Dietitians Say Which Is Healthier

When you’re at the grocery store, it can be tempting to bypass the bread aisle altogether and go straight to the specialty breads under the assumption that they are the healthiest options. But if it’s sourdough vs. gluten-free bread, for instance, two picks that are typically found outside of the bread aisle, is one better for you than the other?

Meet the experts: Amna Haq, M.S., R.D., L.D.N., a registered dietitian and owner of the Inclusive Dietitian in Chicago; Stephanie Crabtree, M.S., R.D., a registered dietitian based in Sarasota, FL.

Here, dietitians explain what you should know about sourdough and gluten-free bread, including the possible perks and downsides, who can benefit from eating each, and whether they deserve a place in your healthy diet.

How do these two types of bread compare from a nutritional standpoint? Since gluten-free bread typically comes in a traditional sliced loaf and sourdough is found in a larger, more artisanal-style loaf, we’re comparing one large slice of sourdough to two standard slices of gluten-free bread.

Sourdough nutrition

According to the U.S. Department of Agriculture (USDA), one medium slice (which is around 59 grams) of sourdough bread contains:

• 188 calories
• 7.67 g of protein
• 1.26 g of fat
• 36.5 g of carbohydrates
• 1.83 g of fiber

Gluten-free bread nutrition

Per the USDA, two slices (about 56 g total) of gluten-free white sandwich bread contain:

• 167 calories
• 3.02 g of protein
• 4.5 g of fat
• 28.6 g of carbohydrates
• 3.08 g of fiber

“Sourdough bread is made through a fermentation process using yeast and lactic acid bacteria, and that fermentation may provide several nutritional benefits,” says Amna Haq, M.S., R.D., L.D.N., a registered dietitian and owner of the Inclusive Dietitian in Chicago. “One benefit is that fermentation partially breaks down fructans (a type of FODMAP or fermentable fiber) as well as some other compounds in the bread, making it easier to digest for some people with sensitive digestion, such as those with IBS.” The fermentation process also breaks down some of the gluten and other starches in the bread, Haq adds, resulting in a gentler blood sugar response. Research in Critical Reviews in Food Science and Nutrition found that sourdough bread created a smaller spike in blood glucose levels than non-fermented bread at both one and two hours post-consumption.

“Fermentation also reduces compounds called phytates, which can improve the bioavailability of minerals like iron, zinc, and magnesium,” notes Stephanie Crabtree, M.S., R.D., a registered dietitian based in Sarasota, FL.

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In short, not all sourdough is created equal. “Many grocery store loaves labeled ‘sourdough’ are made with commercial yeast and sour flavoring rather than a traditional sourdough starter and long fermentation,” Crabtree explains. “Without that extended fermentation, you may not get the same digestive or metabolic benefits associated with authentic sourdough.” What’s more, while the gluten in sourdough is easier to digest than that in regular bread, it’s still there, which means sourdough isn’t safe to eat for people with celiac disease or gluten sensitivity.

“Even though sourdough may have a slightly lower glycemic impact than some breads, portion size can still be important,” Haq adds. “Pairing bread with protein, healthy fats, and fiber can help further support blood sugar management.”

For people with celiac disease or gluten sensitivity, gluten-free bread is essential. Per the Mayo Clinic, celiac disease is an autoimmune condition in which gluten triggers an immune response that can damage the small intestine, plus cause serious GI discomfort.

But what about people who don’t have trouble digesting gluten? “Unless you have celiac disease or gluten sensitivity, there’s no proven health advantage to eating gluten-free bread,” says Crabtree. “Gluten-free doesn’t automatically mean a product is more nutritious.” As is the case with gluten-containing bread, gluten-free breads made with whole grains that are naturally gluten-free deliver significantly more health benefits than breads made with refined grains. “Some gluten-free breads are made with nutritious whole grains like sorghum, millet, buckwheat, or quinoa, which can provide fiber and important vitamins and minerals,” says Haq. “However, the nutritional quality varies widely by brand.”

“Unless you need to avoid gluten, switching to gluten-free bread may actually mean sacrificing fiber and protein,” says Crabtree. “Many gluten-free breads also contain added gums and stabilizers to mimic the texture that gluten naturally provides.” Gluten-free breads typically have longer ingredient lists than gluten-containing breads, especially whole-grain options, which means there’s a higher likelihood you’re eating refined grains and starches. “Some also contain more added sugar, sodium, or fat to improve texture and taste. And they’re often more expensive,” Haq adds.

For people who don’t have a medical reason to eat gluten-free bread, a true fermented sourdough—or better yet, whole-grain sourdough—is the healthiest option, Haq and Crabtree agree. “Whole-grain sourdough combines the benefits of whole grains (including fiber, B vitamins, and minerals) with the potential advantages of fermentation, such as improved digestibility and a more moderate blood sugar response,” says Haq.

Still, if you’re choosing a whole-grain bread that happens to be gluten-free, it can also be a nutritious option. “The ‘healthiest’ bread is the one that fits your individual needs and is made with high-quality ingredients,” says Crabtree. “Whether you’re buying sourdough or gluten-free bread, don’t stop at the front of the package. Flip it over and look for simple ingredients, whole-food flours, and a good source of fiber.” And make sure you’re building a balanced meal around the bread—what you eat with it is often more important than the bread itself.