Your grandson has a peanut allergy. Your daughter-in-law doesn’t eat gluten. Your husband has a dairy intolerance.

Preparing the holiday meal can be tricky enough, but it can be especially difficult for those with family members or guests who have food allergies.

Sarah Francis, an associate professor of food science and human nutrition at Iowa State University (ISU), knows first-hand how food allergies can impact an entire family.

Her 72-year-old mother developed a nut allergy about five years ago. “We as a family are navigating this issue now,” Francis said.

Food allergies aren’t just an inconvenience. They can be debilitating, and even fatal, for people diagnosed with one, Francis says.

“When you have an allergy, the body’s immune system responds to the proteins in that food, and it can cause a series of reactions that can involve many organs of the body,” she explains.

In severe cases, a food allergy can lead to anaphylaxes, a condition that causes a person’s throat to close up and the allergy sufferer to have trouble breathing. In the case of gluten allergies, people can develop intestinal symptoms like nausea and vomiting.

Traditional holiday meals can pose a hazard for family members with food allergies. So home cooks need to make some minor or major alterations to their holiday recipes, depending on the food allergy.

For nut allergies, make sure to avoid putting nuts in a recipe, and keep nuts away from the appetizer or snack table.

“It’s not good enough to say, ‘I made this salad and there’s nuts on it, but you can just take the nuts off.’ The nuts have touched the lettuce. That’s a contact,” Francis says.

The trickier food allergy to work around is a gluten allergy, where you can’t serve side dishes or desserts made from flour.

For many of us, our favorite Thanksgiving foods are made from flour and bread — the stuffing, the dinner rolls, the pies and even the gravy, if flour is used as a thickener.

Check the food labels at the store to see if an ingredient is gluten free or contains any allergens, Francis says. Many grocery stores today offer alternatives to flour in their gluten-free sections, and you can find scores of gluten-free recipes online. (Francis suggests searching for “gluten free” on the website.)

However, if you still want to make traditional holiday dishes, be sure to follow good food safety practices.

The goal is to avoid cross-contact, Francis says. So make sure that any plate, utensil or cooking surface that touched the allergen, such as flour, doesn’t come in contact with an allergen-free dish.

Always wash hands with soap before, during and after meal preparation. And wash cooking utensils with warm, soapy water before use, Francis says.

When serving meals, try to make an allergy “safe zone” on the table or mark all the unsafe foods. “For the holidays, you could use different colored plates, so the blue plate is the gluten-free item, and the red plate has gluten,” Francis says.

Just in case, make sure your guests have the medications they need in case they are exposed to an allergen, Francis adds.

And encourage guests with food allergies to bring their own holiday dish or, if they are traveling from a distance, to share a favorite allergy-free recipe that you can prepare for them.

“Ask the person with the allergy what are the products that are safe or what have you tried that is palatable. And view it as an opportunity to try new recipes,” Francis says. “Maybe you’ve always made bread stuffing, but you try one made with quinoa, and your family loves it. Then it’s a win-win.”