Fresh Garlic is a no-no in dogs (and I beleive cats and horses) See reference 1
Interestingly though, the problem with anemia and garlic seems to go away if AGED garlic is used.
I have never weighed a section of clove garlix.. but I think it wouldn't be too hard to ingest 5 grams.. I wonder if cooking it is the same as aging it??
Hmmmmmmmmm.. I don't eat it every day - or take the supplements, but I cook with it.
Here's an interesting article on garlic. reference 2