Monday, August 15, 2016

The Tannin Hack!

OK, that's not quite as catchy as "The Potato Hack." 

It turns out that certain eating patterns we naturally gravitate towards can increase the amount of food that bypasses normal digestion, and serves as food for our gut bacteria.

Lots of research shows that when tannins are combined with starches, an interaction occurs that makes the starches less digestible, allowing the starches to pass into the large intestine whole, where they serve as prebiotic fiber.


Tannins are a class of plant polyphenols, usually credited with giving a bitter taste. Coffee and tea are very high in tannin content. The word tannin comes from German, for fir tree (oh, tannenbaum...). And tree-derived tannins have long been used to tan animal hides into leather due to a unique interaction that tannins have with animal proteins.

Plants produce tannins presumably as an evolutionary defense to prevent the likelihood of being eaten by animals. But, as Darwinian luck would have it, many animals developed a taste for tannins. The real winner, though, may be our gut bugs. For all we know, they may have engineered this whole elaborate scheme.

Tannins are found in most colorful plants and nuts. Foods often cited highest in tannins are:
  • Pomegranites
  • Berries
  • Hazelnuts
  • Walnuts
  • Pecans
  • Most dried spices
  • Legumes
  • Chocolate
  • Beer and wine
  • Coffee and Tea
  • Fruit juices 
  • Honey (!)
The underlying biochemistry of tannins is quite complex, and I have yet to wrap my mind around it.  People spend their entire lives studying plant polyphenols.  I think it's safe to say that the compounds in plants that give them brilliant colors, tastes, and smells are mainly polyphenols. Two main classes of polyphenols are tannins and flavonoids. Quite possibly other polyphenols besides tannins interact with starch as well. And there are many other benefits to eating these polyphenols than just the starch interactions. Polyphenols are also known as antioxidants.    

The Research

2016 - Polymeric tannins significantly alter properties and in vitro digestibility of partially gelatinized intact starch granule.

2015 - Interaction of Sorghum Tannins with Wheat Proteins and Effect on in Vitro Starch and Protein Digestibility in a Baked Product Matrix.

2013 - Effects of sorghum (Sorghum bicolor (L.) Moench) tannins on α-amylase activity and in vitro digestibility of starch in raw and processed flours.

2012 - Interaction of tannins and other sorghum phenolic compounds with starch and effects on in vitro starch digestibility

1999 - Effects of red wine, tannic acid, or ethanol on glucose tolerance in non-insulin-dependent diabetic patients and on starch digestibility in vitro.

Research articles like these show a clear relationship between between tannins and starch digestibility. Most of this research was done to develop products for the food industry that can be added to snack foods, making them less fattening. Soon, some inventive company will no doubt be marketing a jar of powder that can be sprinkled on your food to make it less digestible. I find it ironic that nature spent billions of years perfecting a way to make animals want to eat less plants, and we are using these same chemicals so that we can eat more. Keep in mind, tannins are often referred to as "anti-nutrients" by the paleo-elite and other advice-giving dietary folks.

The list of antinutrients found in legumes, beans and soy is seemingly endless and includes: lectins, saponins, phytate, polyphenols (tannins, isoflavones), protease inhibitors, raffinose oligosaccharides, cyanogenetic glycosides, and favism glycosides.  I know that this list appears somewhat formidable at first because of all the scientific terms, but don’t be worried – the concepts underlying how these toxins may impair our health are easily understood (Loren Cordain, 2015).

Also of note, the mode of action seems to be from several complex interactions. Tannins can reduce the amount of alpha-amylase we produce, or make it less effective at digesting starch. Tannins also physically bind with the starch granules, making them harder to digest. "Anti" nutrients. Yes. They. Are. But does that mean we should not be eating them?  

The Hack

First, let's look at a typical SAD meal:

Yummy, right?  All those bright colors. I see a few things right with this meal, but mostly just wrong. Sesame seeds have long been eaten alongside bread. Sesame seeds contain lots of tannins, so this practice has roots. The secret recipe of Coca-Cola might contain some tannin-rich plant extracts, but we'll never know.

How about a more traditional meal?:

And for the sake of argument, let's say that the pizza crust is made from whole wheat flour, and the pepperoni is preservative-free, hand-made by some guy named Guido, and the tomato sauce is from sun-ripened, home-grown tomatoes. The spices, freshly ground. And that beer...well, it's perfect!

What I'm attempting to illustrate here is that foods we love often come packaged together with their natural tannin counterparts. But we bastardize our food to a great degree when we try to make it "healthier" or "tastier." Wheat flour used to be a pretty good food, but now it's refined and enriched in a way it's hardly a life-sustaining food.

So, here's the hack. Eat real food, and pair your starches with tannins from more real food. Some ideas:


While the science is heady, the concept is simple. Age-old traditional food pairings were chosen for reasons we are just now starting to understand. We seem to think we can outsmart nature to stay lean and healthy, but using artificial colors and flavors in place of natural tannins is a surefire way to get the science wrong. We need the goodness found in WHOLE foods, not refined, tasty treats.

Let's hear your ideas for the Great Tannin Hack in the comments!



  1. Interesting info! I've never really though about tannins, diet, and gut bugs.

    What seems interesting to me is that I eat most of the foods listed as high in tannins. In fact, I typically drink young red wines typically described as "tannic." (They produce a certain mouthfeel that is sort of gritty and moisture sucking). I also drink beers that are tannic (not Bud Light). Now that I think about it, a large part of my diet is tannins.

    In terms of ideas, put wine and beer back on the good-for-you list. Especially young red, tannic wines. Or good microbrews. Pizza can be a health food, especially with the right accompaniments!

    1. Haha, I wanted to tell about the astringent taste of red wines, and Wilbur was faster :-)

    2. For wines, the highest tannin is from those aged in oak barrels and made of grapes.

      For beers, the "hoppier" and darker, the better.

    3. Sorry, Gemma - but you got to use the fancy term though!

      I like my beers strong and bitter.

      In regards to the pictures, I think at some point after fixing the gut issues that the food pictured does not look appetizing. The pizza maybe but it's not my style. I have no plans to eat donuts because they are not tempting!

      I'm leaving on a road trip. Here's an alternative to donuts that is a tannin bomb! Every main ingredient is high - I added cinnamon to the original recipe as another tannin source.

      3/4 cup pitted dates
      1/2 cup raw hazelnuts
      2 Tbsp raw 100% cacao powder
      2 Tbsp shredded unsweetened coconut
      1/2 tsp pure vanilla extract
      Cinnamon to taste
      Salt to taste

      Put in food processor and process until a fine crumble forms. Then put in a gallon sized resealable plastic bag and squeeze into a ball. Open the bag, break off pieces, and roll into balls.

      They can be stored at room temp for a few days or refrigerated for a couple weeks.

      Even my kid, who could probably eat 3 of those donuts, can only eat a small ball of the above.

      I got the recipe from Chocolate Covered Katie's blog.

    4. Oh, man! Makes my mouth water. I made something similar based on dates a while back, ended up eating like 6000 calories worth in 2 days, lol.

      My old standby is no-bake oatmeal cookies. Almost the same recipe but uses butter or coconut oil and rolled oats in place of the dates.

      I like that this date recipe has no added fats.

    5. Can't wait to try that recipe, Wilbur.
      Something sweet to have on hand for hubby. And I won't feel the "need" to eat it as I would if I made a blueberry crisp.

    6. You brought up a point I've been thinking a lot about, Tim.

      As former broken people, we all fear the loss of control. The unexplained and nonrational cravings that lead us to overeat. I've been there. I still have the fear.

      But then I really think about it. I've introduced a food that my body really loves. Not dates in my case, but dried figs. Although I can see dates too. I think, Jeez, I can't eat enough figs. I eat lots and lots of figs. I panic. But then I let reason take over. What if I get fat eating figs? So I eat "6000 calories of figs" in a few days and it ends. In your case, dates. But it ends.

      What if that's our bodies suddenly demanding nutrition/micronutrients long denied it? I've had that happen with figs, berries, chile peppers, tomatoes, salad greens, and many others. Intense desire, followed by disinterest.

      Over the past 3 years, my weight has remained the same, almost to the tenth of a pound. My health from my perspective has only improved. Especially after pursuing a tannin-rich diet, which I recognize thanks to you!

      Anyway, I guess what I'm trying to say is that there are corrective cravings, like the desire to eat a large amount of dates or figs. Or certain spices. It might be best to give into these. But if the cravings are for a box of Ho-hos, its maybe est to resist.

  2. I must say I am disappointed in this article. I worked really hard and continue to work one day at a time to not eat sugar and refined flour or other flour products. For me, and I imagine many others these foods are addicting. With these foods included in my diet. I could not feel as great or healthy that I am now. They also push out all the healthy food I need to include. I eat at up to 2 pounds of vegetables every day and include 1-2 serving of a measured whole grain every day and often 1 serving of lentils or beans or 4 oz of protein every meal. I also supplement with Hi-Maize and other fibers.

    My efforts have resulted in 54 pounds of weight lost during menopause. I have gained and lost hundreds and hundreds of pounds during my lifetime because of my compulsive eating. Sorry, not going on that roller coaster again. I have so far been able to maintain that weight for almost a year. Maintenance is the real key to maintaining your health.

    So, quote me all the studies you like. I will not be having coffee and donuts or pizza and coke! Still like you though and will continue to read. :)

  3. Okay I get what your saying. BUT the pictures are too strong. :)

    1. Alison, a picture's worth a thousand words, but it's important to read the accompanying text, to see the point that even modern junk food carries on the traditional pairings of tannins and starches, which may have arrisen due to gut bugs craving for indigestable fibre.

    2. lol, yes, the pictures were just attention-getters. I'm not planning on donuts anytime soon, either.

  4. This could not have come at a better time for me. I have recently been reading some info from Dr. Kulreet Chaudhary (The Prime) and wondering how her herb, spices, etc contribute to gut health (which she says is key). Her recipe for Prime tea is to boil 4-5 cups of water, add 1/2 tsp cumin seeds, 1/2 tsp coriander seeds, and 1/2 tsp fennel seeds and allow that to steep for 5 to 10 minutes and then drink that throughout the day. I have not yet read her book but from what little I know about it, this article certainly helps me to understand how what she is saying does effect our gut health. Once again, thanks Tim!


    1. Nice! She probably didn't even know about any of this.

    2. Since she recommends not eating leftovers, I'm betting you are right!

    3. It's like we're a dog chasing its tail, eh? We cut carbs and limit starches to prevent blood glucose problems, and end up depriving our gut bacteria of their preferred food source.

      Then we attempt to make food more appealing by removing all hints of bitterness (ie. Miller Lite) or unsavory bits and pieces (ie. Wonder Bread), removing things that naturally control blood glucose.

      Then we eliminate every food that causes the slightest offense: heartburn, gas, skin flares, etc., further removing us from real foods that should help correct these same problems.

    4. Thank you Anonymous. Last week while waiting for chiropractor I read an article about The Prime and the recipe for tea. Before I could copy it I was called in and left the magazine in the lobby. On my way out someone else was reading it. I was so glad to see your comments and the recipe for Prime Tea. Plan to try it as soon as I get the right seeds. Should have known Tim and his followers would come through as I hope I don't have to go back to Chiropractor soon!

    5. Paula,
      Glad to be able to help.

      The article also recommended triphala which I believe is made from 3 different kind of berries so perhaps that has the tannins???


    6. The "Tea" recipe is used in Ayurvedic medicne as a Detox. (called AmaPachana). It works by inducing your body to release Enzymes that "digest" Toxins. One particular enzyme that is very important here is called Intestinal Alkaline Phosphatase. There are various formulas for this tea. Another one is here:

    7. Thanks Ashwin - good to know what the tea is for and why it works. What do you know about the Triphala?


    8. Gina, I'll answer your question by providing links to two sites that I really like as far as knowledge of Ayurvedic Herbs is concerned and yes, I take Triphala in capsule form every day.

    9. Thanks so very much!

  5. This makes me think of the black walnuts on my dad's farm. How they'd be so green then put out to blacken in the sun. And makes me think of cherries, too. Are cherries high in tannins? They always blacken my hands when I work with them.

    And I see Cordain's point, as far as anti-nutrients and even autoimmune disease. But as Campbell-McBride says in GAPS, you can eliminate everything till the cows come home. But you really need to work on your gut. Well, that's paraphrased. Once/if you get that gut up to snuff, then these foods aren't anti-anything. They're nutrition.

    1. Cherries, walnuts...yep, high in tannins. Have you ever tasted a fresh acorn? So bitter you can barely just touch it to your tongue. Yet, native Americans subsisted on acorns. They discovered that if you soak them in water first, the tannins are mostly removed, and then the acorns can be used in many ways.

      Also, as a doctor, you may find interesting that in the studies on alpha-amylase and other enzyme inhibition by tannins, they use Acarbose, an anti-diabetic drug, as the control. ie.

      So, still lots to learn about "real foods." And remember that "patented oat bran-blueberry smoothie" for diabetes? Blueberries and oat bran are both very high in tannins.

  6. Oh boy, I'd eat loaves of bread and jars of jam, and up up very fat, and all the tannins in the world won't help me then!


  7. If anyone wants to try the home-made sourdough rye experiment, I'll send it to you for free. You pay shipping costs, and if export regulations enter play (I'm in Canada), you have to figure them out. If I get flooded with more than 100 requests, we'll have to figure something else out, but I don't think that is very likely. I make 3 loaves a day, so that should keep me busy for a month. (Shipping only; I won't charge any handling fee on top. This is for Science!)

    1. If you ever want to write it up for a blog post with pictures, I'd be glad to post it here. I'd take you up on this offer, but mail between Alaska and Canada is harder than sending a package to Mars.

    2. I just want the recipe. I tried for several months last year to make homemade sourdough, bought from a local mill both organic wheat and rye, followed great blogs and books, and only made flattish (delicious but difficult to eat) loaves. I want to try again, I have all the equipment. But I am very discouraged.

    3. I'll second a blog post with pictures! I made my first sourdough bread this weekend using my teacher's starter...I made plenty of mista...ahem learning experiences but my two loaves turned out super tangy and hearty. Just had a piece with dried green plantain...not the tastiest but I'm sure my gut will thank me. ;)

      Yaelle, I share your frustration on making your own starter...I too went to a local mill here in Oregon and got some amazing flour...but so far my 3 starters have mostly produced a lot of "hooch" that make light headed when I smell them...which of course is good if I ever decide to go into the moonshine business.

      But...I've learned what I did wrong (starters too big and not given enough food) as in the early stages two of them were bubbling like mad and growing as they should...but not feeding them enough and using too much H20 turned them very acidic and inactive. There really is way too much info online that is confusing and contradictory for making starters and sourdough bread...but we'll see how my attempts to revitalize my starters goes tonight (I tossed out all but 1/2 cup and gave them way more flour so they are nice and thick vs runny). No hooch this morning either. But if they are past saving, then I'll start over.

    4. Definitely use less water when making your starter. Feeding once every 24 hours worked for me, but I used 100% whole grain rye flour to make my starter. Rye has a natural acidity that really helps the process.

      This is the recipe I started with. It works pretty well. Main thing to tweak is a) amount of water b) baking temperature c) baking time.

    5. Thank you for the advice! I just ordered the 100% Rye book too...looks like a good recipe to experiment with. I tossed my original three starters as they smelled horrible and started over. My new one is just 1.5 days old and already bubbling nicely and was at almost double size this morning. Using less water is definitely the hooch this morning and the starter is growing slow and steady. Last time they starting growing really fast...and in this hot weather I think they needed way more food and when I didn't feed them they died out. But that was very runny starter...this stick stuff should be good for feeding once a day. And I'm just doing one this time...that way less to screw up, lol. So much to learn. :)

  8. What about tannins (like walnuts) paired with something like raw honey? This has a lot of history in places like Greece.... and is my go-to simple dessert when I want a sweet treat.

    1. That's a perfect combo. I once sent my Mom and Dad a jar of walnuts and honey I found for sale when I was in Russia or somewhere like that. It looked so cool, I thought it seemed a perfect pairing.

  9. Thanks for sharing this great information. I have been culturing/fermenting vegetables and eating them daily for the wonderful probiotics they supply. Many recipes, especially for pickles, call for adding raspberry, grape, or oak leaves (just to name a few) to the jar before fermenting because the tannins in those leaves keep the veggies crispy. So now it's awesome to learn of the benefits of tannins and to realize that I am getting them and probiotics at the same time!

  10. Bit of standing joke I have with new people I meet (usually at work) - let them try some of my chocolate. I only buy the 100% stuff. I buy it in - melt it down and reset in small cake tins. Don't know why but I think it makes it taste much smoother is the best way I can describe it.

    One guy tried it yesterday on site. "tastes like dog sh*t!" was the response. When I told him my 4 year old eats it - "that's child abuse!"

    I think people think I'm lying when I say I enjoy it and look forward to eating it. Sometimes I might mention how your gut bacteria influence your tastes and you're not eating just for you. I don't know why I bother tbh - the looks I get - like I have 3 heads!

    1. Haha, I do the same! I eat this nearly every day:

      I remember trying it a couple years ago and spitting it out, same reaction almost everyone has. But I love the stuff now.

    2. This comment has been removed by the author.

  11. A whole jug of Malbec (one of my favs) would most likely knock me on my keester, but I'll try a glass sometime. :)

    From what I've been reading there are a lot of tannins in some whole wheat flours. I've been experimenting with hard red whole wheat flour from a local mill (as well as a few other varieties) for making sourdough and it definitely has a flavor that I enjoy. I got tired of finding bright white sourdough (even the local "artisan" stuff) in stores that wasn't very tangy and full of salt (and sugar sometimes) I decided to try and make my own.

    I've found after healing my gut I really started to crave those bitter flavors...Arugula and Dandelion Greens I love now...sometimes I just eat them raw. Still not a super fan of pure cacao...but maybe it deserves another try. ;)

  12. Great post, Tim!

    What's interesting about this is that it very likely explains the high white flour-eating French paradox as well as the paradox of the Japanese eating lots of polished white rice. Both populations may be getting far more fiber than people realize.

    According to FAOSTAT, the French have always eaten 30-40% more wheat flour than Americans do, and almost entirely as white flour.

    The French consume large quantities of tannins: tea, coffee, cocoa, red wine, with every meal. Even French children traditionally dipped their white bread in bowls of chocolate for breakfast.

    The Japanese consume a good deal of polished rice, and almost always eaten fresh. However, the Japanese consume their rice with seaweed and soy sauce. Soy sauce has tannis, but seaweed is a particularly good source of a unique kind of tannins known as Phlorotannins. And, in fact, studies have shown that eating seaweed with white rice reduces the glycemic effect of the white rice. Now we know why!

    What this shows us is that even successful traditional diets, with white rice or white flour, are taking advantage of tannin complexing.

    It also shows us that food pairings and complexing is far more complex than anyone ever realized—we are just straching the surface here. Who knew that a coffee and a donut may offer more than empty calories, lol.

    PS — Tannins also bind with protein, especially gluten. Something to chew on.

    Nice work.

  13. Pomegranates contain a Tannin called Ellagitannins.Certain Gut Bacteria convert this Tannin to a substance called Urolithin-A. Urolithin A has been shown to increase lifespan and improve muscle strength.

    1. Here are some more comments from Ashwin, trapped in the spam loop...sorry! Great comments, Ashwin...thanks!:

      Tannins are anti-nutrients? I'm not too sure. I believe Polyphenols may one day be used to improve the integrity of the Intestinal barrier and cure the "leaky Gut" My thoughts on Tannins and Polyphenols:

      You might remember I suggested taking a combination of fermentable, Viscous fibres together with Raw Potato Starch and Wheat Bran in my post on Freetheanimal (December 2013). In addition I suggested including Polyphenols along with the fibre/Starch mix to modulate the COMPOSITION of the Gut microbiota. I also mentioned taking a complex made up of Polyphenols and Gelatin. This complex would be stable in the acid ph of the Stomach but break up into Polyphenol and Gelatin in the Intestines, thus delivering the Polyphenols where you want them to be. I am very keen on Polyphenols from Pomegranate fuit and seeds, Amla fruit and Neem leaves.

    2. Aha, I was too long of a comment. Continuing, from Ashwin:

      Re: Gelatin and Polyphenols

      Polyphenols in medicinal foods like Turmeric, Indian Gooseberry (Amla), Pomegranate Seeds and Peal, Neem leaves and Bark are mostly Tannins. If you add your chosen Polyphenol source into Vinegar (Acetic Acid), the Polyphenols are hydrolysed and the Phenolic acid is released. On adding Gelatin (pre softened in Vinegar), the Phenolc acids combine with the Gelatin to give you a complex . This Complex is often referred to as GELATIN TANNATE You might be interested in these articles: Gelatin tannate reduces the proinflammatory effects of lipopolysaccharide in human intestinal epithelial cells.

      "Turmeric, Ginger, Neem herb, Green Tea Extract, Red Grape Extract, Cinnamon,Cocoa powder, Raspberries, Strawberries, Pomegranate fruit, Amla Powder, Thyme, Ajwain, Rosemary, Basil, Oregano and many more may be beneficial sources of suitable Polyphenols."

      Some of these actually disable the ability of Pathogenic Bacteria to adhere to the mucosal lining of the GI tract (Neem). Bone Broth with added herbs and spices has historically been seen as a healthy food. I think it contains a complex of Polyphenols and Gelatin that is the healthy ingredient. A complex of Tannin or Plant Polyphenols with Gelatin is known to remain intact in the mouth and Stomach due to the acid ph. However, the alkaline ph of the small intestine and Colon allows the Polyphenol and Gelatin complex to break up to release the active principles which will have arrived at the “site of action”.

      Tannins can be astringent and have a puckering effect on the tongue. Tannins can also bind with Iron and other nutrients (and some Meds) in
      the Stomach and interfere with absorption. This Targeted delivery is really useful and avoids the side effects. You can easily make a complex of any Polyphenol Herb/Spice by adding the whole spice to Gelatin softened in some Distilled or Wine Vinegar (a source of Acetic Acid) and blending for the “reaction” to take place. You can use the resulting mix or allow the vinegar to evaporate to obtain the powder complex!

      Re: Polyphenol mix Amla powder................50G Turmeric powder............50G
      Pomegranate Peel powder....50G
      Green Tea Extract..........50G
      Grape seed extract.........50G
      Quercetin hydrate .........50G

      Neem leaf extract...........50G, Avoid when necessary

      Pomegranate Seed Extract....................50G

      I use an excess of Gelatin (500G) to make the Complex. My thinking is that this will assure most of the Phenolic Acids made in the vinegar are complexed and there is no wastage. I use one litre of Vinegar to soak the Polyphenol powders and One litre to soak the Gelatin.

      Gently heat the Vinegar/polyphenol mix to liberate the free Phenolic acids by acid hydrolysis. A water bath is ideal to prevent damaging the Polyphenols in any way. The heating can be for up to one hour. Then add the softened Gelatin and using an electric Blender/whisk, mix well. pour the mix into an airtight glass jar and leave in a dark place for around 3 to 4 days. The reaction is slow and thorough this way. Then you can pour small amounts into a shallow dish ( I use a silicone Baking dish so that the scraping off of the dried powder is easy). You can grind the final product to a fine powder. I use 500mg of the blend as the "therapeutic" dose.

    3. And finally, from Aswin:

      A Tannic Acid-based Medical Food, Cesinex®, Exhibits Broad-spectrum Antidiarrheal Properties:

      A Mechanistic and Clinical Study

      The therapeutic management of gut barrier leaking: the emerging role for mucosal barrier protectors.

      Dysbiosis of the gut microbiota in disease

      Regulation of tight junction permeability by intestinal bacteria and dietary components.


      The French drink their Red Wine with Cheese. A reaction takes place on the tongue between the Polyphenols in the Red wine and milk proteins to produce a complex. Apart from removing the astringency of the Red wine, I believe this complex improves the intestinal Barrier's ability to exclude Pathogenic microbes and their metabolites (Lipopolysaccharide) from entering the bloodstream.
      Works better still with Roquefort Cheese!!

      French Lifestyle Secret Finally Revealed: Lycotec Publishes Unexpected Findings on Roquefort Cheese

  14. Dolmas, grape leaves stuffed with white rice, make sense now!