Excitotoxic free glutamate delivered to the immature brain of a human kills brain cells in the arcuate nucleus of the hypothalamus causing intractable obesity just as Olney found it caused intractable obesity in animals (Olney, 1969).
Excitotoxic free glutamate delivered to the immature brain of a human kills brain cells in the arcuate nucleus of the hypothalamus causing infertility just as Olney found it caused infertility in animals (Olney, 1969).
There are three conditions needed to produce glutamate-induced brain damage in the arcuate nucleus leading to gross obesity and infertility:
1. An immature brain such as that found in a newborn animal or human fetus,
2. free glutamate in sufficient quantity to be excitotoxic (brain damaging) – available since 1957 when the U.S. producer of free glutamate began mass producing free glutamate for use in flavor-enhancers, and
3. a way to deliver the required large quantity of free glutamate to the immature brain.
For delivery to animals, researchers administered glutamate via free feeding, injection and/or some form of force feeding such as gavage.
For delivery to humans, pregnant women who consume large quantities of free glutamate in processed and ultra-processed foods deliver it across the placenta via the umbilical cord to the arcuate nucleus of the fetal brain where it destroys brain cells that would have regulated appetite, satiety and reproductive function had they not been destroyed. (NOTE: The circumventricular organs among which the arcuate nucleus is found, lie outside of the blood-brain barrier and, therefore, are not protected by the blood-brain barrier.)
Reference
Olney, 1969. Olney JW. Brain lesions, obesity, and other disturbances in mice treated with monosodium glutamate. Science. 1969 May 9;164(3880):719-21. doi: 10.1126/science.164.3880.719. PMID: 5778021.