We have all sorts of animal studies trying to discover mechanisms of human physical and psychological function. Rat studies, dog studies. But...worm studies?
Researchers at the University of Oregon have discovered that woms perform a calculus based on their sensing of salt to determine whether to proceed straight ahead (high salt) or stop and consider other options. If this were the Calaveras County (CA) jumping frog race, we'd put our money on the high-salt roundworm.
Read about it in the July 3 edition of Nature as reported in advance by Physorg.com from which was gleaned this explanatory graphic. A spike in salt concentration in ASEL (left neuron) activates expression that leads a worm to proceed in a straight line. A dip in salt levels in ASER (right neuron) turns on a negative reaction that tells a worm to change to a turning movement to look around. Graphic courtesy of Shawn Lockery.
Using as examples the role of salt in combatting lymphatic filariasis and iodine deficiency, the cover story of the June issue of Geotimes devoted six pages to "Salt of the Earth: the pubilc health community employs a mineral to fight infectious disease ." Pointing out that its economy and ubiquity make salt the "ideal vehicle" to fortify with minerals or medications, author Cassandra Willyard concludes: "The saltshaker has become one of the most powerful weapons in the public health arsenal."
The article recounts the pioneering public health efforts to combat iodine deficiency by iodizing salt, quoting Venkatesh Mannar, executive director of the Ottawa-based Micronutrient Intitiative, explaining that salt is the "food that comes closest to being universally consumed." Salt is preferred because "the risk of overdose is minimal because everyone eats a predictable amount."
Building on the success of salt iodization, salt was fortified with other additives, first fluoride to prevent dental caries and then chloroquine to prevent malaria and most recently DEC (diethylcarbamazine) to combat lymphatic filariasis. Willyard featured the World Health Organization's ongoing work with DEC-fortified salt in Haiti and Guyana.
The article also broaches the question of the adequacy of iodine nutrition in the U.S. where substitution of processed foods using plain salt for home-cooked meals using iodized salt has led to a gradual decline in iodine intake levels. Willyard includes the Salt Institute's views, noting "officials may think about adding iodized salt to processed foods, Hanneman says. The important things, he adds, is to keep monitoring."
