Date: 20 Aug 1994 07:43:34 -0700 From: taltar@vertigo.helix.net (Ted Altar) Subject: Vit K & Vegetarians Newsgroups: rec.food.veg Organization: Helix Internet Lines: 38 VITAMIN K AND VEGETARIANS Ted Altar Let us do forget it since the intestinal synthesized vitamin K is normally not at all that important or essential Vitamin K is provided primarily by plant foods (especially high are cruciferous and leafy vegetables). Therefore, most of the vitamin K ingested is the naturally occurring form, phylloquinone, which is absorbed from the small intestine. The menaquinones (the form of K we find in meat) are synthesized by either external or internal bacteria and absorbed by the distal ileum and colon. While it is believed some menaquinones synthesized by bacteria in the lower digestive tract can be absorbed to SOME extent by humans, this ability is also thought to be quite variable between people. (see J. W. Suttie, "Vitamin K" in Diplock et al. FAT SOLUBLE VITAMINS, 1985, P. 225-331.), Also, it was assumed that intestinal synthesis could vary from 0% to as much as 50% of one's daily requirement. But recent studies (see Suttie, 1985) in which subjects were made K deficient (via elimination of foods high in K) have shown that bacterial synthesis is simply inadequate to meet requirements even when exogenous intake was still 50 ug/day (a 79 kg adult male needs about ug/day and a 63 kg adult female needs 65 ug/day). In any case, a standard diet contains at least some 300 to 500 ug vitamin K per day, several fold the amount we actually need. [see R. Olsen, "Vitamin K" in M. Shils et al., MODERN NUTRITION IN HEALTH AND DISEASE, 1988, P. 328- 39. In certain situations, however, the intestinal production of menaquinones would probably be important, as for example in infants dependent on only milk (which has a low content of K) or in people with an intestinal bypass.