Sourdough bread, one of the earliest forms of leavened bread, is made by fermenting lactic acid bacteria and yeast. Sourdough remains prevalent in many cultures worldwide for its slightly tangy flavor and potential health benefits.
You can find sourdough at most grocery stores or easily make the bread with three basic ingredients—flour, water, and salt. However, it's not the right choice for everyone, namely people with celiac disease.
1. Boosts Gut Health
Sourdough is made from the fermentation of flour and water. The fermented dough, known as sourdough starter, primarily contains lactic acid bacteria and yeasts with prebiotic and probiotic properties that can help improve gut health.
While these probiotics typically don’t survive the high heat of the baking process, sourdough bread retains prebiotics, which feed healthy gut bacteria and support digestion. The lactic acid bacteria in sourdough starters release prebiotics like beta-glucan, which improve probiotic activity in the digestive system.
2. Can Lead to Better Digestion
The lactic acid bacteria in sourdough break down non-digestible carbohydrates in flour.2 FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are short-chain carbohydrates that are poorly absorbed in the small intestine. Since FODMAPs are not easily digested, they may cause bloating, abdominal discomfort, and other digestive issues in people with non-celiac gluten sensitivity (NCGS) or irritable bowel syndrome (IBS).
During fermentation, proteolysis occurs, breaking down proteins in sourdough bread into bioactive peptides and amino acids that are easier to digest.
Limited evidence suggests that sourdough bread may help reduce digestive symptoms in people with IBS. Further research is needed to better understand the effects of sourdough on digestion.
3. Reduces Antinutrients
Antinutrients are plant compounds that can prevent the absorption and use of certain nutrients. Phytic acid, a common antinutrient found in grains, legumes, and nuts, binds to minerals like iron, zinc, and calcium, blocking their absorption.
The sourdough fermentation process breaks down phytic acid, helping the body absorb more nutrients from the bread.
4. Helps Manage and Lower Blood Sugar Levels
Sourdough bread has a lower glycemic index (GI) than other types of bread. The GI measures how quickly a food raises blood sugar levels on a scale of 0 to 100. Research suggests the lower GI in sourdough may be due to the organic acids (acetic and lactic) produced during fermentation.
Acetic acid can help slow gastric emptying, while lactic acid interacts with gluten to reduce the availability of starch, helping to prevent blood sugar spikes.
High-GI foods (those with a GI over 70) are absorbed quickly, causing a rapid spike in blood sugar, whereas low-GI foods (those with a GI under 55) are digested more slowly, resulting in a gradual rise in blood sugar.
Sourdough bread has a significantly lower GI than whole wheat and white bread. A 30 gram serving of whole wheat bread has a GI of 71, while the same amount of sourdough bread has a GI of 54.
Research has found that sourdough bread, especially when made with whole wheat flour, causes a smaller increase in blood sugar after eating than other types of bread. However, more evidence is needed to confirm these findings.
5. Prevents Serious Diseases
Whole wheat sourdough bread, a component of the Mediterranean diet, can be a healthy addition to a low-GI diet. Research shows that low-GI diets may help lower cholesterol levels and reduce the risk of heart disease. They can also lower the risk of developing type 2 diabetes and can support weight management.
6. Contains Less Gluten
Gluten, a protein found in wheat, rye, and barley, can cause digestive issues in people with gluten-related disorders like celiac disease, gluten sensitivity, and gluten intolerance.
Research shows that the fermentation process in sourdough breaks down some of the gluten in wheat, which may make it more tolerable for people with mild gluten sensitivities.
However, it shouldn't be consumed by those with celiac disease who need to avoid all gluten-containing foods.
Sourdough Bread Nutrition
The nutrition in sourdough bread can vary depending on the type of flour and other ingredients used and the preparation method. Sourdough bread made with wheat flour typically has more fiber and some vitamins and minerals than sourdough made with unenriched white flour.
On average, a medium-sized slice of toasted sourdough of about 59 grams (g) provides the following:
Calories: 188
Protein: 7.67 grams (g)
Fat: 1.26 g
Carbs: 36.5 g
Fiber: 1.8 g
Sodium: 425 milligrams (mg)
Thiamine (vitamin B1): 0.252 mg
Niacin (vitamin B3): 3.17 mg
Riboflavin (vitamin B2): 0.218 mg
Manganese: 0.33 mg
Iron: 2.28 mg
Selenium: 17.5 micrograms (mcg)
Folate (vitamin B9): 82.6 mcg
Sourdough bread made with enriched flour is high in several B vitamins, which are involved in red blood cell formation and energy production. It's also a rich source of manganese, a mineral needed for energy production and healthy bones, and selenium, a powerful antioxidant that protects the body from harmful molecules known as free radicals. Selenium is also needed for healthy reproduction, thyroid gland function, and DNA production.
Sourdough bread with enriched flour covers 13% of your daily iron needs. Iron is necessary for forming hemoglobin, the protein in red blood cells that transports oxygen from the lungs to the rest of the body.
A Word From Verywell
It's easy to incorporate sourdough into meals—top toasted sourdough with cottage cheese and tomato, mashed cannellini beans, or a runny egg. Cut the bread into chunks and toast them; add tomatoes and a zesty dressing of olive oil, red wine vinegar, and Italian seasoning for a panzanella salad.
Potential Risks and Downsides
Many store-bought varieties are high in sodium. People with high blood pressure (hypertension) or kidney disease who require a low-sodium diet should opt for alternatives.
While fermentation reduces the gluten content in sourdough bread, it's still not gluten-free. People with celiac disease or a wheat allergy should avoid it. If you require a gluten-free diet, consider gluten-free sourdough options made with flours like brown rice or buckwheat.
If you are taking monoamine oxidase inhibitors (MAOIs) for depression, know that sourdough bread can be high in tyramine. Consuming foods high in tyramine while taking MAOIs may lead to dangerously high blood pressure, headaches, and heart palpitations.
Should You Eat Sourdough Every Day?
Sourdough bread can be part of a balanced diet when eaten in moderation. It contains important vitamins and minerals, and choosing whole wheat sourdough adds more fiber, which supports healthy digestion.
However, watching portion sizes is important, especially if you need to limit carbs or are trying to lose weight. Pairing sourdough bread with healthy fats and lean protein can help stabilize blood sugar levels and keep you feeling full longer.
Summary
Sourdough is a healthy alternative to traditional bread, offering a unique and tangy flavor. The fermentation process increases prebiotic bacteria, which can improve digestion and support gut health. It also reduces the gluten content in wheat, making it potentially easier for people with mild gluten sensitivity to tolerate, though it's still not safe for those with celiac disease.
Fermentation increases nutrient availability, and the organic acids produced during this process may contribute to its low glycemic index, promoting better blood sugar control. Opt for sourdough made with whole wheat flour for additional fiber and health benefits.