Recently we covered the first two segments of our series on MSG, or monosodium glutamate, and the related food additives that contain MSG.
Those segments covered MSG's impact on obesity and brain health.
Today we're looking at the effect these largely hidden additives have on the nation's two main killers -- heart disease and cancer.
Monosodium glutamate is adding flavor to your food, but many researchers believe it's also subtracting years from your life.
Jack Samuels wonders how he's dodged the MSG bullet for 35 years.
"I began to collapse toward the end of certain meals at restaurants," he said. "And frankly, I thought I was dying."
And frankly, he could have -- a physician diagnosed him with atrial fibrillation.
"That is, my heart becomes like Jell-O," said Samuels, "and just beats all over the place. It sometimes takes me five to six days to get over the attack."
But how could MSG be responsible? Dr. Russell Blaylock says it's because glutamate gets into the blood quickly and stays there. So a person eating MSG throughout the day can raise glutamate blood levels dangerously high.
He explained, "In other words, with each meal, it rises, it stays elevated -- you eat another meal, then it rises even further, -- and you eat another meal and it rises even further. It stays elevated through a good portion of the night."
Blaylock says even moderate blood levels of MSG can cause harm because specific organs have actual biological triggers called "glutamate receptors."
A group of them in the heart controls heart rhythm.
"You can induce a fatal arrhythmia," Blaylock warned. "That is, the heart beats abnormally and people could die from it. Well, arrhythmia is the number one cause of death with heart attack. It's been noted in the medical literature for decades that people who die of sudden cardiac death frequently do so after a meal."
And Samuels, a retired hospital administrator, says that ER doctors "immediately recognize that this may be an MSG reaction. Sadly that knowledge has not gone up beyond the first floor."
In other words, most cardiologists don't know about the connection to MSG.
This can even happen to teen football players. Blaylock says glutamate, especially combined with magnesium deficiency, can produce this sudden death. Magnesium deficiency is very common.
And 2006 animal research shows that MSG damages blood vessels with substances known as free radicals. That can lead to weak, clogged arteries and blood clots:
Blaylock said, "With humans consuming it every day -- not just a single injection -- but every day, they're constantly increasing the free radical generation inside the walls of their blood vessels."
That's how most heart attacks and strokes come about.
Research shows that MSG attacks over 40 percent of the population in some obvious way -- migraines, throat swelling, diarrhea, vomiting, or irregular heartbeats.
But what about the less obvious, even silent damage?
Glutamate receptors on the lungs could explain the rising affliction of juvenile asthma.
"This is one of the things everybody agrees on -- that it will produce worsening of asthma, even fatal asthma," Blaylock said.
And don't forget the nasty plague of diabetes affecting tens of millions of Americans. There are glutamate receptors on the pancreas that can lead to diabetes or loss of diabetic control, once the disease is present.
Blaylock has also studied cancer extensively and written a book for cancer patients, Natural Strategies for Cancer Patients."
In the last five years, researchers have found many cancers have -- glutamate receptors.
He said, "The total picture is -- if you're consuming a diet with glutamate in it, particularly high levels, you're making your cancer grow very rapidly. I refer to it as cancer fertilizer."
The cancers of this type include several brain cancers, colon cancer, breast cancer, and others as well.
With all these afflictions, Jack Samuels felt he had to get the word out -- with a Web site called TruthinLabeling.org responding to questions from around the world.
For Samuels and others who are concerned about avoiding MSG's impact on health, there is hope. And as hard as navigating the grocery store to avoid hidden MSG is -- safe shopping is doable.