Why I’m Baking with Sourdough and Protein – And Why You Should Too!

If you’ve followed my recipes, you’ve probably noticed a common thread: many combine sourdough with added protein. You might be wondering why I blend these two ingredients, especially when, as an acquaintance recently remarked, “Why reinvent recipes? The current ones taste just fine!”

But what if “just fine” could be even better – not just in taste, but for your health?

This isn’t about reinventing the wheel, but about unlocking surprising, enhanced benefits that come from combining them. You’re about to discover why this pairing is a game-changer for nutrient absorption, gut health, and even managing weight.

Still curious? Here’s the quick scoop on why this combination is so powerful:

The Key Benefits

• Enhanced Nutrient Absorption: Lactic acid bacteria (LAB) in sourdough break down phytic acid in grains, making minerals like iron, calcium, and zinc more bioavailable.
• Improved Protein Bioavailability: LAB also “pre-digest” proteins from both grains and added dairy, breaking them into smaller, more absorbable molecules.
• Better Lactose Digestion: These same helpful bacteria reduce lactose, making recipes easier to digest, even for those with mild lactose intolerance.
• Blood Sugar Regulation: Sourdough fermentation can slow starch digestion, leading to a more stable blood sugar response and longer-lasting fullness.

How Does This Combination Benefit You?

Benefits Of Sourdough On Its Own

Sourdough is simply flour and water, left to ferment and “fed” daily. This process creates a bubbly, active “starter” or “levain,” teeming with naturally occurring yeasts and, crucially, lactic acid bacteria (LAB).

This starter gives sourdough its characteristic tangy flavor and depth, but it also offers a range of well-established benefits for our bodies:

• Improved gluten digestion: The slow fermentation process breaks down gluten, making it easier to digest, particularly for those with mild sensitivities.
• Reduced FODMAPs: These fermentable carbohydrates are also broken down during the process.
• Gut health support: The lactic acid bacteria act as probiotics, contributing to a healthier gut microbiome.
• Blood sugar regulation – Sourdough fermentation may slow down starch digestion, leading to slower rise in blood sugars and with that longer lasting satiation, as there is no spike and sudden drop which would cause sudden hunger pangs shortly after eating. This is great news when you are trying to lose weight, as sourdough might keep you fuller for longer.
  And it might benefit those that are trying to manage diabetes. Though of course please consult your GP first in that case.

The Power of Enhanced Nutrient Bioavailability

And now we get to the really interesting benefits I want to focus on in this article:

Let’s start with better Mineral bioavailability

Because sourdough bacteria reduce phytic acid (an “anti-nutrient” that binds to minerals like iron, calcium, and zinc), our bodies can absorb these vital nutrients more easily. This is especially good news for women, who are disproportionately affected by iron deficiency.

How would you notice Iron deficiency?

Do you feel/have

• A lack of energy
• Shortness of breath
• fairly pale skin
• Unexplained general weakness
• Rapid heartbeat
• Headache when active
• Unexplained hair loss
• Brittle nails

If you suffer from any of the above or several, you might be iron deficient.

I know the struggle firsthand. For years, despite regular blood tests, my iron deficiency often went unnoticed because ferritin levels can fluctuate, and symptoms can appear long before the “official” deficiency threshold is met. While sourdough bread alone won’t solve severe deficiencies, it’s a valuable part of a balanced approach.

In my own journey, I found increasing iron through food challenging without impacting cholesterol, so I combine sourdough consumption with supplements.

How Sourdough Enhances Protein Absorption

While better mineral absorption is fascinating, let’s dive into another significant benefit:
The impact sourdough has on protein absorption.

You might have heard that sourdough bread boasts more protein than its yeasted counterparts. But have you ever wondered why? It’s a question that sent me down a fascinating rabbit hole of scientific studies. After all, sourdough is just flour and water – so how can it possibly contain more protein, or make existing protein more potent?

Similar to the improved mineral availability above, some magic happens when lactic acid bacteria munch on flour. The sourdough starter contains and produces a wide variety of enzymes, including proteases. These proteases are enzymes that break down protein molecules into smaller peptides and individual amino acids, which our bodies can more easily absorb than their bigger counterparts.

Are you still with me? Eyes not glazed over from too much scientific detail?

Great! Because I have one more pretty scientific paragraph before we get to the practical uses for this.

While extensively studied for its impact on gluten in flour (Gobbetti et al., 2014), this enzymatic action isn’t limited to cereal proteins. Research on fermented dairy products demonstrates that lactic acid bacteria can effectively hydrolyze both whey and casein proteins, potentially increasing their bioavailability and even releasing beneficial bioactive peptides (e.g., studies on dairy fermentation). In the context of sourdough bread, the addition of whey protein and cottage cheese means these dairy-derived proteins also undergo a degree of ‘pre-digestion’ during the fermentation, making them potentially more accessible to your body (Wiśniewska et al., 2014).

Why Protein Matters: The Current Science

I have written a separate post about how and why I add protein to many of my recipes, and you can read about my personal experience in that post.
But since we are talking about the combination of Protein and Sourdough specifically, let me cover quickly the benefits based on current science:

Is the Protein in Your Diet Enough?

• Most of us consume the basic amount of protein to avoid deficiency, but this bare minimum often isn’t enough to meet the higher demands of athletes, people building muscle, those aiming to lose weight without sacrificing muscle, or older adults.
• Many women don’t get enough protein in their diet, as we tend to eat less meat than men
• On top of that women, more so than men, often restrict their food intake to lose weight, risking a loss of muscle mass when not consuming enough protein during that phase.
• Older adults often don’t get enough protein to prevent the loss of muscle mass, as appetite often declines with age.
• The loss of muscle mass and functionality called Sarcopenia is one of the main reasons for fractures in older adults, leading to them being bedridden. Improving nutrition, especially protein intake is, besides physical activity the main method of prevention and treatment of it.

What Benefits does Increased Protein Intake have?

On top of the above mentioned benefit supporting the building and retaining of muscle mass, protein has multiple other benefits:

• Reduces hunger – Connected to the points above, this one is particularly interesting for those of us who either want or need to lose weight for health reasons. Protein was found to decrease ghrelin, which is a hormone responsible for feeling hungry.
• Improves bone density – Despite some of the myths floating around the internet that protein (mostly animal protein is targeted in those cases) harms your bones, studies found the opposite to be true, with protein improving the mineral bone density. This is good news, as it allows us to actively prevent osteoporosis and sarcopenia through our diet. Probably the easiest way to stay healthy.
• Body repair – This may be especially important while aging, but also for those trying to build more muscle, as muscle repair is what helps it grow. And that means the bodies healing powers are required for it and protein supports this process. And if you, like me, suffer from an autoimmune disease, your ability to heal might be impacted by it. This results in even small wounds taking longer than they should to close. Increasing your protein intake can improve the situation.
• May boost metabolic rate – In a 2018 study by Mathijs Drummen et al evidence was found that a high protein diet can help you maintain high energy levels even during a period of weight loss, which in turns helps you burn more calories. And of course together with building muscle using exercise, you burn even more due to muscles using energy to function.
  

How Much Protein Do We Need?

To quote the official recommendation here:
“For healthy adults of both sexes, AR for protein set at 0.66 g per kg body weight per day, while the PRI is set at 0.83g per kg body weight per day.”
This is very similar both in the EU and the US guidelines.

But that’s only half of the picture, as it only states the absolute minimum you need, to not be deficient/malnourished. It does not consider any of the factors stated above. On the same site it is stated that double of the recommended intake is safe. And that people on an exercise regimen or with higher needs due to age, health or other factors should likely eat more of it.

Here is a calculator for your baseline Protein intake if you’d like to calculate it yourself.

What Does That Mean For Practical Applications?

Slow fermentation of sourdough makes protein from both grains and dairy easier available to the body.
This means including more types of protein in bread and other sourdough recipes will allow you to better utilize all of the included protein.

Fabulous, isn’t it?

But I’m Lactose Intolerant!

Ahh, but I have more good news for you!

If you read the explanation above, you might have stumbled over the mention of “Lactic acid bacteria” which are the main type of bacteria inhabiting sourdough.
They are, believe it or not, the same type found in fermented milk products like yoghurt and cheese. And other products you might have heard are great for your gut like Sauerkraut, Kimchi and Kombucha. Yup, same bacteria.

And as helpful bacteria go, those are among the best, because they break down lactose, making it easier to digest. They also produce lactase, the enzyme that helps your body to digest said lactose. So it’s double-beneficial for you.

This means, if you add for example cottage cheese (which is already slightly fermented) and even whey protein powder or casein protein powder to sourdough and slow ferment it, your body can digest all its components more easily and make them work harder for you.

That also goes for the calcium in, say cottage cheese, which helps our bones, especially as we age. And of course above mentioned iron and protein.

But Sonja, I Heard Our Bodies Can Only Absorb About 30g Protein Per Meal!

So why include potentially more?

I know, and I thought the same!

For a long time, common wisdom held that your body could only effectively utilize 20-30g of protein per meal, with anything more being wasteful or even potentially harmful. However, it’s important to note that the ‘harmful’ effects were observed in studies of individuals with pre-existing kidney diseases and do not apply to healthy individuals. (As always, for personalized advice, please consult your GP.) A randomized study by Antonio et al. found no negative effects of a high-protein diet over a one-year period.

While earlier studies, such as one by Witard et al., observed diminishing returns on body protein synthesis over a 4-hour period when exceeding certain doses, resulting in the 20-30g per meal recommendation, recent research offers a more nuanced perspective.

A groundbreaking 2023 study by Jorn Trommelen and colleagues challenged this long-held belief. By examining the body over a 12-hour period instead of just 4, they found no such diminishing returns. Their findings suggest that muscle protein synthesis can be significantly increased by consuming higher amounts of protein, which in turn supports the body’s natural ability to repair and heal.

In short: More is indeed better, in case of protein.

Phew. That was a long explanation, wasn’t it?

So If I Buy Sourdough Bread In The Supermarket, I Eat Really Healthy Bread, Right?

I wish that was true!

But unless you buy from an artisan baker who does use slow fermentation or make your own, you might just get the flavor and none of the benefits!

Unfortunately scarcely any bread you can buy in the supermarket, even those containing sourdough, is slow fermented. Most have a certain percentage of dried, inactive sourdough starter in them to give them the characteristic flavor, but none of the benefits of the fermentation. Unfortunately the name “Sourdough Bread” isn’t defined the same worldwide.

Europe has slightly better standards, but unfortunately even there, mass produced breads are taking over.

There are 3 different standards for “Sourdough”, all having wildly different outcomes in terms of benefits. You can read more about this on Wikipedia, but let me give you the gist of it:

Type 1 – The “classic” sourdough

Used as sole leavening agent in breads, has a PH range from 3.8-5, is fermented within a certain temperature range (20 to 30 °C /68 to 86 °F). Which usually is a wide variety of room temperatures and contains mainly Fructilactobacillus sanfranciscensis, independently from where you are in the world. That’s the type of lactic acid bacteria leading to the PH range and fermentation responsible for most of benefits you read above. Home and artisanal bakers keep it alive and active by feeding daily and fermenting at said comfortable temperature range.

You can slow down growth in the fridge, so daily feeding is not always necessary.

Type 2 – This is the type usually used by Commercial bakeries

The PH is less than 3.5. The sourdough is fermented between 30 to 50 °C /86 to 122 °F, without feeding for days, resulting in the bacteria growth being stopped or slowed by the high temperatures. Because of that, these doughs can be stored chilled, after fermentation, for up to a week. Making them great for shops and bakeries to prepare in bulk and bake on demand.

Unfortunately, due to the much faster fermentation in the higher heat you don’t get the full range of benefits.

Type 3 – Just flavor

These are essentially type 2 in dried form, just added to the dough to provide the classic flavor, but without any of the benefits. The rise in those cases is not a product of fermentation, but rather an artificial mix known as “bread improver” which bakers add to the flour mix.

And currently, unless you make your bread at home, it is really hard to know which type of bread you are getting. Even in Germany, where sourdough is traditionally used in most breads, the sourdough is mixed with yeast to speed up the leavening process, resulting in reduced benefits.

Shop Bought Sourdough Products Don’t Usually Have Added Protein

Apart from the issues with the definition of sourdough above, I have yet to find any sourdough products in shops that have added protein. Maybe that will change one day. But apparently the wisdom from the above cited sources has not yet made it into mainstream.

Coming back to the question from above mentioned acquaintance on why we should improve and change recipes: To make them work better for us. Both in flavor and in nutritional value.

Sourdough Protein Recipes On this Blog

With all these benefits in mind, this is exactly where my homemade sourdough protein recipes come in handy. You control the fermentation time and temperature, allowing you to harness the full range of benefits through slow fermentation.

Since I started this blog, I have created many recipes that have both sourdough and protein. Resulting in a nice range of choices for your daily dose of them.

It starts with pancakes or waffles in different versions for breakfast:

Over a soft sourdough protein sandwich bread:

All the way to desserts like donuts and the firm reader favorite of sourdough protein brownies.

The whole wheat flour I use in many of them gives you even more protein per bite plus a healthy amount of fibre, making them an all round nutritionally fabulous and really flavorful option.

Take a peek into this roundup of 10 sourdough protein recipes, to discover even more.

What’s next?

I’m currently working on a very simple and basic recipe for a sourdough protein bread, which you can then vary to your hearts content and take into a million different directions. The featured image on top of this post and the one right below this paragraph are sneak peeks of this bread, something exciting to look forward to!

And while I’m at it, I’m trying it with 3 different types of protein powder, to be able to give you options and advise on what works and what doesn’t.

Stay tuned for the next recipe. 😊

Now I’d love to hear from you in the comments!

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