B-12 levels in soil highly variable. The table in Mozafar [1994, Table 3, p. 309] indicates that B-12 levels in soil can vary widely. Accordingly, it would be unwise to assume that a particular soil will supply levels of B-12 to plants that are adequate for human nutritional needs.

The table in Mozafar [1994, Table 3, indicates that B-12 levels in soil can vary widely. Accordingly, it would be unwise to assume that a particular soil will supply levels of B-12 to plants that are adequate for human nutritional needs. B-12 losses in shipping and processing? Mozafar analyzed the plant foods at the location where they were grown, just after harvest. Most consumers buy their foods from markets, and the food has been processed and shipped. This raises the question of whether, and how much, post- harvest processing and shipping can change the B-12 levels in foods. Similar questions apply to types of cooking and food processing. Legal risks from use of raw manure. The study used raw animal manure; owing to the liability risks (E. coli) of raw manure, the research should be repeated with composted manure. The use of raw, dry cow dung as a soil amendment is uncommon (nowadays) in farming as it can introduce weed seeds. The use of manure is not universal, even in organic gardening; it is not the case that "organic = manured" or even "organic = composted." Some organic farmers prefer to simply use heavy mulches, with no manure or compost. Some vegan purists reject the use of animal manure. The term used for such gardening is "veganic." Inasmuch as some vegans condemn the use of manure in farming, the information that the only possible "natural" way to get B-12 in the usual plant foods is via the use of manure-- an animal product-- as fertilizer provides yet another contradiction/ irony in veganism. Of course, some might reply that human manure can be used instead. Indeed it can, but if cow dung is abhorrent to vegan purists because it is an "animal product," then is human manure an "animal product" as well? What about human manure from meat- eaters? Per Mozafar, sewage sludge is very high in B-12, but organic food advocates oppose the use of sewage sludge because of possible heavy metal contamination. (The underlying point here is that sewage sludge might be used-- in very small quantities, as a compost additive-- to inoculate soils with B-12.) Raw human feces, aka "night soil," is high in B-12. However, its use in farming raises the risk of parasites, E. coli, and potential liability lawsuits aimed at farmers. It is not a feasible soil additive for farms, at present. The Mozafar [1994] paper is considered controversial by some veg*n nutritionists. For comments, see Craig [1997] as cited in Mozafar [1997], and Mozafar [1997] for reply. Possible exaggerations by raw/veg*n advocates. Given that Mozafar [1994] is only one (limited) study, that it did not test wild foods, fruits or nuts, roots or tubers, then to claim that it "proves" plant foods are adequate sources for B-12 would be an exaggeration. (Mozafar makes no such claims; the claim is occasionally made by raw vegan advocates).

Mozafar analyzed the plant foods at the location where they were grown, just after harvest. Most consumers buy their foods from markets, and the food has been processed and shipped. This raises the question of whether, and how much, post-

Chimps and other apes have been observed engaging in geophagy, i.e., eating dirt, though the predominant hypothesis is that chimp geophagy is done to ingest clay that absorbs excess plant tannins in the GI tract (and not as a B-12 source).

Mozafar [1994] reports 14 mcg B-12 per kg of soil. If we assume this is all true B-12 and no analogues (highly unlikely), it implies a daily intake of ~143 g (0.31 pounds) of soil daily to satisfy B-12 requirements. Such an intake is obviously not feasible. Note that Mozafar lists B-12 values for soil from other studies as well (Table 3, p. 309, Mozafar [1994]). However, many of the studies cited are old and thus the assay methods used should be checked. Mozafar reports that soil is one of the richest sources of B-12, but that there is no information available on the level of analogues vs. true B-12 in soil.



