By Lola O’Rourke RD, GIG Education Manager
Q. Should I have genetic testing for celiac disease?
A. Having the genes associated with celiac disease increases a person’s risk of developing the condition, but not everyone with the genes will develop celiac disease since environmental triggers also play a role. The genes are present in approximately 30% of the general population, while celiac disease affects only about 1%. So, a positive genetic test result does not mean you will develop celiac disease. A negative result is much more definitive, virtually ruling out existence or development of celiac disease.
Genetic testing can be useful for people who have not been tested for celiac disease but have already gone on a gluten-free diet and have experienced relief of symptoms. Standard celiac disease antibody testing would not be effective under these circumstances since gluten has already been removed from the diet. And, people who are feeling better without gluten are understandably reluctant to re-introduce gluten in order to undergo testing. In this scenario, genetic testing could provide useful information (and is not affected by diet): a negative result would virtually rule out the possibility of celiac disease being the cause of symptoms. Other potential causes of symptoms could then be considered, including non-celiac gluten sensitivity, which is not associated with celiac disease genes. A positive genetic test result, taken into account along with the fact that a gluten-free diet led to improvement in symptoms, would provide more information in support of the possible presence of celiac disease. Discuss your own situation with your personal healthcare provider.
Genetic testing can also be informative for families in which a parent has celiac disease. Knowing whether or not a child carries the genes can be beneficial: a positive result would indicate that a child should continue to be monitored for any signs of celiac disease. A negative result would virtually rule out the possibility of celiac disease developing in the future.
Q. Isn’t yeast gluten-free? What is brewer’s yeast and why is it listed as an ingredient to avoid?
A. There are three basic types of yeast used in foods and beverages: baker’s yeast, brewer’s yeast and nutritional yeast. The primary function of baker’s yeast is to create carbon dioxide in bread dough, which causes dough to rise and leads to a lighter, airier product. The yeast itself is not a flavoring agent. Brewer’s yeast ferments other ingredients in beer. The yeast converts sugars to alcohol, creates carbon dioxide and adds unique flavor. Brewer’s yeast is not only used to make beer, but is also often a by-product of beer. So, when it is a by-product of beer it is not gluten-free. Sometimes brewer’s yeast is grown on a gluten-free medium, in which case it would be gluten-free. Brewer’s yeast should be avoided unless it can be confirmed that the source of the yeast was gluten-free. Nutritional yeast is inactive yeast (meaning it will not create carbon dioxide or alcohol) which is consumed for its nutritional benefits and cheesy, nutty flavor. It is gluten-free.
Q. I’m seeing more and more gluten-free flour blends on the market these days. How do I know which is best to use? And when should I use a blend vs. single flour?
A. Flour blends generally yield much better results in baking than do single gluten-free flours. Gluten-free flour blends are usually designed to substitute for traditional wheat flour in most standard recipes. Some blends have an ingredient like xanthan or guar gum already included. When using a blend that does not, you’ll generally want to add some of your own.
Experiment with different gluten-free blends on the market to see which you like best and what yields the results you like in your recipes. Different blends yield differing textures, tastes and nutrition profiles as well, since some contain more whole grains than others.
Be aware that there are also “gluten-free baking mixes” on the market, which are not the same thing. These generally contain not only xanthan or guar gum, but usually other leaveners (e.g. baking powder) as well. These products are usually designed to work in a set group of items with recipes provided on package.
Mixing up your own gluten-free blend will generally be less costly than buying one ready-made, but the convenience of the pre-mixed versions is a draw.
Single gluten-free flours can still be of use when called for in specific recipes, and you may also want to keep at least white rice flour on hand for tasks like flouring baking pans and thickening gravies.