By Russell L. Blaylock, M.D.
The hypothalamus is a small area of the brain, no larger than the fingernail, that despite its small size, is responsible for controlling some of the most vital neural systems in the body. The wiring of the hypothalamus is some of the most complex in the nervous system, with connections not only to the pituitary, but also to the limbic system (emotional control system), hippocampus, striatum and brain stem. Through these connections it regulates emotions, autonomic control ( parasympathetic and sympathetic), hunger and satiety, immunity, memory input, and anger control. Disruptions in this vital piece of brain can result in anything from minor behavioral problems or endocrine malfunctions to major disruptions in sexual functions, obesity, immune suppression and endocrine gland failure.
Newer findings indicate that the hypothalamus is involved in several
endocrine syndromes, neurological diseases and even psychiatric disorders.
As early as 1976, it was shown that aspartame feeding in mice could produce
lesions in the hypothalamus of newborns. It should be realized that these
are lesions (injuries) that can be seen through an ordinary light
microscope. While the lesions produced by aspartame doses equiavlent to MSG
will produce smaller lesions, they are significant none the less. Defenders
of the safety of aspartame and MSG often report studies that have shown no
damage to the hypothalamus when seen under the light microscope. Several
studies have shown that the neurons can be injured without such visible
physical damage being present. The effects may be physiological and
biochemical without physical changes in the neuron.
Within the hypothalamus there are a number of collections of neurons called
nuclei. The arcuate nucleus is consistently the most sensitive of these
nuclei to MSG and aspartame toxicity. We know that this nucleus regulates
growth hormone secretion, by way of the pituitary. But, what is less well
appreciated is the fact that this nucleus has intimate connections to the
other nuclei, such as the supraoptic nucleus and paraventricular nucleus.
Indeed, when animals are given doses of MSG or aspartame, these nuclei are
injured as well. Several studies have shown shrinkage of the pituitary,
thyroid, adrenals and gonads in animals exposed to high concentrations of
these excitotoxins. In addition, a consistent finding is gross obesity in
animals exposed to these excitotoxins early in life. Some have raised the
question concerning the connection between a high intake of food borne
excitotoxins and the dramatic rise in childhood obesity over the past two
In animals made obese by damaging hypothalamic nuclei, one frequently sees
accompanying violent outburst. We also know that directly injecting
micromolar quantities of MSG into certain hypothalamic nuclei can
precipitate an explosion of violence in experimental animals. The
hypothalamus is one of the areas of the brain not protected by the blood-
brain barrier. This is of special concern during childhood, since exposure
to high intakes of excitotoxins, such as aspartame, can alter the
development of the hypothalamus, leading to sexual maldevelopment and
endocrine problems that will appear later in life. For example, we know that
infant animals exposed to excitotoxins will have fewer offspring and the
offspring will be smaller than normal.
When the hypothalamus is exposed to excitotoxins early in life, the neural
connections are often misdirected. Something I have called, mis-wiring of
the brain. What this means is that a mis-wired hypothalamus will not react
normally to the internal and external environmental cues that normally
control our endocrine system. This could lead to infertility,
hypothyroidism, adrenal hypoactivity, growth retardation and even emotional
or intellectual problems later in life. All of these have been reported in
studies using excitotoxin models.
Many other problems have been traced to excitotoxin damage to the
hypothalamus. For example, it is known that exposure of infants to high dose
excitotoxins can result in immune system impairment throughout life. This
would translate into more infections, cancer, and autoimmune diseases.
Recently, Trocho and co-workers discovered that the methanol in aspartame
appears to attach to the DNA of cells after it is metabolized to
formaldehyde, and is not only very difficult to remove, but results in
numerous DNA deletion injuries. This could increase cancer risk as well as
risk of other degenerative diseases, such as lupus, diabetes and Alzheimer’s
It is now known that glutamate ( and therefore aspartate) is the major
neurotransmitter in the hypothalamus and therefore excess concentrations may
affect all of the various nuclei in the hypothalamus. This means that
virtually every function of the hypothalamus is vulnerable to excitotoxin
damage, both subtle and acutely dramatic, depending on the dose. In normal
everyday life we are exposed to numerous excitotoxins added to foods and
drinks, in the form of MSG, cysteine and aspartame. Several studies have
shown that these toxic doses are synergistic, that is, they are more than
just the sum effect of each excitotoxin. Therefore, a meal of MSG laden
soup, a diet cola and foods with hydrolyzed vegetable protein and natural
flavoring, could easily damage the hypothalamus, as well as other portions
of the nervous system. During pregnancy, the deleterious effects could be
even more devastating, since it will affect the development of the brain
Another possibility, is the effect of excitotoxins on the sympathetic
nervous system-controlling centers in the hypothalamus. Over stimulation
could result in cardiac electrical abnormalities leading to sudden death.
This has been demonstrated by hypothalalamic stimulation experiments. There
have been clinical reports of cardiac related emergency room visits
following a meal high in excitotoxin additives. Sudden deaths following such
meals have also been reported. Since most hospitals rarely consider this in
their differential diagnosis, we have no accurate data as to the number of
ER visits and deaths related to this event. I suspect the numbers would be
In conclusion, there is compelling evidence to indicate that food additive
excitotoxins, such as aspartame, pose a serious danger to our well being,
especially so in the case of children and the elderly. It has been
demonstrated that excitotoxins in the diet can dramatically elevate free
radical generation for prolonged periods of time and that once induced, it
triggers a viscous cycle that ends in neuron death. Most authorities now
agree that elevated free radical generation is associated with virtually all
degenerative diseases as well as most injuries and toxins. It makes little
sense to expose the general public to a product that we know increases free
radical generation so dramatically and is associated with laboratory proven
injuries to the nervous system.
Russell L. Blaylock, M.D.
9 Lakeland Circle, Suite A
Jackson, Ms 39216