Salt craving is common among autistic kids. [Medical Hypotheses Dec 2011] Zinc deprived animals are salt cravers. [American Journal Physiology Sept 1981] The same is reported among humans. [Hemodialysis July 2016] Zinc deprived lab animals show some autistic signs. [Frontiers Behavioral Neuroscience March 2016] A shortage of zinc producing an imbalanced zinc/copper ratio is associated with autism. [Iranian Journal Child Neurology Fall 2015]
A shortage of zinc extends beyond autism in the spectrum of zinc-deficiency diseases.
Zinc controls an internal immune switch. Germ-fighting T-cells (white blood cells also called lymphocytes) are activated in the thymus gland by zinc and can produce what are called T-helper cells that produce interferon to control infections. However these T-helper (Th1) cells must be balanced by Th2 cells that normalize the inflammatory response. [Medical Hypotheses July 1997]
Zinc levels are notoriously inaccurate because zinc may be in adequate supply but bound to a storage molecule called metallothioneins. The production of nitric oxide releases zinc. There are various nutrients that activate nitric oxide (arginine, resveratrol, garlic). They may be critically important in liberating zinc for use by the immune system, particularly the thymus gland where T-cells are activated.
Zinc deficiency can result in an imbalance from the more efficient but inflammatory Th1-helper cells compared to the balancing Th2 T-cells that normalize the inflammatory response.
It is described this way: The modern Western diet, with its excess of refined products such as sugar, alcohol and fats, often contains, per calorie, a deficiency of essential nutrients such as zinc, which results in a T-helper cell/Th2 balance, spawns chronic (viral) infections, obesity, atherosclerosis, autoimmunity, allergies and cancer. [Medical Hypotheses July 1999]
Older adults commonly have low zinc intake and/or inadequate release of zinc. Food fortification with zinc was found to activate the thymus gland and increases immunity in 70% of elderly subjects. [Age June 2014] The combination of zinc + thymus hormone has been shown to improve the immune response following vaccination. [Vaccine Oct 1998]
Watch for salt craving, an overt sign of zinc deficiency or inability to release zinc.