How Do Grains, Legumes and Dairy Cause a Leaky Gut? Part 2: Saponins and Protease Inhibitors

March 29, 2012 in Categories: , by

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(Created as a guest post for The Paleo Parents)

One of the fundamental principles of paleolithic nutrition is to protect the lining of the gut by eliminating foods that damage it.  By prioritizing gut health, we are able to treat and prevent the many health issues associated with having a “leaky gut”.  But how exactly do grains, legumes and dairy wreak so much havoc on the digestive tract?  The damage caused by the lectins contained in grains and legumes (see Part 1) is made even worse by two other compounds found in these foods:  saponins and protease inhibitors.
Legumes and pseudo-grains (like quinoa and amaranth) are high in saponins.  All plants contain saponins, often concentrated in the seed of the plant.  These compounds have detergent-like properties and are designed to protect the plants from consumption by microbes and insects by dissolving the cell membranes of these potential predators.  Saponins consist of a fat-soluble core (having either a steroid or triterpenoid structure) with one or more side chains of water-soluble carbohydrates (this combination of both a water-soluble and a fat-soluble component is what makes saponin act like a detergent, i.e., something that can make oil and water mix).  This detergent-like structure gives saponins the ability to interact with the cholesterol molecules imbedded in the surface membrane of every cell in the body and rearrange those cholesterol molecules to form a stable, pore-like complex.  Basically, dietary saponins create holes in the surface membrane of the cells which line the gut (enterocytes), allowing a variety of substances found in the gut to enter the cell.

There are many different types of saponins, and some bind more easily and more tightly to the cholesterol molecules in the cell membrane than others.  As such, different saponins can create larger or smaller pores, which may be more or less stable.  The larger, more stable and/or more numerous the pores, the more difficult it is for the enterocyte to recover.  Small doses of some dietary saponins (like those found in fruits and vegetables) might be important for aiding absorption of some minerals.  However, legumes, and pseudo-grains contain very high doses of saponins (and, in general, contain types of saponins that interact more strongly with cholesterol).  Dietary saponins from these foods are known to increase the permeability of the gut (i.e., cause a leaky gut), likely by killing enterocytes (cells, in general, do not survive large, irreversible changes in membrane permeability).  Interestingly, even when a sub-lethal amount of saponin pores form in the enterocyte surface membrane, the cell loses its ability to actively transport nutrients, especially carbohydrates.  While slowing down sugar transport from the gut to the bloodstream seems like a great thing on the surface (why beans are so often recommended as a carbohydrate source for diabetics!), the irreversible increase in gut permeability is just not worth it!
 

 When large amounts of dietary saponins are consumed (especially in the presence of an already leaky gut), saponins can leak into the bloodstream.  When saponins enter the bloodstream in sufficient concentrations, they cause hemolysis (destruction of the cell membrane of red blood cells).  Saponins also have adjuvant-like activity, which means that they are able to affect the immune system leading to pro-inflammatory cytokine production (again those chemical messengers that tell white blood cells to attack) and can further contribute to inflammation in the body. 

Grains, pseudo-grains (like buckwheat) and dairy contain protease inhibitors.  Protease inhibitors are the seed’s attempt to escape digestion completely.  These are compounds designed to neutralize the digestive enzymes that would normally degrade the proteins (and toxins) found in those plants into their individual component amino acids.  However, when protease inhibitors are present in the digestive tract, it affects degradation of all proteins present at that time.  When the body senses the need to increase protein digestion, the pancreas secretes more digestive enzymes into the small intestine.  Because some digestive enzymes are being inhibited (the proteases which break down protein) while others are not, the balance between the different digestive enzymes is thrown off.  One enzyme that ends up in excessive quantities during this process is trypsin, an enzyme that is very good at destroying the connections between cells.  If there is a large concentration of trypsin in the small intestine, it can weaken the connections between the enterocytes, creating a pathway for the contents of the gut to leak into the blood stream.  To make matters worse, in the presence of an already leaky gut, incompletely digested proteins that cross the enterocyte layer stimulate the resident immune cells of the gut to release inflammatory cytokines and produce antibodies.  The result is generalized and/or specific inflammation. 

Dairy is designed to create a leaky gut.  Scientists still don’t understand all the mechanisms through which dairy products can create a leaky gut.  However, it seems to be an important aspect for what dairy is designed to do:  feed babies (of the same species) optimal nutrition for rapid growth.  In newborn infants, a leaky gut is essential so that some components of mother’s milk can get into the blood stream, like hormones and all the antibodies that a mother makes that helps boost her child’s immune system.  While this is essential for optimal health in babies, it becomes a problem in the adult digestive tract where there are more things present that we don’t want to leak into the blood stream.  Drinking milk from a different species seems to make matters worse since the foreign proteins can cause a larger immune response.

The damage to the gut lining caused by saponins has been heavily studied in the context of animal feed for poultry, cattle and fish farms.  But, while there is a better understanding of the damaging effects of dietary gluten (at least in humans), the gut irritation and inflammation that can be caused by saponins and protease inhibitors should not be underrated. 

Comments

Interesting to ponder as I sit here with my shoulder and elbow joints hurting, and I had cheese for dessert last night….hmmmmm maybe it is time for a food journal….

Interesting! My naturopath diagnosed me with Leaky Gut Syndrome and also Candida overgrowth after my MD told me I have fibromyalgia/CFS (that’s not autoimmune though is it?).. my naturopath says my creatinine is low and that it means my blood protein level is too low (never mind what my MD says about it meaning good kidney funtion, he said!) So I have bought a full-spectrum digestive enzyme blend and have been taking it and I think it is helping me, and it has some HCL in it as well. He says protease is the enzyme that helps you assimilate your proteins, because I am as close to a paleo diet/Atkins diet as I can be and yet my blood protein is Low?? Makes no sense. Even my gastroenterologist confirms what my naturopath said because even he found that I have ‘moderate chronic gastritis’, and even on a paleo diet my stomach is always huge and bloated. Any ideas as to why? Or does that just take some time to work through? ~Tanya

Fibromyalgia is not autoimmune but Chronic Fatigue is. Creatinine levels are not something I know much about (other than high creatinine is a sign of kidney damage), but it is possible that you aren’t absorbing all of the protein from your food if you have yeast overgrowth, gastritis and leaky gut (which area all interconnected). I think digestive enzymes and low-carb are a good choice. I would also have a look at FODMAP food lists just in case that is contributing to your yeast overgrowth and bloating (I’m hoping to have a post about FODMAP-sensitivity next week some time). It would be good to include some healing foods in your diet (like bone broth, liver which you are already eating, and coconut oil) and a food source of probiotics (like homemade sauerkraut or kombucha). The main answer to your question is that yes, it does take some time, and it tends to take longer for people with gut dysbiosis because the yeast/bacteria overgrowth hinder healing and keep the gut leaky (and are causing the bloating). 6 months would be a pretty good guess, but with CFS it could take longer. I hope this helps!

I am very underweight and would like to know if this diet could help me gain weight? My normal body weight is 130+ but after 2 bouts of Lyme disease and many antibiotics and then a “crash” after a flu shot in 2008, I am 102 libs. at 5″8″. I also have osteoporosis. I think this diet would help heal my gut but would I gain weight? Also, could it compromise my electrolyte levels with so much meat? Thank you so much for sharing if you have time and for all your insights. Elaine

Yes. The paleo diet in general is fantastic for regulating weight (which means overweight people tend to lose weight and underweight people tend to gain). Sounds like you will also want to have a strong focus on gut health. I recommend the book Practical Paleo by Diane Sanfilippo (should be a link in the sidebar) for guidance on supplements that may help. I also recommend consuming lots of fish, coconut oil, grass-fed beef, bone broth, organ meat, and raw fermented vegetables. Eating quality meat will actually help you heal and support liver and kidney function (so grass-fed and pastured is best). Make sure you are eating sufficient fat and don’t go too low carb (you can play with whether fruit versus starchy vegetables works better for you, or both). I hope this helps!

Thank you so much for replying so quickly. I appreciate knowing that it’s possible to gain weight on this diet. I just ordered the Practical Paleo and I’m sure that will be so helpful. Thank you for recommending it. I do have problems with fermented and fungal foods because of candida that I have since taking so many antibiotics. I stay away from all the the white flours, sugars, etc. as well. Fruit can sometimes bother me but I can work with some like melons, and papaya. Thanks for giving me hope and all these great suggestions. I SO appreciate your website.

Hi Elaine. I had a candida problem too which I battled with every diet and pill imaginable. Then I got down to the root cause: mercury poisoning from my 20 year old amalgams. I had them removed, then started chelating with DMSA and ALA per Cutler protocol (very low dose every 3 hours for several days at a time, then a rest period). After about a year of this protocol, problem solved. Just thought I’d mention it if you have amalgams and dutifully had all your vaccinations as a child (before anyone knew they contained mercury).

Thank you Anna. I didn’t think this was my issue since I only have one Mercury amalgam left but it’s possible and with not really improving otherwise I will look into it. It was good of you to write and explain the protocol to me. So glad you are doing well and found your answer!

Hi Anna,
I meant to ask you if you felt anything negative after the removal of your mercury fillings? Did you actually feel an improvement? I think I could handle the removal, but I’m not sure about the detox protocol. My gut is so leaky it may make things worse. Thank you so much for this helpful info, Elaine

Yeh Paleo can definitely make you gain weight so that you’re at a healthier weight. It happened to me- I used to eat about double my caloric needs and was underweight and had no energy and lots of joint pain but when I went paleo I put on about 4kg and got my energy back and a bunch of other health issues have resolved. It’s totally worth it but… Well… Being underweight is fashionable and I like how I looked before better than how I look now even though I know I’m healthier now. Still, I would never go back to a SAD diet. I just wonder if there is a modification of paleo that can pull you below your healthy weight for vanity’s sake while maintaining health.

Is it primarily quinoa and amaranth that have saponins? I’m currently underweight and intolerant to so many foods and FODMAPs that I’ve had to make quinoa a staple at every meal, but am concerned about the amounts of saponins, etc that I’m consuming. I do rinse the quinoa at least 3 times, and was soaking and sprouting them until I discovered that this increases the levels of amines, which I suspect I’m sensitive to along with salicylates and free glutamates. I’m trying to reintroduce rice as an option, but the jury’s out as to whether it will work for me. Any thoughts re: the least harmful gluten-free grains to try?

Polished white rice is typically the best tolerated grain with the least anti-nutrients. What about other starchy vegetables like taro root or green plantain? (not sure if those are FODMAPs or not). Otherwise, I’m not sure which grains or pseudograins are better or worse, I guess it really depends on what you tolerate.

I’d like to see in vivo or human studies to support the following: “dietary saponins create holes in the surface membrane of the cells which line the gut (enterocytes)” AND, “Dietary saponins from these foods are known to increase the permeability of the gut (i.e., cause a leaky gut), likely by killing enterocytes”.

Legumes aren’t allowed? I knew about grains, but legumes too? I eat dhal (yellow split pea soup) about once a week, and now chickpeas too since I’m finding it hard to find free range hormone free chicken thats also grass fed. Do yellow split peas and chickpeas grow candida?

Chicken are omnivores, so they are almost always supplemented with some kind of feed. Legumes are very hard to digest (both the proteins and starches in legumes are hard to digest), contain protease inhibitors, saponins, and lectins (mainly agglutinins). Some people tolerate well soaked and thoroughly cooked legumes from time to time, so if you feel that your weekly dhal is working for you, then you don’t need to cut it out.

I don’t think I can find taro root but is fresh taro allowed? We usually boil for indian food. Is it allowed while trying to heal leaky gut? Ive also left out cassava as I want sure and didn’t want to risk having to start diet again! but if boiled taro is allowed that would be great

Both taro and cassava would be allowed. The caveat with cassava is to make sure you are preparing it properly (soaking for 24 hours, then cooking at least an hour) because of the glucocyanides.

thanks for that. I tried googling glucocyanides but couldn’t find what they are haha. They are fine even if I may have leaky gut? thanks for replying to these!!

They are best minimized for everyone. Soaking and extended cooking greatly diminishes them (plus the kind of cassava we can get in stores is the sweet cassava which has less glucocyanides than the bitter one traditionally consumed in Africa).

I have been a vegetarian for 30 years and have an auto immune disorder. My inflammation level is high (from blood test). I am on a low carb diet and taking daily Omega 3s from Algae oil, probiotics, enzymes and Betaine. I have been eating a lot of quinoa and almonds as my main source of protein. I am very disturbed to read that quinoa or buckwheat is not good for me and don’t know how I will keep up my protein levels which are low anyway. I have been taking Whey Isolate powder also. It is against my spiritual practice to eat meat, fish or eggs. Do you have any suggestions? I have lost quite a bit of weight (weigh 115 lbs, 5’4″ tall). I am getting weaker because my immune system seems to be attacking my muscles. I eat a lot of fresh, organic green vegetables and avocados daily.

Unfortunately, I believe you need animal proteins and the vitamins and minerals that are especially rich in these foods in order to heal. I think you can do it as a pescetarian, but vegetarianism is a real obstacle to getting the nutrients your body needs. I suggest finding a functional medicine specialist who can work within your belief structure to customize a meal plan, including supplements, for you.

What are your thoughts on soaking grains the way traditional peoples do, or sprouting the beans before consuming? Thank you for your time.

Traditional preparations definitely reduce many of the more problematic proteins and antinutrients, while also making grains and legumes more digestible and the nutrients in them more bioavailable. And I think that many people can tolerate soaked/sprouted grains and beans (especially if then also fermented and cooked for an extended time) very well. So, if someone does want to go to that work and does tolerate them well, I say go for it! I believe that the key is to find out as an individual what works for your own body but also what makes good diet choices sustainable, and if the only way that you can commit to healthy eating for the rest of your life is to enjoy traditionally prepared sourdough bread from time to time and you don’t experience adverse effects from doing that, then I think that’s great.

Thank you for you quick response. Today, my allergies are killing me and I was thinking I need a change. I will give this all a try.

Tapioca starch is a common sensitivity, use with caution. Most people are okay with coconut milk (be sure to check the ingredients for any emulsifiers). And it also depends on what you use to replace the egg. — Tamar, Sarah’s assistant

Is there any benefit of the fermentation in Kefir for reducing the protease inhibitors in milk. – meaning, is kefir any less a problem than milk in creating gut permeability? Thanks

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