Is your food making you sick? I met a lovely woman at a recent dinner party who said that foods she had been eating throughout her life were now making her sick. It started with a reaction to MSG, and she is now down to five foods she can eat confidently.

This tiny, aging woman told me another story about an acquaintance who became depressed, to the point of being suicidal, and found it was directly related to eating pineapple.

The conversation cascaded. Another story was told, about a fellow with celiac disease who could not eat anything containing gluten (wheat-based products). For him, doing so would be fatal. The stories exploded — everyone seemed to have one.

The discussion suggested there were a lot of food allergies out there. I did a little research after the evening ended and found only 1 percent of the adult population has an honest-to-goodness, clinically proven allergy. Still, that’s six to eight million people. I wanted to know more.

In adults, the most common foods producing allergic reactions are shellfish (shrimp, crayfish, crab), nuts (particularly peanuts and walnuts) and eggs. The reactions vary from cramping, diarrhea and vomiting to hives and sneezing. The first exposure may produce a relatively mild reaction, while subsequent exposures can be life-threatening.

The National Institutes of Health has an allergy and infectious disease component on its Web site: www.nih.gov.

You’ll find lots of information there, everything from cautions about exercise-induced food allergies to controversial treatments that involve holding a diluted solution of the food under your tongue, for half an hour, before consuming it. Really.

There is a difference between allergy and food intolerance, but the terms are often used interchangeably. Many of us have food intolerances. Lactase deficiency is the one we hear about the most, because it affects one in 10 people. Lactase is an enzyme in your gut, and when you don’t have enough of it, milk products don’t "sit well." It’s a fierce little problem, and it makes such unexpected appearances. Milk protein is in more things than you might think.

My husband claims food intolerance when it comes to broccoli. I suspect the experts would call that a food aversion.

This business about food and our reactions is many-sided. The fact is, lots of people have reactions to the food they eat. People sometimes get sick after eating without knowing why. Some people with allergies get very sick and some even die.

At this point, I am inclined to revert to reminders that unpleasant reactions to food may be other than food allergies; they may involve eating food that has been un-refrigerated too long or eating food without washing quite-dirty fingers. I am trying to resist making this a food-safety column. Food allergy is too serious for that.

I love seafood and walnuts (and even broccoli). But if I find my stomach or my respiratory system does not, I will seek medical expertise. The most sobering thing I learned about food allergies: Your first reaction is usually mild. The ones that follow are not.

Sharon Johnson is an assistant professor in family and community development at OSU Extension and a member of the Senior Advisory Council. Reach her at s.johnson@orst.edu.