from Temple University, Pennsylvania, has found what in the diet protects the brain from Alzheimer’s—and how this key ingredient works to prevent cognitive decline and preserve memories.
Previous research had already linked extra virgin olive oil to many of the health benefits of the Mediterranean diet. "The thinking is that extra-virgin olive oil is better than fruits and vegetables alone, and as a monounsaturated vegetable fat, it is healthier than saturated animal fats," senior investigator Domenico Praticò said in a statement.
Published in the Annals of Clinical and Translational Neurology on Wednesday, researchers investigated the relationship of extra virgin olive oil and dementia using a mouse model. (The animals used develop key characteristics of Alzheimer’s, including memory impairment and the build-up of amyloid-beta plaques in the brain.)
Animals were divided into two groups; one received a diet rich in extra virgin olive oil and the other did not. The olive oil was introduced at six months of age, before the mouse Alzheimer’s had set in.
By nine and 12 months, the olive oil mice were performing far better on cognitive tests that evaluate memory and learning abilities. Later studies of their brain tissues showed stark differences between the two groups. The mice that had been fed olive oil had lower levels of amyloid plaques and there were big differences in nerve cell appearance and function.
The connections between the neurons—the synapses—were found to be better preserved in the olive oil group than the control, and there was also an increase in nerve cell autophagy activation. The activation of autophagy is the important discovery—since this is the process that helps clear debris and toxins, including amyloid plaques, from the brain.
At present, scientists believe the reduction in autophagy is involved at the onset of Alzheimer’s—so finding a mechanism that prevents it could help develop therapies to treat or even reverse the disease.
"This is an exciting finding for us," Praticò said. "Thanks to the autophagy activation, memory and synaptic integrity were preserved, and the pathological effects in animals otherwise destined to develop Alzheimer's disease were significantly reduced. This is a very important discovery, since we suspect that a reduction in autophagy marks the beginning of Alzheimer's disease."
The team now plans to give 12-month-old Alzheimer’s mice (which have already developed plaques) extra virgin olive oil to see if it can stop or reverse the disease. “Our studies provide mechanistic support to the positive cross-sectional and longitudinal data on this component of the Mediterranean diet, and most importantly the biological rationale to the novel hypothesis that extra virgin olive oil could be considered as a viable therapeutic opportunity for preventing or halting Alzheimer’s disease,” they conclude.

We all know that we cannot take the medical advice in the Gemara at face value.  Let's look at the other things the Gemara says are good for memory:
פת פחמין וכל שכן פחמין עצמן

 והאוכל ביצה מגולגלת בלא מלח

 והרגיל בשמן זית

 והרגיל ביין

 ובשמים

 והשותה מים של שיורי עיסה

 ויש אומרים אף הטובל אצבעו במלח ואוכל 

פת פחמין וכל שכן פחמין עצמן. Bread baked in charcoal, and certainly charcoal itself. I have almost no training in biology or organic chemistry, but as I understand it, toasting bread generates acrylamides, which are considered carcinogenic. Additionally, acrylamides cause neuropathy. That is definitely not good for memory. 
 והאוכל ביצה מגולגלת בלא מלח. Baked egg without salt, like the egg we put on the seder plate as a zeicher for the Chagiga. 
 והרגיל בשמן זית, olive oil, although it doesn't mention extra virgin.
 והרגיל ביין, habitual drinking of wine. 
 ובשמים and habitual use of fragrant spices.
 והשותה מים של שיורי עיסה, one who drinks water left over from kneading bread. I don't know what this means. Since when is water left over after you knead bread?
 ויש אומרים אף הטובל אצבעו במלח ואוכל, and some say "one who dips his finger in salt and eat it." I guess the finger dipping means a certain amount - a pinch.
In any case, it is likely that some of these are segulos, not medicine, so we have to take this, apropos of this particular Gemara, with a pinch of salt.