Corn - or maize - originated in Central and South America and is thought to have grown wild in Mexico over 9000 years ago. It is still the staple food in these regions, and is often ingested 3 - 4 times a day. Therefore, a corn allergy should always be ruled out in patients of Spanish and Indian descent.

Although corn has notable quantities of the B-complex vitamins, the niacin in corn is largely in a "bound" form which makes it unavailable to the human body. Traditional native American cultures treat corn with alkaline substances such as lime and wood ashes (used in hominy), to aid in the digestion and assimilation of niacin.

Modern food processing, storage methods, and the loss of much traditional wisdom have resulted in many corn products today having little or no available niacin. For those people growing up in cultures where corn is the staple, there is an increased risk for them to develop clinical or sub clinical pellagra.

Pellegra, from the Italian roots "pell" meaning skin, and "agra" meaning "rough," is a nutritional deficiency syndrome resulting from either a deficient intake of niacin or the failure to convert tryptophan to niacin. Pellegra is characterized by the 4 "D's":

• Dermatitis (on areas of the body exposed to light or trauma)
• Diarrhea (and inflammation of the mucous membranes, especially glossitis)
• Depression (irritability, anxiety, confusion)
• Dementia (delusions, disorientation, hallucinations)

It is important to rule out a corn allergy, along with wheat and dairy for that matter in patients who chronically experience one or more of these 4 "D's". Corn is an abundant and inexpensive sweetener and filler in processed foods.Some examples are corn syrup, corn sweeteners, corn oil, corn starch. Patients from North America, Europe, and other "modern" cultures should also be checked for this allergy.