The debate surrounding the safety of aspartame swirls on, as do the rumblings about the dangers of food additives in general. One of the most dangerous classes of additives is something called "excitotoxins," which includes monosodium glutamate (MSG), hydrolyzed vegetable protein and "natural flavoring" as well as aspartame. What makes excitotoxins so dangerous? They overstimulate the nerve cells in our brain -- often stimulating them to death.

I spoke with Russell L. Blaylock, MD, a neurosurgeon and outspoken advocate of the theory that these everyday substances are far from benign. Dr. Blaylock confirmed that excitotoxins are "substances that are added to foods and beverages that can literally stimulate neurons to death, causing brain damage of varying degrees." Meanwhile, these products are prevalent in the foods we eat, much of it hidden under phrases like "natural flavor."

WHAT ARE EXCITOTOXINS?

According to Dr. Blaylock, the main excitotoxins are three amino acids called glutamate, aspartate and cysteine. All are found naturally in the body. Glutamate acts as a neurotransmitter -- it passes information and signals to the cells in the brain (neurons). "But the brain is a chemical factory that depends on careful quality control for its operation," Dr. Blaylock said. "The amounts of these chemicals -- like glutamate -- needed to transmit signals is infinitesimal. Even small fluctuations in these concentrations can result in dramatic disruptions of brain function, and even death of certain cells." It's Dr. Blaylock's contention that ingesting these substances in large amounts -- as many people do when they consume large quantities of diet soft drinks and other aspartame-sweetened products -- can upset the delicate "quality control" mechanisms in the brain, resulting in potential cell death that in turn leads to reduced central nervous system function.

The brain has a structure called the blood-brain barrier that does a great job of protecting this delicate organ from substances that don't belong there. Without this careful regulation, every time you eat a meal your brain would go beserk. But the barrier is not perfect. In fact, some areas of the brain don't have a concrete barrier system and selectively pass circulating substances in. According to Dr. Blaylock, certain neurological disorders including Alzheimer's disease, Huntington's disease, Lou Gehrig's disease, stroke and the biochemical challenges caused by consuming too many excitotoxins can cause the barrier to be broken down or temporarily malfunction. When this happens, normally benign substances such as glutamate can cause real damage.

Most of the disorders of the neurological system -- Alzheimer's, Lou Gehrig's and stroke -- all have been associated with excitotoxicity. It just may be that an accumulation of glutamate is part of the syndrome.

INCREASED SENSITIVITY

According to Dr. Blaylock, stroke, hypoglycemia and overexposure to fluoride, mercury and lead all can make the cells hypersensitive to the actions of glutamate and make the brain less able to "deactivate" it. This is where the problem with food additives containing large amounts of glutamate comes in. "For these people, MSG is a big problem," said Dr. Blaylock. He believes that far more people fall into the category of being sensitive to this phenomenon than previously believed. "Babies," he said, "are five times more sensitive than adults. And excitotoxicity can be triggered by flu, cold, the West Nile virus, even measles."

Of course, not everyone agrees with Dr. Blaylock's theory. Many athletes take the amino acid glutamine as a supplement in order to enhance performance (it is the most predominant amino acid in muscle... it is used up quickly during exercise... and it is believed to slow down the breakdown of muscle), and glutamine converts in the body to glutamate. Glutamate even has its own public relations organization (The Glutamate Association) whose stated mission includes dispensing "research and information on the safety and efficacy of MSG."

HIDDEN SOURCES OF EXCITOTOXINS

It's not just the obvious sources that add extra excitotoxins to our diet. Extra MSG may not be added to the food in your Chinese take-out, but it is always found in...

• Hydrolyzed vegetable protein -- generally soy.
• Textured protein -- generally this is soy used as a food additive.
• Caseinate in baby formulas, especially hypoallergenic formulas.
• Bouillon and "natural flavoring" listed on the package of many food items.
• Soy. This common protein source is high in glutamate as well as the metals manganese and aluminum and all of these can be problematic when consumed in excessive quantities.

"These substances are potentially very dangerous in small children and in the unborn. Pregnant women should never eat them," Dr. Blaylock told me. "And older people should be careful as well. Once you're past 40 -- and especially when you're 50 to 70 -- sensitivity to these substances rises a lot, and the blood-brain barrier is weakened. Exposure to lead, mercury, cadmium, fluoride and aluminum all exacerbate the problem."

STRENGTHENING YOUR BODY'S DEFENSE TO EXCITOTOXINS

Dr. Blaylock recommends avoiding processed food as much as possible. "If your diet is composed mostly of fruits and vegetables, organic meats and whole grains, you'll avoid most of these substances," he told me.

To help strengthen your brain's ability to protect itself, Dr. Blaylock recommends talking to your doctor about taking B vitamins, a substance called silymarin (in milk thistle) and resveratrol (found in red wine and grapes). In addition, white tea actually has the highest concentration of protective catechins.

Be well,

Carole Jackson
Bottom Line's Daily Health News

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