Assisted reproduction

Bava Kamma 82a ~ Is Garlic Good for You?

     בבא קמא עב, א

...עשרה תקנות תיקן עזרא...אוכלין שום בערב שבת... משום עונה דכתיב אשר פריו יתן בעתו וא"ר יהודה... זה המשמש מטתו מערב שבת  לערב שבת. ת"ר חמשה דברים נאמרו בשום משביע ומשחין ומצהיל פנים ומרבה הזרע והורג כנים שבבני מעיים וי"א מכניס אהבה ומוציא את הקנאה

Ezra made ten regultions...That they eat garlic on the eve of Shabbat, on account of the mitzvah to have sexual relations. As it is written [Psalms 1:3]: “He shall be like a tree…that yields its fruit in its proper time,” and Rav Yehuda taught….this verse refers to a person who has sexual intercourse on every eve of Shabbat. The rabbis taught that garlic has five qualities: It satiates and warms the body and brightens the face, it increases semen, and it kills parasites in the intestines. Others add that it instills love and so eliminates jealousy (Bava Kamma 82a)

Many, many years ago I watched a rabbi liberally rubbing garlic into matzah at his home as part of Friday night Shabbat dinner. I thought it was because he liked the taste.  I may have been wrong.

Today, the Talmud (Bava Kamma 82a) lists ten regulations enacted by Ezra when he led the return of the Jewish people from Babylonia to Israel. Some, like reading from the Torah on Mondays and Thursdays, you may have heard of. Others, never became quite so popular. Which brings us to enactment #5: to eat garlic on the eve of Shabbat. The Talmud explains why Ezra decreed (presumably to the men only) that garlic should be eaten on Friday night – because it increases male fertility and Friday night is the prescribed time to have intercourse.  So is the Talmud correct? Does garlic increase fertility? You’d be surprised…

The Medicinal Properties of Garlic

In a 2005 review article from Yeshiva University and the Albert Einstein College of Medicine, Ellen Tattleman noted that garlic has been used for medicinal purposes for thousands of years. Sanskrit records show that it has been in use as a medicine for at least 5,000 years, making the Chinese relative newcomers to the garlic industry, since they’ve only been using it for some 3,000 years. The Egyptians, Babylonians, Greeks, and Romans used garlic for healing purposes, and even the great Louis Pasteur noted garlic’s antibacterial activity, in 1858. In case you want to prepare this at home, it is the root bulb of the garlic plant (fresh, dehydrated, or as a steam-distilled oil) that you need to go for.  This bulb contains allicin which is formed when alliin, a sulfur-containing amino acid, comes into contact with the enzyme alliinase. This reaction happens whenever you chop, crush or chew raw garlic. The antimicrobial, lipid lowering, antioxidant, and anti-clotting effects that have been attributed to garlic are thought to be related to this allicin and other breakdown products. We will return to these medicinal properties later, but for now let’s focus on the effect of garlic on male fertility; after all, that’s what today’s page of Talmud discusses.

Garlic and Sperm Production - in Mice

There is conflicting evidence about the role of garlic on sperm production.  Some studies have shown that it impairs the Leydig and Sertoli cells that are part of the machinery of sperm production – if you are a rat. Other studies have shown that garlic, or rather the allicin that garlic produces, can protect the testes against toxins.  If you are a rat, being exposed to these testicular shriveling toxins. When it comes to the sperm themselves, again, the evidence is conflicting.  In mice, garlic has been shown both to increase and to decrease the production of sperm, and scientists have also noted conflicting results about the effect of garlic on testosterone levels.

In 2001 a group of Japanese researchers investigated the pharmacological activities of four garlic preparations, raw garlic juice, garlic powder, heated garlic juice and aged garlic extract, on testicular hypogonadism (hypospermatogenesis and impotence) induced by warm water treatment. The results showed that aged garlic extract at a 4 ml/kg  dose for a couple of weeks significantly enhanced spermatogenesis and improved impotence after warm water treatment of mice. In contrast, the other preparations were only slightly effective.  So perhaps infertile male mice should try garlic on Friday nights.

Overall, the effects of garlic on sperm production - on rodents -  are not clear.  A 2013 review in Andrologia of the impact of garlic on male fertility of concludes with these remarks:

In traditional oriental medicine, garlic has been used to improve male sexual dysfunction and to recover testicular functions. But in the literature, there are very few studies about the potential effects of garlic on spermatogenesis (about ten studies), and their results are contradictory. These discrepancies could be related to three main factors (i) the type of preparations, (ii) the way of administration [sic] and (iii) the dose.

Garlic and the Quality of Human Sperm

So much for mice and rats; what about the effect of garlic on human sperm production? It turns out that you can buy a combination antioxidant widely touted to improve male fertility. It is called Menevit, and among other substances, each capsule apparently contains 333 micrograms of garlic oil.   But a 2009 study from Australia found that after three-months of therapy with Menevit® there was no significant change in sperm concentration, motility or morphology, although it did produce a significant reduction in sperm DNA fragmentation. Which is confusing because the same team reported that infertile men treated with Menevit® for the same period of time had an improvement in the levels of sperm global DNA methylation, though whether that is a marker of anything important is not clear.  If you are confused, so are the experts. Here is what one expert review concluded, in the excitingly titled Male Infertility: Contemporary Clinical Approaches:


The present body of evidence surrounding the treatment of male factor infertility with antioxidants is difficult to critically interpret because of less than ideal study design (not screening for oxidative stress at enrollment, sperm quality as a primary endpoint instead of pregnancy and a lack of concurrent placebo controls). Furthermore, the use of a large number of different types and dosages of antioxidant and the lack of adequately powered studies to analyse pregnancy outcomes precludes definitive conclusions being made… Firm conclusions relating to antioxidant therapies ability to improve sperm concentration, motility and morphology is presently impossible due to the abundance of contradictory results and inadequately controlled studies.
 

are there Other Benefits of Garlic?

So the evidence that garlic does anything useful to sperm production is, um, not great. But what about the other widely touted health benefits of garlic? For example, some claim that garlic lowers your lipids and in a study published in the prestigious Journal of the American Medical Association, garlic appeared to be have a real, but modest effect on lowering cholesterol, when compared to placebo.  There is also a claim that garlic lowers your blood pressure. In a meta-analysis (which is an analysis of many trials lumped together) of 23 trials only three showed a statistically significant reduction in diastolic blood pressure and one showed a statistically significant reduction in systolic blood pressure (approximately 3 percent) in patients treated with garlic compared with placebo. There are claims that garlic can prevent cancer, and slow the onset of atherosclerosis. Here is a summary from my colleagues at the National Center for Complementary in Integrative Medicine, part of the National Institutes of Health:

  • Some evidence indicates that taking garlic can slightly lower blood cholesterol levels; studies have shown positive effects for short-term (1 to 3 months) use. However, an NCCIH-funded study on the safety and effectiveness of three garlic preparations (fresh garlic, dried powdered garlic tablets, and aged garlic extract tablets) for lowering blood cholesterol levels found no effect.
  • Preliminary research suggests that taking garlic may slow the development of atherosclerosis (hardening of the arteries), a condition that can lead to heart disease or stroke
  • Evidence suggests that taking garlic may slightly lower blood pressure, particularly in people with high blood pressure. 
  • Some studies suggest consuming garlic as a regular part of the diet may lower the risk of certain cancers. However, no clinical trials have examined this. A clinical trial on the long-term use of garlic supplements to prevent stomach cancer found no effect.

And if you are tempted to take a garlic containing pill, because "why not, it can't do any harm" please bear in mind that although it appears to be safe for most adults:

  • Side effects include breath and body odor, heartburn, upset stomach, and allergic reactions. These side effects are more common with raw garlic.
  • Garlic can thin the blood (reduce the ability of blood to clot) in a manner similar to aspirin. This effect may be a problem during or after surgery. So use garlic with caution if you are planning to have surgery or dental work, or if you have a bleeding disorder.
  • Garlic has been found to interfere with the effectiveness of  a drug used to treat HIV infection. Garlic may also interfere with other drugs, though this has not been well studied.

The more things change, the more they stay the same.

In today's page of Talmud it was claimed that garlic does many different things: "It satiates and warms the body and brightens the face, it increases semen, and it kills parasites in the intestines, and it instills love and so eliminates jealousy." How strange then to note that today the supposed health effects of garlic are widely touted.  Plus ça change, plus c'est la même chose.  

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Yevamot 98b ~ On Twins, and the Sperm that Splits in Two

In yesterday's daf (Yevamot 98a), buried in a discussion of paternity, the Talmud states that the mechanism of the development of twin brothers is as follows:  "דטפה אחת היה ונחלקה לשתים"  - "there was one drop of semen that split into two".

Aristotle (384-322 BC) believed that twins were caused by too much seed (which does make a certain intuitive sense I suppose). In the thirteenth century the German theologian Albertus Magnus updated this theory, and suggested that twins were generated when the woman experienced too much sexual pleasure during intercourse. This redistributed the seed throughout the uterus, resulting in twins. 

We now know that there are actually only two ways that twins are formed, and neither depends on sperm splitting, too much seed, or an abundance of sexual pleasure. In monozygotic or identical twins (though they are not always literally identical), one sperm fertilizes one egg, and the resulting zygote then divides into two. Since the two offspring zygotes originated from the same "mother" zygote, they are genetically identical - and hence the twins (or triplets, if the zygote splits three ways) are identical and of course of the same sex.

Formation of identical (monozygotic) twins .   Courtesy Womenshealth.gov

Formation of identical (monozygotic) twinsCourtesy Womenshealth.gov

In dizygotic or fraternal twins, two sperm fertilize two eggs and the two resulting zygotes grow together in the same womb at the same time. They are not genetically identical, and are really two siblings who just happen to be sharing a womb at the same time. 

Formation of fraternal (dizygotic) twins.  Courtesy Womenshealth.gov

Formation of fraternal (dizygotic) twins. Courtesy Womenshealth.gov

That's it. No sperm splits.  Sorry.

Fun facts about twins, Israeli and others

  • For reasons that are not clear, the rate of dizygotic twins varies across the world, (highest in sub-Saharan Africa, lowest in Asia) and varies across women by body habitus (taller women are more likely to have twins - who knew?) and age (older women are four times more likely to have twins) and varies across time (possibly highest when conception is in the summer and fall).
Twinning Rates in the  USA, Europe, Australia and Asia. From Hoekstra et al. Dizygotic Twinning.  Human Reproduction Update  2007.14; 37-47.

Twinning Rates in the  USA, Europe, Australia and Asia. From Hoekstra et al. Dizygotic Twinning. Human Reproduction Update 2007.14; 37-47.

  • From 1915, when records were first started, through the 1970s, the rate of twin births in the US was a constant 2% of all births. But in the early 1980s the number of twin births in the US more than doubled, and today that rate is over 3%. The cause, as you may have guessed, is the increased use of reproductive technologies.
One in every 30 infants born in 2009 was a twin
— US Dept of Health and Human Services. NCHS Data Brief Jan 2012
  • The states that saw the greatest increase in twin birth rates were Connecticut, Hawaii, Massachusetts, New Jersey and Rhode Island. In these states, the twin birth rate more than doubled!
Percentage Increase in Twin Birth Rates  1980-2009. From NCHS Data Brief #80. Jan 2012.

Percentage Increase in Twin Birth Rates  1980-2009. From NCHS Data Brief #80. Jan 2012.

  • Finally, although the rate of twin births has increased for women of all ages over the last three decades, in women older than 40 the rate of twin births increased by 200%. There are at least two causes for this dramatic rise. First, as more women postpone childbirth, more are having children later in life, and older women, as we have already seen, are more likely to have (dizygotic) twins.  And secondly, more older women are using assisted reproduction techniques, which also increases the rate of twin conceptions.
  • In Israel, the incidence of twin births increased three fold in the three decades before 2001, a rate even higher than the increase in the US. The authors of a 2004 study on multiple births in Israel concluded that the "increased incidence of multiple births is explained by the special significance attributed to motherhood in Israeli society, which is met by the socio-political milieu and the availability of assisted reproductive technologies". Indeed.

  • The incidence of twin births in higher in Jewish than it is in Arab Israelis.  This is likely explained by their greater use of assisted reproductive technologies (like in-vitro fertilization).  

Incidence of twin births in Jewish and Arab populations of Israel, 1994-2001. From Blickstein I, Baor L.  Trends in multiple births in Israel.   Harefuah  2004; 143 (11): 794-798.

Incidence of twin births in Jewish and Arab populations of Israel, 1994-2001. From Blickstein I, Baor L. Trends in multiple births in Israel. Harefuah 2004; 143 (11): 794-798.


The Talmud wasn't exactly accurate about how twins are formed, but elsewhere it does capture the sense of wonder that so many of us feel as we hold a newborn baby (or two). It's a transcendent moment in which we may, for a fleeting moment, feel the divine.   

תנו רבנן שלשה שותפין יש באדם הקב”ה ואביו ואמו. אביו מזריע הלובן...אמו מזרעת אודם ... והקב”ה נותן בו רוח ונשמה וקלסתר פנים...

Our Rabbis taught: There are three partners in the creation of a person, the Holy One, blessed be He, the father and the mother. The father supplies the white...the mother supplies the red...and the Holy One, blessed be He, supplies the spirit and the breath and the beauty...
— Niddah, 31a

  

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