11 Top Nutrients & 3 Smart Choices for the Gut-Brain Axis

We share our bodies with a host of fellow travelers, an ecosystem of microorganisms collectively known as the microbiome.  Estimates vary, but you’re carrying at least one passenger microorganism (bacteria, archaea, or fungi) for each of your human cells.  This community of a hundred trillion – as many stars as are found in a thousand galaxies - resides mostly in your gut, and you depend on them tremendously.  They work together to metabolize food into usable calories, modulate fat deposits, synthesize crucial amino acids, control inflammation and fight disease. 1  The vast majority of those microorganisms are from 30-40 species, so it’s vital to keep these stomach florae in balance.  Shortfalls in certain types of microorganisms in the gut microflora (also called microbiota) are linked to Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD) and colorectal cancer, which is the second most common cause of US cancer deaths.2  The microbiome also plays a role in the development of Celiac disease, which involves severe immune reactions to dietary gluten in people who are genetically predisposed.3  Studies have shown that the healthy function of the microbiome is necessary for digestive health, and also, through the important and recently discovered gut-brain connection, for our cognitive health. 

Diet plays a major role in governing our microbiome,4,5 which naturally emerged to handle the foods eaten by early humans: minimally processed wild plants and animals.  The advent of agriculture (roughly 10,000 years ago) and then the explosion in food availability following the industrial revolution brought huge changes to our diets.  Without time to evolve alongside our food choices, the microbiota in the human gut struggles with many new challenges: ultra-processed foods, refined grains, added sugar and dairy fats.  A modern human can digest starchy tubers, green leaves, and fish perfectly well, but an early human would have struggled to digest chicken nuggets, a Hershey bar or bag of potato chips.  New research is showing that the Western diet, also referred to as the Standard American Diet (SAD), is linked so strongly to obesity, diabetes, cardiovascular problems, and accelerated brain aging in large part because our gut microbiomes can barely cope with it. 

The Holidays & Celebrations It Can Be a Tough Time for Your Gut! 

Our digestive systems come under particular pressure during the holidays and celebrations.  Traditional celebratory foods are high in fat (red meat, especially prime rib), contain added salt (ham and other brined meats) or added sugar (cakes, cookies, pies, cranberry sauce).  Some holiday foods have undergone radical changes. Domesticated turkey breast meat provides seven times the fat of its wild cousins, a transformation which has happened much faster than our microbiomes can tolerate.  

Also, the holidays can be an anxious time.  Long-distance travel, airport lines and family friction can lead to stress eating.  Day-long snacking and drinking, as well as larger dinner portions, can easily lead to overindulgence.  And let’s be honest, we’re not reaching for celery and carrot crudité on Christmas day, but for comfort foods like cheese and crackers (high in saturated fats), cookies (excess carbohydrates) and candied nuts (added sugar), none of which our ancestors ate.  It’s a recipe for microbiome distress. 

The Gut-Brain Axis: A Remarkable Two-Way Street 

They might seem like separate systems, but the gut and the brain are intimately connected by a bi-directional communication network which involves several key systems.  This intricate two-way street allows the brain to influence the gut’s immune cell response, while the gut plays an important role in cognition and mood.6  Via the central nervous system, the diversity and abundance of our gut microbiota play a major role in mental health, one that can be influenced by stress, the use of antibiotics, and dietary choices.7 

A healthy gut protects us from toxins and diseases.  But a diet high in processed foods can contribute to permeability of the gut lining.  This allows certain food particles and toxins to pass directly into the bloodstream, where they do not belong.  This intestinal permeability – commonly called “leaky gut” – is associated with a range of serious mental health problems, as well as IBS, Crohn’s Disease, and disorders of the heart, lungs, and pancreas, including type 1 and 2 diabetes.8  

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Promoting a Healthy Gut-Brain Axis with 11 Top Nutrients

Given that our diet has a major impact on our gut microbiota, let’s assess the nutrients and gut-healthy foods that contribute to a robust and diverse microbiome.  

1.  Dietary Fiber provides food for your microbiota, so it is critical for gut microbiota diversity.  Only 5% of Americans eat enough fiber.  Although, it can be easy to add to your diet by eating plenty of whole grains (whole grain bread, oatmeal), beans of all kinds, flax (in pancakes, bread, and even holiday cookies) and chia seeds (sprinkled on breakfasts and desserts).  There are two types of fiber, soluble and insoluble, and both are helpful.  Soluble fiber (found in oats, barley, nuts, and legumes) aids nutrient absorption and protects against leaky gut, while insoluble fiber (in whole grains and some vegetables) boosts gut motility; that is, it keeps those bowel movements “regular.”9,10

2.  Probiotics are microorganisms found in yogurt, kefir (a nutritious, fermented milk drink), pickled vegetables like sauerkraut and kimchi, as well as in dietary supplements.  Consuming probiotics can increase levels of beneficial gut bacteria such as bifidobacteria and lactobacilli, which may reduce gut inflammation and help build the protective layer which guards against leaky bowel syndrome. 11

3.  Polyphenols are natural plant-based antioxidants that provide a probiotic boost for beneficial gut bacteria.  Flavonols such as quercetin, kaempferol and myricetin (found in colorful vegetables) and anthocyanins (found in grapes and berries) encourage the growth of healthy gut bacteria, bifidobacteria and lactobacillus, while reducing harmful gut bacteria.12  Catechins (especially those found in green tea) reduce gut inflammation, among other benefits. 13,14 

4.  Vitamin D is found in fatty fish (mackerel, salmon, tuna) and mushrooms.  A shortfall in vitamin D is linked to IBS, and research shows that it plays a critical role in regulating the gut microbiota, healing the gut lining, reducing inflammation, and regulating the immune system. 15,16

5. Vitamin E has a role in affecting the diversity and composition of the gut microbiome, promotes healing of damaged gut tissue, and may help guard against colorectal cancer. 17  You can find it in seeds, nuts, and avocados.  

6.  Vitamin B3 plays a vital role in reducing inflammation by inhibiting intestinal permeability while promoting gut mucosal healing. 16  Good sources include poultry, fish, legumes, nuts, and seeds.

7.  Vitamin B9 (folate) also helps to regenerate the intestinal lining, among other benefits.  It is found in dark leafy greens (spinach, brussels sprouts, broccoli).

8.  Vitamin B12 deficiency or surplus can influence the growth of gut microbiota, since 80% of gut bacteria require B12 for their metabolic reactions.  Food sources include fatty fish like salmon, sardines, and mackerel, as well as clams, eggs, and fortified nutritional yeast.

9.  Omega-3s are also found in fatty fish.  Among other benefits, they help modulate the diversity and abundance of gut microbiota. 18

10. Zeaxanthin is a powerful antioxidant that can prevent intestinal damage. 19  Eat plenty of dark leafy greens to enhance your intake.

11. L-Theanine might promote the absorption of intestinal nutrients, as well as supporting the intestinal mucosal barrier.20  Find this amino acid in green and black tea, as well as mushrooms. 

In Conclusion:  Three Tips for a Gut-Friendly Holiday Season 

  1. Focus on the nutrients listed above, especially fiber, polyphenols, and probiotics.  A diet that incorporates all of these nutrients is the Mediterranean Diet, which is rich in fiber and has been associated with higher gut microbial diversity.21 
  2. Be aware of your consumption of high-fat, high sugar foods, especially processed foods, which can wreak havoc in the gut. 
  3. Anxiety during the holidays can result in higher levels of the stress hormone, cortisol, which promotes leaky gut and digestive dysfunction.22  So, keep an eye on your stress levels and try to get enough sleep.   

Feasting during the holidays is something we all look forward to, but it can lead to poor dietary choices.  Approach your holiday meals in a healthy way by emphasizing flavor, gut health, and through that, mental wellness.  While this can be a major challenge for many, including a high-quality dietary supplement is a nice way to to help you get daily nutrients to support your gut and brain.  Our nutritional supplement RELEVATE contains many of the nutrients listed above in diet-appropriate doses to help you achieve a brain healthy diet.  To learn more about RELEVATE for your nutritional needs, visit here.  

If you’re still looking for some more guidance on simple changes, recipes, or grocery lists to help your gut-brain axis, download our FREE E-guide “Gut-Brain Healthy Kitchen and Grocery Swaps,” by visiting here.  


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  2. Colorectal Cancer Statistics | How Common Is Colorectal Cancer? | American Cancer Society. (n.d.). Retrieved November 19, 2023, from https://www.cancer.org/cancer/types/colon-rectal-cancer/about/key-statistics.html 
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  9. Usuda, Haruki et al. “Leaky Gut: Effect of Dietary Fiber and Fats on Microbiome and Intestinal Barrier.” International journal of molecular sciences vol. 22,14 7613. 16 Jul. 2021, doi:10.3390/ijms22147613 
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