Julie O’Brien is used to getting phone calls from people about their … ahem, bathroom activities.

It’s par for the course for someone who helps people solve long-term gut issues.

“A woman called me up the other day and said ‘I have to tell you my bowel news,’” O’Brien said, laughing. “People call and they tell me about their good bowel movements. They’re so excited that they’re feeling better, eating healthier and the food is good.”

O’Brien isn’t a doctor, but rather owner, along with Richard Climenhage, of Seattle’s Firefly Kitchens, which specializes in making nutrient-dense, probiotic-rich fermented foods like sauerkraut and kimchi. The two recently released “Fresh &Fermented,” a cookbook based on recipes using products they’ve collected over the years.

“This is food from the old country,” said Climenhage, who, along with O’Brien, has been making fermented foods for more than 20 years.

Fermented foods is having a moment. Whether it’s kombucha or kimchi, fermented foods have become very popular on their own or as substitutes in dishes. Part of the reason is the backlash against heavily processed foods that don’t provide much nutrients and can actually be toxic. Another reason is that they aid people with gut or autoimmune issues. The traditional fermentation methods employed by Firefly Kitchens keep the nutrients in the food and actually help kick-start the digestive process.

“The whole goal is to keep your gut in balance,” Climenhage said. “You want to get nutrients out of those foods. Eating probiotics gives your gut good bacteria and helps build healthy flora in your gut.”

Which leads to the phone calls O’Brien receives.

There is a big difference between the products Firefly Kitchens produces and the stuff on the shelf at most stores. Firefly uses raw organic ingredients and a natural preserving process— instead of high-heat pasteurization or a bunch of chemicals— to ferment its food. Hence the reason you’ll find them in the refrigerated aisle.

“With can or jar sauerkraut it’s flash pasteurized, which kills all the good bacteria,” Climenhage said.

Some of the recipes in the cookbook may seem odd at first glance— sauerkraut in a smoothie?— but O’Brien and Climenhage said that they wanted people to think about the foods they make as more than just a condiment.

“We wanted to take these foods out of the box,” O’Brien said. “We want to inspire people to think differently about healthy food. We tell people to think about it like yogurt (another probiotic-rich food).”

Which leads to different phone calls.

“People start eating this food and they say ‘I’m starting to crave it,’ ” O’Brien said. “They see a real improvement after getting probiotic in the form of food; they can feel it. You can’t fake it with supplements.”

Here are three favorite recipes of O’Brien and Climenhage from “Fresh &Fermented.”

Classic kraut smoothie

1 medium banana

1 cup fresh or frozen blueberries or raspberries

1 apple, nectarine or pear, quartered and cored

1/4 cup classic Kraut

1 cup almond milk or milk of your choice

Put all the ingredients in a blender and whirl until smooth. Drink right away.

Note: The kraut adds a slightly tart zip that enlivens the flavors of the fruits. The almond milk provides protein and a nice creamy, nondairy base.

Makes 2 to 3 servings.

Firefly kimcheese

¾ cup Firefly Kimchi

8 ounces cream cheese

¼ cup goat cheese (1 ounce) (optional)

1 clove garlic, crushed

1 tablespoon chopped fresh parsley

1 teaspoon sriracha, or your favorite hot sauce

Brine or extra-virgin olive oil, for thinning

Salt and freshly ground black pepper

Take the kimchi out of the jar with a clean fork, letting any extra brine drain back into it. Whirl the kimchi in a food processor for 1 minute. Add the cream cheese, goat cheese, and garlic, and blend for another 30 seconds. Add the parsley and hot sauce, and pulse a few more times until the cheese is smooth. If it’s too thick for your liking, add a splash of brine or oil. Season to taste with salt and pepper. Serve chilled.

Note: Add a bit of extra kimchi brine to thin it and stir it into pasta, or add a bit more cheese to make a thicker spread for sandwiches or wraps. It’s also great slathered on any burger.

Makes about 2 cups.

Kimchi kick-start breakfast

4 tablespoons plus 2 teaspoons butter or coconut oil, divided

1 small yellow onion, sliced into thin half moons

¾ pound kale or Swiss chard

Salt and pepper 4 organic eggs

1 cup Firefly Kimchi

1 large avocado, halved, pitted, peeled, and cut into ¼-inch wedges

2 to 4 teaspoons brine (optional)

Melt 2 tablespoons of the butter in a large skillet over medium heat. Add the onions and sauté until they’re translucent, about 10 minutes.

While the onions cook, cut or tear the kale leaves from the thick stalks, discarding the stalks (if you’re using Swiss chard, you can save them for another use). Slice the kale leaves into ¼-inch strips (you should have about 4 cups). Add the kale to the skillet with the onions, and cook until it’s wilted and tender, an additional 6 to 8 minutes. Season the kale mixture to taste with salt and pepper, and divide it between two to four plates.

Fry the eggs in the remaining 2 teaspoons of butter for about 2 minutes, or until they’re done the way you like them.

To serve, place egg or eggs on top of each mound of kale and arrange the avocado slices right on top. Take the kimchi out of the jar with a clean fork, letting any extra brine drain back into it. Top each egg with ¼ cup kimchi. Drizzle 1 to 2 teaspoons of kimchi brine over the top of each dish to add a splash of flavor. Serve warm.

Note: Our secret to cooking over-easy eggs is to add a splash of water— or better yet, kimchi brine— to the pan. Cover the pan and cook the eggs for about two minutes, or until they’re done the way you like them.

Makes 2 to 4 servings.

Firefly Kitchens

Purchase Firefly Kitchens products, like Emerald City Kraut or Firefly Kimchi, at the Sno-Isle Coop in Everett (2804 Grand Ave, Everett). Find “Fresh &Fermented: 85 Delicious Ways to Make Fermented Carrots, Kraut and Kimchi Part of Every Meal” at the University Bookstore in Mill Creek (15311 Main St, Mill Creek) or at www.sasquatchbooks.com.

For more

Visit The Dish blog to learn to make your own sauerkrauben, which offers the best of sauerkraut and sauerruben, combining silky fermented cabbage with the crisp bite of turnip.