Do Jewish and Islamic dietary laws have anything in common?

SDStaff Dex replies:

First, let’s be clear that this report will be a brief summary. The details of Jewish dietary laws are extremely complicated, and would (and do) take up volumes. While the laws of Islam are simpler, there are minor complications that would again make for a very lengthy report. We will therefore content ourselves with the famous 30,000-foot overview. Readers should be aware that every sentence in the table below should have a footnote, probably a page of footnotes, describing exceptions and implications and what-if scenarios.

Second, to be fair, we should add a column for Christianity, but mainstream Christianity has no dietary laws to speak of. There was a time when meat was forbidden to Catholics on Fridays, and many Christians refrain from meat during Lent, but these are more in the nature of “special occasion” meals, rather than everyday dietary rules.

We also want to say that both Islam and Judaism permit violations of the dietary laws if necessary for survival. So, a Muslim or Jew who is stranded on a desert island with nothing but ham sandwiches is permitted to eat them to save her/his life.

Let’s start with the history and origin of the laws in both religions, briefly.

Judaic dietary laws begin with commandments in the Torah (the Pentateuch, the first five books of the Bible). If you are a traditionalist, these date from the Revelation at Mount Sinai, say about 1250 BC. If you are a modernist, then you might date these at 1250 BC, or 1000 BC, or perhaps as late as 500 BC. The Torah gives very stark rules, such as not to “boil a kid in its mother’s milk.” Over centuries of tradition, the rabbis in the rabbinic and Talmudic period (say, 100 BC to 300 AD) codified exactly what the Torah rules mean, down to very, very picky details. Later interpretations of the rules applied them to new situations, and there are rabbinic authorities now who rule on even newer situations — in the era of meat-free soy burgers and milkless cheese, is a cheeseburger possible? When artificial chemicals are added, what is the status of the food? There can be differences of opinion, since there is no single authority recognized by all sects and branches of Judaism. The more liberal branches tend to discard some or all the dietary laws; the most traditional branches tend to be extra-scrupulous in adhering to them.

Islamic dietary laws begin in the Quran, dictated to the Prophet Mohammed by the angel Gabriel around 620 AD. Then there are the sunnah, the deeds of the Prophet, or the things he recommended or approved; and the hadith, the sayings of the Prophet, relayed through people who knew him. The combination of the Quran with the deeds and sayings of the Prophet Mohammed make up the rules of Islam. There is no centralized Islamic authority, so there are differences of opinion based on the shariah (religious legislation), varying by region/country or sect.

From a religious perspective, traditionalists would argue that the dietary rules for Islam and for Judaism are very similar because they come from the same God, and thus express the same underlying concepts of holiness. Historians would say that Islam sprang from Judaism, adapting much of Jewish tradition. The two religions, in fact, have lots more in common than politicians or hate-mongers would dare to admit.

You speak of an “underlying logic” in that there are certain classes of animals that are permitted or prohibited. In that sense, yes, there is a coherent rationale underlying what look like a complex set of rules. However, if you want to delve deeper, there is no “reason” given for any of the dietary prohibitions in either religion — why is this class of animal permitted and that class not? The only reasons are that God commands it or tradition imposes it.

Over the centuries, various rationalists have tried to come up with rationalizations, such as health (“pigs are dirty”) or not socializing (eating) with the pagans. But neither the Torah nor the Quran give reasons for these rules, other than increasing “holiness” through discipline.

One popular rationalization nowadays is that the dietary rules help to teach reverence for life. Eating meat involves slaughtering an animal to fulfill our biological need for food. Life is sacred to both religions, and thus there is a spiritual need to acknowledge the destruction of a life. In Islam, for example, this is expressed in a prayer before slaughter, acknowledging that the life of one of God’s creatures is being taken.

In both Islam and Judaism, blood is viewed as symbolic of life, and so eating or drinking the blood of an animal is forbidden. Christianity also views blood as symbolizing life, but takes a different route — the symbolic drinking of blood is a Christian remembrance of Christ’s sacrifice in order to win eternal life for his people.

With that as background, we now provide a point-by-point comparison. This list necessarily shows the most traditional approach. You can certainly find groups of Muslims and Jews who follow different traditions, especially in the details. I put Judaism first as the older of the two.

Basic rule

Judaism: Only foods (or categories of foods) that are explicitly permitted can be eaten. Such foods are called kosher; foods that are not kosher are called traif.

Islam: Any food that is not explicitly forbidden (haram) is permitted (halal).

Meat

J: Only cloven-hoofed animals that chew their cud can be eaten. Thus, cows, sheep, and goats are OK among domesticated animals, plus the deer family. Pigs (cloven hoofs but don’t chew their cud) are forbidden. By-products made from prohibited animals are also prohibited.

I: Only pigs are explicitly prohibited in the Quran, and related by-products (such as lard, gelatin, etc.). Animals with claws and fangs (predators and carrion eaters) are prohibited implicitly but not explicitly. Some foods are considered disgusting even though not expressly prohibited (makruh). This can vary by region for animals such as donkeys, pelicans, weasels, foxes, ravens, and crocodiles, for instance.

Slaughter

J: Animal must be slaughtered appropriately, which includes the throat being slit in a quick and merciful manner. Any other form of death renders the animal non-kosher. After slaughter, the carcass is examined for defects and disease, the presence of which makes the meat non-kosher. Drinking of blood is prohibited, and this means that all the blood must be drained from the body, and the meat washed and soaked in salt to remove the blood. Certain parts of the animal may not be eaten, including certain fats and the sciatic nerve, both of which are found in the hindquarters; consequently, many Jews do not eat the hindquarters. NOTE: Observant Jews living away from a kosher butcher have to import their meat. Meat slaughtered by a non-kosher butcher is never acceptable (except in cases of starvation or medical necessity).

I: The animal must be slaughtered appropriately, which includes the throat being slit in a quick and merciful manner. Drinking of blood is prohibited, and this means that all the blood must be drained from the body. Game animals are OK, but the meat of any animal killed by a blow, falling from a height, or gored with horns is prohibited. NOTE: Muslims living in an area that does not have an official Muslim slaughterer can eat kosher meat that has met the rules of Jewish slaughter. If there is no kosher meat available, Muslims may eat meat from Christian butchers, excluding pigs.

Birds

J: The rules are complex because the Torah lists specific prohibited species, and the rabbis draw conclusions about broader prohibited characteristics. Basically, the common domesticated birds are OK, such as chicken, turkeys, ducks, geese, and pigeons. Birds of prey are prohibited. Only eggs from kosher birds are permitted.

I: Although not specifically forbidden by the Quran, birds of prey and carrion-eaters are considered to be prohibited.

Fish and seafood

J: Fish must have scales and fins. For example, catfish (fins but no scales) are not permitted. Lobsters, crabs and shrimp are prohibited, having neither fins nor scales. There is no particular slaughter method necessary for fish.

I: All seafood is permitted, and there is no particular slaughter method required. Some Muslims, noting certain sayings of the Prophet that crawling sea creatures (shrimp, crabs, lobsters, etc.) are disgusting, refrain from eating these. Similarly, catfish, while not explicitly prohibited, is not preferred.

Rodents and reptiles

J: Prohibited, since they don’t have cloven hoofs or chew their cuds. Also prohibited as creatures that “creep” and “crawl.” Prohibited by implication, but not directly. Insects Generally prohibited as creatures that “creep and crawl.” A few species of locusts are permitted, but we can no longer identify them with certainty (the ancient Hebrew terms are no longer clear).

I: Prohibited (except for certain locusts).

Alcohol

J: No prohibition, although some authorities require certification of the alcohol to ensure that there was no contact with non-kosher elements.

I: Anything that interferes with the clear functioning of the mind is prohibited. This includes alcohol and intoxicating drugs. Alcohol is prohibited either as a beverage or in food preparation; thus pure vanilla and other extracts pose a problem, as do mouthwashes with alcohol.

Vegetables and fruits

J: There are no prohibitions; any fruit or vegetable is permitted. However, some authorities exclude certain vegetables — like broccoli — to prevent the possibility that small insects or insect parts might have lodged in the tiny crevices.

I: There are no prohibitions; any fruit or vegetable is permitted.

Other

J: Any food that has been consecrated to an idol is prohibited. Eating meat and dairy products in the same meal is not permitted. The rules here become very complex, including separate dishes and silverware to be used for “meat” meals and for “dairy” meals. Traditional Jews check the ingredients on foods (thanks to modern labeling!) to ensure there is no mixture of dairy and meat products. The rules on cheeses are very complex, since cheese is curdled in rennet (a meat by-product, but not itself a food).

I: Any food that has been consecrated to another deity is prohibited. (Kosher food is OK, since it is killed in the name of Allah’s earlier Revelation.) Islam has no rules on mixtures of types of foods.

In addition, both religions have holidays that involve special restrictions or special foods. For instance, both religions have certain fast days. The most sacred Islamic fast is the month-long Ramadan, when one does not eat (or engage in merrymaking) from sunrise to sunset. The most sacred Jewish fast is Yom Kippur, lasting 24 hours from sunset to sunset.

Jews have a special set of dietary rules for Passover, celebrating the Exodus from Egypt. These rules include eating unleavened bread, and refraining from eating anything with leavening. Muslims have a special meal on the Feast of Sacrifice, celebrating Abraham as the father of the religion.

Food (or its absence) is usually an important part of any celebration. Although Christianity does not have specific dietary prohibitions, the rite of communion involves bread and wine, and Catholics tend to refrain from eating meat during Lent. Traditions such as Christmas puddings or Easter eggs also tie foods into religious celebration. And families, in all religions, tend to have traditional meals on holidays.

A shared meal creates a sense of bonding and comradeship. By surrounding food with prohibitions and prayer, Islam and Judaism try to bring religious practitioners together for meals, creating a feeling of community. In that sense, religious dietary rules can be seen as a sociological way of bringing people closer and reinforcing the ties that bind people to each other.

SDStaff Dex, Straight Dope Science Advisory Board

Send questions to Cecil via cecil@straightdope.com.

STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL’S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU’D BETTER KEEP YOUR FINGERS CROSSED.