Vitamins on Shabbat

Sorry for the long break in posting. Things got hot for a while at my other blog.

Daf Yomi is now dealing with medical treatments on Shabbat. The Mishnah on 109b gives a general principle:

משנה. אין אוכלין איזביון בשבת, לפי שאינו מאכל בריאים. אבל אוכל הוא את יועזר, ושותה אבוברואה. כל האוכלין אוכל אדם לרפואה וכל המשקין שותה, חוץ ממי דקלים וכוס עיקרין, מפני שהן לירוקה. אבל שותה הוא מי דקלים לצמאו, וסך שמן עיקרין שלא לרפואה.

The relevant part in English:

One may eat any food for healing purposes, or drink any liquid, except for palm tree water and root drink, which are for jaundice. But one may drink palm tree water for thirst, or apply root oil for purposes other than healing.

In other words, foods that are normally eaten by healthy people are exempt from the rabbinic decree against medicine on Shabbat, even when they eat those foods specifically for medicinal benefits. Foods that are normally eaten only for medicinal benefit may also be eaten by healthy people, but only if they don't specifically want the medicinal benefit.

A practical case today would be vitamins, which healthy people eat, but only for the health benefits.

How does this law view vitamins? Are they medicine? If so, are they prohibited to healthy people?

Mistakes about science

Today's daf talks about spontaneously generated lice. There's a dispute among tannai'm whether you can kill a louse on Shabbat (Shabbat 12a, 107b). Rav Yosef explains that the disagreement only applies to insects that "do not reproduce," but killing all other insects is forbidden (107b). The rishonim then discuss which species of insect are generated from sweat, from rot, from dirt, etc., or from eggs. The halakhah concludes that killing lice is permitted.

There are much more dramatic Torah-versus-science issues out there than this one. If you're looking for explosive controversy, you want evolution. If you're looking for out-of-date science in the Talmud, this collection is just a start; Pesahim 94b is a big one in particular. If you're looking for a legal and moral mess, look into organ donation.

But, even if relatively undramatic, the issue of spontaneous generation is centrally important to science versus Halakhah. It's unique as a black-and-white case of a canonized halakhah based on rejected science.