In one of the worst examples of scientific speculations we have seen, researchers have proposed that seeds of a pesky weed called nutsedge helped prevent cavities in prehistoric man. How did they develop this theory? Well, they found seeds of the nutsedge in tombs containing skeletons with most of their teeth intact. Ergo: nutsedge seeds may have helped prehistoric humans fight cavities. Never mind that such a theory finds no support in the science. Seeds contain phytic acid which can block calcium assimilation and lead to cavities. We now know that the key vitamin for preventing tooth decay is vitamin K, which is mostly found in animal fats and organ meats, not in seeds. Vitamin K works with the support of vitamins A and D, and with calcium, phosphorus, magnesium and probably many other minerals and vitamins. It was nutrient-density, especially of the fat-soluble vitamins, that prevented cavities in prehistoric man, not the seeds of the nutsedge weed (Washington Post, July 17, 2014).