Up to 40 percent of the population may be sensitive to monosodium glutamate (MSG), a flavor-enhancing additive, found in almost all processed foods. Consumption leads to headaches, flushing, sweating, numbness, tingling, burning, heart palpitations, chest pain, and shortness of breath, nausea or weakness.

MSG was developed in Japan in 1908 as a way to make processed foods taste and smell better and fresher. This man-made ingredient is approximately 78 percent free glutamic acid, 21 percent sodium and up to one percent contaminants.

The ingredient became widespread in the U.S. after World War II and has found its way into all kinds of processed food products, including canned soups, crackers, meats, salad dressing, frozen dinners and much more. It’s found in fast-food, restaurants, school cafeterias and even baby food.

The Food and Drug Administration (FDA) labeled MSG as “Generally Recognized as Safe” in 1959. Ten years later, a condition known as “Chinese Restaurant Syndrome” was identified where individuals dining on MSG-seasoned Chinese food, suffered numerous side effects, including numbness and heart palpitations.

Today, the syndrome is called “MSG Symptom Complex,” which the FDA describes as “short-term reactions,” including numbness, burning sensation, tingling, facial pressure or tightness, chest pain or difficulty breathing, headache, nausea, rapid heartbeat, drowsiness or weakness. In contract, there are documented long-term health problems, including brain lesions, obesity, type-II diabetes, eye damage, metabolic syndrome, brain damage, fatigue, depression and more.

What to look for on labels? It’s FDA required that food manufacturers list MSG on food labels. However, MSG can be listed under dozens of names on an ingredient list, including glutamic acid, glutamate, yeast extract, autolyzed yeast, hydrolyzed protein, sodium caseinate, caseinate, natural flavors, seasoning, spices, enzymes.

These ingredients often contain MSG or create MSG during processing: flavoring, natural chicken flavoring, stock, soy sauce, broth, carrageenan, corn starch, maltodextrin, citric acid, soy protein, pectin, powdered milk, bouillon, barley malt, anything protein fortified and more.

How do you keep MSG out of your diet? As a rule, you can assume that if it’s processed food, it contains MSG. Stick to a whole, fresh foods diet to avoid this additive.