Food sensitivities can be the culprit in all kinds of health problems -- from headaches to chronic tummy problems -- and they're more common than you might think. Naturopath Sara Celik explains what causes food sensitivities and how you can figure out if you're affected.

Q: What are food sensitivities?

A: Food sensitivities are conditions that can cause the individual suffering from them to have an immune reaction in response to eating certain foods. Your body's immune system, which is meant to protect you from pathogens and other harmful elements, ends up being activated by the particular food that you have a sensitivity to.

If you experience a severe allergic reaction immediately after being exposed to an allergen (offending food), you have experienced a Type I hypersensitivity reaction (IgE). However, if you feel subtle, uncomfortable symptoms hours or days after exposure, this may be a delayed hypersensitivity reaction, a Type III reaction (IgG), also referred to as a food sensitivity.

Q: Are they common?

A: Food sensitivities, unfortunately, are quite common in North America and are directly related to the average North American diet and an over-consumption of processed foods (junk food, fast food), foods that create inflammation in the body (dairy), suppress the immune system (sugars, refined carbohydrates) and high-fat meats or other foods high in saturated fats.

Q: What kinds of problems/reactions can they cause?

A: Food sensitivities can cause symptoms that range from very mild (face flushing after eating certain foods, or bloating) to fairly severe. In my practice, I have successfully treated the following conditions by addressing food sensitivities: headaches, chronic yeast infections, digestive disturbances, fatigue and skin conditions (acne, psoriasis and eczema).

Q: How can you tell if you have a sensitivity to a certain type of food?

A: The problem with a person trying to determine food sensitivities on their own is that the symptoms that evidence a food sensitivity may be so mild that the person doesn't even consider them to be an indication of a problem. In addition, a symptom evidencing a food sensitivity may be removed in time from the ingestion of the offending food and the person may not remember how eating a certain food made them feel.

Two effective tools used by naturopathic doctors to determine food sensitivities are elimination diets, which restrict a person to very few foods and then gradually reintroduce certain foods to determine what foods cause what responses, and blood tests, which determine food sensitivities based on the presence of antibodies in a person's bloodstream in response to eating certain foods.

Q: If you do have a food sensitivity, do you have to steer clear of that food forever?

A: In some instances, depending upon the severity of the reaction, yes. In other cases, the individual will have to weigh the desirability of indulging in the particular food against the discomfort and duration of the symptoms. Most of my patients completely remove offending foods from their diet for a period of three months. After the three-month period, many of them find that they can reintroduce the foods in moderation with little or no reaction at all.