It is my sincere hope that in this lifetime I will be able to make talking about intestinal things more glamorous than Jamie Lee Curtis does in the Activia commercials. So maybe if I talk about the huge responsibility of the gut / intestinal tract / microbiome, people will get excited about it. I’m excited about it. Okay here goes.
The intestinal tract (often called the “second brain”) is a pretty big deal, both in size and function. It’s double the size of the tennis court and houses 10^14 viable microorganisms. To put things in perspective, this is 10 times the number of cells in the rest of the human body. The gut also produces 75% of neurotransmitters in the body (happy brain chemicals!!!) and contains two thirds of the body’s immune system. Perhaps most importantly, it interacts with the outside world every single day via the food you eat.
Here’s what a well functioning microbiome does:
- stimulates the immune system
- synthesizes vitamins (B group and K)
- facilitates nutrient and vitamin acquisition
- promotes tissue integrity and development
- enhances gastrointestinal motility and function (go poops!!)
- stimulates adequate digestive juices, enzymes, and pH
- responsible for xenobiotic (foreign things) metabolism (gets foreign things out)
- protects against pathogenic bacteria in the intestinal tract
- plays a role in weight management (obese microbiota have increased capacity to harvest energy from diet)
- improves digestion and nutrient absorption (calcium, magnesium, and trace minerals)
- improves gas-induced abdominal dissension
- inhibits pathogens (colonization resistance)
- metabolizes important plant compounds/drugs
The microbiome develops during infancy and childhood and there are a few things that impact its formation. Antibiotic use in healthy infants disrupts the diversity and complexity of commensal bacteria. Other factors that influence early microbiota formation are: delivery (vaginal or C-section), environment, first foods (breastmilk or formula) and diet.
Things that affect the microbiome
Behaviors throughout life continue to affect the microbiome, such as nutrition and stress response. While the good bacteria are mighty and fierce, they’re not indestructible and are easily susceptible to damage. Things like modern diet and lifestyle (lots of processed, high-sugar and inflammatory foods), regular use of some medications like antibiotics, sedentary lifestyle, and STRESS can not only change the bowel flora but can lead to an overgrowth of harmful microorganisms, resulting in something called dysbiosis. Packaged fruit juices, baked goods, junk foods, white bread, alcohol, high protein, high animal fat, high saturated fat, high refined carbohydrate, and low fiber diets can all negatively affect the microbiome.
Psychological or physical stress can also alter the microflora for a few days, and can lead to things like slow gastric acid release (and in turn poor digestion), alterations in motility (how well things are moving), and increased bicarbonate production, meaning the good bacteria are less likely to survive.
Leaky gut / intestinal permeability
The gut is intended to be a barrier to foreign proteins like foods and bacteria. In a healthy intestine, tight junctions create a barrier that provides limited access for substances from outside to be absorbed inside the body. In an unhealthy intestine: tight junctions become “leaky” and large molecules (unprocessed proteins / large amino acids with antigenic sites) slip into circulation, which results in intestinal permeability / “leaky gut.”
Signs and symptoms of leaky gut include: abdominal pain and bloating, gas, diarrhea, headaches, nerve pain, skin rashes and joint aches. The diagnoses that result are Celiac disease, Crohn’s disease and irritable bowel syndrome, multiple sclerosis, migraines, attention deficit, autism, depression, eczema, acne, rheumatoid arthritis, fibromyalgia, diabetes, and chronic fatigue.
There are many whole plant foods (re: fruits, vegetables, and whole grain cereals) that interact with gut bacteria and are main energy sources for colonic fermentation. Polyphenol-rich chocolate, for example, is shown to increase good bacteria in fecal matter (meaning good bacteria is in your gut and leaving your gut).
Eating enough dietary fiber is also important, as it’s the main source of carbohydrate for gut microbiota production. The recommended amount of fiber consumption is 30-40g per day. Carbohydrate fermentation is the chief energy source for gut microbiota, leading to the production of short chain fatty acids, which play a role in supplying energy to intestinal mucosa, heart, brain and muscle, and play an important role in cell differentiation, proliferation, programmed cell death, regulation of immune function, thermogenesis, and lipid metabolism.
In sum, whole plant foods, polyphenols, and dietary fibers change both the species content and composition within the gut microbiota, increasing commensal bacteria thought to be associated with human health.
10 tips to improve gut health:
- Get fun with fiber! fiber (30-40g / day) via whole grains, legumes, nuts and seeds. Some good forms of prebiotic fiber include: artichokes, asparagus, leek, onions, artichokes, legumes, barley, banana (dried has more than raw), honey, maple syrup, lentils, chickpeas/hummus, green peas, lima beans, kidney beans, sweet potatoes.
- Eat a forkful of fermented foods a day, like kimchi and sauerkraut. These have populations of 10^8 bacteria/mL (A LOT!) by the end stages of fermentation, which have therapeutic effects when consumed.
- Reserve antibiotic use for necessity and use probiotics during antibiotic treatment. This will help replenish the good bacteria that is eliminated by using an antibiotic.
- Take a probiotic supplement daily with a meal to increase the likelihood of the beneficial bacteria reaching the colon and having a clinical effect. By doing this, you’re taking advantage of the decreased acidity of the gastric environment, in turn increasing the likelihood of bacterial survival. The most successful probiotic supplements are those that have 10^9 bacteria per dose, and 10^9 – 10^11 is best. Those that are best to enhance growth of indigenous beneficial bacteria and decrease potential pathogen populations are: B lactis HN019 / Bb12 and L. casei Shirota and L. rhamnosus GG.
- If you don’t have a dairy sensitivity, eat dairy sources of probiotics. Bacteria provided in dairy-base sources have a greater number of live bacteria than those provided in capsule. Strains should be >10^6bacteria/mL to exert therapeutic effect. Yogurt is an ideal transport medium for probiotic bacteria, as it has been shown to enhance survival of bacteria through the upper gastrointestinal tract.
- Use cacao powder – in smoothies, cookies, brownies, whatever! High cocoa flavonol drinks results in increases in fecal bifidobacteria and lactobacilli (good bacteria) and reduced clostridial counts (bad bacteria), plasma triglicerides (fats), and C-reactive proteins (inflammation markers).
- Practice gratitude: cortisol has an immediate and direct effect in terms of change in the microbiome, and increasing permeability. The less cortisol, the better gut health. Expressing and practicing gratitude has the most direct benefit on decreasing cortisol levels.
- Activate the vagus nerve, which is the link between your gut and your brain: hum, sing, gargle, laugh – all of these things work!
- Exercise! 20 minutes of aerobics six days a week (getting your heartrate 180 minus your age) is what’s recommended, according to Dr. Perlmutter, author of Grain Brain. Those who were in better cardiorespiratory health, as measured through max V02 levels, had more diverse gut bacteria.
- Cut sugar, eat more GOOD fat, and avoid artificial sweeteners. Consuming artificial sweeteners results in a higher risk of obesity. Israeli researchers found that the reason behind this premise is due to changes that happen in the microbiome. Researchers then took this study to a crossover between animals and humans. They induced the microbiome changes in humans by giving them artificial sweeteners and then transplanted their stool into the laboratory animals. The laboratory animals suddenly got fat with no change in their diets, and had an increased risk of type II diabetes.
It is best to work with a provider for your specific healing plan, but the general tenets of healing poor gut health are sometimes referred to as the 4R’s:
- Remove: this refers to both triggering foods as well as any infections that may be occurring within the gut. To identify food sensitivities and potential allergies, it may be best to start with an elimination diet
- Replace: this involves improving digestion with digestive enzymes. If there isn’t sufficient stomach acid, food isn’t able to be digested properly, resulting in symptoms such as bloating, gas, and acid reflux. There is also a change of failure to absorb nutrients from food, especially B12. This may take the four of lemon juice, apple cider vinegar, or a digestive enzyme. It is important to emphasize mindful eating around mealtimes in order to decrease stress and increase ease of digestion.
- Reinoculate: Get those good bacteria back up and running! This can take the form of both probiotics (some tips on how to find a good probiotic here) as well as foods that contain probiotics: fermented foods like sauerkraut, kefir, full fat dairy yogurt and pickled vegetables.
- Repair: addressing leaky gut -this may be caused by a multitude of different triggers, which is my it’s important to work one on one with a practitioner. These include: high cortisol levels, hormonal imbalances, food sensitivities, etc. The list is extensive. Some foods that may help with repair: prebiotics and probiotics, fermented foods, homemade stocks and broths like bone broth, collagen, butyric acid (from proper country butter), l-glutamine supplement (an amino acid) and aloe vera.
Overall food plan for gut healing
- whole foods rich in variety of fruits and vegetables
- fiber (30-40g / day) via whole grains, legumes, nuts and seeds
- well-sourced animal protein
- monounsaturated and omega-3 fatty acids (salmon, flax seed, chia seeds, sardines,cod liver, walnuts, bone broth, fatty fish, grass fed meats / eggs)
- minimal / be mindful of consumption: processed foods, sugar, omega-6 fatty acids (vegetable oils, grapeseed oil, sunflower oil, canola oil, soybean oil, safflower oil, margarine, shortening, high fructose corn syrup, trans-fatty acids, caffeine, alcohol), refined polyunsaturated oils, fake fats, refined sugars, high fructose corn syrup, refined carbohydrates, artificial sweeteners, food toxins and genetically engineered foods
- take a probiotic
Gut healthy grocery list:
The key to a good functioning gut are increasing intake of prebiotics, probiotics, and colonic foods, and synbiotics (combination of prebiotics and probiotics).
- whole plant foods: moderate fat and protein, rich in variety, rich in fiber; whole grains; legumes; fruits; vegetables; nuts
- polyphenol-rich foods: black elderberries, black currants, blueberries, cherries , strawberries, blackberries, plums, raspberries, apples (red), black grapes, flaxseed meal, chestnuts, hazelnuts, pecans, purple carrots, red carrots, purple/red potatoes, red cabbage, spinach, red onions, broccoli, carrots (orange), red lettuce, red rice, black rice, whole grain rye bread, black olives, olive oil
- probiotic-rich foods: kefir, sauerkraut, kimchi, kombucha, coconut kefir, natto, yogurt, kvass, raw cheese, pickles (in salt water), dark chocolate, microalgae
- prebiotic-rich foods: jerusalem artichokes, globe artichokes, asparagus, leek, garlic, rye, dandelion, bacon tubers, burdock roots, chicory roots, dandelion roots, onions, artichokes, legumes, brassica-family vegetables, fresh beans, beetroot, rye sourdough, sunflower seeds, pumpkin seeds, LSA mix, barley, banana (dried has more than raw), wheat, chicory (roasted as coffee has 41.7% of its weight as prebiotics), salsify, burdock, yacon, honey, beer, chinese chives, maple syrup, lentils, chickpeas/hummus, green peas, lima beans, kidney beans
- prebiotic-like foods: brown rice, carrots, black currants, dark cocoa (14g/day showed increased bifidobacteria and lactobacilli – good bacteria), almonds, green tea (5/6 cups per day = increased good bacteria)
- resistant starch-rich foods: red lentils, kidney beans, adzuki beans, less ripe bananas, cooked and cooled potatoes, roasted have higher than steamed, cassava, sweet potatoes, rye bread, oats (higher amounts in uncooked), cashew nuts
- synbiotic combinations: yogurt, or kefir, and honey; yogurt, or kefir and honey and acacia gums; beans (legumes), and pickles; yogurt, sour cream, or kefir with garlic; feta cheese and onions; yogurt with oats; greens sautéed with garlic and sour cream; kombucha with Chia seeds; kombucha with acacia gum
Last but not least, probiotics are strain specific, meaning certain strains are better for certain ailments. Click on the link below to see which probiotics are researched to have clinical effects for different medical issues (may take a little time to load, but worth it!) Pages 984-989!!!
pre and probiotic foods (3) – gut healthy grocery list print out
This table came from a study regarding probiotic strains for skin disorders.
Blaser M.J. & Falkow, S. (2009). What are the consequences of the disappearing human microbiota? Perspectives, 7, 887-894
Hawrelak, J. Probiotics In: Pizzorno, J.E., Murray, M. (eds). Textbook of Natural Medicine (4th ed) Elsevier. 2013. 979-994
Hawrelak, J.A. & Myers, S.P. (2004). The causes of intestinal dysbiosis: A review. Intestinal Dysbiosis, 9(2), 180-197
Tuohy, K.M., Conterno, L., Gasperotti, M., & Viola, R. (2012). Up-regulating the human intestinal micro biome using whole plant foods, polyphenols, and/or fiber. Journal of Agricultural and Food Chemistry, 60, 8776-8782 doi: 10.1021/jf2053959
Ozdemir, O. (2010). Various effects of different probiotic strains in allergic disorders: an update from laboratory and clinical data. Clinical & Experimental Immunology, 160(3), 295-304. doi: 10.1111/j.1365-2249.2010.04109.x
Cut sugar, eat more GOOD fat, and avoid artificial sweeteners. Consuming artificial sweeteners results in a higher risk of obesity. Israeli researchers found that the reason behind this premise is due to changes that happen in the microbiome. Researchers then took this study to a crossover between animals and humans. They induced the microbiome changes in humans by giving them artificial sweeteners and then transplanted their stool into the laboratory animals. The laboratory animals suddenly got fat with no change in their diets, and had an increased risk of type II diabetes.
^^ how do you feel about stevia?? I’m typically very conscious about added & refined sugars and use maple syrup and honey, but occasionally I want a ‘guilt-free’ way of enjoying something sweet and will resort to using stevia in oats or coffee. I haven’t done extensive research, but have heard that stevia is one of the ‘trusted’ natural sources to use as a low-cal sweetener. How much truth is there behind this, what are your thoughts?? 🙂
Hi Molly! Okay one study reports that “short term stevia consumption in rats was suggested to be associated with weight gain in a yet unknown mechanism. Similarly interesting in that regard is another group of sugar substitutes, sugar alcohols such as xylitol, mannitol and sorbitol, that are added as supplements to numerous foods and have been recently suggested to interact with the gut microbiome.” This study also reported “weight gain in rats following consumption of saccharin,
acesulfame-potassium, or stevia.” That study is here. Another, study, however, found that fermented stevia effective against food-borne pathogenic bacteria, with no significant killing activity against gut microbes. This suggests stevia could be a useful tool in manipulating the gut microbiome to promote human health (here). And then another study found that lactobacilli and bifidobacteria were able to utilise steviol glycosides (stevia) as a carbon source to a very limited extent, meaning that stevia is a potential prebiotic fiber, though the effect was not large enough to be declared significant (here). So clearly the results are inconclusive and varied. I’ve brought it up with my instructor and I’ll update if he has anything to add.
Do you personally use stevia? what are your views on it? I used to use it but I’m just not sure of it.. it would help to hear your thoughts on it!
I do not. If I use added sugar, I reach for maple syrup, honey, or dates. Stevia is so so so much sweeter than regular sugar, and I really just don’t prefer it, honestly.
thank you… definitely helpful to have this info, you rule!
Haha thanks, Molly! xo
hi katie, looking for some advice..had a lot of stomach pains over the last few years, a lot due to stress and I’m sure a lot to do with diet. It has gotten a lot better I try my best to reduce stress and eat healthy but it only happens for a few days/a week at a time before I’m back eating junk and feeling awful. I try to make better choices; drinking plant based milks as much as I can and eating as many fruit and veggies as I can, but every time I try it all goes bad on me before I get a chance to eat it or try some new recipe with it. I tell myself I don’t have as much time as I would like to cook and prep any meals. how often do you grocery shop and how do you keep fresh food from going bad on you? I know a lot if not all of it is in my head and it can be so simple but how do I change my mindset, save time, and keep it simple without wasting so much food?
Hi Kristen! Do you buy any frozen vegetables? Frozen broccoli and cauliflower always come in such handy to me. I also try to eat veggies that I know will go bad first, e.g. lettuce, tomatoes, zucchini. Whereas carrots, peppers, celery tend to stay good for a little longer. So maybe I’ll have lots of salads in the beginning of the week, and then stir fry up some carrots, peppers and celery with some eggs by the end of the week. I find sweet potatoes tend to stay pretty well, too! I’m also big on canned beans and even canned salmon. I’ll mix the salmon with avocado and toss it on a brown rice wrap (I buy these in the frozen aisle so they stay good for a long time). It’s so helpful for me to plan things in the beginning of the weeks so it takes the guessing game out. Hope this helps!
Hi! What are your opinions on probiotic drinks like Yakult? Are they a good source of probiotics?
Haven’t heard of them, sorry!
Omg I just want to say THANK YOU for all the research you’ve done on probiotics and making it available to read! I’m super nerdy when it comes to this stuff and so appreciate your work! I just started the Silver Fern probiotic and read through your post (twice now) and just discovered this post! I LOVE the attached PDF of the specific probiotic strains. So much good info! I’ve been researching for months on how to improve my digestion and health. Last year I discovered I had perioral dermatitis outbreak from gluten and dairy (which I’ve cut out). And the past few months I’ve been focused on adjusting my diet to help heal my teeth decay. I’ve waaayyy up’d my fats and started taking a cod liver/butter oil for the fat soluble vitamins (The book Cure Tooth Decay is very informative regarding this topic).. but didn’t see a difference. I started testing my pH level of my mouth and discovered I’m super acidic! So I’ve come to the conclusion that I don’t believe I’m absorbing nutrients properly.. and my gut needs some healing. So.. onto probiotics! Lol.. long story I know. Just wanted to express my gratitude in helping along with my health and healing journey!.. and if you may have any other insights. Cheers to probiotics!
Thank you so much for taking the time to write this, Christina!! I’m so glad you found this post helpful. I continue to try to update it as I come across more information. So grateful that you took the time to read it at all!! sounds like you’re on an awesome journey, and I love that you approach your health with such curiosity! Your research will definitely pay off!! xo
KATIE!! You are such a smart young woman! I’m sharing this with my mom/rest of the fam bc it’s so interesting!
PS: The “apple test” gave me a laugh, lol!
Haha thank you so much, Emily! And thank you for sharing it – means so much!! xo