According to the FDA, 1 in 100 people are sensitive to sulfites, which were banned in 1986 for use on supermarket produce and in restaurant salad bars. But these sulfur-based compounds are still used to inhibit bacteria growth and preserve flavor in wine, grape juice, soup mixes, dried fruit, and canned vegetables. Symptoms of sensitivity — such as skin redness, tingling in extremities, and airway constriction — usually present within minutes of consuming sulfites. Asthmatics are five times more likely to suffer an adverse reaction.

How to avoid them: Manufacturers must indicate on labels if a product contains at least 10 parts per million sulfites. Avoid dried fruits that look especially colorful, a sign of preservatives. Also, choose USDA certified organic wine, which cannot contain added sulfites.

Monosodium glutamate (MSG)

A flavor enhancer found in Asian food, canned vegetables, soups, and processed meats, MSG stimulates taste buds and adds a salty flavor. But it can also exacerbate true allergies, as well as cause headaches, upper-body tingling, numbness, and burning sensations.

How to avoid it: Ask for MSG-free meals at Asian restaurants. Foods labeled “No MSG” might still contain glutamate derivatives like hydrolyzed plant protein, yeast extract, and autolyzed yeast, so read ingredients lists carefully.

Toxins in your home: