Diet & Nutrition

Focus on Prebiotics: Get Nutty With Walnuts!

Focus on Prebiotics: Get Nutty With Walnuts!

They take banana bread from good to great, can make or break a trail mix, and are the secret to a pie crust you'll never forget––and they're even good for your health. What are we talking about? The humble walnut, of course!

Chock full of omega-3 fatty acids, alpha-linoleic acid, and phenols, this superstar nut also has one of the highest concentrations of antioxidants per serving. You'd have to eat three times the amount of blackberries as walnuts to get the same amount of antioxidants, and well over 10 times the amount of spinach or kiwifruit!1

They're also a great source of magnesium and phosphorous (which support bone and muscle health), and they help mitigate the effects of temporary inflammation throughout the body, are high in protein, and may even be able to help reverse the unwanted cognitive changes that sometimes come with age.

What's more, research has shed light on yet another health benefit connected with eating walnuts: they're good for your gut microbiome.

How Walnuts Affect Your Gut

A recent study found that rats who ate a diet that included walnuts had much healthier gut microbiomes, particularly in their descending colons.2 They not only had higher levels of beneficial bacteria and lower levels of unwanted bacteria; they also had a lot more species of bacteria in their gut. (Remember, the more diverse your gut microbiome is, the healthier it tends to be.)

Interestingly, the study also showed that you couldn't substitute similar components and get the same results: rats who ate a control diet containing fat, fiber, and protein in amounts mimicking those found in walnuts didn't experience the same benefits as the rats who actually ate the walnuts.

So why are walnuts so good for your gut bacteria? The main reason appears to be the type of fiber they contain—researchers think that it acts as a prebiotic that nourishes beneficial bacteria. And the best part? The scientists running the study were able to see those positive changes in the gut by feeding the rats the equivalent of just half a cup of walnuts a day in human-sized servings.

Why Are Prebiotics So Important?

Probiotics are having a moment both in the research world and in popular consciousness, which we couldn't be happier about; after all, they are the foundation of good health! But it's also important to understand how to give your beneficial bacteria the support they need so they can give your body the support it needs to stay healthy.

That's where prebiotics come in. Prebiotics are like fertilizer for probiotics; without a specific variety of prebiotic fibers to eat, probiotics simply can't grow and thrive the way they need to if they're going to support your optimal health.3

The problem is, most of us don't get nearly enough prebiotic fiber in our daily diets. Health authorities currently encourage people to consume about 20 grams of fiber every day; most people actually only eat about 10 grams. And when you consider that our ancestors consumed an incredible 100-150 grams of various types of fiber a day, you can see how your microbial friends might be struggling.4

Diet vs Fiber Supplements

While you can help your microscopic good guys out by adding more prebiotic foods to your diet––green bananas, garlic, onions, Jerusalem artichokes, and of course, walnuts are all great options––it's really hard to eat enough of them every day to get the level of prebiotics your gut bacteria need. That's why many people prefer to take prebiotic supplements (like our organic prebiotic powder) in addition to eating more high-fiber foods to make sure they’re getting all of the fiber their microbes need.

Not just any fiber supplement will do, however. The best prebiotic supplement powders are made with a mix of food-based fibers that bacteria naturally gravitate towards, rather than fibers made from artificial sources, or supplements that contain only one type of fiber.5 Think about it this way: while you could theoretically live on a diet of, say, oatmeal (at least for a little while, until your vitamin and mineral levels got too low), it’s not what your body needs to thrive. Similarly, your bacteria need a mix of the foods they’re meant to consume. And, different types of bacteria require certain types of prebiotic fiber, which is what makes a prebiotic powder supplement a great way to cover your bases and support your microbiome!

Of course, ideally, you would both add prebiotic foods to your diet and take a supplement to make sure you’re getting all the nutrients your beneficial bacteria need...which brings us back to walnuts. Since they’re so beneficial for your health all around and an excellent source of prebiotic fiber, why not incorporate them in your diet a little more?

3 Unexpected Ways to Use Walnuts

You've probably already thought about putting walnuts in porridge or on top of salads. And let's be honest, who can turn down a scrumptious chocolate chip-walnut cookie? The good news is that you can incorporate walnuts in all kinds of other ways, too, including:

1. As a secret ingredient for extra-smooth smoothies.

Nuts in a smoothie? It might sound a little weird, but walnuts actually work really well when you blend them together with other ingredients. Their mild flavor gives the barest hint of nuttiness to your smoothie, while their high content of good fat lends a rich texture. So try adding a couple of tablespoons of chopped walnuts to your next salted caramel or cinnamon berry smoothie—they could become your new favorite ingredient. (And don’t forget, you can really double up on the prebiotic goodness by adding both walnuts and a scoop of prebiotic powder to all your smoothies!) If you prefer a little crunch in your smoothie, try a yummy smoothie bowl topped with walnuts and fresh fruit.

2. As a substitute for other nuts––especially in pesto.

Toasted walnuts make great additions to salad and pasta dishes, but did you know you can also use them in lieu of other types of nuts in many recipes? One really interesting twist on a classic is using toasted walnuts instead of pine nuts in pesto. They take on a darker, more complex flavor when you toast them that can really add some depth to your pesto’s flavor profile.

3. As a base for a prebiotic-rich spread.

Love hummus but trying to stay away from beans? You can use walnuts to make an alternative dip. While walnuts and olive oil blended together in your food processor make for a super basic spread, you could also experiment and try some muhammara, a classic Syrian dip made with walnuts, red peppers, and garlic (which are also both good sources of prebiotic fiber and antioxidants). Or if you’re in the mood for something sweeter, why not try a honey walnut spread made with walnuts, honey (another delicious prebiotic), pears, and herbs?

With so many options, it's easy to make this prebiotic powerhouse a staple in your diet. So give walnuts a try, and enjoy knowing that you're giving your good guys the nutrition they need to really go nuts supporting your health!


1. Halvorsen, B.L., Carlsen, M.H., Phillips, K.M., Bøhn, S.K. . . . Blomhoff, R. (2006). Content of Redox-Active Compounds (ie, Antioxidants) in Foods Consumed in the United States. The American Journal of Clinical Nutrition, 84(1).

2.Byerleya, L.O., Samuelson, D., Blanchard, E. . . . Taylor, C.M. (2017). Changes in the Gut Microbial Communities Following Addition of Walnuts to the Diet. The Journal of Nutritional Biochemistry, 48. doi:10.1016/j.jnutbio.2017.07.001

3. Brownawell, A.M., Caers, W., Gibson, G.R., Kendall, C.W.C. . . . Slavin, J.L. (2012). Prebiotics and the Health Benefits of Fiber: Current Regulatory Status, Future Research, and Goals. The Journal of Nutrition, 142(5).

4. Leach, J.D., Sobolik, K.D. (2010). High Dietary Intake of Prebiotic Inulin-Type Fructans in the Prehistoric Chihuahuan Desert. British Journal of Nutrition, 103(11). doi: 10.1017/S0007114510000966

5. Hoffen, E. V., Ruiter, B., Faber, J., M'rabet, L., Knol, E., Stahl, B., . . . Garssen, J. (2009). A specific mixture of short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides induces a beneficial immunoglobulin profile in infants at high risk for allergy. Allergy, 64(3), 484-487. doi:10.1111/j.1398-9995.2008.01765.x


Rachel Allen is a writer at Hyperbiotics who's absolutely obsessed with learning about how our bodies work. She's fascinated by the latest research on bacteria and the role they play in health, and loves to help others learn about how probiotics can help the body get back in balance. For more ideas on how you can benefit from the power of probiotics and live healthier days, be sure to subscribe to our newsletter. To learn more about how a healthy microbiome can enrich your life, subscribe to our newsletter.