Sprinkling your own oil and vinegar on salad is the FODMAPS-friendly way to dress it, since most commercial salad dressings have one or more ingredients that are not allowed during the elimination phase of the diet. I am often asked which vinegars are OK to use? The answer is that any filtered vinegar will do, in a 1 tablespoon portion. Filtered vinegars include white vinegar, white or red wine vinegar, champagne vinegar, rice or rice wine vinegar, and most flavored vinegars.
Unfiltered cider vinegar does retain some sugar in it, and it has an excess of fructose, so it is probably not appropriate during the elimination phase unless it is a minuscule portion. You can recognize unfiltered cider vinegar because it is cloudy in appearance, not transparent, like filtered or distilled vinegars are.
Balsamic vinegar has a 2 grams of sugar in a 1 Tb. portion, but luckily for us balsamic lovers, there is more glucose than fructose in it, so it is allowed on the elimination phase. For more information about the role of the fructose to glucose ratio, click here.
Update on 1/20/2010: Remember, even if a person has a verified problem with FODMAPS, other kinds of adverse food reactions can occur. Please read my post entitled: One of My Problem Foods is Allowed on the Elimination Diet. Vinegar is complicated. A person could be sensitive to the food the vinegar was made from. Vinegars vary in their degree of acidity. Aged vinegars like balsamic may contain phenylethylamine. Flavored vinegars may have additives; for example some commercially seasoned sushi vinegars contain high fructose corn syrup. Some stray yeasts can be present in raw vinegars. Malt vinegar contains gluten. And so on. All of these factors might influence a body's experience with consuming vinegar.