MSG and our children's brains

Ashrei

Thu, Nov 26 2009, 9:26 pm

I read about this in a great book, "What's Going on in There" by Lise Eliot. I'm quoting and paraphrasing below. I thought it might be of general interest, since so many recipes call for soup mixes...

Monosodium Glutamate (MSG) and Aspartate (such as in NutraSweet, Equal, and other artificial sweeteners) in Infancy and Early Childhood

MSG is… composed of a common amino acid, glutamate, together with one molecule of sodium. Although we often hear about the health risks of high sodium intake, it’s the glutamate in MSG that is more worrisome with regard to brain development. Glutamate is a potent flavor enhancer commonly used in Asian cuisines, but it is also present in many prepared and convenience foods, especially [canned soups & soup mixes, salad dressings, sauces, marinades, deli meats, frozen meals, flavored chips and crackers, and flavored mixes for rice and pasta.]

[Other names for MSG: Hydrolyzed vegetable protein, HVP, flavoring, or even “natural flavoring.”*]

Concern about glutamate arises from the fact that high doses are known to kill brain cells, and younger animals [in laboratory studies] are especially susceptible to its toxic effects. …Neurons communicate across the synaptic gap using neurotransmitters; these chemical messengers come in two types- excitatory and inhibitory. Glutamate is the most prevalent excitatory neurotransmitter in the brain. When neurons are overexcited by glutamate, as happens, for example, in regions of the brain undergoing an epileptic seizure, they can be damaged or even killed, much as an electrical appliance can be damaged if too much current passes through it.

[During pregnancy, MSG is not a huge concern because it doesn’t cross the placenta very well.]

Unlike the situation in pregnancy, there is more serious basis for concern about glutamate and aspartate exposure after birth. Without the placenta both amino acids have readier access to babies’ brains, particularly to the hypothalamus, a major regulatory structure that lies largely outside the protective blood-brain barrier. When young rats or mice are fed large doses of glutamate, significant numbers of hypothalamic neurons die, and the rodents later show hormonal disturbances leading to problems like obesity, infertility, or delayed puberty. Aspartate has [a similar effect].

Although there is no clinical or epidemiological evidence to suggest that children’s brains are being damaged by excess glutamate and aspartate, the growing prevalence of these flavoring agents in all kinds of foods is considered by some researchers as potentially quite dangers. Infants and young children are particularly vulnerable because their neurons are known to be more sensitive than adults’ go glutamate, and because the same serving of any particular food, such as dehydrated noodle soup cup, will deliver a much greater dose of glutamate to say, a 30 pound toddler than to a 150 pound adult. Manufacturers voluntarily stopped adding MSG to baby food nearly thirty years ago, but thus far the Food and Drug Administration has decided tnot to regulate glutamate addition to processed food. While the amount of aspartate in sugar-free yogurt, chewing gum, or soda is rather small, it can add to the high levels of glutamate alreadyh present in many children’s diets, potentially threatening their neuronal health.