I was about to buy An Orchard Invisible: A Natural History of Seeds when a quote-spewing review caught my eye:

"In the mid-1970s it was found that orthodox Hindus who had been quite healthy on a vegan diet in their native India began to suffer from a high incidence of megaloblastic anemia after living for some time in England consuming the same diet. The cause was traced to vitamin B-12 deficiency, which in India was prevented by insect contamination of grains."

Tell me more, Dr. Science! Alas, Megaloblastic anaemia in a vegetarian Hindu community from The Lancet is trapped behind a paywall and Googling "hindu anemia insects" greets me with the slightly-unreliable-sounding healingnaturallybybee.com and vegetarian-diet.info, so we're going to have to file this under apocryphal facts for cocktail parties.