Olives-The restrictions in eating olives due to fear of memory loss:[1]

One who is accustomed[2] to eating olives, forgets his learning.[3] It can cause one to forget his learning of the past 70 years.[4]

Pickled versus raw olives: Some Poskim[5] rule that this worry applies only to raw olives over which one sets a meal over, however, pickled or canned olives which are eaten as a mere desert do not cause one to forget his learning. Other Poskim[6], however, rule that it applies to all olives, whether pickled or raw. Practically, one is to be stringent in this matter to eat even pickled olives with the intent brought below. According to all it applies to raw olives which are soaked simply in water without salt.[7]

Eating with special intent:[8] One who eats olives with the special meditation [i.e. Kavanah] does not get memory damage from it, as it is only the ignoramus who eats it without Kavana who gets damaged. [This intent is as follows: Keil-Elokim-Matzpatz which is the numerical value of Zayis/olive.[9] One is to have this intent when eating the olives in order to prevent memory loss.]

Adding olive oil:[10] Some Poskim[11] rule that if one adds olive oil to the olives then eating the olives no longer causes forgetfulness. Other Poskim[12], however, rule that the olives can cause forgetfulness even in such a case. [The custom is like the former opinion.[13] The oil does not need to be added to each individual olive.[14]]

Olive oil:[15] Olive oil helps improve one’s memory. It can cause one to remember his learning of the past 70 years.[16]

Is the above restriction obligatory or optional:[17]

It is a biblical prohibition for one to forget his Torah learning.[18] Numerous hazards recorded in the Talmud and Poskim are due to that lack of keeping them can damage one’s memory of his Torah learning. This is known as “Kasha Leshichicha.” Nonetheless it is not clear if a person is obligated be careful to adhere by these hazards, and if doing so is optional, or a Rabbinical or even biblical obligation and if one who does not abide by them transgresses the above negative command against forgetting one’s Torah learning. Some Poskim[19] indeed rule that there is no actual obligation to abide by the memory loss hazards, as would only transgresses forgetting his Torah learning if he does something active to remove it from his heart. However, from other sources it is evident that one is obligated to abide by these matters[20], and some Poskim[21] even hold that one who transgresses it, transgresses a Biblical prohibition against forgetting one’s Torah learning.

Who should avoid matters that cause memory loss?[22] It is questionable whether memory loss hazards are applicable to ignoramuses, women, and children, who do not have the same level of obligation in Torah learning. The following is a Halachic analysis on the subject: Torah scholars are to beware very much from those matters that cause forgetfulness.[23] Some Poskim[24] rule that non-Torah Scholars, and certainly women, however, do not need to be careful in this matter, and on the contrary, it is better that they not abide by it so they can forget all the nonsense that they enter their minds. Other Poskim[25], however, imply that these warnings apply to all men but not to women. Other Poskim[26] rule that it applies also to pregnant women, although all other women may eat it. Others write it applies also to nursing women and to women at the time that they can become pregnant.[27] Other Poskim[28] rule that it applies to all people, man or woman. Regarding children, some Poskim[29] write that even children are to be careful to avoid matters that cause memory loss, while other Poskim[30] write that there is no need for them to be careful in this as they have not learned anything that they can forget.

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[1] See Kaf Hachaim O.C. 157:27; Y.D. 116:168; Sefer Zikaron 2:11; Sefer Shemiras Haguf Vihanefesh [Lerner] 8; Piskeiy Teshuvos 170:10 footnote 77

[2] The definition of accustomed: It is unclear as to what is the definition of accustomed. From some sources one can argue that it refers to one who eats olives within every 30 days. If, however, he only eats it within every 31 days, then it is not defined that he is accustomed. [Salmas Chaim 870 based on Brachos 40a] From other sources one can argue that it refers to one who eats olives within every 40 days. If, however, he only eats it within every 41 days, then it is not defined that he is accustomed. [See Shabbos 110a; See Sefer Zikaron] Others say that accustomed means that he eats it three times. [Ben Yehoyada ibid] See Sefer Shemiras Haguf Vihanefesh [Lerner] 8 footnote 3

[3] M”A 170:19; Horiyos 13b; Rabbeinu Bechayeh Vayishlach; Hagahos Rebbe Akiva Eiger 2; Aruch Hashulchan 2:5; 170:15; Ben Ish Chaiy Pinchas 2:17; Kaf Hachaim O.C. 157:27; Y.D. 116:168; Torah Or Tetzaveh 81b; See Sefer Zikaron 2:11; Sefer Shemiras Haguf Vihanefesh [Lerner] 8:1

[4] Rebbe Yochanon in Horiyos ibid; Torah Or Tetzaveh 81b

[5] Hagahos Yaavetz on Horiyos ibid and Mur Uketzia 170; Shemira Meialya 178; Pischeiy Olam 2:1; See Yevamos 15b; Brachos 38b; Kaf Hachaim Falagi 24:43; Kaf Hachaim 157:27

^[6] Meiri; Yifei Laleiv 3 Kuntrus Acharon Y.D. 116:10; Sefer Zikaron 2:11; Kaf Hachaim O.C. 157:27; Y.D. 116:168

[7] Kaf Hachaim ibid

[8] M”A 170:19; Shaar Hamitzvos Parshas Vaeschanon; Negid Mitzvah p. 18; Likkutei Torah Eikev; Ben Yehoyada end of Horiyos; Elya Raba 157:24; Aruch Hashulchan 170:15; Kaf Hachaim 157:27; Bnei Yissachar Mamarei Chodesh Kisleiv 4:15; See Salmas Chaim 1:41; Yaskil Avdi 8 Hashmatos Hashmatos Y.D. 8:1; Sefer Shemiras Haguf Vihanefesh [Lerner] 8:3

[9] Nagid Mitzvah ibid; Kaf Hachaim O.C. 157:27

[10] See Sefer Zikaron 2:11; Sefer Shemiras Haguf Vihanefesh [Lerner] 8; Piskeiy Teshuvos 170:10 footnote 77

[11] Salmas Chayim 1:41; Hagahos Divrei Yisrael on Shemiras Hanefesh

[12] Sefer Zikaron 2:11

[13] Halichos Shlomo Tefila 2 footnote 103 in name of Rav SZ”A that so was the custom in Jerusalem for generations and that so was his personal custom; Piskeiy Teshuvos ibid

[14] Halichos Shlomo p. 23

[15] Horiyos 13b; Torah Or Tetzaveh 81b

[16] Rebbe Yochanon in Horiyos ibid

[17] See Sefer Shemiras Haguf Vihanefesh [Lerner] Mavo 17-19

[18] Admur Hilchos Talmud Torah 2:4; Avos 3:8; Menachos 99b

[19] Mishneh Halachos 3:62 and 5:101; Sefer Zikaron 2 Hakdama, based on Sefer Chassidim 1008; Yabia Omer 2 Y.D. 8; Taharas Hamayim Shin 14

[20] Setimas Kol Haposkim who record memory loss hazards; Reishis Chochmah Shaar Hakedusha 5; All Poskim in  next footnote

[21] Hisorerus Teshuvah 1 and 367; Chesed Lealafim 157:6; Shem Mishimon Y.D. 17; Divrei Malkiel 4:1; Mili Deavos 5 Y.D. 5-3; Salmas Chaim 1:41; Likkutei Maharich; Teshuvos Vehanhagos 3 in name of Chazon Ish; Lehoros Nasan 1:59

[22] See Sefer Shemiras Haguf Vihanefesh [Lerner] Hakdama 19

^[23] Magen Avraham 170:19 writes that although by olives those which have correct intentions do not need to beware from eating them, nevertheless regarding the heart he writes that all are to be stringent.

[24] See Sefer Chassidim 1008; P”M 72 A”A 7, brought in Darkei Teshuvah 72:5; See Chochmas Adam ibid that only the Midakdekin are careful in this; Tel Talpiyos 5:140-3; Vayitzbor Yosef 43; Yad Yitzchak 2:84-17; Givas Pinchas 65:11-44; Darkei Teshuvah 72:5; Kaf Hachaim O.C. 157:18; Y.D. 72:6; Sefer Zikaron 2 Hakdama; Yabia Omer 2 Y.D. 8

[25] Chavas Daas Y.D. 72:2; Darkei Teshuvah 72:5; Givas Pinchas 65:11-44; Sefer Zikaron Hakdama 2

[26] Beis Lechem Yehuda 72:3; Kneses Hagedola; Mishmeres Shalom 72 S.D. 2; Ben Ish Chaiy Acharei 2:11

[27] Sefer Zechira Inyanei Zivug; Ben Ish Chaiy Acharei 2:11 regarding nursing

[28] Halichos Beisa 28 footnote 24; Kaf Hachaim [Falagi] 24:45 that a woman once ate an animal heart and got severely injured; Kaf Hachaim 157:18; Givas Pinchas 65:11-44 in answer of his brother in law in end of Sefer in name of Ruach Chaim and that so is implied in Mishnas Chassidim; Implication of Kaf Hachaim ibid who writes that the worry is not just to due memory loss, but also due to the Yetzer Hara; See Shulchan Chaiy 9 footnote 2

[29] Sefer Zikaron

[30] Eiyneiy Kol Chaiy Horiyos 13; Vayitzbor Yosef 42